BACKGROUND
1. Technical Field
[0002] The present disclosure relates to a print head control circuit, a print head, and
a liquid discharge apparatus.
2. Related Art
[0003] A liquid discharge apparatus such as an ink jet printer forms characters or an image
on a recording medium in a manner that the liquid discharge apparatus drives a piezoelectric
element provided in a print head by a driving signal and thus discharges a liquid
such as an ink with which a cavity is filled, from a nozzle. In such a liquid discharge
apparatus, when a problem occurs in the print head, discharge abnormality in which
it is not possible to normally discharge the liquid from the nozzle may occur. When
such discharge abnormality occurs, discharge accuracy of the ink discharged from the
nozzle may be decreased, and quality of an image formed on the recording medium may
be decreased.
[0004] JP-A-2017-114020 discloses a print head having a self-diagnosis function of determining whether or
not a dot satisfying normal print quality can be formed, in accordance with a plurality
of signals input to a print head by a head unit (print head) itself.
[0005] In the liquid discharge apparatus disclosed in
JP-A-2017-114020, when the waveform of a signal input to the print head for performing the self-diagnosis
function is distorted, the self-diagnosis function of the print head may not be normally
performed. A technology for reducing distortion of the waveform of a signal for performing
the above-described self-diagnosis function is not disclosed in
JP-A-2017-114020.
SUMMARY
[0006] According to an aspect of the present disclosure, a print head control circuit controls
an operation of a print head including a driving element that drives based on a driving
signal, so as to discharge a liquid from a nozzle, a driving signal selection circuit
that controls a supply of the driving signal to the driving element, a first terminal,
a second terminal, a third terminal, a fourth terminal, a fifth terminal, a sixth
terminal, a seventh terminal, and a diagnosis circuit that diagnoses whether or not
normal discharge of the liquid is possible, based on a first diagnosis signal input
to the first terminal, a second diagnosis signal input to the second terminal, a third
diagnosis signal input to the third terminal, a fourth diagnosis signal input to the
fourth terminal. The print head control circuit includes a first diagnosis signal
propagation wiring for propagating the first diagnosis signal, a second diagnosis
signal propagation wiring for propagating the second diagnosis signal, a third diagnosis
signal propagation wiring for propagating the third diagnosis signal, a fourth diagnosis
signal propagation wiring for propagating the fourth diagnosis signal, a fifth diagnosis
signal propagation wiring for propagating a fifth diagnosis signal which is input
to the fifth terminal and indicates a diagnosis result of the diagnosis circuit, a
first voltage signal propagation wiring for propagating a first voltage signal which
is input to the sixth terminal and is supplied to the driving signal selection circuit,
a second voltage signal propagation wiring for propagating a second voltage signal
input to the seventh terminal, a diagnosis signal output circuit that outputs the
first diagnosis signal, the second diagnosis signal, the third diagnosis signal, and
the fourth diagnosis signal, and a driving signal output circuit that outputs the
driving signal. When the fifth diagnosis signal propagation wiring and the second
voltage signal propagation wiring are electrically coupled to the print head, the
fifth diagnosis signal propagation wiring and the second voltage signal propagation
wiring are electrically coupled to each other via the fifth terminal and the seventh
terminal. The first diagnosis signal propagation wiring and the second diagnosis signal
propagation wiring are located to be aligned. The first diagnosis signal propagation
wiring and the second voltage signal propagation wiring are located to be adjacent
to each other in a direction in which the first diagnosis signal propagation wiring
and the second diagnosis signal propagation wiring are aligned.
[0007] According to another aspect of the present disclosure, a print head control circuit
controls an operation of a print head including a driving element that drives based
on a driving signal, so as to discharge a liquid from a nozzle, a driving signal selection
circuit that controls a supply of the driving signal to the driving element, a first
terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal,
a sixth terminal, a seventh terminal, and a diagnosis circuit that diagnoses whether
or not normal discharge of the liquid is possible, based on a first diagnosis signal
input to the first terminal, a second diagnosis signal input to the second terminal,
a third diagnosis signal input to the third terminal, a fourth diagnosis signal input
to the fourth terminal. The print head control circuit includes a first diagnosis
signal propagation wiring for propagating the first diagnosis signal, a second diagnosis
signal propagation wiring for propagating the second diagnosis signal, a third diagnosis
signal propagation wiring for propagating the third diagnosis signal, a fourth diagnosis
signal propagation wiring for propagating the fourth diagnosis signal, a fifth diagnosis
signal propagation wiring for propagating a fifth diagnosis signal which is input
to the fifth terminal and indicates a diagnosis result of the diagnosis circuit, a
first voltage signal propagation wiring for propagating a first voltage signal which
is input to the sixth terminal and is supplied to the driving signal selection circuit,
a second voltage signal propagation wiring for propagating a second voltage signal
input to the seventh terminal, a diagnosis signal output circuit that outputs the
first diagnosis signal, the second diagnosis signal, the third diagnosis signal, and
the fourth diagnosis signal, and a driving signal output circuit that outputs the
driving signal. When the fifth diagnosis signal propagation wiring and the second
voltage signal propagation wiring are electrically coupled to the print head, the
fifth diagnosis signal propagation wiring and the second voltage signal propagation
wiring are electrically coupled to the each other via the fifth terminal and the seventh
terminal. The first diagnosis signal propagation wiring and the second diagnosis signal
propagation wiring are located to be aligned. The first diagnosis signal propagation
wiring and the second voltage signal propagation wiring are located to overlap each
other in a direction intersecting a direction in which the first diagnosis signal
propagation wiring and the second diagnosis signal propagation wiring are aligned.
[0008] In the print head control circuit, the fifth diagnosis signal propagation wiring
may also be used as a wiring for propagating a signal indicating whether or not temperature
abnormality occurs in the print head.
[0009] The print head control circuit may further include a first ground signal propagation
wiring for propagating a ground signal. The first diagnosis signal propagation wiring
and the first ground signal propagation wiring may be located to be adjacent to each
other in the direction in which the first diagnosis signal propagation wiring and
the second diagnosis signal propagation wiring are aligned.
[0010] The print head control circuit may further include a third voltage signal propagation
wiring for propagating a third voltage signal having a voltage value larger than a
voltage value of the first voltage signal. The second voltage signal propagation wiring
and the third voltage signal propagation wiring may not be located to be adjacent
to each other in the direction in which the first diagnosis signal propagation wiring
and the second diagnosis signal propagation wiring are aligned.
[0011] The print head control circuit may further include a third voltage signal propagation
wiring for propagating a third voltage signal having a voltage value larger than a
voltage value of the first voltage signal. The second voltage signal propagation wiring
and the third voltage signal propagation wiring may not be located to overlap each
other in a direction perpendicular to the direction in which the first diagnosis signal
propagation wiring and the second diagnosis signal propagation wiring are aligned.
[0012] The print head control circuit may further include a second ground signal propagation
wiring for propagating the ground signal. The third voltage signal propagation wiring
and the second ground signal propagation wiring may be located to be adjacent to each
other in the direction in which the first diagnosis signal propagation wiring and
the second diagnosis signal propagation wiring are aligned.
[0013] The print head control circuit may further include a second ground signal propagation
wiring for propagating the ground signal. The third voltage signal propagation wiring
and the second ground signal propagation wiring may be located to overlap each other
in a direction intersecting the direction in which the first diagnosis signal propagation
wiring and the second diagnosis signal propagation wiring are aligned.
[0014] In the print head control circuit, the print head may include a first connector including
the first terminal, the second terminal, the third terminal, the fourth terminal,
and the fifth terminal and a substrate. The first connector and the diagnosis circuit
may be provided on the same surface of the substrate. The first diagnosis signal propagation
wiring, the second diagnosis signal propagation wiring, the third diagnosis signal
propagation wiring, the fourth diagnosis signal propagation wiring, and the fifth
diagnosis signal propagation wiring may be provided in the same cable. The cable may
be electrically coupled to the first connector.
[0015] In the print head control circuit, the first diagnosis signal propagation wiring
may also be used as a wiring for propagating a clock signal.
[0016] In the print head control circuit, the second diagnosis signal propagation wiring
may also be used as a wiring for propagating a signal for defining a discharge timing
of the liquid.
[0017] In the print head control circuit, the third diagnosis signal propagation wiring
may also be used as a wiring for propagating a signal for defining a waveform switching
timing of the driving signal.
[0018] In the print head control circuit, the fourth diagnosis signal propagation wiring
may also be used as a wiring for propagating a signal for defining selection of a
waveform of the driving signal.
[0019] According to an aspect of the present disclosure, a print head includes a driving
element that drives based on a driving signal, so as to discharge a liquid from a
nozzle, a driving signal selection circuit that controls a supply of the driving signal
to the driving element, a diagnosis circuit that diagnoses whether or not normal discharge
of the liquid is possible, based on a first diagnosis signal, a second diagnosis signal,
a third diagnosis signal, and a fourth diagnosis signal, a first terminal to which
the first diagnosis signal is input, a second terminal to which the second diagnosis
signal is input, a third terminal to which the third diagnosis signal is input, a
fourth terminal to which the fourth diagnosis signal is input, a fifth terminal to
which a fifth diagnosis signal indicating a diagnosis result of the diagnosis circuit
is input, a sixth terminal to which a first voltage signal to be supplied to the driving
signal selection circuit is input, and a seventh terminal to which a second voltage
signal is input. The fifth terminal and the seventh terminal are electrically coupled
to each other. The first terminal and the second terminal are located to be aligned.
The first terminal and the seventh terminal are located to be adjacent to each other
in a direction in which the first terminal and the second terminal are aligned.
[0020] According to another aspect of the present disclosure, a print head includes a driving
element that drives based on a driving signal, so as to discharge a liquid from a
nozzle, a driving signal selection circuit that controls a supply of the driving signal
to the driving element, a diagnosis circuit that diagnoses whether or not normal discharge
of the liquid is possible, based on a first diagnosis signal, a second diagnosis signal,
a third diagnosis signal, and a fourth diagnosis signal, a first terminal to which
the first diagnosis signal is input, a second terminal to which the second diagnosis
signal is input, a third terminal to which the third diagnosis signal is input, a
fourth terminal to which the fourth diagnosis signal is input, a fifth terminal to
which a fifth diagnosis signal indicating a diagnosis result of the diagnosis circuit
is input, a sixth terminal to which a first voltage signal to be supplied to the driving
signal selection circuit is input, and a seventh terminal to which a second voltage
signal is input. The fifth terminal and the seventh terminal are electrically coupled
to each other. The first terminal and the second terminal are located to be aligned.
The first terminal and the seventh terminal are located to overlap each other in a
direction intersecting a direction in which the first terminal and the second terminal
are aligned.
[0021] The print head may further include a temperature abnormality detection circuit that
diagnoses whether or not temperature abnormality occurs. The fifth terminal may also
be used as a wiring for propagating a signal indicating whether or not temperature
abnormality occurs.
[0022] The print head may further include a first ground terminal to which a ground signal
is input. The first terminal and the first ground terminal may be located to be adjacent
to each other in the direction in which the first terminal and the second terminal
are aligned.
[0023] The print head may further include an eighth terminal to which a third voltage signal
having a voltage value larger than a voltage value of the first voltage signal. The
seventh terminal and the eighth terminal may not be located to be adjacent to each
other in the direction in which the first terminal and the second terminal are aligned.
[0024] The print head may further include an eighth terminal to which a third voltage signal
having a voltage value larger than a voltage value of the first voltage signal. The
seventh terminal and the eighth terminal may not be located to overlap each other
in a direction perpendicular to the direction in which the first terminal and the
second terminal are aligned.
[0025] The print head may further include a second ground terminal to which the ground signal
is input. The eighth terminal and the second ground terminal may be located to be
adjacent to each other in the direction in which the first terminal and the second
terminal are aligned.
[0026] The print head may further include a second ground terminal to which the ground signal
is input. The eighth terminal and the second ground terminal may be located to overlap
each other in a direction intersecting the direction in which the first terminal and
the second terminal are aligned.
[0027] The print head a first connector including the first terminal, the second terminal,
the third terminal, the fourth terminal, and the fifth terminal, and a substrate.
The first connector and the diagnosis circuit may be provided on the same surface
of the substrate.
[0028] In the print head, the first terminal may also be used as a terminal to which a clock
signal is input.
[0029] In the print head, the second terminal may also be used as a terminal to which a
signal for defining a discharge timing of the liquid is input.
[0030] In the print head, the third terminal may also be used as a terminal to which a signal
for defining a waveform switching timing of the driving signal is input.
[0031] In the print head, the fourth terminal may also be used as a terminal to which a
signal for defining selection of a waveform of the driving signal is input.
[0032] According to an aspect of the present disclosure, a liquid discharge apparatus includes
a print head, and a print head control circuit that controls an operation of the print
head. The print head includes a driving element that drives based on a driving signal,
so as to discharge a liquid from a nozzle, a driving signal selection circuit that
controls a supply of the driving signal to the driving element, a diagnosis circuit
that diagnoses whether or not normal discharge of the liquid is possible, based on
a first diagnosis signal, a second diagnosis signal, a third diagnosis signal, and
a fourth diagnosis signal, a first terminal to which the first diagnosis signal is
input, a second terminal to which the second diagnosis signal is input, a third terminal
to which the third diagnosis signal is input, a fourth terminal to which the fourth
diagnosis signal is input, a fifth terminal to which a fifth diagnosis signal indicating
a diagnosis result of the diagnosis circuit is input, a sixth terminal to which a
first voltage signal to be supplied to the driving signal selection circuit is input,
and a seventh terminal to which a second voltage signal is input. The print head control
circuit includes a first diagnosis signal propagation wiring for propagating the first
diagnosis signal, a second diagnosis signal propagation wiring for propagating the
second diagnosis signal, a third diagnosis signal propagation wiring for propagating
the third diagnosis signal, a fourth diagnosis signal propagation wiring for propagating
the fourth diagnosis signal, a fifth diagnosis signal propagation wiring for propagating
the fifth diagnosis signal, a first voltage signal propagation wiring for propagating
the first voltage signal, a second voltage signal propagation wiring for propagating
the second voltage signal, a diagnosis signal output circuit that outputs the first
diagnosis signal, the second diagnosis signal, the third diagnosis signal, and the
fourth diagnosis signal, and a driving signal output circuit that outputs the driving
signal. The first diagnosis signal propagation wiring is electrically in contact with
the first terminal at a first contact section. The second diagnosis signal propagation
wiring is electrically in contact with the second terminal at a second contact section.
The third diagnosis signal propagation wiring is electrically in contact with the
third terminal at a third contact section. The fourth diagnosis signal propagation
wiring is electrically in contact with the fourth terminal at a fourth contact section.
The fifth diagnosis signal propagation wiring is electrically in contact with the
fifth terminal at a fifth contact section. The first voltage signal propagation wiring
is electrically in contact with the sixth terminal at a sixth contact section. The
second voltage signal propagation wiring is electrically in contact with the seventh
terminal at a seventh contact section. The fifth diagnosis signal propagation wiring
and the second voltage signal propagation wiring are electrically coupled to each
other via the fifth terminal, the fifth contact section, the seventh contact section,
and the seventh terminal. The first contact section and the second contact section
are located to be aligned. The first contact section and the seventh contact section
are located to be adjacent to each other in a direction in which the first contact
section and the second contact section are aligned.
[0033] According to an aspect of the present disclosure, a liquid discharge apparatus includes
a print head, and a print head control circuit that controls an operation of the print
head. The print head includes controls an operation of a print head including a driving
element that drives based on a driving signal, so as to discharge a liquid from a
nozzle, a driving signal selection circuit that controls a supply of the driving signal
to the driving element, a diagnosis circuit that diagnoses whether or not normal discharge
of the liquid is possible, based on a first diagnosis signal, a second diagnosis signal,
a third diagnosis signal, and a fourth diagnosis signal, a first terminal to which
the first diagnosis signal is input, a second terminal to which the second diagnosis
signal is input, a third terminal to which the third diagnosis signal is input, a
fourth terminal to which the fourth diagnosis signal is input, a fifth terminal to
which a fifth diagnosis signal indicating a diagnosis result of the diagnosis circuit
is input, a sixth terminal to which a first voltage signal to be supplied to the driving
signal selection circuit, and a seventh terminal to which a second voltage signal
is input. The print head control circuit includes a first diagnosis signal propagation
wiring for propagating the first diagnosis signal, a second diagnosis signal propagation
wiring for propagating the second diagnosis signal, a third diagnosis signal propagation
wiring for propagating the third diagnosis signal, a fourth diagnosis signal propagation
wiring for propagating the fourth diagnosis signal, a fifth diagnosis signal propagation
wiring for propagating the fifth diagnosis signal, a first voltage signal propagation
wiring for propagating the first voltage signal, a second voltage signal propagation
wiring for propagating the second voltage signal, a diagnosis signal output circuit
that outputs the first diagnosis signal, the second diagnosis signal, the third diagnosis
signal, and the fourth diagnosis signal, and a driving signal output circuit that
outputs the driving signal. The first diagnosis signal propagation wiring is electrically
in contact with the first terminal at a first contact section. The second diagnosis
signal propagation wiring is electrically in contact with the second terminal at a
second contact section. The third diagnosis signal propagation wiring is electrically
in contact with the third terminal at a third contact section. The fourth diagnosis
signal propagation wiring is electrically in contact with the fourth terminal at a
fourth contact section. The fifth diagnosis signal propagation wiring is electrically
in contact with the fifth terminal at a fifth contact section. The first voltage signal
propagation wiring is electrically in contact with the sixth terminal at a sixth contact
section. The second voltage signal propagation wiring is electrically in contact with
the seventh terminal at a seventh contact section. The fifth diagnosis signal propagation
wiring and the second voltage signal propagation wiring are electrically coupled to
each other via the fifth terminal, the fifth contact section, the seventh contact
section, and the seventh terminal. The first contact section and the seventh contact
section are located to overlap each other in a direction intersecting a direction
in which the first contact section and the second contact section are aligned.
[0034] In the liquid discharge apparatus, the print head may further include a temperature
abnormality detection circuit that diagnoses whether or not temperature abnormality
occurs. The fifth diagnosis signal propagation wiring may also be used as a wiring
for propagating a signal indicating whether or not the temperature abnormality occurs.
[0035] In the liquid discharge apparatus, the print head may further include a first ground
terminal to which a ground signal is input. The print head control circuit may further
include a first ground signal propagation wiring for propagating the ground signal.
The first ground signal propagation wiring may be electrically in contact with the
first ground terminal at a first ground contact section. The first contact section
and the first ground contact section may be located to be adjacent to each other in
the direction in which the first contact section and the second contact section are
aligned.
[0036] In the liquid discharge apparatus, the print head may further include an eighth terminal
to which a third voltage signal having a voltage value larger than a voltage value
of the first voltage signal is input. The print head control circuit may further include
a third voltage signal propagation wiring for propagating the third voltage signal.
The third voltage signal propagation wiring may be electrically in contact with the
eighth terminal at an eighth contact section. The seventh contact section and the
eighth contact section may not be located to be adjacent to each other in the direction
in which the first contact section and the second contact section are aligned.
[0037] In the liquid discharge apparatus, the print head may further include an eighth terminal
to which a third voltage signal having a voltage value larger than a voltage value
of the first voltage signal is input. The print head control circuit may further include
a third voltage signal propagation wiring for propagating the third voltage signal.
The third voltage signal propagation wiring may be electrically in contact with the
eighth terminal at an eighth contact section. The seventh contact section and the
eighth contact section may not be located to overlap each other in a direction perpendicular
to the direction in which the first contact section and the second contact section
are aligned.
[0038] In the liquid discharge apparatus, the print head may further include a second ground
terminal to which the ground signal is input. The print head control circuit may further
include a second ground signal propagation wiring for propagating the ground signal.
The second ground signal propagation wiring may be electrically in contact with the
second ground terminal at a second ground contact section. The eighth contact section
and the second ground contact section may be located to be adjacent to each other
in the direction in which the first contact section and the second contact section
are aligned.
[0039] In the liquid discharge apparatus, the print head may further include a second ground
terminal to which the ground signal is input. The print head control circuit may further
include a second ground signal propagation wiring for propagating the ground signal.
The second ground signal propagation wiring may be electrically in contact with the
second ground terminal at a second ground contact section. The eighth contact section
and the second ground contact section may be located to overlap each other in a direction
intersecting the direction in which the first contact section and the second contact
section are aligned.
[0040] In the liquid discharge apparatus, the print head may further include a first connector
including the first terminal, the second terminal, the third terminal, the fourth
terminal, and the fifth terminal and a substrate. The first connector and the diagnosis
circuit may be provided on the same surface of the substrate. The first diagnosis
signal propagation wiring, the second diagnosis signal propagation wiring, the third
diagnosis signal propagation wiring, the fourth diagnosis signal propagation wiring,
and the fifth diagnosis signal propagation wiring may be provided in the same cable.
The cable may be electrically coupled to the first connector.
[0041] In the liquid discharge apparatus, the first diagnosis signal propagation wiring
may also be used as a wiring for propagating a clock signal.
[0042] In the liquid discharge apparatus, the second diagnosis signal propagation wiring
may also be used as a wiring for propagating a signal for defining a discharge timing
of the liquid.
[0043] In the liquid discharge apparatus, the third diagnosis signal propagation wiring
may also be used as a wiring for propagating a signal for defining a waveform switching
timing of the driving signal.
[0044] In the liquid discharge apparatus, the fourth diagnosis signal propagation wiring
may also be used as a wiring for propagating a signal for defining selection of a
waveform of the driving signal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045]
FIG. 1 is a diagram illustrating an overall configuration of a liquid discharge apparatus.
FIG. 2 is a block diagram illustrating an electrical configuration of the liquid discharge
apparatus.
FIG. 3 is a diagram illustrating an example of a waveform of a driving signal COM.
FIG. 4 is a diagram illustrating an example of a waveform of a driving signal VOUT.
FIG. 5 is a diagram illustrating a configuration of a driving signal selection circuit.
FIG. 6 is a diagram illustrating decoding contents in a decoder.
FIG. 7 is a diagram illustrating a configuration of a selection circuit corresponding
to one discharge section.
FIG. 8 is a diagram illustrating an operation of the driving signal selection circuit.
FIG. 9 is a diagram illustrating a configuration of a temperature abnormality detection
circuit.
FIG. 10 is a schematic diagram illustrating an internal configuration of the liquid
discharge apparatus when viewed from a Y-direction.
FIG. 11 is a diagram illustrating a configuration of a cable.
FIG. 12 is a perspective view illustrating a configuration of a print head.
FIG. 13 is a plan view illustrating a configuration of an ink discharge surface.
FIG. 14 is a diagram illustrating an overall configuration of one of a plurality of
discharge sections in the head.
FIG. 15 is a plan view when a substrate is viewed from a surface 322.
