BACKGROUND
1. Technical Field
[0001] The present invention relates to a printing apparatus.
2. Related Art
[0002] In recent years, an ink jet type printing apparatus that performs printing of patterns,
or the like, on a fabric by discharging an ink toward an outer surface of the fabric,
has been used in textile printing on fabrics such as cotton, silk, wool, chemical
fibers, and blended fabrics. In order to handle a stretchable fabric as a recording
medium, a printing apparatus that is used in textile printing moves a recording medium
by mounting the recording medium on an endless belt having a sticky property. In this
kind of printing apparatus, an error in the movement amount of the endless belt occurs
due to variations in the dimensions in the thickness direction of the endless belt.
Therefore, for example, Japanese Patent No.
5332884 discloses an ink jet recording apparatus (a printing apparatus) that corrects a feeding
amount of an endless belt by determining a corrected feeding amount that depends on
a feeding position of a transport belt (the endless belt) using a test print. As a
result of this, it is stated that it is possible to control fluctuations in the feeding
amount caused by the thickness of a joining section of the endless belt.
[0003] In a printing apparatus that is provided with this kind of endless belt, in addition
to variations in the thickness of the endless belt, a movement error amount of an
endless belt differs depending on various printing conditions that are stipulated
at a time of printing such as decentering of a belt driving roller that moves the
endless belt, the type of recording medium, and the like. However, the printing apparatus
that is disclosed in Japanese Patent No.
5332884 is not provided with a unit that corrects movement error of the endless belt caused
by factors other than variations in the thickness of the endless belt.
US-A1-2007/0236528 describes an ink-jet printer as defined in the preamble of present claims 1 and 2.
SUMMARY
[0004] The invention can be realized in the following aspects or application examples.
Application Example 1
[0005] According to this application example, there is provided a printing apparatus including
a driving roller, an endless belt that transports a recording medium using rotation
of the driving roller, a roller correction table acquisition unit that acquires a
roller correction table, which represents a relationship between a point of origin
position of the driving roller and a movement error of the endless belt, a belt correction
table acquisition unit that acquires a belt correction table, which represents a relationship
between a point of origin position of the endless belt and a movement error of the
endless belt, and a control section that controls driving of the driving roller by
calculating a rotation amount of the driving roller on the basis of the roller correction
table and the belt correction table.
[0006] According to the application example, the printing apparatus includes the roller
correction table acquisition unit that acquires a roller correction table, which represents
a relationship between a point of origin position of the driving roller and a movement
error of the endless belt. In other words, the printing apparatus includes a unit
that determines a movement error of the endless belt caused by decentering of the
driving roller. In addition, the printing apparatus includes a belt correction table
acquisition unit that acquires a belt correction table, which represents a relationship
between a point of origin position of the endless belt and a movement error of the
endless belt. In other words, the printing apparatus includes a unit that determines
a movement error of the endless belt caused by the thickness of the endless belt.
Since the control section of the printing apparatus drives the driving roller by calculating
a rotation amount of the driving roller on the basis of the roller correction table
and the belt correction table, a movement error of the endless belt caused by decentering
of the driving roller is corrected in addition to variations in the thickness of the
endless belt. As a result of this, since the movement accuracy of the endless belt
and the transport accuracy of a recording medium, which is mounted on the endless
belt, are improved, it is possible to improve the printing quality of an image that
is formed on the recording medium. Accordingly, it is possible to provide a printing
apparatus in which the transport accuracy of a recording medium is improved and the
printing quality of an image is improved.
Application Example 2
[0007] It is preferable that the printing apparatus according to the application example
further includes roller correction tables and belt correction tables that correspond
to printing conditions that are stipulated at a time of printing, and that the control
section selects a roller correction table and a belt correction table that match the
stipulated printing conditions.
[0008] According to the application example, the printing apparatus includes roller correction
tables and a belt correction tables that are acquired on the basis of various printing
conditions that are stipulated at the time of printing. As a result of the control
section of the printing apparatus driving the driving roller by calculating a rotation
amount of the driving roller by selecting a roller correction table and a belt correction
table that match the stipulated printing conditions, it is possible to perform correction
that includes a movement error of the endless belt caused by the printing conditions.
Application Example 3
[0009] In the printing apparatus according to the application example, it is preferable
that the printing conditions include printing quality.
[0010] According to the application example, the printing apparatus includes the roller
correction tables and a belt correction tables that are acquired on the basis of a
printing quality that is stipulated at the time of printing. For example, a mode in
which printing quality is prioritized, a mode in which printing velocity is prioritized,
and the like, are examples of the printing quality. More specifically, the printing
velocity differs depending on the printing quality. Since a movement error of the
endless belt differs depending on the printing velocity, the printing apparatus of
the present application example can perform correction that includes a movement error
of the endless belt caused by differences in the printing velocity, which depends
on the printing quality.
Application Example 4
[0011] In the printing apparatus according to the application example, it is preferable
that the printing conditions include a medium type of the recording medium.
[0012] According to the application example, the printing apparatus includes the printing
roller correction tables and a belt correction tables that are acquired on the basis
of a recording medium to be used in the printing. Since a movement error of the endless
belt differs depending on the stretchability, and the like, of a recording medium
to be used, the printing apparatus of the present application example can perform
correction that includes a movement error of the endless belt caused by the recording
medium to be used.