FIG. 16 is a plan view when the substrate is viewed from a surface 321.
FIG. 17 is a diagram illustrating a configuration of a connector.
FIG. 18 is a diagram illustrating another configuration of the connector.
FIG. 19 is a diagram illustrating a specific example when the cable is attached to
the connector.
FIG. 20 is a diagram illustrating details of a signal propagated in the cable.
FIG. 21 is a schematic diagram illustrating an internal configuration of a liquid
discharge apparatus according to a second embodiment when viewed from the Y-direction.
FIG. 22 is a perspective view illustrating a configuration of a print head in the
second embodiment.
FIG. 23 is a diagram illustrating configurations of connectors in the second embodiment.
FIG. 24 is a diagram illustrating details of a signal propagated in a cable 19a in
the second embodiment.
FIG. 25 is a diagram illustrating details of a signal propagated in a cable 19b in
the second embodiment.
FIG. 26 is a block diagram illustrating an electrical configuration of a liquid discharge
apparatus according to a third embodiment.
FIG. 27 is a schematic diagram illustrating an internal configuration of the liquid
discharge apparatus in the third embodiment when viewed from the Y-direction.
FIG. 28 is a perspective view illustrating a configuration of a print head in the
third embodiment.
FIG. 29 is a diagram illustrating configurations of connectors in the third embodiment.
FIG. 30 is a diagram illustrating details of a signal propagated in a cable 19a in
the third embodiment.
FIG. 31 is a diagram illustrating details of a signal propagated in a cable 19b in
the third embodiment.
FIG. 32 is a diagram illustrating details of a signal propagated in a cable 19c in
the third embodiment.
FIG. 33 is a diagram illustrating details of a signal propagated in a cable 19d in
the third embodiment.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0046] Hereinafter, preferred embodiments of the present disclosure will be described with
reference to the drawings. The drawings are used for easy descriptions. The embodiments
described below do not limit the scope of the present disclosure described in the
claims. All components described later are not necessarily essential constituent elements
of the present disclosure.
1. First Embodiment
1.1. Outline of Liquid Discharge Apparatus
[0047] FIG. 1 is a diagram illustrating an overall configuration of a liquid discharge apparatus
1. The liquid discharge apparatus 1 is a serial printing type ink jet printer that
forms an image on a medium P in a manner that a carriage 20 discharges an ink to the
transported medium P with reciprocating. In the carriage 20, a print head 21 that
discharges the ink as an example of a liquid is mounted. In the following descriptions,
descriptions will be made on the assumption that a direction in which the carriage
20 moves is an X-direction, a direction in which the medium P is transported is a
Y-direction, and a direction in which the ink is discharged is a Z-direction. Descriptions
will be made on the assumption that the X-direction, the Y-direction, and the Z-direction
are perpendicular to each other. As the medium P, any printing target such as print
paper, a resin film, and a cloth can be used.
[0048] The liquid discharge apparatus 1 includes a liquid container 2, a control mechanism
10, the carriage 20, a movement mechanism 30, and a transport mechanism 40.
[0049] Plural kinds of inks to be discharged onto a medium P are stored in the liquid container
2. As the color of the ink stored in the liquid container 2, black, cyan, magenta,
yellow, red, and gray are exemplified. As the liquid container 2 in which such an
ink is stored, an ink cartridge, a bag-like ink pack formed of a flexible film, an
ink tank capable of replenishing ink, or the like is used.
[0050] The control mechanism 10 includes, for example, a processing circuit such as a central
processing unit (CPU) or a field programmable gate array (FPGA) and a storage circuit
such as a semiconductor memory. The control mechanism 10 controls elements of the
liquid discharge apparatus 1.
[0051] The print head 21 is mounted in the carriage 20. The carriage 20 is fixed to an endless
belt 32 of the movement mechanism 30. The liquid container 2 may also be mounted in
the carriage 20.
[0052] A control signal Ctrl-H and one or a plurality of driving signals COM are input to
the print head 21. The control signal Ctrl-H is output by the control mechanism 10
and is used for controlling the print head 21. The driving signal COM is output by
the control mechanism 10 and is used for driving the print head 21. The print head
21 discharges an ink supplied from the liquid container 2 based on the control signal
Ctrl-H and the driving signal COM.
[0053] The movement mechanism 30 includes a carriage motor 31 and the endless belt 32. The
carriage motor 31 operates based on a control signal Ctrl-C input from the control
mechanism 10. The endless belt 32 rotates by the operation of the carriage motor 31.
Thus, the carriage 20 fixed to the endless belt 32 reciprocates in the X-direction.
[0054] The transport mechanism 40 includes a transport motor 41 and a transport roller 42.
The transport motor 41 operates based on a control signal Ctrl-T input from the control
mechanism 10. The transport roller 42 rotates by the operation of the transport motor
41. A medium P is transported in the Y-direction with the rotation of the transport
roller 42.
[0055] As described above, the liquid discharge apparatus 1 forms a desired image on a medium
P by landing an ink at any position on the surface of the medium P in a manner that
the liquid discharge apparatus discharges the ink from the print head 21 mounted in
the carriage 20 with transport of the medium P by the transport mechanism 40 and reciprocation
of the carriage 20 by the movement mechanism 30.
1.2. Electrical Configuration of Liquid Discharge Apparatus
[0056] FIG. 2 is a block diagram illustrating an electrical configuration of the liquid
discharge apparatus 1. The liquid discharge apparatus 1 includes the control mechanism
10, the print head 21, the carriage motor 31, the transport motor 41, and a linear
encoder 90.
[0057] The control mechanism 10 includes a driving signal output circuit 50, a control circuit
100, and a power circuit 110. The control circuit 100 includes a processor such as
a microcontroller, for example. The control circuit 100 generates and outputs data
or various signals for controlling the liquid discharge apparatus 1, based on various
signals such as image data, which are input from a host computer.
[0058] Specifically, the control circuit 100 recognizes a scanning position of the print
head 21 based on a detection signal input from the linear encoder 90. The control
circuit 100 generates and outputs various signals corresponding to the scanning position
of the print head 21. Specifically, the control circuit 100 generates the control
signal Ctrl-C for controlling reciprocation of the print head 21 and outputs the control
signal Ctrl-C to the carriage motor 31. The control circuit 100 generates the control
signal Ctrl-T for controlling transport of the medium P and outputs the control signal
Ctrl-T to the transport motor 41. The control signal Ctrl-C may be signal-converted
via a carriage motor driver (not illustrated) and then be input to the carriage motor
31. Similarly, the control signal Ctrl-T may be signal-converted via a transport motor
driver (not illustrated) and then be input to the transport motor 41.
[0059] The control circuit 100 generates print data signals SI1 to Sin, a change signal
CH, a latch signal LAT, and a clock signal SCK as the control signal Ctrl-H for controlling
the print head 21, based on the various signals such as image data, which are input
from the host computer and the scanning position of the print head 21. Then, the control
circuit 100 outputs the generated signals to the print head 21.
[0060] The control circuit 100 generates diagnosis signals DIG-A to DIG-D used when the
print head 21 diagnoses whether or not normal discharge of a liquid is possible. Then,
the control circuit 100 outputs the generated signals to the print head 21. Here,
although details will be described later, in the liquid discharge apparatus 1 in the
first embodiment, each of the diagnosis signals DIG-A to DIG-D and each of the latch
signal LAT, the clock signal SCK, the change signal CH, and the print data signal
SI1 are propagated to the print head 21 by common wirings. Specifically, the diagnosis
signal DIG-A and the latch signal LAT are propagated in a common wiring. The diagnosis
signal DIG-B and the clock signal SCK are propagated in a common wiring. The diagnosis
signal DIG-C and the change signal CH are propagated in a common wiring. The diagnosis
signal DIG-D and the print data signal SI1 are propagated in a common wiring. Here,
the control circuit 100 is an example of a diagnosis signal output circuit that generates
the diagnosis signals DIG-A to DIG-D and outputs the signals DIG-A to DIG-D to the
print head 21.
[0061] The control circuit 100 outputs a driving control signal dA as a digital signal to
the driving signal output circuit 50.
[0062] The driving signal output circuit 50 includes a driving circuit 50a. The driving
control signal dA is input to the driving circuit 50a. The driving circuit 50a generates
the driving signal COM by performing D-class amplification on an analog signal obtained
by performing digital-to-analog signal conversion on the driving control signal dA.
That is, the driving control signal dA is a digital signal for defining a waveform
of the driving signal COM. The driving circuit 50a generates the driving signal COM
by performing D-class amplification on a waveform defined by the driving control signal
dA. The driving signal output circuit 50 outputs the driving signal COM generated
by the driving circuit 50a. Thus, the driving control signal dA may be a signal capable
of defining the waveform of the driving signal COM. For example, the driving control
signal dA may be an analog signal. The driving circuit 50a may be capable of amplifying
the waveform defined by the driving control signal dA. For example, the driving circuit
50a may be configured by an A-class amplifier circuit, a B-class amplifier circuit,
or an AB-class amplifier circuit.
[0063] The driving signal output circuit 50 outputs a reference voltage signal CGND indicating
a reference potential of the driving signal COM. The reference voltage signal CGND
may be, for example, a signal which has a voltage value of 0 V and has a ground potential.
The reference voltage signal CGND may be a signal having a DC voltage having a voltage
value of 6 V, for example.
[0064] The driving signal COM and the reference voltage signal CGND are divided in the control
mechanism 10 and then are output to the print head 21. Specifically, the driving signal
COM is divided into n pieces of driving signals COM1 to COMn respectively corresponding
to n pieces of driving signal selection circuits 200 described later in the control
mechanism 10. Then, the driving signals COM1 to COMn are output to the print head
21. Similarly, the reference voltage signal CGND is divided into n pieces of reference
voltage signals CGND1 to CGNDn in the control mechanism 10, and then is output to
the print head 21. The driving signal COM including the driving signals COM1 to COMn
is an example of the driving signal.
[0065] The power circuit 110 generates and outputs voltages VHV, VDD1, and VDD2 and a ground
signal GND. The voltage VHV is a signal having a DC voltage having a voltage value
of 42 V, for example. The voltages VDD1 and VDD2 are signals having a DC voltage having
a voltage value of 3.3 V, for example. The ground signal GND is a signal indicating
the reference potential of the voltages VHV, VDD1, and VDD2. For example, the ground
signal GND is a signal having a voltage value of 0 V and having a ground potential.
The voltage VHV is used, for example, as a voltage for amplification in the driving
signal output circuit 50. Each of the voltages VDD1 and VDD2 is used, for example,
as a power source voltage or a control voltage of various components in the control
mechanism 10. The voltages VHV, VDD1, and VDD2 and the ground signal GND are also
output to the print head 21. The voltage values of the voltages VHV, VDD1, and VDD2
and the ground signal GND are not limited to 42 V, 3.3 V, and 0 V as described above.
The power circuit 110 may generate signals having a plurality of voltage values in
addition to the voltages VHV, VDD1, and VDD2 and the ground signal GND.
[0066] The print head 21 includes driving signal selection circuits 200-1 to 200-n, a temperature
detection circuit 210, a diagnosis circuit 240, temperature abnormality detection
circuits 250-1 to 250-n, and a plurality of discharge sections 600.
[0067] The diagnosis signal DIG-A and the latch signal LAT propagated in the common wiring,
the diagnosis signal DIG-B and the clock signal SCK propagated in the common wiring,
the diagnosis signal DIG-C and the change signal CH propagated in the common wiring,
and the diagnosis signal DIG-D and the print data signal SI1 propagated in the common
wiring are input to the diagnosis circuit 240. The diagnosis circuit 240 diagnoses
whether or not normal discharge of the ink is possible, based on the diagnosis signals
DIG-A to DIG-D.
[0068] For example, the diagnosis circuit 240 may detect whether or not the voltage value
of the any or all of the input diagnosis signals DIG-A to DIG-D is normal. The diagnosis
circuit 240 may diagnose whether or not the print head 21 and the control mechanism
10 are normally coupled to each other, based on the detection result. The diagnosis
circuit 240 may operate any component, for example, the driving signal selection circuits
200-1 to 200-n and the piezoelectric element 60 in the print head 21, in accordance
with a logical level of any signal or a combination of the logical levels of all the
signals of the input diagnosis signals DIG-A to DIG-D. The diagnosis circuit 240 may
detect whether or not the voltage value obtained by the operation is normal. Then,
the diagnosis circuit 240 may diagnose whether or not a normal operation of the print
head 21 is possible, based on the detection result. That is, the print head 21 performs
self-diagnosis of diagnosing whether or not normal discharge of the ink is possible,
based on the diagnosis result of the diagnosis circuit 240.
[0069] When the diagnosis circuit 240 diagnoses that normal discharge of the ink is possible
in the print head 21, the diagnosis circuit 240 outputs the latch signal LAT, the
clock signal SCK, and the change signal CH as a latch signal cLAT, a clock signal
cSCK, and a change signal cCH. Here, the diagnosis signal DIG-D and the print data
signal SI1 are branched in the print head 21. One branched signal is input to the
diagnosis circuit 240, and the other is input to the driving signal selection circuit
200-1. The print data signal SI1 is a signal having a high transfer rate. When the
waveform of the print data signal SI1 is distorted, the print head 21 may erroneously
operate. If the print data signal SI1 is branched in the print head 21, and then only
one branched signal is input to the diagnosis circuit 240, it is possible to reduce
a possibility of distorting the waveform of the print data signal SI1 input to the
driving signal selection circuit 200-1.
[0070] The change signal cCH, the latch signal cLAT, and the clock signal cSCK output by
the diagnosis circuit 240 may be signals having the same waveforms as the change signal
CH, the latch signal LAT, and the clock signal SCK input to the diagnosis circuit
240. The change signal cCH, the latch signal cLAT, and the clock signal cSCK may be
signals having waveforms obtained by correcting the change signal CH, the latch signal
LAT, and the clock signal SCK. In the embodiment, descriptions will be made on the
assumption that the change signal cCH, the latch signal cLAT, and the clock signal
cSCK have the same waveforms as the change signal CH, the latch signal LAT, and the
clock signal SCK.
[0071] The diagnosis circuit 240 generates a diagnosis signal DIG-E indicating a diagnosis
result in the diagnosis circuit 240 and outputs the diagnosis signal DIG-E to the
control circuit 100. Here, in the first embodiment, the diagnosis circuit 240 is configured,
for example, by one or a plurality of integrated circuit (IC) apparatuses.
[0072] The voltages VHV and VDD1, the clock signal cSCK, the latch signal cLAT, and the
change signal cCH are input to each of the driving signal selection circuits 200-1
to 200-n. The driving signals COM1 to COMn and the print data signals SI1 to SIn are
input to the driving signal selection circuits 200-1 to 200-n, respectively. The voltages
VHV and VDD1 are used as a power source voltage or a control voltage of each of the
driving signal selection circuits 200-1 to 200-n. The driving signal selection circuits
200-1 to 200-n select or do not select the driving signals COM1 to COMn based on the
print data signals SI1 to SIn, the clock signal cSCK, the latch signal cLAT, and the
change signal cCH so as to generate driving signals VOUT1 to VOUTn, respectively.
[0073] Each of the driving signals VOUT1 to VOUTn respectively generated by the driving
signal selection circuits 200-1 to 200-n is supplied to the piezoelectric element
60 which is provided in the corresponding discharge section 600 and is an example
of a driving element. If each of the driving signals VOUT1 to VOUTn is supplied, the
piezoelectric element 60 performs displacement. The ink of an amount depending on
the displacement is discharged from the discharge section 600.
[0074] Specifically, the driving signal COM1, the print data signal SI1, the latch signal
cLAT, the change signal cCH, and the clock signal cSCK are input to the driving signal
selection circuit 200-1. The driving signal selection circuit 200-1 selects or does
not select the waveform of the driving signal COM1 based on the print data signal
SI1, the latch signal cLAT, the change signal cCH, and the clock signal cSCK, so as
to generate the driving signal VOUT1. The driving signal VOUT1 is supplied to one
end of the piezoelectric element 60 in the discharge section 600 provided to correspond
to the driving signal VOUT1. The reference voltage signal CGND1 is supplied to the
other end of the piezoelectric element 60. The piezoelectric element 60 performs displacement
by a potential difference between the driving signal VOUT1 and the reference voltage
signal CGND1.
[0075] Similarly, the driving signal COMi, the print data signal Sli (i is any of 1 to n),
the latch signal cLAT, the change signal cCH, and the clock signal cSCK are input
to the driving signal selection circuit 200-i. The driving signal selection circuit
200-i selects or does not select the waveform of the driving signal COMi based on
the print data signal Sli, the latch signal cLAT, the change signal cCH, and the clock
signal cSCK, so as to generate the driving signal VOUTi. The driving signal VOUTi
is supplied to one end of the piezoelectric element 60 in the discharge section 600
provided to correspond to the driving signal VOUTi. The reference voltage signal CGNDi
is supplied to the other end of the piezoelectric element 60. The piezoelectric element
60 performs displacement by a potential difference between the driving signal VOUTi
and the reference voltage signal CGNDi.
[0076] Here, the driving signal selection circuits 200-1 to 200-n have the similar circuit
configuration. Therefore, when it is not necessary to distinguish the driving signal
selection circuits 200-1 to 200-n from each other in the following descriptions, the
driving signal selection circuits 200-1 to 200-n are referred to as a driving signal
selection circuit 200. In this case, the driving signals COM1 to COMn input to the
driving signal selection circuit 200 are referred to as a driving signal COM. The
print data signals SI1 to SIn are referred to as a print data signal SI, and the driving
signals VOUT1 to VOUTn output from the driving signal selection circuit 200 are referred
to as a driving signal VOUT. Details of the operation of the driving signal selection
circuit 200 will be described later. Here, each of the driving signal selection circuits
200-1 to 200-i is configured by an integrated circuit apparatus, for example.
[0077] The temperature abnormality detection circuits 250-1 to 250-n are provided to correspond
to the driving signal selection circuits 200-1 to 200-n, respectively. Each of the
temperature abnormality detection circuits 250-1 to 250-n diagnoses whether or not
temperature abnormality occurs in the corresponding circuit of the driving signal
selection circuits 200-1 to 200-n. Specifically, the temperature abnormality detection
circuits 250-1 to 250-n operate using the voltage VDD2 as the power source voltage.
Each of the temperature abnormality detection circuits 250-1 to 250-n detects the
temperature of the corresponding circuit of the driving signal selection circuits
200-1 to 200-n. When the temperature abnormality detection circuit diagnoses that
the temperature is normal, the temperature abnormality detection circuit generates
an abnormality signal XHOT having a high level (H level) and outputs the abnormality
signal XHOT to the control circuit 100. When the temperature abnormality detection
circuit diagnoses that the temperature of the corresponding circuit of the driving
signal selection circuits 200-1 to 200-n is abnormal, each of the temperature abnormality
detection circuits 250-1 to 250-n generates the abnormality signal XHOT having a low
level (L level) and outputs the abnormality signal XHOT to the control circuit 100.
[0078] Here, the temperature abnormality detection circuits 250-1 to 250-n have the similar
circuit configuration. Therefore, when it is not necessary to distinguish the temperature
abnormality detection circuits 250-1 to 250-n from each other in the following descriptions,
the temperature abnormality detection circuits 250-1 to 250-n are referred to as a
temperature abnormality detection circuit 250. Here, although details will be described
later, the diagnosis signal DIG-E and the abnormality signal XHOT are propagated in
a common wiring. Details of the temperature abnormality detection circuit 250 will
be described later. Each of the temperature abnormality detection circuits 250-1 to
250-i is configured by an integrated circuit apparatus, for example. The temperature
abnormality detection circuit 250-i and the driving signal selection circuit 200-i
may be configured by one integrated circuit apparatus.
[0079] The temperature detection circuit 210 includes a temperature detection element such
as a thermistor. The temperature detection circuit 210 generates a temperature signal
TH which is an analog signal and includes temperature information of the print head
21, based on a detection signal obtained by detection of the temperature detection
element. The temperature detection circuit outputs the temperature signal TH to the
control circuit 100.
1.3. Example of Waveform of Driving Signal
[0080] Here, an example of the waveform of the driving signal COM generated by the driving
signal output circuit 50 and an example of the waveform of the driving signal VOUT
supplied to the piezoelectric element 60 will be described with reference to FIGs.
3 and 4.
[0081] FIG. 3 is a diagram illustrating an example of the waveform of the driving signal
COM. As illustrated in FIG. 3, the driving signal COM is a waveform in which a trapezoid
waveform Adp1, a trapezoid waveform Adp2, and a trapezoid waveform Adp3. The trapezoid
waveform Adp1 is disposed in a period T1 from when the latch signal LAT rises until
the change signal CH rises. The trapezoid waveform Adp2 is disposed in a period T2
until the change signal CH rises the next time after the period T1. The trapezoid
waveform Adp3 is disposed in a period T3 until the latch signal LAT rises the next
time after the period T2. When the trapezoid waveform Adp1 is supplied to the one
end of the piezoelectric element 60, the medium amount of the ink is discharged from
the discharge section 600 corresponding to this piezoelectric element 60. When the
trapezoid waveform Adp2 is supplied to the one end of the piezoelectric element 60,
the ink having an amount smaller than the medium amount is discharged from the discharge
section 600 corresponding to this piezoelectric element 60. When the trapezoid waveform
Adp3 is supplied to the one end of the piezoelectric element 60, the ink is not discharged
from the discharge section 600 corresponding to this piezoelectric element 60. The
trapezoid waveform Adp3 is a waveform for finely vibrating the ink in the vicinity
of a nozzle opening portion of the discharge section 600 to prevent an increase of
ink viscosity.
[0082] Here, a period Ta (illustrated in FIG. 3) from the latch signal LAT rises until the
latch signal LAT rises the next time corresponds to a printing period in which a new
dot is formed on the medium P. That is, the latch signal LAT and the latch signal
cLAT are signals for defining a discharge timing of the ink from the print head 21.
The change signal CH and the change signal cCH are signals for defining a waveform
switching timing between the trapezoid waveforms Adp1, Adp2, and Adp3 in the driving
signal COM.
[0083] All voltages at a start timing and an end timing of each of the trapezoid waveforms
Adp1, Adp2, and Adp3 are common and a voltage Vc. That is, each of the trapezoid waveforms
Adp1, Adp2, and Adp3 is a waveform which starts at the voltage Vc and ends at the
voltage Vc. The driving signal COM may be a signal having a waveform in which one
or two trapezoid waveforms are continuous in the period Ta, or may be a signal having
a waveform in which four trapezoid waveforms or more are continuous in the period
Ta.
[0084] FIG. 4 is a diagram illustrating an example of the waveform of the driving signal
VOUT corresponding to each of "a large dot", "a medium dot", "a small dot", and "non-recording".