Application Example 5
[0013] In the printing apparatus according to the application example, it is preferable
that the printing conditions include a condition relating to a tension at a time of
transporting the recording medium.
[0014] According to the application example, the printing apparatus includes roller correction
tables and a belt correction tables that are acquired on the basis of a condition
relating to a tension that is applied when transporting the recording medium, the
condition being stipulated at the time of printing. For example, a "tension mode"
that transports a recording medium by applying a predetermined amount of tension thereto,
and a "slack mode" that reduces damage and transports a recording medium, and the
like, are examples of transport methods. Since the amount of a movement error of the
endless belt differs depending on a transport mode of a recording medium, the printing
apparatus of the present application example can perform correction that includes
a movement error of the endless belt caused by the transport method of the recording
medium.
Application Example 6
[0015] It is preferable that the printing apparatus according to the application example
further includes a tension measurement section that measures an amount of tension
that is applied to the recording medium on at least one of an upstream side and a
downstream side of the endless belt in a movement direction of the recording medium;
and roller correction tables and belt correction tables that correspond to tension
that can be measured by the tension measurement section, and that the control section
selects a roller correction table and a belt correction table that match the tension
that is measured by the tension measurement section.
[0016] According to the application example, the printing apparatus includes the roller
correction tables and a belt correction tables that are acquired on the basis of an
amount of tension of the recording medium, which is measured by the tension measurement
section. Since the control section selects a roller correction table and a belt correction
table that match the tension that is measured by the tension measurement section,
it is even possible to perform correction that includes a movement error of the endless
belt caused by tension in a case in which there are fluctuations in the amount of
tension of a recording medium during printing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Embodiments of the invention will now be described by way of example only with reference
to the accompanying drawings, wherein like numbers reference like elements.
Fig. 1 is a schematic diagram that schematically shows an overall configuration of
a printing apparatus according to Embodiment 1.
Fig. 2 is a perspective view in which an endless belt is displayed in an enlarged
manner.
Fig. 3 is a cross-sectional view of a movement amount detection sensor.
Fig. 4 is an electrical block diagram that shows an electrical configuration of the
printing apparatus.
Fig. 5 is a view that shows an example of a transport error of the endless belt.
Fig. 6 is a view that describes a point of origin of a driving axis of a belt driving
roller.
Fig. 7 is a view that shows an example of a roller correction table.
Fig. 8 is a view that describes a belt phase of the endless belt.
Fig. 9 is a view that shows an example of a belt correction table.
Fig. 10 is a flowchart that describes a printing operation of the printing apparatus.
Fig. 11 is a schematic diagram that schematically shows an overall configuration of
a printing apparatus according to Embodiment 2.
Fig. 12 is an enlarged view of a tension measurement section.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0018] Hereinafter, embodiments of the invention will be described with reference to the
drawings. Additionally, in each of the drawings below, the scale of each layer and
each member is altered from a practical scale in order to make each layer and each
member have a size that is easy to understand.
[0019] In addition, in Figs. 1 to 3 and Figs. 6, 8, 11 and 12, for the sake of convenience,
an X axis, a Y axis and a Z axis are illustrated as three axes that are orthogonal
to one another, a tip end side of an arrow that illustrates an axial direction is
referred to as a "+ side", and a base end side thereof is referred to as a "- side".
In addition, hereinafter, a direction that is parallel to the X axis is referred to
as an "X axis direction", a direction that is parallel to the Y axis is referred to
as a "Y axis direction" and a direction that is parallel to the Z axis is referred
to as a "Z axis direction".
Embodiment 1
Outline Configuration of Printing Apparatus
[0020] Fig. 1 is a schematic diagram that schematically shows an overall configuration of
a printing apparatus according to Embodiment 1. A printing apparatus 100 is an apparatus
that performs textile printing on a recording medium 95 by forming an image, or the
like on the recording medium 95. For example, a fabric such as cotton, wool, a chemical
fiber or a blended fabric can be used as the recording medium 95. In the present embodiment,
a configuration that forms an image on a band-like recording medium 95 using a roll
method will be illustrated by way of example, but the embodiment is not limited to
this configuration. For example, the embodiment may use a method such as a sheet technique.
[0021] As shown in Fig. 1, the printing apparatus 100 includes a recording medium supply
section 10, a recording medium transport section 20, a recording medium recovery section
30, a printing section 40, a cleaning unit 50, a medium adhesion section 60, a drying
section 97, and the like. Further, the printing apparatus 100 includes a control section
1 that controls each of these sections. Each section of the printing apparatus 100
is attached to a frame section 92.
[0022] The recording medium supply section 10 is a section that supplies a recording medium
95 on which an image is to be formed, to a printing section 40 side. The recording
medium supply section 10 includes a supply shaft section 11 and a bearing section
12. The supply shaft section 11 is formed in a cylindrical shape or a columnar shape,
and is provided so as to be rotatable in a circumferential direction. A band-like
recording medium 95 is wound around the supply shaft section 11 in roll shape. The
supply shaft section 11 is attached to the bearing section 12 in an attachable and
detachable manner. As a result of this, a recording medium 95 in a state of being
wound around the supply shaft section 11 in advance, can be attached to the supply
shaft section 11 and the bearing section 12.