[0085] As illustrated in FIG. 4, the driving signal VOUT corresponding to "the large dot"
has a waveform in which the trapezoid waveform Adp1 disposed in the period T1, the
trapezoid waveform Adp2 disposed in the period T2, and a waveform which is disposed
in the period T3 and is constant at the voltage Vc are continuous in the period Ta.
When the driving signal VOUT is supplied to the one end of the piezoelectric element
60, the medium amount of the ink and the small amount of the ink are discharged from
the discharge section 600 corresponding to this piezoelectric element 60, in the period
Ta. Thus, the inks are landed on the medium P and are coalesced, and thereby a large
dot is formed on the medium P.
[0086] The driving signal VOUT corresponding to "the medium dot" has a waveform in which
the trapezoid waveform Adp1 disposed in the period T1 and a waveform which is disposed
in the periods T2 and T3 and is constant at the voltage Vc are continuous in the period
Ta. When the driving signal VOUT is supplied to the one end of the piezoelectric element
60, the medium amount of the ink is discharged from the discharge section 600 corresponding
to this piezoelectric element 60, in the period Ta. Thus, the ink is landed on the
medium P, and thereby a medium dot is formed on the medium P.
[0087] The driving signal VOUT corresponding to "the small dot" has a waveform in which
a waveform which is disposed in the periods T1 and T3 and is constant at the voltage
Vc and the trapezoid waveform Adp2 disposed in the period T2 are continuous in the
period Ta. When the driving signal VOUT is supplied to the one end of the piezoelectric
element 60, the small amount of the ink is discharged from the discharge section 600
corresponding to this piezoelectric element 60, in the period Ta. Thus, the ink is
landed on the medium P, and thereby a small dot is formed on the medium P.
[0088] The driving signal VOUT corresponding to "non-recording" has a waveform in which
a waveform which is disposed in the periods T1 and T2 and is constant at the voltage
Vc and the trapezoid waveform Adp3 disposed in the period T3 are continuous in the
period Ta. When the driving signal VOUT is supplied to the one end of the piezoelectric
element 60, in the period Ta, only the ink in the vicinity of the nozzle opening portion
of the discharge section 600 corresponding to this piezoelectric element 60 finely
vibrates, and the ink is not discharged. Thus, the ink is not landed on the medium
P and a dot is not formed on the medium P.
[0089] Here, the waveform constant at the voltage Vc means a waveform in which the previous
voltage Vc is configured by a voltage held by a capacitive component of the piezoelectric
element 60 when any of the trapezoid waveforms Adp1, Adp2, and Adp3 is not selected
as the driving signal VOUT. Therefore, when any of the trapezoid waveforms Adp1, Adp2,
and Adp3 is not selected as the driving signal VOUT, the voltage Vc is supplied to
the piezoelectric element 60 as the driving signal VOUT.
[0090] The driving signal COM and the driving signal VOUT illustrated in FIGs. 3 and 4 are
just examples. Signals having various combinations of waveforms may be used in accordance
with a moving speed of the carriage 20 in which the print head 21 is mounted, the
physical properties of the ink to be supplied to the print head 21, the material of
the medium P, and the like.
1.4. Configuration of Driving Signal Selection Circuit
[0091] Next, a configuration and an operation of the driving signal selection circuit 200
will be described. FIG. 5 is a diagram illustrating a configuration of the driving
signal selection circuit 200. As illustrated in FIG. 5, the driving signal selection
circuit 200 includes a selection control circuit 220 and a plurality of selection
circuits 230.
[0092] The print data signal SI, the latch signal cLAT, the change signal cCH, and the clock
signal cSCK are input to the selection control circuit 220. A set of a shift register
(S/R)222, a latch circuit 224, and a decoder 226 is provided in the selection control
circuit 220 to correspond to each of the plurality of discharge sections 600. That
is, the driving signal selection circuit 200 includes sets of shift registers 222,
latch circuits 224, and decoders 226. The number of sets is equal to the total number
m of discharge sections 600. Here, the print data signal SI is a signal for defining
selection of a waveform of the driving signal COM. The clock signal SCK and the clock
signal cSCK are clock signals for defining a timing at which the print data signal
SI is input.
[0093] Specifically, the print data signal SI is a signal synchronized with the clock signal
cSCK. The print data signal SI is a signal which has 2m bits in total and includes
2-bit print data [SIH, SIL] for selecting any of "the large dot", "the medium dot",
"the small dot", and "non-recording" for each of m pieces of discharge sections 600.
Regarding the print data signal SI, each 2-bit print data [SIH, SIL] which corresponds
to the discharge section 600 and is included in the print data signal SI is held in
the shift register 222. Specifically, the shift registers 222 from the first stage
to the m-th stage, which correspond to the discharge sections 600 are cascade-coupled
to each other, and the print data signal SI input in a serial manner is sequentially
transferred to the subsequent stage in accordance with the clock signal cSCK. In FIG.
5, in order to distinguish the shift registers 222 from each other, the shift registers
222 are described as being the first stage, the second stage, ..., and the m-th stage
in order from the upstream on which the print data signal SI is input.
[0094] Each of the m pieces of latch circuits 224 latches the 2-bit print data [SIH, SIL]
held in each of the m pieces of shift registers 222, at a rising edge of the latch
signal cLAT.
[0095] Each of the m pieces of decoders 226 decodes the 2-bit print data [SIH, SIL] latched
by each of the m pieces of latch circuits 224. The decoder 226 outputs a selection
signal S for each of the periods T1, T2, T3 defined by the latch signal cLAT and the
change signal cCH.
[0096] FIG. 6 is a diagram illustrating decoding contents in the decoder 226. The decoder
226 outputs the selection signal S in accordance with the latched 2-bit print data
[SIH, SIL]. For example, when the 2-bit print data [SIH, SIL] is [1, 1], the decoder
226 outputs the selection signal S having a logical level which is respectively set
to an H level, an H level, and an L level in the periods T1, T2, and T3.
[0097] The selection circuits 230 are provided to correspond to the discharge sections 600,
respectively. That is, the number of selection circuits 230 of the driving signal
selection circuit 200 is equal to the total number m of the discharge sections 600.
FIG. 7 is a diagram illustrating a configuration of the selection circuit 230 corresponding
to one discharge section 600. As illustrated in FIG. 7, the selection circuit 230
includes an inverter 232 being a NOT circuit, and a transfer gate 234.
[0098] The selection signal S is logically inverted by the inverter 232 and is input to
a negative control end of the transfer gate 234, which is marked with a circle, while
the selection signal S is input to a positive control end of the transfer gate 234,
which is not marked with a circle. The driving signal COM is supplied to an input
end of the transfer gate 234. Specifically, the transfer gate 234 electrically connects
(turns on between) the input end and an output end when the selection signal S has
an H level, and does not electrically connect (turns off between) the input end and
the output end when the selection signal S has an L level. In this manner, the driving
signal VOUT is output from the output end of the transfer gate 234.
[0099] Here, the operation of the driving signal selection circuit 200 will be described
with reference to FIG. 8. FIG. 8 is a diagram illustrating the operation of the driving
signal selection circuit 200. The print data signal SI is serially input in synchronization
with the clock signal cSCK and is sequentially transferred into the shift registers
222 corresponding to the discharge sections 600. If the input of the clock signal
cSCK stops, the 2-bit print data [SIH, SIL] corresponding to each of the discharge
sections 600 is held in each of the shift registers 222. The print data signal SI
is input in order of the discharge sections 600 corresponding to the m-th stage, ...,
the second stage, and the first stage of shift registers 222.
[0100] If the latch signal cLAT rises, the latch circuits 224 simultaneously latch the 2-bit
print data [SIH, SIL] held by the shift registers 222. In FIG. 8, LT1, LT2, ..., and
LTm indicate the 2-bit print data [SIH, SIL] latched by the latch circuits 224 respectively
corresponding to the first stage, the second stage, ..., and the m-th stage of shift
registers 222.
[0101] The decoder 226 outputs the logical level of the selection signal S in each of the
periods T1, T2, and T3, based on the contents in FIG. 6, in accordance with the size
of a dot defined by the latched 2-bit print data [SIH, SIL].
[0102] Specifically, when the print data [SIH, SIL] is [1, 1], the decoder 226 sets the
selection signal S to have an H level, an H level, and an L level in the periods T1,
T2, and T3. In this case, the selection circuit 230 selects the trapezoid waveform
Adp1 in the period T1, selects the trapezoid waveform Adp2 in the period T2, and does
not select the trapezoid waveform Adp3 in the period T3. As a result, the driving
signal VOUT corresponding to "the large dot" illustrated in FIG. 4 is generated.
[0103] When the print data [SIH, SIL] is [1, 0], the decoder 226 sets the selection signal
S to have an H level, an L level, and an L level in the periods T1, T2, and T3. In
this case, the selection circuit 230 selects the trapezoid waveform Adp1 in the period
T1, does not select the trapezoid waveform Adp2 in the period T2, and does not select
the trapezoid waveform Adp3 in the period T3. As a result, the driving signal VOUT
corresponding to "the medium dot" illustrated in FIG. 4 is generated.
[0104] When the print data [SIH, SIL] is [0, 1], the decoder 226 sets the selection signal
S to have an L level, an H level, and an L level in the periods T1, T2, and T3. In
this case, the selection circuit 230 does not select the trapezoid waveform Adp1 in
the period T1, selects the trapezoid waveform Adp2 in the period T2, and does not
select the trapezoid waveform Adp3 in the period T3. As a result, the driving signal
VOUT corresponding to "the small dot" illustrated in FIG. 4 is generated.
[0105] When the print data [SIH, SIL] is [0, 0], the decoder 226 sets the selection signal
S to have an L level, an L level, and an H level in the periods T1, T2, and T3. In
this case, the selection circuit 230 does not select the trapezoid waveform Adp1 in
the period T1, does not select the trapezoid waveform Adp2 in the period T2, and selects
the trapezoid waveform Adp3 in the period T3. As a result, the driving signal VOUT
corresponding to "non-recording" illustrated in FIG. 4 is generated.
[0106] As described above, the driving signal selection circuit 200 selects the waveform
of the driving signal COM based on the print data signal SI, the latch signal cLAT,
the change signal cCH, and the clock signal cSCK, and outputs the driving signal VOUT.
In other words, the driving signal selection circuit 200 controls a supply of the
driving signal COM to the piezoelectric element 60.
1.5. Configuration of Temperature Abnormality Detection Circuit
[0107] Next, the temperature abnormality detection circuit 250 will be described with reference
to FIG. 9. FIG. 9 is a diagram illustrating a configuration of the temperature abnormality
detection circuit 250. As illustrated in FIG. 9, the temperature abnormality detection
circuit 250 includes a comparator 251, a reference voltage generation circuit 252,
a transistor 253, a plurality of diodes 254, and resistors 255 and 256. As described
above, all the temperature abnormality detection circuits 250-1 to 250-n have the
same configuration. Therefore, in FIG. 9, detailed illustrations of the configuration
of the temperature abnormality detection circuit 250-2 to 250-n are omitted.
[0108] The voltage VDD2 is input to the reference voltage generation circuit 252. The reference
voltage generation circuit 252 generates a voltage Vref by transforming the voltage
VDD2 and supplies the voltage Vref to a positive-side input terminal of the comparator
251. The reference voltage generation circuit 252 is configured by a voltage regulator
circuit, for example.
[0109] The plurality of diodes 254 is coupled in series. Among the plurality of diodes 254
coupled in series, the voltage VDD2 is supplied to an anode terminal of the diode
254 located on the highest potential side via the resistor 255, and the ground signal
GND is supplied to a cathode terminal of the diode 254 located on the lowest potential
side. Specifically, the temperature abnormality detection circuit 250 has diodes 254-1,
254-2, 254-3, and 254-4 as the plurality of diodes 254. The voltage VDD2 is supplied
to the anode terminal of the diode 254-1 via the resistor 255, and the anode terminal
of the diode 254-1 is coupled to a negative-side input terminal of the comparator
251. A cathode terminal of the diode 254-1 is coupled to an anode terminal of the
diode 254-2. A cathode terminal of the diode 254-2 is coupled to an anode terminal
of the diode 254-3. A cathode terminal of the diode 254-3 is coupled to an anode terminal
of the diode 254-4. The ground signal GND is supplied to the cathode terminal of the
diode 254-4. With the resistor 255 and the plurality of diodes 254 configured in a
manner as described above, a voltage Vdet is supplied to a negative-side input terminal
of the comparator 251. The voltage Vdet is the sum of forward voltages of the plurality
of diodes 254. The number of the plurality of diodes 254 in the temperature abnormality
detection circuit 250 is not limited to four.
[0110] The comparator 251 operates by a potential difference between the voltage VDD2 and
the ground signal GND. The comparator 251 compares the voltage Vref supplied to the
positive-side input terminal and the voltage Vdet supplied to the negative-side input
terminal to each other, and outputs a signal based on the comparison result from an
output terminal.
[0111] The voltage VDD2 is supplied to the drain terminal of the transistor 253 via the
resistor 256. The gate terminal of the transistor 253 is coupled to the output terminal
of the comparator 251. The ground signal GND is supplied to the source terminal of
the transistor 253. The voltage supplied to the drain terminal of the transistor 253
coupled in a manner as described above is output from the temperature abnormality
detection circuit 250 as the abnormality signal XHOT.
[0112] The voltage value of the voltage Vref generated by the reference voltage generation
circuit 252 is less than the voltage Vdet when the temperature of the plurality of
diodes 254 is within a predetermined range. In this case, the comparator 251 outputs
a signal having an L level. Thus, the transistor 253 is controlled to turn off. As
a result, the temperature abnormality detection circuit 250 outputs the abnormality
signal XHOT having an H level.
[0113] The forward voltage of the diode 254 has characteristics in which the forward voltage
decreases as the temperatures increases. Thus, when temperature abnormality occurs
in the print head 21, the temperature of the diode 254 increases, and thereby the
voltage Vdet decreases. When the voltage Vdet becomes less than the voltage Vref by
the temperature increase, the output signal of the comparator 251 changes from an
L level to an H level. Accordingly, the transistor 253 is controlled to turn on. As
a result, the temperature abnormality detection circuit 250 outputs the abnormality
signal XHOT having an L level. That is, if the transistor 253 is controlled to turn
on or off based on the temperature of the driving signal selection circuit 200, the
temperature abnormality detection circuit 250 outputs the voltage VDD2 supplied as
the pull-up voltage of the transistor 253, as the abnormality signal XHOT having an
H level and outputs the ground signal GND as the abnormality signal XHOT having an
L level.
[0114] As illustrated in FIG. 9, outputs of the n pieces of temperature abnormality detection
circuits 250-1 to 250-n are commonly coupled. Thus, when temperature abnormality occurs
in any of the temperature abnormality detection circuits 250-1 to 250-n, the transistor
253 corresponding to the temperature abnormality detection circuit 250 in which the
temperature abnormality occurs is controlled to turn on. As a result, the ground signal
GND is supplied to a node to which the abnormality signal XHOT is output, via the
transistor 253. Thus, the abnormality signals XHOT output by the temperature abnormality
detection circuits 250-1 to 250-n are controlled to have an L level. That is, the
temperature abnormality detection circuits 250-1 to 250-n are coupled in a wired-OR
manner. Thus, even when the plurality of temperature abnormality detection circuits
250 is provided in the print head 21, it is possible to propagate the abnormality
signal XHOT indicating whether or not temperature abnormality occurs in the print
head 21, without increasing the number of wirings for propagating the abnormality
signal XHOT.
1.6. Configurations of Print Head and Print Head Control Circuit
[0115] Next, details of an electrical coupling between the control mechanism 10 and the
print head 21 will be described. In the following descriptions, descriptions will
be made on the assumption that the print head 21 in the first embodiment includes
four driving signal selection circuits 200-1 to 200-4. That is, four print data signals
SI1 to SI4, four driving signals COM1 to COM4, and four reference voltage signals
CGND1 to CGND4, which respectively correspond to the four driving signal selection
circuits 200-1 to 200-4 are input to the print head 21 in the first embodiment.
[0116] FIG. 10 is a schematic diagram illustrating an internal configuration of the liquid
discharge apparatus 1 when viewed from the Y-direction. As illustrated in FIG. 10,
the liquid discharge apparatus 1 includes a main substrate 11, a cable 19, and the
print head 21.
[0117] Various circuits including the driving signal output circuit 50, the control circuit
100, and the power circuit 110 provided in the control mechanism 10 illustrated in
FIGs. 1 and 2 are mounted on the main substrate 11. A connector 12 to which one end
of the cable 19 is attached is mounted on the main substrate 11. FIG. 10 illustrates
one circuit substrate as the main substrate 11. However, the main substrate 11 may
be configured by two circuit substrates or more.
[0118] The print head 21 includes a head 310, a substrate 320, and a connector 350. The
other end of the cable 19 is attached to the connector 350. Thus, various signals
generated by the control mechanism 10 are input to the print head 21 via the cable
19. Details of the configuration of the print head 21 and details of the signal propagated
in the cable 19 will be described later.
[0119] The liquid discharge apparatus 1 configured in a manner as described above controls
the operation of the print head 21 based on various signals including the driving
signals COM1 to COM4, the reference voltage signals CGND1 to CGND4, the print data
signals SI1 to SI4, the latch signal LAT, the change signal CH, the clock signal SCK,
and the diagnosis signals DIG-A to DIG-D, which are output from the control mechanism
10 mounted on the main substrate 11. That is, in the liquid discharge apparatus 1
illustrated in FIG. 10, a configuration including the control mechanism 10 that outputs
various signals for controlling the operation of the print head 21 and the cable 19
for propagating the various signals for controlling the operation of the print head
21 is an example of the print head control circuit 15 that controls the operation
of the print head 21 having a function of performing self-diagnosis.
[0120] FIG. 11 is a diagram illustrating a configuration of the cable 19. The cable 19 has
a substantially rectangular shape having short sides 191 and 192 facing each other
and long sides 193 and 194 facing each other. For example, the cable 19 is a flexible
flat cable (FFC). The cable 19 includes a plurality of terminals 195 aligned in parallel
along the short side 191, a plurality of terminals 196 aligned in parallel along the
short side 192, and a plurality of wirings 197 that electrically couples the plurality
of terminals 195 and the plurality of terminals 196 to each other.
[0121] Specifically, 29 terminals 195 are aligned in parallel from the long side 193 toward
the long side 194, on the short side 191 side of the cable 19 in order of the terminals
195-1 to 195-29. 29 terminals 196 are aligned in parallel from the long side 193 toward
the long side 194, on the short side 192 side of the cable 19 in order of the terminals
196-1 to 196-29. In the cable 19, 29 wirings 197 that electrically couple the terminals
195 and the terminals 196 to each other are aligned in parallel from the long side
193 toward the long side 194 in order of the wirings 197-1 to 197-29. The wiring 197-1
electrically couples the terminal 195-1 and the terminal 196-1 to each other. Similarly,
the wiring 197-k (k is any of 1 to 29) electrically couples the terminal 195-k and
the terminal 196-k to each other.
[0122] The wirings 197-1 to 197-29 are insulated between the wirings and between the wiring
and the outside of the cable 19, by an insulator 198. The cable 19 causes a signal
input from the terminal 195-k to propagate in the wiring 197-k and to be output from
the terminal 196-k. The configuration of the cable 19 illustrated in FIG. 11 is an
example, and the embodiment is not limited thereto. For example, the plurality of
terminals 195 and the plurality of terminals 196 may be provided on the different
surfaces of the cable 19. The number of terminals 195, the number of terminals 196,
and the number of wirings 197, which are provided in the cable 19, are not limited
to 29.
[0123] Next, the configuration of the print head 21 will be described. FIG. 12 is a perspective
view illustrating the configuration of the print head 21. As illustrated in FIG. 12,
the print head 21 includes the head 310 and the substrate 320. An ink discharge surface
311 on which the plurality of discharge sections 600 are formed is located on a lower
surface of the head 310 in the Z-direction.
[0124] FIG. 13 is a plan view illustrating a configuration of the ink discharge surface
311. As illustrated in FIG. 13, four nozzle plates 632 are provided on the ink discharge
surface 311 to be aligned in the X-direction. The nozzle plate 632 has nozzles 651
provided in the plurality of discharge sections 600. In each of the nozzle plates
632, the nozzles 651 are provided to be aligned in the Y-direction. That is, four
nozzle columns L1 to L4 are formed in the ink discharge surface 311. In FIG. 13, the
nozzles 651 are provided to be aligned in one line in the Y-direction, in each of
the nozzle columns L1 to L4 which are respectively formed in the nozzle plates 632.
However, the nozzles 651 may be provided to be aligned in two or more lines in the
Y-direction.
[0125] The nozzle columns L1 to L4 are provided to correspond to the driving signal selection
circuits 200-1 to 200-4, respectively. Specifically, the driving signal VOUT1 output
by the driving signal selection circuit 200-1 is supplied to the one end of the piezoelectric
element 60 in a plurality of discharge sections 600 provided in the nozzle column
L1. The reference voltage signal CGND1 is supplied to the other end of this piezoelectric
element 60. Similarly, the driving signals VOUT2 to VOUT4 output by the driving signal
selection circuits 200-2 to 200-4 are respectively supplied to one ends of the piezoelectric
elements 60 in a plurality of discharge sections 600 provided in the nozzle columns
L2 to L4. The reference voltage signals CGND2 to CGND4 are supplied to the other ends
of the corresponding piezoelectric elements 60, respectively.
[0126] Next, the configuration of the discharge section 600 in the head 310 will be described
with reference to FIG. 14. FIG. 14 is a diagram illustrating an overall configuration
of one of the plurality of discharge sections 600 in the head 310. As illustrated
in FIG. 14, the head 310 includes the discharge section 600 and a reservoir 641.
[0127] The reservoir 641 is provided to correspond to each of the nozzle columns L1 to L4.
The ink is supplied from the ink supply port 661 into the reservoir 641.
[0128] The discharge section 600 includes the piezoelectric element 60, a vibration plate
621, a cavity 631, and the nozzle 651. The vibration plate 621 deforms by displacement
of the piezoelectric element 60 provided on an upper surface in FIG. 14. The vibration
plate 621 functions as a diaphragm of increasing and reducing the internal volume
of the cavity 631. The cavity 631 is filled with the ink. The cavity 631 functions
as a pressure chamber having an internal volume which changes by the displacement
of the piezoelectric element 60. The nozzle 651 is an opening portion which is formed
in the nozzle plate 632 and communicates with the cavity 631. The ink stored in the
cavity 631 is discharged from the nozzle 651 by the change of the internal volume
of the cavity 631.