[0023] The bearing section 12 supports both ends in an axial direction of the supply shaft
section 11 in a rotatable manner. The recording medium supply section 10 includes
a rotational driving section (not illustrated in the drawing) that drives the supply
shaft section 11 in a rotational manner. The rotational driving section rotates the
supply shaft section 11 in a direction in which a recording medium 95 is fed out.
The operation of the rotational driving section is controlled by the control section
1.
[0024] The recording medium transport section 20 is a section that transports a recording
medium 95 from the recording medium supply section 10 to the recording medium recovery
section 30. The recording medium transport section 20 includes a transport roller
21, a tension roller 22, a transport roller 23, a belt rotation roller 24, a belt
driving roller 25 as a driving roller, an endless belt 26, a transport roller 27,
a tension roller 28 and a transport roller 29.
[0025] The transport rollers 21 and 23, and the tension roller 22 relay a recording medium
95 from the recording medium supply section 10 to the endless belt 26. The transport
rollers 21 and 23 are fixed rollers that are fixed to the frame section 92, and the
tension roller 22 is provided between the transport roller 21 and the transport roller
23, and is a movable roller that is movable in a vertical direction (the Z axis direction).
As a result of being able to move the tension roller 22 in the vertical direction,
the amount of tension of a recording medium 95, which is supplied to the endless belt
26 from the recording medium supply section 10, can be varied.
[0026] The endless belt 26 is formed in an endless shape in which both end portions of a
band-like belt are connected to one another, and is hung on the belt rotation roller
24 and the belt driving roller 25. The endless belt 26 is maintained in a state in
which a predetermined tension is applied thereto so that a portion between the belt
rotation roller 24 and the belt driving roller 25 is parallel to a floor surface 99.
A sticky layer 26c, which causes a recording medium 95 to stick to the endless belt
26, is provided on an outer surface (a support surface) 26a of the endless belt 26.
The endless belt 26 supports (maintains) a recording medium 95, which is supplied
from the transport roller 23, and is adhered to the sticky layer 26c by the medium
adhesion section 60, which will be described later. As a result of this, it is possible
to handle a stretchable fabric, or the like as a recording medium 95.
[0027] The belt rotation roller 24 and the belt driving roller 25 support an inner circumferential
surface 26b of the endless belt 26. Additionally, a configuration in which a support
section that supports the endless belt 26, is provided between the belt rotation roller
24 and the belt driving roller 25, may also be used.
[0028] The endless belt 26 moves a recording medium using rotation of the belt driving roller
25. To explain in more detail, when the belt driving roller 25 is driven, the endless
belt 26 rotates in accordance with rotation of the belt driving roller 25, and the
belt rotation roller 24 rotates due to rotation of the endless belt 26. As a result
of rotation of the endless belt 26, a recording medium 95, which is supported on the
endless belt 26, is transported in a predetermined transport direction, which is illustrated
by an arrow, and an image is formed on the recording medium 95 by the printing section
40, which will be described later. In the present embodiment, a recording medium 95
is supported on a side (a +Z axis side) on which the outer surface 26a of the endless
belt 26 faces the printing section 40, and the recording medium 95 is transported
from a belt rotation roller 24 side to a belt driving roller 25 side along with the
endless belt 26. In addition, on a side (a -Z axis side) on which the outer surface
26a of the endless belt 26 faces the cleaning unit 50, only the endless belt 26 moves
from the belt driving roller 25 side to the belt rotation roller 24 side.
[0029] The transport roller 27 causes a recording medium 95, on which an image is formed,
to peel away from the sticky layer 26c of the endless belt 26. The transport rollers
27 and 29, and the tension roller 28 relay a recording medium 95 from the endless
belt 26 to the recording medium recovery section 30. The transport rollers 27 and
29 are fixed rollers that are fixed to the frame section 92, and the tension roller
28 is provided between the transport roller 27 and the transport roller 29, and is
a movable roller that is movable in the vertical direction (the Z axis direction).
As a result of being able to move the tension roller 28 in the vertical direction,
the amount of tension of a recording medium 95, which is peeled away from the endless
belt 26 and recovered by the recording medium recovery section 30, can be varied.
Additionally, a "tension mode", and a "slack mode", which will be described later,
and which are conditions relating to the tension when transporting the recording medium
95, are realized due to the movability of the tension rollers 22 and 28.
[0030] The recording medium recovery section 30 recovers a recording medium 95 that is transported
by the recording medium transport section 20. The recording medium recovery section
30 includes a wind-up shaft section 31 and a bearing section 32. The wind-up shaft
section 31 is formed in a cylindrical shape or a columnar shape, and is provided so
as to be rotatable in a circumferential direction. A band-like recording medium 95
is wound up onto the wind-up shaft section 31 in roll shape. The wind-up shaft section
31 is attached to the bearing section 32 in an attachable and detachable manner. As
a result of this, a recording medium 95 in a state of being wound-up onto the wind-up
shaft section 31, is released along with the wind-up shaft section 31.