[0129] The piezoelectric element 60 has a structure in which a piezoelectric substance 601
is interposed between a pair of electrodes 611 and 612. In the piezoelectric element
60 having such a structure, the central portions of the electrodes 611 and 612 and
the vibration plate 621 bend with respect to both end portions thereof in an up-and-down
direction in FIG. 14, in accordance with a voltage supplied to the electrodes 611
and 612. Specifically, the driving signal VOUT is supplied to the electrode 611, and
the reference voltage signal CGND is supplied to the electrode 612. If the voltage
of the driving signal VOUT is high, the central portion of the piezoelectric element
60 bends upward. If the voltage of the driving signal VOUT is low, the central portion
of the piezoelectric element 60 bends downward. That is, if the piezoelectric element
60 bends upward, the internal volume of the cavity 631 increases. Thus, the ink is
drawn from the reservoir 641. If the piezoelectric element 60 bends downward, the
internal volume of the cavity 631 is reduced. Accordingly, the ink of the amount depending
on the degree of the internal volume of the cavity 631 being reduced is discharged
from the nozzle 651. As described above, the piezoelectric element 60 drives by the
driving signal VOUT based on the driving signal COM, and the ink is discharged from
the nozzle 651 by the piezoelectric element 60 driving. The piezoelectric element
60 is not limited to the structure illustrated in FIG. 14. Any type may be provided
so long as the piezoelectric element is capable of discharging the ink with the displacement
of the piezoelectric element 60. The piezoelectric element 60 is not limited to flexural
vibration, and may be configured to use longitudinal vibration.
[0130] Returning to FIG. 12, the substrate 320 has a surface 321 and a surface 322 different
from the surface 321. Here, the surface 321 and the surface 322 are surfaces located
to face each other with a base material of the substrate 320 interposed between the
surfaces 321 and 322. In other words, the surface 321 and the surface 322 are the
front surface and the back surface of the substrate 320. The substrate 320 has a substantially
rectangular shape formed by a side 323, a side 324 (facing the side 323 in the X-direction),
a side 325, and a side 326 (facing the side 325 in the Y-direction). In other words,
the substrate 320 has the side 323, the side 324 different from the side 323, the
side 325 intersecting the sides 323 and 324, and the side 326 different from the side
325 intersecting the sides 323 and 324. Here, the sides 325 and 326 intersecting the
sides 323 and 324 mean a case where a virtual extension line of the side 325 intersects
a virtual extension line of the side 323 and a virtual extension line of the side
324, and a virtual extension line of the side 326 intersects a virtual extension line
of the side 323 and a virtual extension line of the side 324. That is, the shape of
the substrate 320 is not limited to a rectangle. For example, the shape of the substrate
320 may be a polygon such as a hexagon or an octagon, or may have a shape in which
a notch or an arc is formed at a portion thereof.
[0131] Here, details of the substrate 320 will be described with reference to FIGs. 15 and
16. FIG. 15 is a plan view when the substrate 320 is viewed from the surface 322.
FIG. 16 is a plan view when the substrate 320 is viewed from the surface 321. As illustrated
in FIG. 15, electrode groups 330a to 330d are provided on the surface 322 of the substrate
320. Specifically, each of the electrode groups 330a to 330d includes a plurality
of electrodes aligned in the Y-direction. The electrode groups 330a to 330d are provided
to be aligned from the side 323 toward the side 324 in order of the electrode groups
330a, 330b, 330c, and 330d. A flexible printed circuit (FPC) (not illustrated) is
electrically coupled to each of the electrode groups 330a to 330d provided in a manner
as described above.
[0132] As illustrated in FIGs. 15 and 16, FPC insertion holes 332a and 332b and ink supply
path insertion holes 331a to 331d being through-holes penetrating the surfaces 321
and 322 are formed in the substrate 320.
[0133] The FPC insertion hole 332a is located between the electrode group 330a and the electrode
group 330b in the X-direction. An FPC electrically coupled to the electrode group
330a and an FPC electrically coupled to the electrode group 330b are inserted into
the FPC insertion hole 332a. The FPC insertion hole 332b is located between the electrode
group 330c and the electrode group 330d in the X-direction. An FPC electrically coupled
to the electrode group 330c and an FPC electrically coupled to the electrode group
330d are inserted into the FPC insertion hole 332b.
[0134] The ink supply path insertion hole 331a is located on the side 323 side of the electrode
group 330a in the X-direction. The ink supply path insertion holes 331b and 331c are
located between the electrode group 330b and the electrode group 330c in the X-direction.
The ink supply path insertion holes 331b and 331c are located to be aligned in the
Y-direction such that the ink supply path insertion hole 331b is located on the side
325 side, and the ink supply path insertion hole 331c is located on the side 326 side.
The ink supply path insertion hole 331d is located on the side 324 side of the electrode
group 330d in the X-direction. A portion of an ink supply path (not illustrated) is
inserted into each of the ink supply path insertion holes 331a to 331d. The ink supply
path communicates with an ink supply port 661 for supplying the ink to the discharge
section 600 corresponding to each of the nozzle columns L1 to L4.
[0135] As illustrated in FIGs. 15 and 16, the substrate 320 has fixation portions 346 to
349 for fixing the substrate 320 in the print head 21 to the carriage 20 illustrated
in FIG. 1. Each of the fixation portions 346 to 349 is a through-hole penetrating
the surfaces 321 and 322 of the substrate 320. The substrate 320 is fixed to the carriage
20 in a manner that screws (not illustrated) inserted into the fixation portion 346
to 349 are attached to the carriage 20. The fixation portions 346 to 349 are not limited
to through-holes formed in the substrate 320. For example, the substrate 320 may be
fixed to the carriage 20 by fitting the fixation portions 346 to 349.
[0136] The fixation portions 346 and 347 are located on the side 323 side of the ink supply
path insertion hole 331a in the X-direction and are provided to be aligned such that
the fixation portion 346 is located on the side 325 side, and the fixation portion
347 is located on the side 326 side. The fixation portions 348 and 349 are located
on the side 324 side of the ink supply path insertion hole 331d in the X-direction
and are provided to be aligned such that the fixation portion 348 is located on the
side 325 side, and the fixation portion 349 is located on the side 326 side.
[0137] As illustrated in FIG. 16, an integrated circuit 241 constituting the diagnosis circuit
240 illustrated in FIG. 2 is provided on the surface 321 of the substrate 320. Specifically,
the integrated circuit 241 is provided between the fixation portion 347 and the fixation
portion 349 and is provided on the side 326 side of the electrode groups 330a to 330d,
on the surface 321 side of the substrate 320. The integrated circuit 241 constituting
the diagnosis circuit 240 diagnoses whether or not normal discharge of the ink from
the nozzle 651 is possible, based on the diagnosis signals DIG-A to DIG-D.
[0138] As illustrated in FIG. 16, the connector 350 is provided on the substrate 320. The
connector 350 is provided along the side 323 on the surface 321 side of the substrate
320. That is, the connector 350 and the integrated circuit 241 constituting the diagnosis
circuit 240 are provided on the same surface of the substrate 320.
[0139] Here, a configuration of the connector 350 will be described with reference to FIG.
17. FIG. 17 is a diagram illustrating the configuration of the connector 350. As illustrated
in FIG. 17, the connector 350 includes a housing 351, a cable attachment section 352
formed in the housing 351, and a plurality of terminals 353. The plurality of terminals
353 is aligned in parallel along the side 323. Specifically, 29 terminals 353 are
aligned in parallel along the side 323 in the connector 350 in the first embodiment.
Here, the 29 terminals 353 are referred to as terminals 353-1, 353-2, ..., and 353-29
in order from the side 325 toward the side 326 in a direction along the side 323.
The cable attachment section 352 is located on the substrate 320 side of the plurality
of terminals 353 in the Z-direction. The cable 19 is attached to the cable attachment
section 352. When the cable 19 is attached to the cable attachment section 352, the
terminals 196-1 to 196-29 in the cable 19 electrically come into contact with the
terminals 353-1 to 353-29 in the connector 350, respectively.
[0140] Here, in the connector 350 illustrated in FIG. 17, the cable attachment section 352
is located on the substrate 320 side in the Z-direction, and the plurality of terminals
353 is located on the ink discharge surface 311 side in the Z-direction. However,
as in the connector 350 illustrated in FIG. 18, the plurality of terminals 353 is
preferably located on the substrate 320 side in the Z-direction, and the cable attachment
section 352 is preferably located on the ink discharge surface 311 side in the Z-direction.
[0141] FIG. 18 is a diagram illustrating another configuration of the connector 350. In
the liquid discharge apparatus 1, most of the ink discharged from the nozzle 651 are
landed on a medium P and form an image. However, a portion of the ink discharged from
the nozzle 651 may be misted before being landed on the medium P, and thus may float
in the liquid discharge apparatus 1. Even after the ink discharged from the nozzle
651 is landed on the medium P, the ink landed on the medium P may float again in the
liquid discharge apparatus 1 by an air flow generated with moving the carriage 20
in which the print head 21 is mounted or transporting the medium P. Thus, when the
ink floating in the liquid discharge apparatus 1 adheres to the plurality of terminals
353 in the connector 350 or to the terminals 196 in the cable 19 for propagating a
signal to the print head 21, the terminals may be short-circuited. As a result, the
waveforms of the various signals input to the print head 21 may be distorted, and
thus discharge accuracy of the ink discharged from the print head 21 may be deteriorated.
[0142] As in the connector 350 illustrated in FIG. 18, when the plurality of terminals 353
is located on the substrate 320 side in the Z-direction, the cable attachment section
352 is located on the ink discharge surface 311 side in the Z-direction, and the cable
19 is attached to the connector 350, a possibility that the terminal 353 and the terminal
196 are exposed to the ink discharge surface 311 side having a high possibility of
the floating ink adhering is reduced. Therefore, it is possible to reduce the concern
that the plurality of terminals 353 in the connector 350 or the terminals 196 in the
cable 19 are short-circuited by the ink floating in the liquid discharge apparatus
1. Accordingly, it is possible to reduce the concern that the signal propagated in
the cable 19 is distorted.
[0143] Here, a specific example of electrical coupling between the cable 19 and the connector
350 will be described with reference to FIG. 19. FIG. 19 is a diagram illustrating
a specific example when the cable 19 is attached to the connector 350. As illustrated
in FIG. 19, the terminal 353 of the connector 350 has a substrate attachment section
353a, a housing insertion section 353b, and a cable maintaining section 353c. The
substrate attachment section 353a is located at a lower portion of the connector 350
and is provided between the housing 351 and the substrate 320. The substrate attachment
section 353a is electrically coupled to an electrode (not illustrated) provided on
the substrate 320, by a solder, for example. The housing insertion section 353b is
inserted into the housing 351. The housing insertion section 353b electrically couples
the substrate attachment section 353a and the cable maintaining section 353c to each
other. The cable maintaining section 353c has a curved shape that protrudes toward
the inside of the cable attachment section 352. When the cable 19 is attached to the
cable attachment section 352, the cable maintaining section 353c and the terminal
196 electrically come into contact with each other via a contact section 180. Thus,
the cable 19 is electrically coupled to the connector 350 and the substrate 320. In
this case, since the cable 19 is attached, stress is applied to the curved shape formed
at the cable maintaining section 353c. With the stress, the cable 19 is held in the
cable attachment section 352.
[0144] As described above, the cable 19 and the connector 350 are electrically coupled to
each other by the terminal 196 and the terminal 353 coming into contact with each
other via the contact section 180. FIG. 11 illustrates contact sections 180-1 to 180-29
at which each of the terminals 196-1 to 196-29 is electrically in contact with the
terminal 353 of the connector 350. Thus, the terminal 195-k in the cable 19 is electrically
coupled to the connector 12, and the terminal 196-k in the cable 19 is electrically
coupled to the connector 350 via the contact section 180-k.
[0145] In the print head 21 configured in a manner as described above, a plurality of signals
including the driving signals COM1 to COM4, the reference voltage signals CGND1 to
CGND4, the print data signals SI1 to SI4, the latch signal LAT, the change signal
CH, and the clock signal SCK, which are output from the control mechanism 10, is input
to the print head 21 via the connector 350. The plurality of signals is propagated
in a wiring pattern (not illustrated) provided on the substrate 320 and then is input
to each of the electrode groups 330a to 330d.
[0146] The various signals input to each of the electrode groups 330a to 330d are input
to the driving signal selection circuits 200-1 to 200-4 respectively corresponding
to the nozzle columns L1 to L4, via an FPC electrically coupled to each of the electrode
groups 330a to 330d. The driving signal selection circuits 200-1 to 200-4 generate
the driving signals VOUT1 to VOUT4 based on the input signals and supply the driving
signals VOUT1 to VOUT4 to the piezoelectric elements 60 in the nozzle columns L1 to
L4, respectively. In this manner, the various signals input to the connector 350 are
supplied to the piezoelectric elements 60 in the plurality of discharge sections 600.
Each of the driving signal selection circuits 200-1 to 200-4 may be provided in the
head 310 or may be mounted on an FPC in a manner of chip-on-film (COF).
1.7. Details of Signal Propagated in Cable
[0147] In the liquid discharge apparatus 1 configured in a manner as described above, details
of the signal propagated between the print head control circuit 15 and the print head
21 will be described with reference to FIG. 20.
[0148] FIG. 20 is a diagram illustrating details of the signal propagated in the cable 19.
As illustrated in FIG. 20, the cable 19 includes wirings for propagating the driving
signals COM1 to COM4, wirings for propagating the reference voltage signals CGND1
to CGND4, wirings for propagating the temperature signal TH, the latch signal LAT,
the clock signal SCK, the change signal CH, the print data signal SI1, and the abnormality
signal XHOT, wirings for propagating the diagnosis signals DIG-A to DIG-E, wirings
for propagating the voltages VHV, VDD1, and VDD2, and a plurality of wirings for propagating
a plurality of ground signals GND.
[0149] Specifically, the driving signals COM1 to COM4 and the reference voltage signals
CGND1 to CGND4 are input from the terminals 195-1 to 195-8 to the cable 19 and are
propagated in the wiring 197-1 to 197-8, respectively. Then, the driving signals COM1
to COM4 and the reference voltage signals CGND1 to CGND4 are input to the terminals
353-1 to 353-8 of the connector 350 via the terminals 196-1 to 196-8 and the contact
sections 180-1 to 180-8, respectively.
[0150] The diagnosis signal DIG-A is input from the terminal 195-25 to the cable 19 and
is propagated in the wiring 197-25. Then, the diagnosis signal DIG-A is input to the
terminal 353-25 of the connector 350 via the terminal 196-25 and the contact section
180-25. Similarly, the latch signal LAT is input from the terminal 195-25 to the cable
19 and is propagated in the wiring 197-25. Then, the latch signal LAT is input to
the terminal 353-25 of the connector 350 via the terminal 196-25 and the contact section
180-25. That is, the wiring 197-25 functions as the wiring for propagating the diagnosis
signal DIG-A and the wiring for propagating the latch signal LAT. The terminal 353-25
functions as the terminal to which the diagnosis signal DIG-A is input and the terminal
to which the latch signal LAT is input. The contact section 180-25 is electrically
in contact with the wiring for propagating the diagnosis signal DIG-A and is also
electrically in contact with the wiring for propagating the latch signal LAT. The
diagnosis signal DIG-A is an example of a second diagnosis signal in the first embodiment.
The wiring 197-25 for propagating the diagnosis signal DIG-A is an example of a second
diagnosis signal propagation wiring in the first embodiment. The terminal 353-25 to
which the diagnosis signal DIG-A is input is an example of a second terminal in the
first embodiment. The contact section 180-25 at which the wiring 197-25 and the terminal
353-25 are electrically in contact with each other is an example of a second contact
section in the first embodiment.
[0151] The diagnosis signal DIG-B is input from the terminal 195-23 to the cable 19 and
is propagated in the wiring 197-23. Then, the diagnosis signal DIG-B is input to the
terminal 353-23 of the connector 350 via the terminal 196-23 and the contact section
180-23. Similarly, the clock signal SCK is input from the terminal 195-23 to the cable
19 and is propagated in the wiring 197-23. Then, the clock signal SCK is input to
the terminal 353-23 of the connector 350 via the terminal 196-23 and the contact section
180-23. That is, the wiring 197-23 functions as the wiring for propagating the diagnosis
signal DIG-B and the wiring for propagating the clock signal SCK. The terminal 353-23
functions as the terminal to which the diagnosis signal DIG-B is input and the terminal
to which the clock signal SCK is input. The contact section 180-23 is electrically
in contact with the wiring for propagating the diagnosis signal DIG-B and is also
electrically in contact with the wiring for propagating the clock signal SCK. The
diagnosis signal DIG-B is an example of a first diagnosis signal in the first embodiment.
The wiring 197-23 for propagating the diagnosis signal DIG-B is an example of a first
diagnosis signal propagation wiring in the first embodiment. The terminal 353-23 to
which the diagnosis signal DIG-B is input is an example of a first terminal in the
first embodiment. The contact section 180-23 at which the wiring 197-23 and the terminal
353-23 are electrically in contact with each other is an example of a first contact
section in the first embodiment.
[0152] The diagnosis signal DIG-C is input from the terminal 195-21 to the cable 19 and
is propagated in the wiring 197-21. Then, the diagnosis signal DIG-C is input to the
terminal 353-21 of the connector 350 via the terminal 196-21 and the contact section
180-21. Similarly, the change signal CH is input from the terminal 195-21 to the cable
19 and is propagated in the wiring 197-21. Then, the change signal CH is input to
the terminal 353-21 of the connector 350 via the terminal 196-21 and the contact section
180-21. That is, the wiring 197-21 functions as the wiring for propagating the diagnosis
signal DIG-C and the wiring for propagating the change signal CH. The terminal 353-21
functions as the terminal to which the diagnosis signal DIG-C is input and the terminal
to which the change signal CH is input. The contact section 180-21 is electrically
in contact with the wiring for propagating the diagnosis signal DIG-C and is also
electrically in contact with the wiring for propagating the change signal CH. The
diagnosis signal DIG-C is an example of a third diagnosis signal in the first embodiment.
The wiring 197-21 for propagating the diagnosis signal DIG-C is an example of a third
diagnosis signal propagation wiring in the first embodiment. The terminal 353-21 to
which the diagnosis signal DIG-C is input is an example of a third terminal in the
first embodiment. The contact section 180-21 at which the wiring 197-21 and the terminal
353-21 are electrically in contact with each other is an example of a third contact
section in the first embodiment.
[0153] The diagnosis signal DIG-D is input from the terminal 195-19 to the cable 19 and
is propagated in the wiring 197-19. Then, the diagnosis signal DIG-D is input to the
terminal 353-19 of the connector 350 via the terminal 196-19 and the contact section
180-19. Similarly, the print data signal SI1 is input from the terminal 195-19 to
the cable 19 and is propagated in the wiring 197-19. Then, the print data signal SI1
is input to the terminal 353-19 of the connector 350 via the terminal 196-19 and the
contact section 180-19. That is, the wiring 197-19 functions as the wiring for propagating
the diagnosis signal DIG-D and the wiring for propagating the print data signal SI1.
The terminal 353-19 functions as the terminal to which the diagnosis signal DIG-D
is input and the terminal to which the print data signal SI1 is input. The contact
section 180-19 is electrically in contact with the wiring for propagating the diagnosis
signal DIG-D and is also electrically in contact with the wiring for propagating the
print data signal SI1. The diagnosis signal DIG-D is an example of a fourth diagnosis
signal in the first embodiment. The wiring 197-19 for propagating the diagnosis signal
DIG-D is an example of a fourth diagnosis signal propagation wiring in the first embodiment.
The terminal 353-19 to which the diagnosis signal DIG-D is input is an example of
a fourth terminal in the first embodiment. The contact section 180-19 at which the
wiring 197-19 and the terminal 353-19 are electrically in contact with each other
is an example of a fourth contact section in the first embodiment.
[0154] The diagnosis signal DIG-E is input to the terminal 353-11 of the connector 350 and
is input to the cable 19 via the contact section 180-11 and the terminal 196-11. The
diagnosis signal DIG-E is propagated in the wiring 197-11, and then is input from
the terminal 195-11 to the main substrate 11. Similarly, the abnormality signal XHOT
is input to the terminal 353-11 of the connector 350 and is input to the cable 19
via the contact section 180-11 and the terminal 196-11. The abnormality signal XHOT
is propagated in the wiring 197-11, and then is input from the terminal 195-11 to
the main substrate 11. That is, the wiring 197-11 functions as the wiring for propagating
the diagnosis signal DIG-E and the wiring for propagating the abnormality signal XHOT.
The terminal 353-11 functions as the terminal to which the diagnosis signal DIG-E
is input and the terminal to which the abnormality signal XHOT is input. The contact
section 180-11 is electrically in contact with the wiring for propagating the diagnosis
signal DIG-E and is also electrically in contact with the wiring for propagating the
abnormality signal XHOT. The diagnosis signal DIG-E is an example of a fifth diagnosis
signal in the first embodiment. The wiring 197-11 for propagating the diagnosis signal
DIG-E is an example of a fifth diagnosis signal propagation wiring in the first embodiment.
The terminal 353-11 to which the diagnosis signal DIG-E is input is an example of
a fifth terminal in the first embodiment. The contact section 180-11 at which the
wiring 197-11 and the terminal 353-11 are electrically in contact with each other
is an example of a fifth contact section in the first embodiment.
[0155] As described above, in the first embodiment, each of the diagnosis signals DIG-A
to DIG-E and each of the latch signal LAT, the clock signal SCK, the change signal
CH, the print data signal SI1, and the abnormality signal XHOT are propagated in the
common wiring. Here, an example of a method of propagating each of the diagnosis signals
DIG-A to DIG-E and each of the latch signal LAT, the clock signal SCK, the change
signal CH, the print data signal SI1, and the abnormality signal XHOT in the common
wiring and of inputting the signals to the common terminal will be described.
[0156] For example, the control circuit 100 generates the diagnosis signal DIG-A, the latch
signal LAT, the diagnosis signal DIG-B, the clock signal SCK, the diagnosis signal
DIG-C, the change signal CH, the diagnosis signal DIG-D, and the print data signal
SI1 in time division, in accordance with operation states of the liquid discharge
apparatus 1 and the print head 21. Specifically, when the liquid discharge apparatus
1 is in a print state of discharging the ink, the control circuit 100 generates the
latch signal LAT, the clock signal SCK, the change signal CH, and the print data signal
SI1 and outputs the generated signals to the print head 21. When the liquid discharge
apparatus 1 is not in the print state of discharging the ink, and the print head 21
performs self-diagnosis, the control circuit 100 generates the diagnosis signals DIG-A
to DIG-D and outputs the generated signals to the print head 21. Thus, each of the
latch signal LAT, the clock signal SCK, the change signal CH, and the print data signal
SI1 and each of the diagnosis signals DIG-A to DIG-D can be propagated in the common
wiring, and can be input to the common terminal via the common contact section.
[0157] As a method of propagating the diagnosis signal DIG-E and the abnormality signal
XHOT in the common wiring and inputting the diagnosis signal DIG-E and the abnormality
signal XHOT to the common terminal, for example, a wiring from which the diagnosis
signal DIG-E indicating the diagnosis result in the diagnosis circuit 240 and a wiring
from which the abnormality signal XHOT is output are coupled in a wired-OR manner
in the print head 21. Then, a signal obtained by the coupling in the wired-OR manner
is input to the common terminal, and then is propagated in the common wiring. Thus,
when abnormality occurs in at least any of a diagnosis result of diagnosing whether
or not the temperature of the temperature abnormality detection circuit 250 is abnormal
and a diagnosis result in the diagnosis circuit 240, a signal which has an L level
and indicates that normal discharge of the ink in the print head 21 is not possible
is propagated. When both the diagnosis result of diagnosing whether or not the temperature
of the temperature abnormality detection circuit 250 is abnormal and the diagnosis
result in the diagnosis circuit 240 are normal, a signal which has an H level and
indicates that normal discharge of the ink in the print head 21 is possible is propagated.
[0158] As described above, a method of propagating each of the diagnosis signals DIG-A to
DIG-E and each of the latch signal LAT, the clock signal SCK, the change signal CH,
the print data signal SI1, and the abnormality signal XHOT in the common wiring and
inputting the signals to the common terminal is an example. The signal propagated
in the wiring and the signal input to the terminal may be switched by a selector,
for example.
[0159] The print data signal SI, the change signal CH, the latch signal LAT, the clock signal
SCK, and the abnormality signal XHOT are signals important for controlling discharging
of the print head 21. When a coupling problem occurs in the wiring in which the signals
are propagated, the discharge accuracy of the ink may be deteriorated. The wiring
in which such important signals are propagated and the wiring in which the signal
when the print head 21 performs self-diagnosis are set to the common wiring, and the
terminal to which the important signals are input and the terminal to which the signal
when the print head 21 performs self-diagnosis is input are set to the common terminal
coupled to the common contact section. Thus, it can be diagnosed whether or not the
print data signal SI1, the change signal CH, the latch signal LAT, the clock signal
SCK, and the abnormality signal XHOT are normally propagated, based on the result
of the self-diagnosis of the print head 21. Further, since the plurality of signals
is propagated in one wiring, and the plurality of signals is input to one terminal,
it is possible to reduce the number of wirings to be provided in the cable 19 and
the number of terminals provided in the connector 350.
[0160] The print data signal SI2 to SI4 are input to the cable 19 from the terminals 195-17,
195-15, and 195-13 and are propagated in the wirings 197-17, 197-15, and 197-13, respectively.
Then, the print data signal SI2 to SI4 are input to the terminals 353-17, 353-15,
and 353-13 of the connector 350 via the terminals 196-17, 196-15, and 196-13 and the
contact sections 180-17, 180-15, and 180-13, respectively.
[0161] The voltage VHV is input from the terminal 195-9 to the cable 19 and is propagated
in the wiring 197-9. Then, the voltage VHV is input to the terminal 353-9 of the connector
350 via the terminal 196-9 and the contact section 180-9. The voltage VHV is a signal
having a voltage value larger than the voltage VDD1. The voltage VHV supplied to the
terminal 353-9 is supplied to the driving signal selection circuit 200. The voltage
VHV is used as a voltage for performing level shift of the logical level of the selection
signal S to a high amplitude logic level in the driving signal selection circuit 200.
[0162] The voltage VDD1 is input from the terminal 195-29 to the cable 19 and is propagated
in the wiring 197-29. Then, the voltage VDD1 is input to the terminal 353-29 of the
connector 350 via the terminal 196-29 and the contact section 180-29. The voltage
VDD1 supplied to the terminal 353-29 is supplied to the driving signal selection circuit
200. The voltage VDD1 is used as the power source voltage of the driving signal selection
circuit 200 and is used as a voltage for generating various control signals for controlling
the operation of the driving signal selection circuit 200.
[0163] The voltage VDD2 is input from the terminal 195-24 to the cable 19 and is propagated
in the wiring 197-24. Then, the voltage VDD2 is input to the terminal 353-24 of the
connector 350 via the terminal 196-24 and the contact section 180-24. The voltage
VDD2 supplied to the terminal 353-24 is supplied to the temperature abnormality detection
circuit 250. Thus, the voltage VDD2 is used as the power source voltage of the comparator
251 as illustrated in FIG. 9 and is used as a pull-up voltage for generating the abnormality
signal XHOT and the diagnosis signal DIG-E. That is, when the wiring 197-11 for propagating
the abnormality signal XHOT and the diagnosis signal DIG-E and the wiring 197-24 for
propagating the voltage VDD2 are electrically coupled to the print head 21, the wiring
197-11 for propagating the abnormality signal XHOT and the diagnosis signal DIG-E
and the wiring 197-24 for propagating the voltage VDD2 are electrically coupled via
the terminals 353-11 and terminal 353-24 of the connector 350. In other words, in
the print head 21, the terminal 353-11 of the connector 350 is electrically coupled
to the terminal 353-24. Further, the contact section 180-11 and the contact section
180-24 are electrically coupled. The phrase of being electrically coupled is not limited
to a case of being directly or indirectly via a wiring pattern provided on the substrate
320 and includes, for example, a case of being electrically coupled via a resistor
element or a capacitor element.
[0164] Here, the voltage VDD1 is an example of a first voltage signal in the first embodiment.
The wiring 197-29 for propagating the voltage VDD1 is an example of a first voltage
signal propagation wiring in the first embodiment. The terminal 353-29 to which the
voltage VDD1 is input is an example of a sixth terminal in the first embodiment. The
contact section 180-29 at which the wiring 197-29 is electrically in contact with
the terminal 353-29 is an example of a sixth contact section in the first embodiment.
The voltage VDD2 is an example of a second voltage signal in the first embodiment.
The wiring 197-24 for propagating the voltage VDD2 is an example of a second voltage
signal propagation wiring in the first embodiment. The terminal 353-24 to which the
voltage VDD2 is input is an example of a seventh terminal in the first embodiment.
The contact section 180-24 at which the wiring 197-24 is electrically in contact with
the terminal 353-24 is an example of a seventh contact section in the first embodiment.
The voltage VHV is an example of a third voltage signal in the first embodiment. The
wiring 197-9 for propagating the voltage VHV is an example of a third voltage signal
propagation wiring in the first embodiment. The terminal 353-9 to which the voltage
VHV is input is an example of an eighth terminal in the first embodiment. The contact
section 180-9 at which the wiring 197-9 is electrically in contact with the terminal
353-9 is an example of an eighth contact section in the first embodiment.
[0165] The temperature signal TH is input to the terminal 353-27 of the connector 350 and
is input to the cable 19 via the contact section 180-27 and the terminal 196-27. The
temperature signal TH is propagated in the wiring 197-27, and then is input from the
terminal 195-27 to the main substrate 11.
[0166] The ground signal GND is input to the cable 19 from each of the terminals 195-10,
195-12, 195-14, 195-16, 195-18, 195-20, 195-22, 195-26, and 195-28 and is propagated
in each of the wirings 197-10, 197-12, 197-14, 197-16, 197-18, 197-20, 197-22, 197-26,
and 197-28. Then, the ground signal GND is input to each of the terminals 353-10,
353-12, 353-14, 353-16, 353-18, 353-20, 353-22, 353-26, and 353-28 of the connector
350 via each of the terminals 196-10, 196-12, 196-14, 196-16, 196-18, 196-20, 196-22,
196-26, and 196-28 and each of the contact sections 180-10, 180-12, 180-14, 180-16,
180-18, 180-20, 180-22, 180-26, and 180-28.
[0167] The voltages VHV and VDD1 are supplied to the driving signal selection circuit 200.
The voltages VHV and VDD1 are used as voltages for generating the various control
signals for controlling the operation of the driving signal selection circuit 200.
The driving signal selection circuit 200 selects or does not select the waveform of
the driving signal COM so as to generate the driving signal VOUT. Thus, the driving
signal selection circuit 200 operates at a high speed in accordance with a discharge
rate of the ink. Therefore, noise depending on the operation of the driving signal
selection circuit 200 may be superimposed on the voltages VHV and VDD1 used as the
power source voltage and the various control voltages of the driving signal selection
circuit 200.
[0168] On the contrary, the voltage VDD2 is supplied to the temperature abnormality detection
circuit 250. The voltage VDD2 is used as a power source voltage of the temperature
abnormality detection circuit 250 and as a pull-up voltage for generating the abnormality
signal XHOT and the diagnosis signal DIG-E. The logical levels of the abnormality
signal XHOT and the diagnosis signal DIG-E are L levels when at least any diagnosis
result of the diagnosis result of diagnosing whether or not the temperature of the
temperature abnormality detection circuit 250 is abnormal and the diagnosis result
in the diagnosis circuit 240 indicates abnormality. In addition, the logical levels
of the abnormality signal XHOT and the diagnosis signal DIG-E are H levels when both
the diagnosis results of the diagnosis result of diagnosing whether or not the temperature
of the temperature abnormality detection circuit 250 is abnormal and the diagnosis
result in the diagnosis circuit 240 are normal. In other words, the logical levels
of the abnormality signal XHOT and the diagnosis signal DIG-E do not change when abnormality
does not occur in the print head 21. Thus, the voltage VDD2 used as the power source
voltage of the temperature abnormality detection circuit 250 and the pull-up voltage
has a low possibility of noise being superimposed thereon.
[0169] The ground signal GND is a signal of a reference potential for a plurality of signals
including the voltages VHV, VDD1, and VDD2. Therefore, a current caused by the plurality
of signals including the voltages VHV, VDD1, and VDD2 flows in the wiring in which
the ground signal GND is propagated. That is, when noise caused by the operation of
the driving signal selection circuit 200 is superimposed on the voltages VHV and VDD1,
a current caused by the voltages VHV and VDD1 on which the noise is superimposed flows
in the wiring in which the ground signal GND is propagated. As a result, noise may
also be superimposed in the wiring in which the ground signal GND is propagated.
[0170] As described above, the voltage VDD2 is a signal having a more stable potential when
compared to the voltages VDD1 and VHV and the ground signal GND. As illustrated in
FIG. 20, in the print head control circuit 15 of the liquid discharge apparatus 1
in the first embodiment, the wiring 197-23 for propagating the diagnosis signal DIG-B
and the wiring 197-25 for propagating the diagnosis signal DIG-A are provided to be
aligned. The wiring 197-24 in which the voltage VDD2 being a stable potential is propagated
and the wiring 197-23 in which the diagnosis signal DIG-B is propagated are located
to be adjacent to each other in a direction in which the wiring 197-23 and the wiring
197-25 are aligned. In other words, the wiring 197-24 in which the voltage VDD2 being
a stable potential is propagated and the wiring 197-23 in which the diagnosis signal
DIG-B is propagated are provided in the same cable 19 and are located to be adjacent
to each other. Here, the phrase of being located to be adjacent includes a case in
which the wiring 197-23 and the wiring 197-24 in the cable 19 are located to be adjacent
to each other through the insulator 198, a space, or the like.
[0171] In the print head 21 of the liquid discharge apparatus 1 in the first embodiment,
the terminal 353-23 to which the diagnosis signal DIG-B is input and the terminal
353-25 to which the diagnosis signal DIG-A is input are provided to be aligned. Thus,
the terminal 353-24 to which the voltage VDD2 being a signal having a stable potential
is input and the terminal 353-23 to which the clock signal SCK is input are provided
to be adjacent to each other in a direction in which the terminal 353-23 and the terminal
353-25 are aligned. In other words, the terminal 353-23 to which the diagnosis signal
DIG-B is input and the terminal 353-24 to which the voltage VDD2 is input are provided
in the same connector 350 and are located to be adjacent to each other. Here, the
phrase of being located to be adjacent includes a case in which the terminal 353-23
and the terminal 353-24 in the connector 350 are located to be adjacent to each other
through an insulating member such as the housing 351, an internal space of the cable
attachment section 352, or the like.
[0172] That is, in the connector 350, the terminal 353-24 to which the voltage VDD2 is input
is located in the vicinity of the terminal 353-23 to which the diagnosis signal DIG-B
is input. In other words, in the connector 350, the shortest distance between the
terminal 353-23 and the terminal 353-24 is shorter than the shortest distance between
the terminal 353-23 and the terminal 353-29 to which the voltage VDD1 is input and
is shorter than the shortest distance between the terminal 353-23 and the terminal
353-9 to which the voltage VHV is input, in the direction in which the terminal 353-23
and the terminal 353-25 are aligned.
[0173] In the liquid discharge apparatus 1 in the first embodiment, the contact section
180-23 to which the diagnosis signal DIG-B is input and the contact section 180-25
to which the diagnosis signal DIG-A is input are provided to be aligned. Thus, the
contact section 180-24 to which the voltage VDD2 being a signal having a stable potential
is input and the contact section 180-23 to which the diagnosis signal DIG-B is input
are provided to be adjacent to each other in a direction in which the contact section
180-23 and the contact section 180-25 are aligned. In other words, the contact section
180-23 to which the diagnosis signal DIG-B is input and the contact section 180-24
to which the voltage VDD2 is input are included in the plurality of contact sections
180 at which the same cable 19 and the same connector 350 are electrically in contact
with each other, and are located to be adjacent to each other. Here, the phrase of
being located to be adjacent includes a case in which the contact section 180-23 and
the contact section 180-24 in the plurality of contact sections 180 at which the cable
19 and the connector 350 are electrically in contact with each other are located to
be adjacent to each other through an insulating member such as the housing 351, an
internal space, the insulator 198 in the cable 19, and the like.
[0174] That is, in the plurality of contact sections 180, the terminal 353-24 to which the
voltage VDD2 is input is located in the vicinity of the contact section 180-23 to
which the diagnosis signal DIG-B is input. In other words, in the connector 350, the
shortest distance between the terminal 353-23 and the terminal 353-24 is shorter than
the shortest distance between the terminal 353-23 and the terminal 353-29 to which
the voltage VDD1 is input and is shorter than the shortest distance between the terminal
353-23 and the terminal 353-9 to which the voltage VHV is input, in the direction
in which the terminal 353-23 and the terminal 353-25 are aligned.
[0175] In the print head control circuit 15, the print head 21, and the liquid discharge
apparatus 1 configured as described above, the wiring in which the voltage VDD2 having
a stable potential, the terminal to which the voltage VDD2 is input, and the contact
section at which the wiring and the terminal are in contact with each other are located
to be adjacent to the wiring in which the diagnosis signal DIG-B being one of the
signals for diagnosing whether or not normal discharge of the ink from the print head
21 is possible is propagated, the terminal to which the diagnosis signal DIG-B is
input, and the contact section at which the wiring and the terminal are in contact
with each other. Thus, a concern that the waveform of the diagnosis signal DIG-B is
distorted is reduced. Accordingly, it is possible to reduce a concern that the self-diagnosis
function of the print head 21 does not normally operate.
[0176] As illustrated in FIG. 20, preferably, the diagnosis signal DIG-B provided to be
adjacent to the voltage VDD2 is propagated in the common wiring 197-23 along with
the clock signal SCK, and then is input to the common terminal 353-23.
[0177] As described above, the clock signal SCK is a signal for defining a timing at which
the print data signal SI is input. Therefore, if noise is superimposed on the clock
signal SCK, and the waveform of the clock signal SCK is distorted, the timing of the
print data signal SI in synchronization with the clock signal SCK varies. As a result,
discharge accuracy of the ink discharged from the plurality of corresponding nozzles
651 is deteriorated. If the wiring 197-23 is provided to be adjacent to the wiring
197-24 in which the voltage VDD2 is propagated functions as the wiring for the diagnosis
signal DIG-B and the clock signal SCK, the concern that the waveform of the clock
signal SCK is distorted is reduced. Thus, it is possible to improve discharge accuracy
of the ink discharged from the print head 21.
[0178] Similarly, if the terminal 353-23 provided to be adjacent to the terminal 353-24
to which the voltage VDD2 is input functions as the terminal for the diagnosis signal
DIG-B and the clock signal SCK, the concern that the waveform of the clock signal
SCK is distorted is reduced. Similarly, if the contact section 180-23 provided to
be adjacent to the contact section 180-24 to which the voltage VDD2 is input functions
as the contact section to which the diagnosis signal DIG-B is input and as the contact
section to which the clock signal SCK is input, the concern that the waveform of the
clock signal SCK is distorted is reduced. Thus, it is possible to improve discharge
accuracy of the ink discharged from the print head 21.
[0179] As illustrated in FIG. 20, the followings are preferable. That is, the wiring 197-23
in which the diagnosis signal DIG-B is propagated and the wiring 197-22 in which the
ground signal GND is propagated are located to be adjacent to each other in the direction
in which the wiring 197-23 and the wiring 197-25 are aligned. The terminal 353-23
to which the diagnosis signal DIG-B is input and the terminal 353-22 to which the
ground signal GND is input are located to be adjacent to each other in the direction
in which the terminal 353-23 and the terminal 353-25 are aligned. The contact section
180-23 to which the diagnosis signal DIG-B is input and the contact section 180-22
to which the ground signal GND is input are located to be adjacent to each other in
the direction in which the contact section 180-23 and the contact section 180-25 are
aligned. In other words, the followings are preferable. That is, the wiring 197-23
in which the diagnosis signal DIG-B is propagated is located between the wiring 197-24
in which the voltage VDD2 is propagated and the wiring 197-22 in which the ground
signal GND is propagated, in the cable 19. In the connector 350, the terminal 353-23
to which the diagnosis signal DIG-B is input is located between the terminal 353-24
to which the voltage VDD2 is input and the terminal 353-22 to which the ground signal
GND is input. The contact section 180-23 to which the diagnosis signal DIG-B is input
is located between the contact section 180-24 to which the voltage VDD2 is input and
the contact section 180-22 to which the ground signal GND is input.
[0180] Thus, the wiring 197-22 in which the ground signal GND is propagated, the terminal
353-22 to which the ground signal GND is input, and the contact section 180-22 to
which the ground signal GND is input function as a shield that reduces interference
of other signals with the voltage VDD2. Accordingly, it is possible to more reduce
the concern that the waveform of the diagnosis signal DIG-B is distorted, and thus
to more reduce the concern that the self-diagnosis function of the print head 21 does
not normally operate. Here, the wiring 197-22 in which the ground signal GND is propagated
is an example of a first ground signal propagation wiring in the first embodiment.
The terminal 353-22 which is electrically coupled to the wiring 197-22 and to which
the ground signal GND is input is an example of a first ground terminal in the first
embodiment. The contact section 180-22 at which the wiring 197-22 and the terminal
353-22 are electrically in contact with each other is an example of a first ground
contact section in the first embodiment.
[0181] As illustrated in FIG. 20, the followings are preferable. That is, the wiring 197-24
in which the voltage VDD2 is propagated and the wiring 197-9 in which the voltage
VHV is propagated are not located to be adjacent to each other in the direction in
which the wiring 197-23 and the wiring 197-25 are aligned. The terminal 353-24 to
which the voltage VDD2 is input and the terminal 353-9 to which the voltage VHV is
input are not located to be adjacent to each other in the direction in which the terminal
353-23 and the terminal 353-25. The contact section 180-24 to which the voltage VDD2
is input and the contact section 180-9 to which the voltage VHV is input are not located
to be adjacent to each other in the direction in which the contact section 180-23
and the contact section 180-25 are aligned. Further, in this case, the followings
are preferable. That is, the wiring 197-9 in which the voltage VHV is propagated and
the wiring 197-10 in which the ground signal GND is propagated are located to be adjacent
to each other in the direction in which the wiring 197-23 and the wiring 197-25 are
aligned. The terminal 353-9 to which the voltage VHV is input and the terminal 353-10
to which the ground signal GND is input are located to be adjacent to each other in
the direction in which the terminal 353-23 and the terminal 353-25. The contact section
180-9 to which the voltage VHV is input and the contact section 180-10 to which the
ground signal GND is input are located to be adjacent to each other in the direction
in which the contact section 180-23 and the contact section 180-25 are aligned.
[0182] The voltage VHV has a voltage value larger than the voltages VDD1 and VDD2. Therefore,
when a noise component is superimposed on the voltage VHV, the noise component included
in the voltage VHV may interfere with the signal propagated in the wiring adjacent
to the wiring in which the voltage VHV is propagated, the signal input to the terminal
adjacent to the terminal to which the voltage VHV is input, and the signal input to
the contact section adjacent to the contact section to which the voltage VHV is input.
That is, when the wiring 197-24, the contact section 180-24, and the terminal 196-24
used for propagating and inputting the voltage VDD2 having a stable potential to the
print head 21 are adjacent to the wiring 197-11, the contact section 180-11, and the
terminal 196-11 used for propagating and inputting the voltage VHV to the print head
21, the noise component included in the voltage VHV may interfere with the voltage
VDD2 having a stable potential. Thus, when the noise component interferes with the
voltage VDD2, the waveform of the diagnosis signal DIG-B may be distorted.
[0183] As illustrated in FIG. 20, if the wiring 197-24 in which the voltage VDD2 is propagated
is not provided to be adjacent to the wiring 197-9 in which the voltage VHV is propagated,
the terminal 353-24 to which the voltage VDD2 is input is not provided to be adjacent
to the terminal 353-9 to which the voltage VHV is input, and the contact section 180-24
to which the voltage VDD2 is input is not provided to be adjacent to the contact section
180-9 to which the voltage VHV is input, it is possible to more reduce a concern that
the voltage VHV interferes with the voltage VDD2 being the signal having a stable
potential. Further, if the wiring 197-10 in which the ground signal GND is propagated
is provided to be adjacent to the wiring 197-9 in which the voltage VHV is propagated,
the terminal 353-10 to which the ground signal GND is input is provided to be adjacent
to the terminal 353-9 to which the voltage VHV is input, and the contact section 180-10
to which the ground signal GND is input is provided to be adjacent to the contact
section 180-9 to which the voltage VHV is input, the wiring 197-10, the terminal 353-10,
and the contact section 180-10 function as the shield. As a result, it is possible
to reduce a concern that the voltage VHV interferes with other signals including the
voltage VDD2. The wiring 197-10 in which the ground signal GND is propagated is an
example of a second ground signal propagation wiring in the first embodiment. The
terminal 353-10 to which the ground signal GND is input via the wiring 197-10 is an
example of a second ground terminal in the first embodiment. The contact section 180-10
at which the wiring 197-10 and the terminal 353-10 are electrically in contact with
each other is an example of a second ground contact section in the first embodiment.
[0184] Here, the connector 350 which is provided in the print head 21 and has the terminal
353-23, the terminal 353-25, the terminal 353-21, the terminal 353-19, and the terminal
353-11 is an example of a first connector in the first embodiment.