[0031] The bearing section 32 supports both ends in an axial direction of the wind-up shaft
section 31 in a rotatable manner. The recording medium recovery section 30 includes
a rotational driving section (not illustrated in the drawing) that drives the wind-up
shaft section 31 in a rotational manner. The rotational driving section rotates the
wind-up shaft section 31 in a direction in which a recording medium 95 is wound up.
The operation of the rotational driving section is controlled by the control section
1.
[0032] Additionally, in the present embodiment, a drying section 97 is disposed between
the transport roller 27 and the tension roller 28. The drying section 97 is a section
that dries an image formed on a recording medium 95. For example, by including an
IR heater in the drying section 97, and driving the IR heater, it is possible to dry
an image formed on a recording medium 95 in a short period of time. As a result of
this, it is possible to wind up a band-like recording medium 95 on which an image
is formed, onto the wind-up shaft section 31.
[0033] The medium adhesion section 60 is a section that causes a recording medium 95 to
adhere to the endless belt 26. The medium adhesion section 60 is disposed further
on an upstream side (a -X axis side) than the printing section 40 in the transport
direction of a recording medium 95. The medium adhesion section 60 includes a pressing
roller 61, a pressing roller driving section 62 and a roller support section 63. The
pressing roller 61 is formed in a cylindrical shape or a columnar shape, and is provided
rotatable so as to be rotatable in a circumferential direction. The pressing roller
61 is disposed so that an axial direction thereof intersects the transport direction
in a manner in which the pressing roller 61 rotates in a direction along the transport
direction. The roller support section 63 is provided on an inner circumferential surface
26b side of the endless belt 26, which faces the pressing roller 61 with the endless
belt 26 interposed therebetween.
[0034] The pressing roller driving section 62 moves the pressing roller 61 in the transport
direction (a +X axis direction) and a direction (a -X axis direction) that is opposite
to the transport direction while pressing the pressing roller 61 toward a lower side
in the vertical direction (the -Z axis side). A recording medium 95 that is transported
from the transport roller 23, and superimposed on the endless belt 26, is pressed
against the endless belt 26 between the pressing roller 61 and the roller support
section 63. As a result of this, it is possible to reliably cause a recording medium
95 to stick to the sticky layer 26c, which is provided on the outer surface 26a of
the endless belt 26, and therefore, it is possible to prevent lifting of a recording
medium 95 above the endless belt 26.
[0035] The printing section 40 includes an ink jet type discharge head 42 that discharges
an ink toward a recording medium 95 as liquid droplets, a carriage movement section
41 that moves a carriage 43, in which the discharge head 42 is mounted, and the like.
The printing section 40 is disposed above a disposition position of the endless belt
26 (on the +Z axis side). A discharge surface 44, on which a plurality of nozzle rows
45 are formed, is provided in the discharge head 42. For example, four nozzle rows
45 are formed on the discharge surface 44, and a different color of ink (for example,
cyan: C, magenta: M, yellow: Y and black: K) is discharged from each nozzle row 45.
The discharge surface 44 faces a recording medium 95 that is transported by the endless
belt 26.
[0036] The carriage movement section 41 moves the discharge head 42 in a direction that
intersects the transport direction of a recording medium 95 (a width direction of
a recording medium 95 (the Y axis direction)). The carriage 43 is supported by a guide
rail (not illustrated in the drawing), which is disposed along the Y axis direction,
and the carriage 43 is configured so as to be able to reciprocate in a ±Y axis direction
as a result of the carriage movement section 41. For example, it is possible to use
a configuration in which a ball screw and a ball nut are combined, a linear guide
mechanism or the like, as the carriage movement section 41.
[0037] Furthermore, a motor (not illustrated in the drawing) is provided in the carriage
movement section 41 as a motive power source for moving the carriage 43 along the
Y axis direction. When the motor is driven due to the control of the control section
1, the discharge head 42 reciprocates along the Y axis direction along with the carriage
43. Additionally, in the present embodiment, a serial head type discharge head, which
is installed in a movable carriage and discharges an ink while moving in the width
direction of a recording medium 95 (the ±Y axis direction), is illustrated as the
discharge head 42 by way of example, but a line head type in which the discharge head
is fixedly arranged extending in the width direction of a recording medium 95 (the
Y axis direction) may be used instead.
[0038] The printing apparatus 100 is provided with the cleaning unit 50 for cleaning the
endless belt 26. The cleaning unit 50 includes a cleaning section 51, a pressing section
52 and a movement section 53. The movement section 53 can be fixed in a predetermined
position by moving the cleaning unit 50 along the floor surface 99 in an integral
manner. The cleaning unit 50 is disposed between the belt rotation roller 24 and the
belt driving roller 25 in the X axis direction.