1.8. Advantageous Effects
[0185] As described above, in the print head control circuit 15 in the first embodiment,
the diagnosis signal DIG-A and the voltage VDD2 propagated in the same cable 19 are
provided to be adjacent to each other. Specifically, the wiring 197-23 for propagating
the diagnosis signal DIG-A and the wiring 197-24 in which the voltage VDD2 is propagated
are located to be adjacent to each other in the direction in which the wiring 197-23
and the wiring 197-25 are aligned.
[0186] The voltage VDD2 is a signal propagated in the wiring different from the wiring for
the voltage VDD1 supplied to the driving signal selection circuit 200 and is supplied
to the temperature abnormality detection circuit 250 that generates the abnormality
signal XHOT. The driving signal selection circuit 200 controls the supply of the driving
signal COM to the piezoelectric element 60. That is, the driving signal selection
circuit 200 operates at a high speed in accordance with a discharge rate of the ink
discharged from the nozzle. Thus, noise depending on the operation of the driving
signal selection circuit 200 may be superimposed on the voltage VDD1 supplied to the
driving signal selection circuit 200. The voltage VDD1 supplied to the driving signal
selection circuit 200 is fed back via the wiring in which the ground signal GND is
propagated. That is, when the noise caused by the operation of the driving signal
selection circuit 200 is superimposed on the voltage VDD1, a current caused by the
voltage VDD1 on which the noise is superimposed flows in the wiring in which the ground
signal GND is propagated.
[0187] On the contrary, the temperature abnormality detection circuit 250 diagnoses whether
or not temperature abnormality occurs in the print head 21 and outputs the abnormality
signal XHOT. Therefore, when the temperature of the print head 21 is within a normal
temperature range, the logical level does not change. Thus, the voltage VDD2 supplied
to the temperature abnormality detection circuit 250 is a signal having a potential
more stable than the voltage VDD1 and the ground signal GND.
[0188] Since the wiring 197-24 in which the voltage VDD2 having a stable potential as described
above is propagated and the wiring 197-23 for propagating the diagnosis signal DIG-B
are located to be adjacent to each other in the direction in which the wiring 197-23
and the wiring 197-25 are aligned, it is possible to reduce the concern that the waveform
of the diagnosis signal DIG-B is distorted in the cable 19. Thus, the diagnosis signal
DIG-B is input to the diagnosis circuit 240 with high accuracy. Accordingly, it is
possible to reduce the concern that the self-diagnosis function of the print head
21 does not normally operate.
[0189] Similarly, in the print head 21 in the first embodiment, the terminal 353-23 to which
the diagnosis signal DIG-B is input and the terminal 353-24 to which the voltage VDD2
is input are located to be adjacent to each other in the direction in which the terminal
353-23 and the terminal 353-25 are aligned. In addition, in the liquid discharge apparatus
1 in the first embodiment, the contact section 180-23 to which the diagnosis signal
DIG-B is input and the contact section 180-24 to which the voltage VDD2 is input are
located to be adjacent to each other in the direction in which the contact section
180-23 and the contact section 180-25 are aligned. With such a configuration, it is
possible to reduce the concern that the waveform of the diagnosis signal DIG-B is
distorted. Thus, the diagnosis signal DIG-B is input to the diagnosis circuit 240
with high accuracy. Accordingly, it is possible to reduce the concern that the self-diagnosis
function of the print head 21 does not normally operate.
2. Second Embodiment
[0190] Next, a liquid discharge apparatus 1, a print head control circuit 15, and a print
head 21 according to a second embodiment will be described. When the liquid discharge
apparatus 1, the print head control circuit 15, and the print head 21 in the second
embodiment are described, components similar to those in the first embodiment are
denoted by the same reference signs, and descriptions thereof will not be repeated
or will be briefly made.
[0191] FIG. 21 is a schematic diagram illustrating an internal configuration of the liquid
discharge apparatus 1 in the second embodiment when viewed from the γ-direction. As
illustrated in FIG. 21, in the second embodiment, the liquid discharge apparatus 1
includes a main substrate 11, cables 19a and 19b, and a print head 21. That is, the
liquid discharge apparatus 1 in the second embodiment is different from that in the
first embodiment in that the main substrate 11 and the print head 21 are electrically
coupled to each other by the two cables 19a and 19b, and thus various signals are
propagated in the cables 19a and 19b. In addition, the liquid discharge apparatus
1 in the second embodiment is different from that in the first embodiment in that
the main substrate 11 includes a connector 12a to which one end of the cable 19a is
attached and a connector 12b to which one end of the cable 19b is attached, and the
print head 21 includes a connector 350 to which the other end of the cable 19a is
attached and a connector 360 to which the other end of the cable 19b is attached.
[0192] Here, in the liquid discharge apparatus 1 in the second embodiment, a configuration
in which a control mechanism 10 that outputs various signals for controlling an operation
of the print head 21 and the cables 19a and 19b for propagating the various signals
for controlling the operation of the print head 21 are provided is an example of a
print head control circuit 15 that controls the operation of the print head 21 having
a function to perform self-diagnosis in the second embodiment.
[0193] The cables 19a and 19b have a configuration similar to that of the cable 19 in the
first embodiment except that the numbers of terminals 195 and 196 and wirings 197
are different. Therefore, detailed descriptions of the configuration of the cables
19a and 19b will not be repeated. In the following descriptions, a terminal 195-k
provided in the cables 19a and 19b is referred to as a terminal 195a-k and a terminal
195b-k. A terminal 196-k is referred to as a terminal 196a-k and a terminal 196b-k.
A wiring 197-k is referred to as a wiring 197a-k and a wiring 197b-k. A contact section
180-k is referred to as a contact section 180a-k and a contact section 180b-k. The
terminals 195a-k and 195b-k are electrically coupled to connectors 12a and 12b, respectively.
The terminals 196a-k and 196b-k are electrically coupled to the connectors 350 and
360 via the contact sections 180a-k and 180b-k, respectively.
[0194] In the second embodiment, descriptions will be made on the assumption that the print
head 21 includes six driving signal selection circuits 200-1 to 200-6. Thus, six print
data signals SI1 to SI6 respectively corresponding to the six driving signal selection
circuits 200-1 to 200-6, six driving signals COM1 to COM6, and six reference voltage
signals CGND1 to CGND6 are input to the print head 21 in the second embodiment.
[0195] FIG. 22 is a perspective view illustrating a configuration of the print head 21 in
the second embodiment. As illustrated in FIG. 22, the print head 21 includes a head
310 and a substrate 320. An ink discharge surface 311 on which the plurality of discharge
sections 600 are formed is located on a lower surface of the head 310 in the Z-direction.
[0196] The substrate 320 has a surface 321 and a surface 322 facing the surface 321 and
has a substantially rectangular shape formed by a side 323, a side 324 (facing the
side 323 in the X-direction), a side 325, and a side 326 (facing the side 325 in the
Y-direction). Similar to the first embodiment, an integrated circuit 241 constituting
a diagnosis circuit 240 is provided on the side 326 side of the surface 321 of the
substrate 320.
[0197] The connectors 350 and 360 are provided on the substrate 320. The connector 350 is
provided along the side 323 on the surface 321 side of the substrate 320. The connector
360 is provided along the side 323 on the surface 322 side of the substrate 320.
[0198] A configuration of the connectors 350 and 360 will be described with reference to
FIG. 23. FIG. 23 is a diagram illustrating the configuration of the connectors 350
and 360 in the second embodiment. The connector 350 includes a housing 351, a cable
attachment section 352 formed in the housing 351, and a plurality of terminals 353.
The plurality of terminals 353 is aligned in parallel along the side 323. Specifically,
26 terminals 353 are provided along the side 323 to be aligned. Here, the 26 terminals
353 are referred to as terminals 353-1, 353-2, ..., and 353-26 in order from the side
325 toward the side 326 in a direction along the side 323. The cable attachment section
352 is located on the substrate 320 side of the plurality of terminals 353 in the
Z-direction. The cable 19a is attached to the cable attachment section 352. When the
cable 19a is attached to the cable attachment section 352, terminals 196a-1 to 196a-26
in the cable 19a electrically come into contact with the terminals 353-1 to 353-26
in the connector 350, respectively. As illustrated in FIG. 18, in the connector 350,
the plurality of terminals 353 may be located on the substrate 320 side of the cable
attachment section 352 in the Z-direction.
[0199] The connector 360 includes a housing 361, a cable attachment section 362 formed in
the housing 361, and a plurality of terminals 363. The plurality of terminals 363
is aligned in parallel along the side 323. Specifically, 26 terminals 363 are provided
along the side 323 to be aligned. Here, the 26 terminals 363 are referred to as terminals
363-1, 363-2, ..., and 363-26 in order from the side 325 toward the side 326 in a
direction along the side 323. The cable attachment section 362 is located on the substrate
320 side of the plurality of terminals 363 in the Z-direction. The cable 19b is attached
to the cable attachment section 362. When the cable 19b is attached to the cable attachment
section 362, terminals 196b-1 to 196b-26 in the cable 19b electrically come into contact
with the terminals 363-1 to 363-26 in the connector 360, respectively.
[0200] Next, details of a signal which are propagated in each of the cables 19a and 19b
and is input to the print head 21 will be described with reference to FIGs. 24 and
25.
[0201] FIG. 24 is a diagram illustrating details of a signal propagated in the cable 19a
in the second embodiment. As illustrated in FIG. 24, the cable 19a includes wirings
for propagating driving signals COM1 to COM6, wirings for propagating reference voltage
signals CGND1 to CGND6, wirings for propagating a temperature signal TH, a latch signal
LAT, a clock signal SCK, a change signal CH, a print data signal SI1, and an abnormality
signal XHOT, wirings for propagating diagnosis signals DIG-A to DIG-E, a wiring for
propagating a voltage VHV, and a plurality of wirings for propagating a plurality
of ground signals GND.
[0202] Specifically, the driving signals COM1 to COM6 and the reference voltage signals
CGND1 to CGND6 are input from the terminals 195a-1 to 195a-12 to the cable 19a and
are propagated in the wiring 197a-1 to 197a-12, respectively. Then, the driving signals
COM1 to COM6 and the reference voltage signals CGND1 to CGND6 are input to the terminals
353-1 to 353-12 of the connector 350 via the terminals 196a-1 to 196a-12 and the contact
sections 180a-1 to 180a-12, respectively.
[0203] The diagnosis signal DIG-A and the latch signal LAT are input from the terminal 195a-23
to the cable 19a and are propagated in the wiring 197a-23. Then, the diagnosis signal
DIG-A and the latch signal LAT are input to the terminal 353-23 of the connector 350
via the terminal 196a-23 and the contact section 180a-23. That is, the wiring 197a-23
functions as a wiring for propagating the diagnosis signal DIG-A and a wiring for
propagating the latch signal LAT. The terminal 353-23 functions as a terminal to which
the diagnosis signal DIG-A is input and a terminal to which the latch signal LAT is
input. The contact section 180a-23 is electrically in contact with the wiring for
propagating the diagnosis signal DIG-A and is also electrically in contact with the
wiring for propagating the latch signal LAT. The diagnosis signal DIG-A is an example
of a second diagnosis signal in the second embodiment. The wiring 197a-23 for propagating
the diagnosis signal DIG-A is an example of a second diagnosis signal propagation
wiring in the second embodiment. The terminal 353-23 to which the diagnosis signal
DIG-A is input is an example of a second terminal in the second embodiment. The contact
section 180a-23 at which the wiring 197a-23 and the terminal 353-23 are electrically
in contact with each other is an example of a second contact section in the second
embodiment.
[0204] The diagnosis signal DIG-B and the clock signal SCK are input from the terminal 195a-21
to the cable 19a and are propagated in the wiring 197a-21. Then, the diagnosis signal
DIG-B and the clock signal SCK are input to the terminal 353-21 of the connector 350
via the terminal 196a-21 and the contact section 180a-21. That is, the wiring 197a-21
functions as a wiring for propagating the diagnosis signal DIG-B and a wiring for
propagating the clock signal SCK. The terminal 353-21 functions as a terminal to which
the diagnosis signal DIG-B is input and a terminal to which the clock signal SCK is
input. The contact section 180a-21 is electrically in contact with the wiring for
propagating the diagnosis signal DIG-B and is also electrically in contact with the
wiring for propagating the clock signal SCK. The diagnosis signal DIG-B is an example
of a first diagnosis signal in the second embodiment. The wiring 197a-21 for propagating
the diagnosis signal DIG-B is an example of a first diagnosis signal propagation wiring
in the second embodiment. The terminal 353-21 to which the diagnosis signal DIG-B
is input is an example of a first terminal in the second embodiment. The contact section
180a-21 at which the wiring 197a-21 and the terminal 353-21 are electrically in contact
with each other is an example of a first contact section in the second embodiment.
[0205] The diagnosis signal DIG-C and the change signal CH are input from the terminal 195a-19
to the cable 19a and are propagated in the wiring 197a-19. The diagnosis signal DIG-C
and the change signal CH are input to the terminal 353-19 of the connector 350 via
the terminal 196a-19 and the contact section 180a-19. That is, the wiring 197a-19
functions as a wiring for propagating the diagnosis signal DIG-C and a wiring for
propagating the change signal CH. The terminal 353-19 functions as a terminal to which
the diagnosis signal DIG-C is input and a terminal to which the change signal CH is
input. The contact section 180a-19 is electrically in contact with the wiring for
propagating the diagnosis signal DIG-C and is also electrically in contact with the
wiring for propagating the change signal CH. The diagnosis signal DIG-C is an example
of a third diagnosis signal in the second embodiment. The wiring 197a-19 for propagating
the diagnosis signal DIG-C is an example of a third diagnosis signal propagation wiring
in the second embodiment. The terminal 353-19 to which the diagnosis signal DIG-C
is input is an example of a third terminal in the second embodiment. The contact section
180a-19 at which the wiring 197a-19 and the terminal 353-19 are electrically in contact
with each other is an example of a third contact section in the second embodiment.
[0206] The diagnosis signal DIG-D and the print data signal SI1 are input from the terminal
195a-17 to the cable 19a and are propagated in the wiring 197a-17. Then, the diagnosis
signal DIG-D and the print data signal SI1 are input to the terminal 353-17 of the
connector 350 via the terminal 196a-17 and the contact section 180a-17. That is, the
wiring 197a-17 functions as a wiring for propagating the diagnosis signal DIG-D and
a wiring for propagating the print data signal Sl1. The terminal 353-17 functions
as a terminal to which the diagnosis signal DIG-D is input and a terminal to which
the print data signal SI1 is input. The contact section 180a-17 is electrically in
contact with the wiring for propagating the diagnosis signal DIG-D and is also electrically
in contact with the wiring for propagating the print data signal Sl1. The diagnosis
signal DIG-D is an example of a fourth diagnosis signal in the second embodiment.
The wiring 197a-17 for propagating the diagnosis signal DIG-D is an example of a fourth
diagnosis signal propagation wiring in the second embodiment. The terminal 353-17
to which the diagnosis signal DIG-D is input is an example of a fourth terminal in
the second embodiment. The contact section 180a-17 at which the wiring 197a-17 and
the terminal 353-17 are electrically in contact with each other is an example of a
fourth contact section in the second embodiment.
[0207] The diagnosis signal DIG-E and the abnormality signal XHOT are input to the terminal
353-15 of the connector 350, and then are input to the cable 19a via the contact section
180a-15 and the terminal 196a-15. The diagnosis signal DIG-E and the abnormality signal
XHOT are propagated in the wiring 197a-15, and then are input from the terminal 195a-15
to the main substrate 11. That is, the wiring 197a-15 functions as a wiring for propagating
the diagnosis signal DIG-E and a wiring for propagating the abnormality signal XHOT.
The terminal 353-15 functions as a terminal to which the diagnosis signal DIG-E is
input and a terminal to which the abnormality signal XHOT is input. The contact section
180a-15 is electrically in contact with the wiring for propagating the diagnosis signal
DIG-E and is also electrically in contact with the wiring for propagating the abnormality
signal XHOT. The diagnosis signal DIG-E is an example of a fifth diagnosis signal
in the second embodiment. The wiring 197a-15 for propagating the diagnosis signal
DIG-E is an example of a fifth diagnosis signal propagation wiring in the second embodiment.
The terminal 353-15 to which the diagnosis signal DIG-E is input is an example of
a fifth terminal in the second embodiment. The contact section 180a-15 at which the
wiring 197a-15 and the terminal 353-15 are electrically in contact with each other
is an example of a fifth contact section in the second embodiment.
[0208] The temperature signal TH is input to the terminal 353-25 of the connector 350, and
then is input to the cable 19a via the terminal 196a-25 and the contact section 180a-25.
The temperature signal TH is propagated in the wiring 197a-25, and then is input from
the terminal 195a-25 to the main substrate 11.
[0209] The voltage VHV is input from the terminal 195a-13 to the cable 19a and is propagated
in the wiring 197a-13. Then, the voltage VHV is input to the terminal 353-13 of the
connector 350 via the terminal 196a-13 and the contact section 180a-13. The voltage
VHV is an example of a third voltage signal in the second embodiment. The wiring 197a-13
for propagating the voltage VHV is an example of a third voltage signal propagation
wiring in the second embodiment. The terminal 353-13 to which the voltage VHV is input
is an example of an eighth terminal in the second embodiment. The contact section
180a-13 at which the wiring 197a-13 and the terminal 353-13 are electrically in contact
with each other is an example of an eighth contact section in the second embodiment.
[0210] The ground signal GND is input from each of the terminals 195a-14, 195a-16, 195a-18,
195a-20, 195a-22, 195a-24, and 195a-26 to the cable 19a and is propagated in each
of the wirings 197a-14, 197a-16, 197a-18, 197a-20, 197a-22, 197a-24, and 197a-26.
Then, the ground signal GND is input to each of the terminals 353-14, 353-16, 353-18,
353-20, 353-22, 353-24, and 353-26 of the connector 350 via each of the terminals
196a-14, 196a-16, 196a-18, 196a-20, 196a-22, 196a-24, and 196a-26 and each of the
contact sections 180a-14, 180a-16, 180a-18, 180a-20, 180a-22, 180a-24, and 180a-26.
[0211] Next, details of a signal propagated in the cable 19b will be described with reference
to FIG. 25. FIG. 25 is a diagram illustrating details of a signal propagated in a
cable 19b in the second embodiment. As illustrated in FIG. 25, the cable 19b includes
wirings for propagating the driving signals COM1 to COM6, wirings for propagating
the reference voltage signals CGND1 to CGND6, wirings for propagating print data signals
SI2 to SI6, wirings for propagating voltages VDD1 and VDD2, and a plurality of wirings
for propagating a plurality of ground signals GND.
[0212] Specifically, the driving signals COM1 to COM6 and the reference voltage signals
CGND1 to CGND6 are input from the terminals 195b-1 to 195b-12 to the cable 19b and
are propagated in the wiring 197b-1 to 197b-12, respectively. Then, the driving signals
COM1 to COM6 and the reference voltage signals CGND1 to CGND6 are input to the terminals
363-1 to 363-12 of the connector 360 via the terminals 196b-1 to 196b-12 and the contact
sections 180b-1 to 180b-12, respectively.
[0213] The print data signals SI2 to SI6 are input from the terminals 195b-24, 195b-22,
195b-20, 195b-18, and 195b-16 to the cable 19b, and are propagated in the wirings
197b-24, 197b-22, 197b-20, 197b-18, and 197b-16, respectively. Then, the print data
signals SI2 to SI6 are input to the terminals 363-24, 363-22, 363-20, 363-18, and
363-16 of the connector 360 via the terminals 196b-24, 196b-22, 196b-20, 196b-18,
and 196b-16 and the contact sections 180b-24, 180b-22, 180b-20, 180b-18, and 180b-16,
respectively.
[0214] The voltage VDD1 is input from the terminal 195b-26 to the cable 19b and is propagated
in the wiring 197b-26. Then, the voltage VDD1 is input to the terminal 363-26 of the
connector 360 via the terminal 196b-26 and the contact section 180b-26. Here, the
voltage VDD1 is an example of a first voltage signal in the second embodiment. The
wiring 197b-26 for propagating the voltage VDD1 is an example of a first voltage signal
propagation wiring in the second embodiment. The terminal 363-26 to which the voltage
VDD1 is input is an example of a sixth terminal in the second embodiment. The contact
section 180b-26 at which the wiring 197b-26 and the terminal 363-26 are electrically
in contact with each other is an example of a sixth contact section in the second
embodiment.
[0215] The voltage VDD2 is input from the terminal 195b-21 to the cable 19b and is propagated
in the wiring 197b-21. Then, the voltage VDD2 is input to the terminal 363-21 of the
connector 360 via the terminal 196b-21 and the contact section 180b-21. The voltage
VDD2 is an example of a second voltage signal in the second embodiment. The wiring
197b-21 for propagating the voltage VDD2 is an example of a second voltage signal
propagation wiring in the second embodiment. The terminal 363-21 to which the voltage
VDD2 is input is an example of a seventh terminal in the second embodiment. The contact
section 180b-21 at which the wiring 197b-21 and the terminal 363-21 are electrically
in contact with each other is an example of a seventh contact section in the second
embodiment.
[0216] The ground signal GND is input to the cable 19a from each of the terminals 195b-13,
195b-15, 195b-17, 195b-19, 195b-23, and 195b-25 and is propagated in each of the wirings
197b-13, 197b-15, 197b-17, 197b-19, 197b-23, and 197b-25. Then, the ground signal
GND is input to each of the terminals 363-13, 363-15, 363-17, 363-19, 363-23, and
363-25 of the connector 360 via each of the terminals 196b-13, 196b-15, 196b-17, 196b-19,
196b-23, and 196b-25 and each of the contact sections 180b-13, 180b-15, 180b-17, 180b-19,
180b-23, and 180b-25.
[0217] In the liquid discharge apparatus 1 in the second embodiment, as illustrated in FIGs.
24 and 25, in the print head control circuit 15, the wiring 197a-21 in which the diagnosis
signal DIG-B is propagated and the wiring 197b-21 in which the voltage VDD2 having
a stable potential is propagated are located to overlap each other in a direction
intersecting a direction in which the wiring 197a-21 and the wiring 197a-23 are aligned.
In other words, in the print head control circuit 15, the wiring 197a-21 in which
the diagnosis signal DIG-B is propagated and the wiring 197b-21 in which the voltage
VDD2 having a stable potential is propagated are provided in the cable 19a and the
cable 19b different from each other and are located to face each other.
[0218] In the print head 21, the terminal 353-21 to which the diagnosis signal DIG-B is
input and the terminal 363-21 to which the voltage VDD2 having a stable potential
is input are located to overlap each other in a direction intersecting a direction
in which the terminal 353-21 and the terminal 353-23 are aligned. In other words,
in the print head 21, the terminal 353-21 to which the diagnosis signal DIG-B is input
and the terminal 363-21 to which the voltage VDD2 is input are provided in the connector
350 and the connector 360 different from each other and are located to face each other.