[0039] The pressing section 52 is an elevation device that is configured by an air cylinder
56 and a ball bush 57, and is capable of moving the cleaning section 51, which is
provided above the pressing section 52, between a cleaning position and a retreat
position. The cleaning position is a position in which a cleaning roller 58 and a
blade 55 abut against the endless belt 26. The retreat position is a position in which
the cleaning roller 58 and the blade 55 are separated from the endless belt 26. In
the cleaning position, the cleaning section 51 cleans the outer surface 26a (the support
surface) of the endless belt 26, which is hanging in a state in which a predetermined
amount of tension is applied between the belt rotation roller 24 and the belt driving
roller 25, from below (a -Z axis direction). Additionally, Fig. 1 shows a case in
which the cleaning section 51 is raised and disposed in the cleaning position.
[0040] The cleaning section 51 includes a cleaning tub 54, the cleaning roller 58 and the
blade 55. The cleaning tub 54 is a tub in which a cleaning solution that is used in
the cleaning of ink and foreign matter that is attached to the outer surface 26a of
the endless belt 26, is retained, and the cleaning roller 58 and the blade 55 are
provided on an inner side of the cleaning tub 54. For example, it is possible to use
water, a water-soluble solvent (an alcohol aqueous solution or the like), or the like,
as the cleaning solution, and a surfactant, an antifoaming agent, and the like may
be added thereto according to necessity.
[0041] A lower side (the -Z axis side) of the cleaning roller 58 is immersed in the cleaning
solution that is retained in the cleaning tub 54. When the cleaning roller 58 is rotated
in the cleaning position, the cleaning solution is supplied to the outer surface 26a
of the endless belt 26, and the cleaning roller 58 slides along the endless belt 26.
As a result of this, ink and fibers or the like of a fabric of a recording medium
95, which are attached to the endless belt 26, are washed away using the cleaning
roller 58.
[0042] For example, the blade 55 is configured by a material having a flexible property
such as a silicon rubber. The blade 55 is provided further on a downstream side than
the cleaning roller 58 in the transport direction of the endless belt 26. Cleaning
solution that remains on the outer surface 26a of the endless belt 26, is removed
as a result of the endless belt 26 sliding along the blade 55.
[0043] Fig. 2 is a perspective view in which an endless belt is displayed in an enlarged
manner. Fig. 3 is a cross-sectional view of a movement amount detection sensor. A
movement amount detection sensor 70 and a belt point of origin sensor 80 that determine
a point of origin position and a movement amount of the endless belt 26 will be described
with reference to Figs. 2 and 3.
[0044] The belt point of origin sensor 80 is a sensor that detects a point of origin of
the endless belt 26. As shown in Fig. 2, markers 81 are provided at both end portions
in the width direction of the endless belt 26 (the Y axis direction) on the outer
surface 26a, on which the sticky layer 26c is not formed, as points of origin of the
endless belt 26. The belt point of origin sensor 80 is provided above (in a +Z axis
direction) the marker 81 in the vertical direction. When the marker 81 moves in accordance
with movement of the endless belt 26 and passes under the belt point of origin sensor
80, the belt point of origin sensor 80 detects the marker 81 and outputs a detection
signal thereof.
[0045] The movement amount detection sensor 70 is a sensor that performs image process measurement
of a practical (or an actual amount of movement in practice) movement amount of the
endless belt 26. The movement amount detection sensor 70 captures images for determining
a practical movement amount that the endless belt 26 moves in a practical sense through
comparison of positions before movement and after movement of the endless belt 26.
As shown in Figs. 2 and 3, the movement amount detection sensor 70 is provided in
a position that faces the printing section 40 (refer to Fig. 1) with the endless belt
26 interposed therebetween, and captures images of the inner circumferential surface
26b of the endless belt 26.
[0046] Additionally, in the present embodiment, a configuration in which the movement amount
detection sensor 70 is provided on the inner circumferential surface 26b of the endless
belt 26 is shown, but the movement amount detection sensor 70 is not limited to this
configuration. The movement amount detection sensor 70 may be provided in any position
in which it is possible to capture images of the outer surface 26a, on which the sticky
layer 26c of the endless belt 26 is not formed, the outer surface of a recording medium
95 that is mounted on the endless belt 26, or the like. In addition, it is preferable
that the movement amount detection sensor 70 is provided in the vicinity of the printing
section 40. In addition, in a case in which images of the outer surface 26a or the
inner circumferential surface 26b of the endless belt 26 are captured, it is preferable
that undulations are formed on the outer surface of a target of the image capture
section. As a result of this, since a clear image is captured, the calculate accuracy
of the movement amount of the endless belt 26 is improved.
[0047] As shown in Fig. 3, the movement amount detection sensor 70 is provided with a light-emitting
section 72, a condensing lens 73, and an image capturing element 74 on an inner side
of a case 76.
[0048] The case 76 configures the exterior of the movement amount detection sensor 70. The
case 76 has a truncated cone shape, and a light-transmissive glass 71 is attached
to a tip end portion (an upper end portion) thereof. The light-transmissive glass
71 faces a gap between the light-transmissive glass 71 and the inner circumferential
surface 26b of the endless belt 26 in a vertical manner in a state in which a gap
is interposed therebetween.
[0049] The light-emitting section 72 is a section that radiates light toward the endless
belt 26. The light-emitting section 72 is provided on an inner wall surface of the
case 76 with an angled posture in which it is possible to emit light toward the light-transmissive
glass 71. For example, it is possible to use a light emitting diode (LED) as the light-emitting
section 72.
[0050] The condensing lens 73 is a lens that condenses reflected light that passes through
the light-transmissive glass 71 for a second time and is incident to the inside of
the case 76 after light that is emitted from the light-emitting section 72 and passes
through the light-transmissive glass 71 is reflected by the inner circumferential
surface 26b of the endless belt 26, and is provided in a cylindrical portion of the
case 76.
[0051] The image capturing element 74 is an element that captures images of the inner circumferential
surface 26b of the endless belt 26, which are condensed by the condensing lens 73,
and includes an image capturing surface 74a in a position in which images are formed.
The image capturing element 74 is provided on an inner bottom surface of the case
76. Additionally, the condensing lens 73 is retained at a height at which an image
of the inner circumferential surface 26b of the endless belt 26 on the image capturing
surface 74a of the image capturing element 74 can obtained, by a retention member
75.
[0052] The movement amount detection sensor 70 outputs image capturing data that is captured
by the image capturing element 74, to the control section 1. The control section 1
compares image capturing data before and after movement of the endless belt 26, and
outputs a practical movement amount that the endless belt 26 has moved in a practical
sense.
[0053] Additionally, in the present embodiment, a method that uses the movement amount detection
sensor 70 as a measurement method of the practical movement amount of the endless
belt 26, is illustrated by way of example, but the measurement method is not limited
to this configuration. The measurement method of the practical movement amount of
the endless belt 26 may be a method that uses a laser length measurement machine.
For example, it is possible to measure the practical movement amount of the endless
belt 26 by providing a reflective body, which reflects laser light emitted along a
movement direction of the endless belt 26, on the endless belt 26, and measuring a
distance between a laser length measurement machine and the reflective body, which
moves along with the endless belt 26. In addition, it is possible to determine the
practical movement amount of the endless belt 26 by repeating movement of the endless
belt 26 and the discharge of liquid droplets onto a recording medium 95 such as photographic
paper, and measuring a position of a measurement pattern (dots) that is formed on
the recording medium 95.
Electrical Configuration of Printing Apparatus
[0054] Fig. 4 is an electrical block diagram that shows an electrical configuration of the
printing apparatus. Next, the electrical configuration of the printing apparatus 100
will be described with reference to Fig. 4.
[0055] The control section 1 is a control unit for performing control of the printing apparatus
100. The control section 1 is configured to include a control circuit 4, an interface
section (I/F) 2, a CPU (Central Processing Unit) 3, and a storage section 5. The interface
section 2 is a section for performing the communication of data between an external
apparatus 6, which handles images, such as a computer or a digital camera, and the
printing apparatus 100. The CPU 3 is an arithmetic processing device for performing
an input signal process from various detector groups 7 and overall control of the
printing apparatus 100. The detector groups 7 include the movement amount detection
sensor 70 for measuring the movement amount of the endless belt 26, the belt point
of origin sensor 80 that detects a belt point of origin of the endless belt 26, and
a driving shaft point of origin sensor 85 that detects a driving shaft point of origin
of the belt driving roller 25.
[0056] The storage section 5 is a section for securing a region that stores a program of
the CPU 3, a work region, or the like, and includes storage elements such as RAM (Random
Access Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or the
like. In addition, roller correction tables and belt correction tables that correct
a transport error of the endless belt 26, which will be described later, are stored
in the storage section 5.
[0057] The CPU 3 controls the belt driving roller 25 that moves the endless belt 26 in the
transport direction, the carriage movement section 41 that moves the carriage 43,
in which the discharge head 42 is mounted, in a direction that intersects the transport
direction, the discharge head 42 that discharges ink toward a recording medium 95,
and each device that is not illustrated in the drawings, on the basis of printing
data and printing conditions that are received from the external apparatus 6 using
the control circuit 4. Additionally, for example, a printing quality, which is represented
by "clear", "fast", or the like, a medium type to be used as a recording medium 95,
a condition relating to the tension when transporting the recording medium, which
is represented by a "tension mode", a "slack mode", or the like, are included as the
printing conditions of the present embodiment.
Transport Error
[0058] Next, a transport error of the endless belt 26 will be described.
[0059] Fig. 5 is a view that shows an example of a transport error of the endless belt.
The horizontal axis in Fig. 5 represents an integrated movement amount when the endless
belt 26 is rotated a single time by repeatedly moving the endless belt 26 by a predetermined
movement amount from a predetermined position (for example, a point of origin position
of the marker 81). That is, a maximum value of the horizontal axis in Fig. 5 is equivalent
to the length of the endless belt 26. The vertical axis in Fig. 5 represents a difference
(hereinafter, also referred to as a transport error) between practical movement amounts,
which are calculated from image capturing data that is captured before and after movement
of the endless belt 26, with respect to a predetermined (or intended) movement amount.
[0060] As shown in Fig. 5, in the transport error, an error that is expressed periodically
in a period of an interval A, and an error, which is shown by an interval B, that
is expressed specifically. The length of the interval A is substantially equivalent
to the length of the outer periphery of the belt driving roller 25, and it can be
understood that the transport error of the interval A is caused by driving of the
belt driving roller 25. The reason for this is that the interval A is a so-called
transport error that occurs as a result of decentering of the belt driving roller
25, in which the center of the circumference (the outer periphery) of the belt driving
roller 25 and the center of the axis of rotation that drives the belt driving roller
25 in a rotational manner, are shifted. The interval B is equivalent to a position
of a connection section of the endless belt 26, and it can be understood that the
transport error of the interval B is caused by the thickness of the endless belt 26.