[0219] In the liquid discharge apparatus 1, the contact section 180a-21 to which the diagnosis
signal DIG-B is input and the contact section 180b-21 to which the voltage VDD2 having
a stable potential is input are located to overlap each other in a direction intersecting
a direction in which the contact section 180a-21 and the contact section 180a-23 are
aligned. In other words, in the liquid discharge apparatus 1, the contact section
180a-21 to which the diagnosis signal DIG-B is input and the contact section 180b-21
to which the voltage VDD2 is input are provided in the connector 350 and the connector
360 different from each other and are located to face each other.
[0220] As described above, the wiring 197a-21 in which the diagnosis signal DIG-B being
one of the signals for diagnosing whether or not normal discharge of the ink from
the print head 21 is possible and the wiring 197b-21 in which the voltage VDD2 having
a stable potential is propagated are located to overlap each other in the direction
intersecting the direction in which the wiring 197a-21 and the wiring 197a-23 are
aligned. Thus, similar to the first embodiment, the concern that the waveform of the
diagnosis signal DIG-B is distorted is reduced. Similarly, since the terminal 353-21
to which the diagnosis signal DIG-B is input and the terminal 363-21 to which the
voltage VDD2 having a stable potential is input are located to overlap each other
in the direction intersecting the direction in which the terminal 353-21 and the terminal
353-23 are aligned, the concern that the waveform of the diagnosis signal DIG-B is
distorted is reduced, similar to the first embodiment. Similarly, since the contact
section 180a-21 to which the diagnosis signal DIG-B is input and the contact section
180b-21 to which the voltage VDD2 having a stable potential is input are located to
overlap each other in the direction intersecting the direction in which the contact
section 180a-21 and the contact section 180a-23 are aligned, the concern that the
waveform of the diagnosis signal DIG-B is distorted is reduced, similar to the first
embodiment. Accordingly, it is possible to reduce a concern that the self-diagnosis
function of the print head 21 does not normally operate.
[0221] Here, the phrase of being located to face each other may have the meaning that the
substrate 320, a housing 351 of the connector 350, a housing 361 of the connector
360, or the like is interposed between the wiring 197a-k and the wiring 197b-k, between
the terminal 353-k and the terminal 363-k, and between the contact section 180a-k
and the contact section 180b-k, in addition to the meaning that a space is provided
between the wiring 197a-k and the wiring 197b-k, between the terminal 353-k and the
terminal 363-k, and between the contact section 180a-k and the contact section 180b-k.
In other words, the phrase of being located to face each other means that another
wiring 197 is not located between the wiring 197a-k and the wiring 197b-k, other terminals
353 and 363 are not located between the terminal 353-k and the terminal 363-k, and
another contact section 180 is not located between the contact section 180a-k and
the contact section 180b-k, when viewed from a specific direction.
[0222] That is, when the wiring 197a-21 in which the diagnosis signal DIG-B being one of
the signals for diagnosing whether or not normal discharge of the ink from the print
head 21 is possible is propagated and the wiring 197b-21 in which the voltage VDD2
having a stable potential is propagated are provided in the cables 19a and 19b different
from each other, the wiring 197a-21 and the wiring 197b-21 are located in the vicinity
of each other. In other words, the shortest distance between the wiring 197a-21 provided
in the cable 19a and the wiring 197b-21 provided in the cable 19b is shorter than
the shortest distance between the wiring 197a-21 provided in the cable 19a and the
wiring provided in the cable 19b other than the wiring 197b-21.
[0223] When the terminal 353-21 to which the diagnosis signal DIG-B being one of the signals
for diagnosing whether or not normal discharge of the ink from the print head 21 is
possible is input and the terminal 363-21 to which the voltage VDD2 having a stable
potential is input are provided in the connectors 350 and 360 different from each
other, the terminal 353-21 and the terminal 363-21 are located in the vicinity of
each other. In other words, the shortest distance between the terminal 353-21 provided
in the connector 350 and the terminal 363-21 provided in the connector 360 is shorter
than the shortest distance between the terminal 353-21 and the terminal 363 provided
in the connector 360 other than the terminal 363-21.
[0224] Similarly, when the contact section 180a-21 to which the diagnosis signal DIG-B being
one of the signals for diagnosing whether or not normal discharge of the ink from
the print head 21 is possible is input is provided in the plurality of contact sections
180a at which the cable 19a and the connector 350 are electrically in contact with
each other, and the contact section 180b-21 to which the voltage VDD2 having a stable
potential is input are provided in the plurality of contact sections 180b which is
different from the plurality of contact sections 180a and at which the cable 19b and
the connector 360 are electrically in contact with each other, the contact section
180a-21 and the contact section 180b-21 are located in the vicinity of each other.
In other words, the shortest distance between the contact section 180a-21 in the plurality
of contact sections 180a at which the cable 19a and the connector 350 are electrically
in contact with each other, and the contact section 180b-21 in the plurality of contact
sections 180b at which the cable 19b and the connector 360 are electrically in contact
with each other is shorter than the shortest distance between the contact section
180a-21 and the contact section 180b in the plurality of contact sections 180b other
than the contact section 180b-21.
[0225] In the liquid discharge apparatus 1 in the second embodiment, the descriptions are
made on the assumption that the wiring 197a-k of the cable 19a and the wiring 197b-k
of the cable 19b are located to face each other, the terminal 353-k of the connector
350 and the terminal 363-k of the connector 360 are located to face each other, and
the contact section 180a-k and the contact section 180b-k are located to face each
other. However, the embodiment is not limited thereto.
[0226] As illustrated in FIGs. 24 and 25, the wiring 197a-21 in which the diagnosis signal
DIG-B is propagated and the wiring 197a-22 in which the ground signal GND is propagated
are preferably located to be adjacent to each other in the direction in which the
wiring 197a-21 and the wiring 197a-23 are aligned. In other words, preferably, the
wiring 197a-21 in which the diagnosis signal DIG-B is propagated and the wiring 197a-22
in which the ground signal GND is propagated are provided in the same cable 19a and
are located to be adjacent to each other. The terminal 353-21 to which the diagnosis
signal DIG-B is input and the terminal 353-22 to which the ground signal GND is input
are preferably located to be adjacent to each other in the direction in which the
terminal 353-21 and the terminal 353-23 are aligned. In other words, preferably, the
terminal 353-21 to which the diagnosis signal DIG-B is input and the terminal 353-22
to which the ground signal GND is input are provided in the same connector 350 and
are located to be adjacent to each other. The contact section 180a-21 to which the
diagnosis signal DIG-B is input and the contact section 180a-22 to which the ground
signal GND is input are preferably located to be adjacent to each other in the direction
in which the contact section 180a-21 and the contact section 180a-23 are aligned.
In other words, preferably, the contact section 180a-21 to which the diagnosis signal
DIG-B is input and the contact section 180a-22 to which the ground signal GND is input
are provided in the plurality of contact sections 180a at which the cable 19a and
the connector 350 are electrically in contact with each other, and are located to
be adjacent to each other.
[0227] Thus, the wiring 197a-22 in which the ground signal GND is propagated, the terminal
353-22 to which the ground signal GND is input, and the contact section 180a-22 to
which the ground signal GND is input function as a shield that reduces interference
of other signals with the voltage VDD2. Accordingly, it is possible to more reduce
the concern that the waveform of the diagnosis signal DIG-B is distorted, and thus
to more reduce the concern that the self-diagnosis function of the print head 21 does
not normally operate. The wiring 197a-22 in which the ground signal GND is propagated
is an example of a first ground signal propagation wiring in the second embodiment.
The terminal 353-22 to which the ground signal GND is input is an example of a first
ground terminal in the second embodiment. The contact section 180a-22 at which the
wiring 197a-22 and the terminal 353-22 are electrically in contact with each other
is an example of a first ground contact section in the second embodiment.
[0228] As illustrated in FIGs. 23 and 24, preferably, the wiring 197b-21 in which the voltage
VDD2 is propagated and the wiring 197a-13 in which the voltage VHV is propagated are
not located to be adjacent to each other in a direction perpendicular to the direction
in which the wiring 197a-21 and the wiring 197a-23 are aligned. In other words, preferably,
the wiring 197b-21 in which the voltage VDD2 is propagated and the wiring 197a-13
in which the voltage VHV is propagated are provided in the cable 19a and the cable
19b different from each other and are not located to face each other. Preferably,
the terminal 363-21 to which the voltage VDD2 is input and the terminal 353-13 to
which the voltage VHV is input are not located to be adjacent to each other in a direction
perpendicular to the direction in which the terminal 353-21 and the terminal 353-23
are aligned. In other words, preferably, the terminal 363-21 to which the voltage
VDD2 is input and the terminal 353-13 to which the voltage VHV is input are provided
in the connector 350 and the connector 360 different from each other and are not located
to face each other. Preferably, the contact section 180b-21 to which the voltage VDD2
is input and the contact section 180a-13 to which the voltage VHV is input are not
located to be adjacent to each other in a direction perpendicular to the direction
in which the contact section 180a-21 and the contact section 180a-23 are aligned.
In other words, preferably, the contact section 180b-21 to which the voltage VDD2
is input and the contact section 180a-13 to which the voltage VHV is input are provided
in the plurality of contact sections 180a at which the cable 19a and the connector
350 are electrically in contact with each other, and the plurality of contact sections
180b which is different from the plurality of contact sections 180a and at which the
cable 19b different from the cable 19a and the connector 360 different from the connector
350 are electrically in contact with each other, and are not located to face each
other.
[0229] Further, in this case, the wiring 197a-13 in which the voltage VHV is propagated
and the wiring 197b-13 in which the ground signal GND is propagated are preferably
located to be adjacent to each other in the direction intersecting the direction in
which the wiring 197a-21 and the wiring 197a-23 are aligned. In other words, preferably,
the wiring 197a-13 in which the voltage VHV is propagated and the wiring 197b-13 in
which the ground signal GND is propagated are provided in the cable 19a and the cable
19b different from each other and are located to face each other. The terminal 353-13
to which the voltage VHV is input and the terminal 363-13 to which the ground signal
GND is input are preferably located to be adjacent to each other in the direction
intersecting the direction in which the terminal 353-21 and the terminal 353-23 are
aligned. In other words, preferably, the terminal 353-13 to which the voltage VHV
is input and the terminal 363-13 to which the ground signal GND is input are provided
in the connector 350 and the connector 360 different from each other and are located
to face each other. The contact section 180a-13 to which the voltage VHV is input
and the contact section 180b-13 to which the ground signal GND is input are preferably
located to be adjacent to each other in the direction intersecting the direction in
which the contact section 180a-21 and the contact section 180a-23 are aligned. In
other words, preferably, the contact section 180a-13 to which the voltage VHV is input
and the contact section 180b-13 to which the ground signal GND is input are provided
in the plurality of contact sections 180a at which the cable 19a and the connector
350 are electrically in contact with each other and the plurality of contact sections
180b which is different from the plurality of contact sections 180a and at which the
cable 19b different from the cable 19a and the connector 360 different from the connector
350 are electrically in contact with each other, and are located to face each other.
[0230] The voltage VHV has a voltage value larger than the voltages VDD1 and VDD2. Therefore,
when a noise component is superimposed on the voltage VHV, the noise component included
in the voltage VHV may interfere with the signal propagated in the wiring facing the
wiring in which the voltage VHV is propagated and the signal input to the terminal
facing the terminal to which the voltage VHV is input. Therefore, when the wiring
197b-21 for propagating the voltage VDD2 having a stable potential is located to face
the wiring 197a-13 in which the voltage VHV is propagated, the noise component included
in the voltage VHV may interfere with the voltage VDD2. Thus, when the noise component
interferes with the voltage VDD2, the waveform of the diagnosis signal DIG-B may be
distorted.
[0231] As illustrated in FIGs. 24 and 25, in the print head control circuit 15, the print
head 21, and the liquid discharge apparatus 1 in the second embodiment, the wiring
197b-21 in which the voltage VDD2 is propagated is not provided to face the wiring
197a-13 in which the voltage VHV is propagated, the terminal 363-21 to which the voltage
VDD2 is input is not provided to face the terminal 353-13 to which the voltage VHV
is input, and the contact section 180b-21 to which the voltage VDD2 is input is not
provided to face the contact section 180a-13 to which the voltage VHV is input. With
such a configuration, it is possible to reduce a concern that the voltage VHV interferes
with the voltage VDD2 being a signal having a stable potential.
[0232] Further, the wiring 197b-13 in which the ground signal GND is propagated is provided
to face the wiring 197-11 in which the voltage VHV is propagated, the terminal 363-13
to which the ground signal GND is input is provided to face the terminal 353-13 to
which the voltage VHV is input, and the contact section 180b-13 to which the ground
signal GND is input is provided to face the contact section 180a-13 to which the voltage
VHV is input. With such a configuration, similar to the first embodiment, it is possible
to reduce the concern that the voltage VHV interferes with other signals including
the voltage VDD2. The wiring 197b-13 in which the ground signal GND is propagated
is an example of a second ground signal propagation wiring in the second embodiment.
The terminal 363-13 to which the ground signal GND is input via the wiring 197b-13
is an example of a second ground terminal in the second embodiment. The contact section
180b-13 at which the wiring 197b-13 and the terminal 363-13 are electrically in contact
with each other is an example of a second ground signal contact section in the second
embodiment.
[0233] Here, the connector 350 which is provided in the print head 21 and has the terminal
353-21, the terminal 353-23, the terminal 353-19, and the terminal 353-17 is an example
of a first connector in the second embodiment.
3. Third Embodiment
[0234] Next, a liquid discharge apparatus 1, a print head control circuit 15, and a print
head 21 according to a third embodiment will be described. When the liquid discharge
apparatus 1, the print head control circuit 15, and the print head 21 in the third
embodiment are described, components similar to those in the first embodiment are
denoted by the same reference signs, and descriptions thereof will not be repeated
or will be briefly made.
[0235] FIG. 26 is a block diagram illustrating an electrical configuration of the liquid
discharge apparatus 1 in the third embodiment. As illustrated in FIG. 26, a control
circuit 100 in the third embodiment is different from that in the first embodiment
in that the control circuit 100 generates two latch signals LAT1 and LAT2 for defining
a discharge timing of the print head 21, two change signals CH1 and CH2 for defining
a waveform switching timing of the driving signal COM, and two clock signals SCK1
and SCK2 for defining a timing at which a print data signal SI is input, and outputs
the generated signals to the print head 21. The control circuit 100 in the third embodiment
is different from that in the first embodiment in that the control circuit 100 generates
diagnosis signals DIG-A to DIG-D and DIG-F to DIG-I used when the print head 21 diagnoses
whether or not normal discharge of a liquid is possible, and outputs the generated
signals to the print head 21.
[0236] In the third embodiment, in the liquid discharge apparatus 1, the diagnosis signal
DIG-A and the latch signal LAT1 are output to a diagnosis circuit 240 in the print
head 21 via a common wiring. The diagnosis signal DIG-B and the clock signal SCK1
are output to the diagnosis circuit 240 via a common wiring. The diagnosis signal
DIG-C and the change signal CH1 are output to the diagnosis circuit 240 via a common
wiring. The diagnosis signal DIG-D and the print data signal SI1 are output to the
diagnosis circuit 240 via a common wiring. The diagnosis signal DIG-F and the latch
signal LAT2 are output to the diagnosis circuit 240 via a common wiring. The diagnosis
signal DIG-G and the clock signal SCK2 are output to the diagnosis circuit 240 via
a common wiring. The diagnosis signal DIG-H and the change signal CH2 are output to
the diagnosis circuit 240 via a common wiring. The diagnosis signal DIG-I and the
print data signal SIn are output to the diagnosis circuit 240 via a common wiring.
[0237] The diagnosis circuit 240 diagnoses whether or not normal discharge of the ink is
possible, based on the diagnosis signals DIG-A to DIG-D and the diagnosis signals
DIG-F to DIG-I. When the diagnosis circuit 240 diagnoses that the normal discharge
of the ink is possible in the print head 21, based on the diagnosis signals DIG-A
to DIG-D, the latch signal LAT1, the clock signal SCK1, and the change signal CH1
input along with the diagnosis signals DIG-A to DIG-C via the common wirings are output
as a latch signal cLAT1, a clock signal cSCK1, and a change signal cCH1. When the
diagnosis circuit 240 diagnoses that the normal discharge of the ink is possible in
the print head 21, based on the diagnosis signals DIG-F to DIG-I, the latch signal
LAT2, the clock signal SCK2, and the change signal CH2 input along with the diagnosis
signals DIG-F to DIG-H via the common wirings are output as a latch signal cLAT2,
a clock signal cSCK2, and a change signal cCH2.
[0238] Here, the print data signal SI1 input along with the diagnosis signal DIG-D via the
common wiring among the signals input to the diagnosis circuit 240 is branched in
the print head 21. One branched signal is input to the diagnosis circuit 240, and
the other is input to the driving signal selection circuit 200-1. The print data signal
SIn input along with the diagnosis signal DIG-I via the common wiring among the signals
input to the diagnosis circuit 240 is branched in the print head 21. One branched
signal is input to the diagnosis circuit 240, and the other is input to the driving
signal selection circuit 200-n.
[0239] FIG. 27 is a schematic diagram illustrating an internal configuration of the liquid
discharge apparatus 1 in the third embodiment when viewed from the Y-direction. As
illustrated in FIG. 27, the liquid discharge apparatus 1 in the third embodiment includes
a main substrate 11, cables 19a, 19b, 19c, and 19d, and a print head 21. That is,
the liquid discharge apparatus 1 in the third embodiment is different from that in
the first embodiment in that the main substrate 11 and the print head 21 are electrically
coupled to each other by the four cables 19a, 19b, 19c, and 19d, and various signals
are propagated in the four cables 19a, 19b, 19c, and 19d. The liquid discharge apparatus
1 in the third embodiment is different from that in the first embodiment in that the
main substrate 11 includes a connector 12a to which one end of the cable 19a is attached,
a connector 12b to which one end of the cable 19b is attached, a connector 12c to
which one end of the cable 19c is attached, and a connector 12d to which one end of
the cable 19d is attached, and the print head 21 includes a connector 350 to which
the other end of the cable 19a is attached, a connector 360 to which the other end
of the cable 19b is attached, a connector 370 to which the other end of the cable
19c is attached, and a connector 380 to which the other end of the cable 19d is attached.
[0240] Here, in the liquid discharge apparatus 1 in the third embodiment, a configuration
in which a control mechanism 10 that outputs various signals for controlling an operation
of the print head 21 and the cables 19a, 19b, 19c, and 19d for propagating the various
signals for controlling the operation of the print head 21 are provided is an example
of a print head control circuit 15 that controls the operation of the print head 21
having a function to perform self-diagnosis in the third embodiment.
[0241] The cables 19a, 19b, 19c, and 19d have a configuration similar to that of the cable
19 in the first embodiment except that the numbers of terminals 195 and 196 and wirings
197 are different. Therefore, detailed descriptions of the configuration of the cables
19a, 19b, 19c, and 19d will not be repeated. In the following descriptions, a terminal
195-k provided in the cables 19a, 19b, 19c, and 19d is referred to as terminals 195a-k,
195b-k, 195c-k, and 195d-k. A terminal 196-k is referred to as terminals 196a-k, 196b-k,
196c-k, and 196d-k. A wiring 197-k is referred to as wirings 197a-k, 197b-k, 197c-k,
and 197d-k. A contact section 180-k is referred to as contact sections 180a-k, 180b-k,
180c-k, and 180d-k. The terminals 195a-k, 195b-k, 195c-k, and 195b-k are electrically
coupled to the connectors 12a, 12b, 12c, and 12d, respectively. The terminals 196a-k,
196b-k, 196c-k, and 196d-k are electrically coupled to the connectors 350, 360, 370,
and 380 via the contact sections 180a-k, 180b-k, 180c-k, and 180d-k, respectively.
[0242] In the third embodiment, descriptions will be made on the assumption that the print
head 21 includes ten driving signal selection circuits 200-1 to 200-10. Thus, 10 print
data signals SI1 to SI10 respectively corresponding to the ten driving signal selection
circuits 200-1 to 200-10, 10 driving signals COM1 to COM10, and 10 reference voltage
signals CGND1 to CGND10 are input to the print head 21 in the third embodiment.
[0243] FIG. 28 is a perspective view illustrating a configuration of the print head 21 in
the third embodiment. As illustrated in FIG. 28, the print head 21 includes a head
310 and a substrate 320. An ink discharge surface 311 on which the plurality of discharge
sections 600 are formed is located on a lower surface of the head 310 in the Z-direction.
[0244] The substrate 320 has a surface 321 and a surface 322 facing the surface 321 and
has a substantially rectangular shape formed by a side 323, a side 324 (facing the
side 323 in the X-direction), a side 325, and a side 326 (facing the side 325 in the
Y-direction). Similar to the first embodiment, an integrated circuit 241 constituting
a diagnosis circuit 240 is provided on the side 326 side of the surface 321 of the
substrate 320.
[0245] The connectors 350, 360, 370, and 380 are provided on the substrate 320. The connector
350 is provided along the side 323 on the surface 321 side of the substrate 320. The
connector 360 is provided along the side 323 on the surface 322 side of the substrate
320. Here, the third embodiment is different from the second embodiment in that the
number of a plurality of terminals included in each of the connector 350 and the connector
360 is 20. Other components of the connector 350 or the connector 360 are similar
to those illustrated in FIG. 23. Therefore, detailed descriptions of the connector
350 and the connector 360 in the third embodiment will not be repeated. In the third
embodiment, 20 terminals 353 provided in the connector 350 to be aligned are referred
to as terminals 353-1, 353-2, ..., and 353-20 in order from the side 325 toward the
side 326 in a direction along the side 323. 20 terminals 363 provided in the connector
360 to be aligned are referred to as terminals 363-1, 363-2, ..., and 363-20 in order
from the side 325 toward the side 326 in a direction along the side 323.
[0246] The connector 370 is provided along the side 324 on the surface 321 side of the substrate
320. The connector 380 is provided along the side 324 on the surface 322 side of the
substrate 320.
[0247] A configuration of the connectors 370 and 380 will be described with reference to
FIG. 29. FIG. 29 is a diagram illustrating the configuration of the connectors 370
and 380 in the third embodiment. The connector 370 includes a housing 371, a cable
attachment section 372 formed in the housing 371, and a plurality of terminals 373.