Additionally, a transport error caused by the thickness of the endless belt 26 in
portions other than a connection section of the endless belt 26, are also included
in practice.
[0061] Fig. 6 is a view that describes a point of origin of a driving axis of a belt driving
roller. The belt driving roller 25 is provided with the driving shaft point of origin
sensor 85. In addition, in the present description, the position of the driving shaft
point of origin sensor 85 is set as a reference position of the belt driving roller
25. For example, it is possible to use a rotary encoder, which is provided with a
marker as a driving shaft point of origin, or the like, as the driving shaft point
of origin sensor 85. The position of the driving shaft point of origin moves as a
result of rotational driving of the belt driving roller 25. Additionally, in the following
description, the position of the driving shaft point of origin represents an angle
θ that is formed by a line that connects the center of the belt driving roller 25
and the reference position, and a line that connects the center of the belt driving
roller 25 and the driving shaft point of origin. In this way, the point of origin
sensor 85 measures how much the driving roller has rotated. Additionally, the driving
shaft point of origin of the belt driving roller 25 may be determined using an absolute-type
rotary encoder that outputs an absolute position of the driving shaft point of origin
that depends on a rotational angle.
[0062] Fig. 7 is a view that shows an example of a roller correction table. The roller correction
table represents a relationship between a point of origin position of a driving roller
and a movement error of the endless belt. In the present embodiment, a plurality of
roller correction tables, which correspond to a plurality of printing conditions,
are stored in the storage section 5.
[0063] Positions of the driving shaft point of origin of the belt driving roller 25 are
shown using the angles θ in the parameters in the rows of the roller correction table
that is shown in Fig. 7, and reference movement amounts Kn are shown as predetermined
movement amounts of the endless belt 26 in the parameters of the rows. Further, correction
values α of the movement amounts are shown in intersecting positions of the respective
parameters (the angles θ and the reference movement amounts Kn).
[0064] A roller correction table acquisition unit, which acquires roller correction tables,
calculates correction values α of movement amounts from the reference movement amounts
Kn, by which the control section 1 feeds out the endless belt 26 by driving (rotating)
the belt driving roller 25, and practical movement amounts of the endless belt 26,
which are determined using the movement amount detection sensor 70. Correction values
α of at least a single circuit (an amount that is equivalent to 360°) of the belt
driving roller 25 are determined as a result of the control section 1 repeating rotation
of the belt driving roller 25 and calculation of the correction values α. As a result
of this, it is possible to acquire the roller correction tables that are illustrated
by way of example in Fig. 7, and correct movement errors caused by decentering of
the belt driving roller 25. Additionally, it is preferable that the correction values
α are determined in a case in which the connection section of the endless belt 26
is not positioned at the belt rotation roller 24 or the belt driving roller 25. As
a result of this, it is possible to eliminate the effects of transport errors caused
by the thickness of the endless belt 26.
[0065] Fig. 8 is a view that describes a belt phase of the endless belt. In the present
description, the position of the belt point of origin sensor 80 is set as a reference
position of the endless belt 26. The position of the marker 81, as the point of origin
position of the endless belt 26, moves as a result of rotational driving of the belt
driving roller 25. In the following description, a difference between the marker 81,
as the point of origin position of the endless belt 26, and a reference position is
represented by a belt phase D.
[0066] Fig. 9 is a view that shows an example of a belt correction table. The belt correction
table represents a relationship between a point of origin position of an endless belt
and a movement error of the endless belt. In the present embodiment, a plurality of
belt correction tables, which correspond to a plurality of printing conditions, are
stored in the storage section 5.
[0067] Point of origin positions (the positions of the markers 81) of the endless belt 26
are shown using the belt phases D in the parameters in the rows of the belt correction
table that is shown in Fig. 9, and reference movement amounts Kn are shown as predetermined
movement amounts of the endless belt 26 in the parameters of the rows. Further, correction
values σ of the movement amounts are shown in intersecting positions of the respective
parameters (the belt phases D and the reference movement amounts Kn).
[0068] A belt correction table acquisition unit, which acquires belt correction tables,
calculates correction values σ of movement amounts from the reference movement amounts
Kn, by which the control section 1 feeds out the endless belt 26 by driving (rotating)
the belt driving roller 25, and practical movement amounts of the endless belt 26,
which are determined using the movement amount detection sensor 70. Correction values
σ of at least a single circuit (an amount that is equivalent to 360°) of the endless
belt 26 are determined as a result of the control section 1 repeating rotation of
the belt driving roller 25 and calculation of the correction values σ. As a result
of this, it is possible to acquire the belt correction tables that are illustrated
by way of example in Fig. 9, and correct movement errors caused by the thickness of
the endless belt 26. Additionally, at the time of acquiring the belt correction tables,
it is possible to acquire correction values σ in which transport errors caused by
decentering of the belt driving roller 25 are eliminated, by determining the position
(the angle θ) of the driving shaft point of origin of the belt driving roller 25 and
taking the roller correction table into consideration.