The plurality of terminals 373 is provided to be aligned along the side 324. Specifically,
20 terminals 373 are provided to be aligned along the side 324. Here, the 20 terminals
373 are referred to as terminals 373-1, 373-2, ..., and 373-20 in order from the side
325 toward the side 326 in a direction along the side 324. The cable attachment section
372 is located on the substrate 320 side of the plurality of terminals 373 in the
Z-direction. The cable 19c is attached to the cable attachment section 372. When the
cable 19c is attached to the cable attachment section 372, the terminals 196c-1 to
196c-20 in the cable 19c are electrically coupled to the terminals 373-1 to 373-20
in the connector 370, respectively. Similar to FIG. 18, in the connector 370, the
plurality of terminals 373 may be located on the substrate 320 side of the cable attachment
section 352 in the Z-direction.
[0248] The connector 380 includes a housing 381, a cable attachment section 382 formed in
the housing 381, and a plurality of terminals 383. The plurality of terminals 383
is provided to be aligned along the side 324. Specifically, 20 terminals 383 are provided
to be aligned along the side 324. Here, the 20 terminals 383 are referred to as terminals
383-1, 383-2, ..., and 383-20 in order from the side 325 toward the side 326 in a
direction along the side 324. The cable attachment section 382 is located on the substrate
320 side of the plurality of terminals 383 in the Z-direction. The cable 19d is attached
to the cable attachment section 382. When the cable 19d is attached to the cable attachment
section 382, the terminals 196d-1 to 196d-20 in the cable 19d are electrically coupled
to the terminals 383-1 to 383-20 in the connector 380, respectively.
[0249] Next, details of a signal which are propagated in each of the cables 19a, 19b, 19c,
and 19d and is input to the print head 21 will be described with reference to FIGs.
30 to 33.
[0250] FIG. 30 is a diagram illustrating details of a signal propagated in the cable 19a
in the third embodiment. As illustrated in FIG. 30, the cable 19a includes wirings
for propagating driving signals COM1 to COM5, wirings for propagating reference voltage
signals CGND1 to CGND5, wirings for propagating a temperature signal TH, a latch signal
LAT1, a clock signal SCK1, a change signal CH1, and a print data signal SI1, wirings
for propagating diagnosis signals DIG-A to DIG-D, and a plurality of wirings for propagating
a plurality of ground signals GND.
[0251] Specifically, the driving signals COM1 to COM5 and the reference voltage signals
CGND1 to CGND5 are input from the terminals 195a-1 to 195a-10 to the cable 19a and
are propagated in the wirings 197a-1 to 197a-10, respectively. Then, the driving signals
COM1 to COM5 and the reference voltage signals CGND1 to CGND5 are input to the terminals
353-1 to 353-10 of the connector 350 via the terminals 196a-1 to 196a-10 and the contact
sections 180a-1 to 180a-10, respectively.
[0252] The diagnosis signal DIG-A and the latch signal LAT1 are input from the terminal
195a-17 to the cable 19a and are propagated in the wiring 197a-17. Then, the diagnosis
signal DIG-A and the latch signal LAT1 are input to the terminal 353-17 of the connector
350 via the terminal 196a-17 and the contact section 180a-17. That is, the wiring
197a-17 functions as a wiring for propagating the diagnosis signal DIG-A and a wiring
for propagating the latch signal LAT1. The terminal 353-17 functions as a terminal
to which the diagnosis signal DIG-A is input and a terminal to which the latch signal
LAT1 is input. The contact section 180a-17 is electrically in contact with the wiring
for propagating the diagnosis signal DIG-A and is also electrically in contact with
the wiring for propagating the latch signal LAT1.
[0253] The diagnosis signal DIG-B and the clock signal SCK1 are input from the terminal
195a-15 to the cable 19a and are propagated in the wiring 197a-15. The diagnosis signal
DIG-B and the clock signal SCK1 are input to the terminal 353-15 of the connector
350 via the terminal 196a-15 and the contact section 180a-15. That is, the wiring
197a-15 functions as a wiring for propagating the diagnosis signal DIG-B and a wiring
for propagating the clock signal SCK1. The terminal 353-15 functions as a terminal
to which the diagnosis signal DIG-B is input and a terminal to which the clock signal
SCK1 is input. The contact section 180a-15 is electrically in contact with the wiring
for propagating the diagnosis signal DIG-B and is also electrically in contact with
the wiring for propagating the clock signal SCK1.
[0254] The diagnosis signal DIG-C and the change signal CH1 are input from the terminal
195a-13 to the cable 19a and are propagated in the wiring 197a-13. Then, the diagnosis
signal DIG-C and the change signal CH1 are input to the terminal 353-13 of the connector
350 via the terminal 196a-13 and the contact section 180a-13. That is, the wiring
197a-13 functions as a wiring for propagating the diagnosis signal DIG-C and a wiring
for propagating the change signal CH1. The terminal 353-13 functions as a terminal
to which the diagnosis signal DIG-C is input and a terminal to which the change signal
CH1 is input. The contact section 180a-13 is electrically in contact with the wiring
for propagating the diagnosis signal DIG-C and is also electrically in contact with
the wiring for propagating the change signal CH1.
[0255] The diagnosis signal DIG-D and the print data signal SI1 are input from the terminal
195a-11 to the cable 19a and are propagated in the wiring 197a-11. Then, the diagnosis
signal DIG-D and the print data signal SI1 are input to the terminal 353-11 of the
connector 350 via the terminal 196a-11 and the contact section 180a-11. That is, the
wiring 197a-11 functions as a wiring for propagating the diagnosis signal DIG-D and
a wiring for propagating the print data signal Sl1. The terminal 353-11 functions
as a terminal to which the diagnosis signal DIG-D is input and a terminal to which
the print data signal SI1 is input. The contact section 180a-11 is electrically in
contact with the wiring for propagating the diagnosis signal DIG-D and is also electrically
in contact with the wiring for propagating the print data signal Sl1.
[0256] The temperature signal TH is input to the terminal 353-19 of the connector 350 and
then is input to the cable 19a via the contact section 180a-19 and the terminal 196a-19.
The temperature signal TH is propagated in the wiring 197a-19 and then is input from
the terminal 195a-19 to the main substrate 11.
[0257] The ground signal GND is input to the cable 19a from each of the terminals 195a-12,
195a-14, 195a-16, 195a-18, and 195a-20 and is propagated in each of the wirings 197a-12,
197a-14, 197a-16, 197a-18, and 197a-20. Then, the ground signal GND is input to each
of the terminals 353-12, 353-14, 353-16, 353-18, and 353-20 of the connector 350 via
each of the terminals 196a-12, 196a-14, 196a-16, 196a-18, and 196a-20 and each of
the contact sections 180a-12, 180a-14, 180a-16, 180a-18, and 180a-20.
[0258] FIG. 31 is a diagram illustrating details of a signal propagated in the cable 19b
in the third embodiment. As illustrated in FIG. 31, the cable 19b includes wirings
for propagating the driving signals COM1 to COM5, wirings for propagating the reference
voltage signals CGND1 to CGND5, wirings for propagating print data signals SI2 to
SI5, a wiring for propagating a voltage VDD1, and a plurality of wirings for propagating
a plurality of ground signals GND.
[0259] Specifically, the driving signals COM1 to COM5 and the reference voltage signals
CGND1 to CGND5 are input from the terminals 195b-1 to 195b-10 to the cable 19b and
are propagated in the wiring 197b-1 to 197b-10, respectively. Then, the driving signals
COM1 to COM5 and the reference voltage signals CGND1 to CGND5 are input to the terminals
363-1 to 363-10 of the connector 360 via the terminals 196b-1 to 196b-10 and the contact
sections 180b-1 to 180b-10, respectively.
[0260] The print data signals SI2 to SI5 are input to the cable 19b from the terminals 195b-18,
195b-16, 195b-14, and 195b-12 and are propagated in the wirings 197b-18, 197b-16,
197b-14, and 197b-12, respectively. Then, the print data signals SI2 to SI5 are input
to the terminals 363-18, 363-16, 363-14, and 363-12 of the connector 360 via the terminals
196b-18, 196b-16, 196b-14, and 196b-12 and the contact sections 180b-18, 180b-16,
180b-14, and 180b-12, respectively.
[0261] The voltage VDD1 is input from the terminal 195b-20 to the cable 19b and is propagated
in the wiring 197b-20. Then, the voltage VDD1 is input to the terminal 363-20 of the
connector 360 via the terminal 196b-20 and the contact section 180b-20. Here, the
voltage VDD1 is an example of a first voltage signal in the third embodiment. The
wiring 197b-20 for propagating the voltage VDD1 is an example of a first voltage signal
propagation wiring in the third embodiment. The terminal 363-20 to which the voltage
VDD1 is input is an example of a sixth terminal in the third embodiment. The contact
section 180b-20 at which the wiring 197b-20 and the terminal 363-20 are electrically
in contact with each other is an example of a sixth contact section in the third embodiment.
[0262] The ground signal GND is input to the cable 19b from each of the terminals 195b-11,
195b-13, 195b-15, 195b-17, and 195b-19 and is propagated in each of the wirings 197b-11,
197b-13, 197b-15, 197b-17, and 197b-19. Then, the ground signal GND is input to each
of the terminals 363-11, 363-13, 363-15, 363-17, and 363-19 of the connector 360 via
each of the terminals 196b-11, 196b-13, 196b-15, 196b-17, and 196b-19 and each of
the contact sections 180b-11, 180b-13, 180b-15, 180b-17, and 180b-19.
[0263] FIG. 32 is a diagram illustrating details of a signal propagated in the cable 19c
in the third embodiment. As illustrated in FIG. 32, the cable 19c includes wirings
for propagating driving signals COM6 to COM10, wirings for propagating reference voltage
signals CGND6 to CGND10, wirings for propagating an abnormality signal XHOT, a latch
signal LAT2, a clock signal SCK2, a change signal CH2, and a print data signal SI10,
wirings for propagating diagnosis signals DIG-E to DIG-I, and a plurality of wirings
for propagating a plurality of ground signals GND.
[0264] Specifically, the driving signals COM6 to COM10 and the reference voltage signals
CGND6 to CGND10 are input from the terminals 195c-1 to 195c-10 and the contact sections
180c-1 to 180c-10 to the cable 19c and are propagated in the wiring 197c-1 to 197c-10,
respectively. Then, the driving signals COM6 to COM10 and the reference voltage signals
CGND6 to CGND10 are input to the terminals 373-1 to 373-10 of the connector 370 via
the terminals 196c-1 to 196c-10, respectively.
[0265] The diagnosis signal DIG-E and the abnormality signal XHOT are input to the terminal
373-12 of the connector 370 and then is input to the cable 19c via the contact section
180c-12 and the terminal 196c-12. The diagnosis signal DIG-E is propagated in the
wiring 197c-12 and then is input from the terminal 195c-12 to the main substrate 11.
That is, the wiring 197c-12 functions as a wiring for propagating the diagnosis signal
DIG-E and a wiring for propagating the abnormality signal XHOT. The terminal 373-12
functions as a terminal to which the diagnosis signal DIG-E is input and a terminal
to which the abnormality signal XHOT is input. The contact section 180c-12 is electrically
in contact with the wiring for propagating the diagnosis signal DIG-E and is also
electrically in contact with the wiring for propagating the abnormality signal XHOT.
The diagnosis signal DIG-E is an example of a fifth diagnosis signal in the third
embodiment. The wiring 197c-12 for propagating the diagnosis signal DIG-E is an example
of a fifth diagnosis signal propagation wiring in the third embodiment. The terminal
373-12 to which the diagnosis signal DIG-E is input is an example of a fifth terminal
in the third embodiment. The contact section 180c-12 at which the wiring 197c-12 and
the terminal 373-12 are electrically in contact with each other is an example of a
fifth contact section in the third embodiment.
[0266] The diagnosis signal DIG-F and the latch signal LAT2 are input from the terminal
195c-14 to the cable 19c and are propagated in the wiring 197c-14. Then, the diagnosis
signal DIG-F and the latch signal LAT2 are input to the terminal 373-14 of the connector
370 via the terminal 196c-14 and the contact section 180c-14. That is, the wiring
197c-14 functions as a wiring for propagating the diagnosis signal DIG-F and a wiring
for propagating the latch signal LAT2. The terminal 373-14 functions as a terminal
to which the diagnosis signal DIG-F is input and a terminal to which the latch signal
LAT2 is input. The contact section 180c-14 is electrically in contact with the wiring
for propagating the diagnosis signal DIG-F and is also electrically in contact with
the wiring for propagating the latch signal LAT2. The diagnosis signal DIG-F is an
example of a second diagnosis signal in the third embodiment. The wiring 197c-14 for
propagating the diagnosis signal DIG-F is an example of a second diagnosis signal
propagation wiring in the third embodiment. The terminal 373-14 to which the diagnosis
signal DIG-F is input is an example of a second terminal in the third embodiment.
The contact section 180c-14 at which the wiring 197c-14 and the terminal 373-14 are
electrically in contact with each other is an example of a second contact section
in the third embodiment.
[0267] The diagnosis signal DIG-G and the clock signal SCK2 are input from the terminal
195c-16 to the cable 19c and are propagated in the wiring 197c-16. Then, the diagnosis
signal DIG-G and the clock signal SCK2 are input to the terminal 373-16 of the connector
370 via the terminal 196c-16 and the contact section 180c-16. That is, the wiring
197c-16 functions as a wiring for propagating the diagnosis signal DIG-G and a wiring
for propagating the clock signal SCK2. The terminal 373-16 functions as a terminal
to which the diagnosis signal DIG-G is input and a terminal to which the clock signal
SCK2 is input. The contact section 180c-16 is electrically in contact with the wiring
for propagating the diagnosis signal DIG-G and is also electrically in contact with
the wiring for propagating the clock signal SCK2. The diagnosis signal DIG-G is an
example of a first diagnosis signal in the third embodiment. The wiring 197c-16 for
propagating the diagnosis signal DIG-G is an example of a first diagnosis signal propagation
wiring in the third embodiment. The terminal 373-16 to which the diagnosis signal
DIG-G is input is an example of a first terminal in the third embodiment. The contact
section 180c-16 at which the wiring 197c-16 and the terminal 373-16 are electrically
in contact with each other is an example of a first contact section in the third embodiment.
[0268] The diagnosis signal DIG-H and the change signal CH2 are input from the terminal
195c-18 to the cable 19c and are propagated in the wiring 197c-18. Then, the diagnosis
signal DIG-H and the change signal CH2 are input to the terminal 373-18 of the connector
370 via the terminal 196c-18 and the contact section 180c-18. That is, the wiring
197c-18 functions as a wiring for propagating the diagnosis signal DIG-H and a wiring
for propagating the change signal CH2. The terminal 373-18 functions as a terminal
to which the diagnosis signal DIG-H is input and a terminal to which the change signal
CH2 is input. The contact section 180c-18 is electrically in contact with the wiring
for propagating the diagnosis signal DIG-H and is also electrically in contact with
the wiring for propagating the change signal CH2. The diagnosis signal DIG-H is an
example of a third diagnosis signal in the third embodiment. The wiring 197c-18 for
propagating the diagnosis signal DIG-H is an example of a third diagnosis signal propagation
wiring in the third embodiment. The terminal 373-18 to which the diagnosis signal
DIG-H is input is an example of a third terminal in the third embodiment. The contact
section 180c-18 at which the wiring 197c-18 and the terminal 373-18 are electrically
in contact with each other is an example of a third contact section in the third embodiment.
[0269] The diagnosis signal DIG-I and the print data signal SI10 are input from the terminal
195c-20 to the cable 19c and are propagated in the wiring 197c-20. Then, the diagnosis
signal DIG-I and the print data signal SI10 are input to the terminal 373-20 of the
connector 370 via the terminal 196c-20 and the contact section 180c-20. That is, the
wiring 197c-20 functions as a wiring for propagating the diagnosis signal DIG-I and
a wiring for propagating the print data signal SI10. The terminal 373-20 functions
as a terminal to which the diagnosis signal DIG-I is input and a terminal to which
the print data signal SI10 is input. The contact section 180c-20 is electrically in
contact with the wiring for propagating the diagnosis signal DIG-I and is also electrically
in contact with the wiring for propagating the print data signal SI10. The diagnosis
signal DIG-I is an example of a fourth diagnosis signal in the third embodiment. The
wiring 197c-20 for propagating the diagnosis signal DIG-I is an example of a fourth
diagnosis signal propagation wiring in the third embodiment. The terminal 373-20 to
which the diagnosis signal DIG-I is input is an example of a fourth terminal in the
third embodiment. The contact section 180c-20 at which the wiring 197c-20 and the
terminal 373-20 are electrically in contact with each other is an example of a fourth
contact section in the third embodiment.
[0270] The ground signal GND is input to the cable 19c from each of the terminals 195c-11,
195c-13, 195c-15, 195c-17, and 195c-19 and is propagated in each of the wirings 197c-11,
197c-13, 197c-15, 197c-17, and 197c-19. Then, the ground signal GND is input to each
of the terminals 373-11, 373-13, 373-15, 373-17, and 373-19 of the connector 370 via
each of the terminals 196c-11, 196c-13, 196c-15, 196c-17, and 196c-19 and each of
the contact sections 180c-11, 180c-13, 180c-15, 180c-17, and 180c-19. Here, at least
one of the wiring 197c-15 and the wiring 197c-17 which are adjacent to the wiring
197c-16 in which the diagnosis signal DIG-G is propagated, and are used for propagating
the ground signal GND is an example of a first ground signal propagation wiring in
the third embodiment. At least one of the terminal 373-15 and the terminal 373-17
to which the ground signal GND propagated in the wiring 197c-15 and the wiring 197c-17
is input is an example of a first ground terminal in the third embodiment. At least
one of the contact section 180c-15 and the contact section 180c-17, at which at least
one of the wiring 197c-15 and the wiring 197c-17 and at least one of the terminal
373-15 and the terminal 373-17 are electrically in contact with each other is an example
of a first ground contact section in the third embodiment.
[0271] FIG. 33 is a diagram illustrating details of a signal propagated in the cable 19d
in the third embodiment. As illustrated in FIG. 32, the cable 19d includes wirings
for propagating the driving signals COM6 to COM10, wirings for propagating the reference
voltage signals CGND6 to CGND10, wirings for propagating print data signals SI6 to
SI9, wirings for propagating voltages VHV and VDD2, and a plurality of wirings for
propagating a plurality of ground signals GND.
[0272] Specifically, the driving signals COM6 to COM10 and the reference voltage signals
CGND6 to CGND10 are input from the terminals 195d-1 to 195d-10 to the cable 19d and
are propagated in the wiring 197d-1 to 197d-10, respectively. Then, the driving signals
COM6 to COM10 and the reference voltage signals CGND6 to CGND10 are input to the terminals
383-1 to 383-10 of the connector 380 via the terminals 196d-1 to 196d-10 and the contact
sections 180d-1 to 180d-10, respectively.
[0273] The print data signals SI6 to SI9 are input to the cable 19d from the terminals 195d-13,
195d-15, 195d-17, and 195d-19 and are propagated in the wirings 197d-13, 197d-15,
197d-17, and 197d-19, respectively. The print data signals SI6 to SI9 are input to
the terminals 383-13, 383-15, 383-17, and 383-19 of the connector 380 via the terminals
196d-13, 196d-15, 196d-17, and 196d-19 and the contact sections 180d-13, 180d-15,
180d-17, and 180d-19, respectively.
[0274] The voltage VHV is input from the terminal 195d-11 to the cable 19d and is propagated
in the wiring 197d-11. Then, the voltage VHV is input to the terminal 383-11 of the
connector 380 via the terminal 196d-11 and the contact section 180d-11. The voltage
VHV is an example of a third voltage signal in the third embodiment. The wiring 197d-11
for propagating the voltage VHV is an example of a third voltage signal propagation
wiring in the third embodiment. The terminal 383-11 to which the voltage VHV is input
is an example of an eighth terminal in the third embodiment. The contact section 180d-11
at which the wiring 197d-11 and the terminal 383-11 are electrically in contact with
each other is an example of an eighth contact section in the third embodiment.
[0275] The voltage VDD2 is input from the terminal 195d-16 to the cable 19d and is propagated
in the wiring 197d-16. Then, the voltage VDD2 is input to the terminal 383-16 of the
connector 380 via the terminal 196d-16 and the contact section 180d-16. The voltage
VDD2 is an example of a second voltage signal in the third embodiment. The wiring
197d-16 for propagating the voltage VDD2 is an example of a second voltage signal
propagation wiring in the third embodiment. The terminal 383-16 to which the voltage
VDD2 is input is an example of a seventh terminal in the third embodiment. The contact
section 180d-16 at which the wiring 197d-16 and the terminal 383-16 are electrically
in contact with each other is an example of a seventh contact section in the third
embodiment.
[0276] The ground signal GND is input to the cable 19d from each of the terminals 195d-12,
195d-14, 195d-18, and 195d-20 and is propagated in each of the wirings 197d-12, 197d-14,
197d-18, and 197d-20. Then, the ground signal GND is input to each of the terminals
383-12, 383-14, 383-18, and 383-20 of the connector 380 via each of the terminals
196d-12, 196d-14, 196d-18, and 196d-20 and each of the contact sections 180d-12, 180d-14,
180d-18, and 180d-20. Here, the wiring 197d-10 which is adjacent to the wiring 197d-11
in which the voltage VHV is propagated, and in which the ground signal GND is propagated
is an example of a second ground signal propagation wiring in the third embodiment.
The terminal 383-11 to which the ground signal GND propagated in the wiring 197d-11
is input is an example of a second ground terminal in the third embodiment. The contact
section 180d-11 at which the wiring 197d-11 and the terminal 383-11 are electrically
in contact with each other is an example of a second ground signal contact section
in the third embodiment.
[0277] As described above, in the liquid discharge apparatus 1, the print head 21, and the
print head control circuit 15 in the third embodiment, the wiring 197c-16 in which
the diagnosis signal DIG-G is propagated and the wiring 197d-16 in which the voltage
VDD2 is propagated are provided in the cable 19c and the cable 19d different from
each other and are located to face each other. The terminal 373-16 to which the diagnosis
signal DIG-G is input and the terminal 383-16 to which the voltage VDD2 is input are
provided in the connector 370 and the connector 380 different from each other and
are located to face each other. Thus, effects similar to those in the first embodiment
are also exhibited in the liquid discharge apparatus 1, the print head 21, and the
print head control circuit 15 in the third embodiment.
[0278] Hitherto, the embodiments and the modification examples are described. However, the
present disclosure is not limited to the above embodiments, and various forms can
be made in a range without departing from the gist thereof. For example, combinations
of the above embodiments can be appropriately made.
[0279] The present disclosure includes configurations which are substantially the same as
the configurations described in the above embodiments (for example, configurations
having the same functions, methods, and results or configurations having the same
purposes and effects). The present disclosure includes configurations in which non-essential
components of the configurations described in the embodiments are replaced. The present
disclosure includes configurations having the same advantageous effects as those of
the configurations described in the embodiments or includes configurations capable
of achieving the same object. The present disclosure includes configurations in which
a known technique is added to the configurations described in the embodiments.