[0069] In the present embodiment, a roller correction table and a belt correction table
that were acquired by driving the printing apparatus 100 using printing conditions
of "clear", "medium type A" and "tension mode" are illustrated by way of example,
but the printing conditions are not limited to these printing conditions. For example,
the correction values α and σ of the belt correction tables and the roller correction
tables differ depending on printing conditions such as the printing quality, which
is represented by "clear", "fast", or the like, the medium type to be used as a recording
medium 95, a condition relating to the tension when transporting a recording medium
95, which is represented by the "tension mode", the "slack mode", or the like, and
the like. Therefore, the printing apparatus 100 of the present embodiment includes
roller correction tables and belt correction tables that correspond to printing conditions
that are stipulated at the time of printing. To explain in more detail, a plurality
of roller correction tables and a plurality of belt correction tables, which are acquired
by driving the printing apparatus 100 on the basis of these printing conditions, are
included in the storage section 5.
[0070] The control section 1 of the printing apparatus 100 selects a roller correction table
and a belt correction table that match the printing conditions stipulated at the time
of printing.
[0071] To explain in more detail, in a case in which printing conditions that include printing
quality are stipulated at the time of printing, the control section 1 selects a roller
correction table and a belt correction table that match the printing conditions including
the stipulated printing quality, from the plurality of roller correction tables and
the plurality of belt correction tables that are saved in the storage section 5 by
performing acquisition including the printing quality as a parameter. As a result
of this, it is possible to obtain correction values α and σ that include movement
errors of the endless belt 26 caused by differences in the printing velocity, which
depends on the printing quality.
[0072] In a case in which printing conditions that include the medium type are stipulated
at the time of printing, the control section 1 selects a roller correction table and
a belt correction table that match the printing conditions including the stipulated
medium type, from the plurality of roller correction tables and the plurality of belt
correction tables that are saved in the storage section 5 by performing acquisition
including the medium type of a recording medium 95 as a parameter. As a result of
this, it is possible to obtain correction values α and σ that include movement errors
of the endless belt 26 caused by differences in the type of recording medium 95.
[0073] In a case in which printing conditions that include the condition relating to the
tension when transporting a recording medium 95 are stipulated at the time of printing,
the control section 1 selects a roller correction table and a belt correction table
that match the printing conditions including the stipulated condition relating to
the tension, from the plurality of roller correction tables and the plurality of belt
correction tables that are saved in the storage section 5 by performing acquisition
including the condition relating to the tension as a parameter. As a result of this,
it is possible to obtain correction values α and σ that include movement errors of
the endless belt 26 caused by differences in the condition relating to the amount
of tension of a recording medium 95.
Printing Operation of Printing Apparatus
[0074] Fig. 10 is a flowchart that describes a printing operation of the printing apparatus.
A printing operation of the printing apparatus 100 will be described with reference
to Figs. 4 and 10.
[0075] In Step S1, printing data is received. The CPU 3 receives printing data to record
an image on a recording medium 95 and stipulated conditions from the external apparatus
6, and saves the printing data and printing conditions in the storage section 5.
[0076] In Step S2, the selection of correction tables is performed. The CPU 3 selects a
roller correction table and a belt correction table that match the printing conditions
received in Step S1 from a plurality of roller correction tables and a plurality of
belt correction tables, which are saved in the storage section 5 and are acquired
by setting various printing conditions as parameters. For example, the printing quality,
which is represented by "clear", "fast", or the like, the medium type to be used as
a recording medium 95, the tension when transporting the recording medium, which is
represented by a "tension mode", a "slack mode", or the like, are included as the
printing conditions. For example, in a case in which the received printing conditions
are "clear", "medium type A" and "tension mode", the CPU 3 selects the roller correction
table that is shown in Fig. 7 and the belt correction table that is shown in Fig.
9.
[0077] In Step S3, a feeding amount of the belt driving roller 25 is calculated. The control
section 1 (the CPU 3) calculates a rotation amount of the belt driving roller 25 on
the basis of the roller correction table and the belt correction table. To explain
in more detail, the CPU 3 calculates a point of origin position (an angle θ) of the
belt driving roller 25 and a point of origin position (a belt phase D) of the endless
belt 26 by receiving signals that are output from the belt point of origin sensor
80 and the driving shaft point of origin sensor 85. Further, a feed out amount (a
rotation amount) of the belt driving roller 25 is calculated by referring to the roller
correction table and the belt correction table that were selected in Step S2. The
feed out amount is a value in which a correction value α that is determined from the
angle θ and a reference movement amount Kn, and a correction value σ that is determined
from the belt phase D and the reference movement amount Kn, are added to the reference
movement amount Kn.
[0078] In Step S4, the recording medium 95 is transported and ink is discharged. The control
section 1 moves the endless belt 26 by rotating the belt driving roller 25 by the
feed out amount that was calculated in Step S3, as a result of controlling the driving
of the belt driving roller 25. As a result of this, the recording medium 95, which
is mounted on the endless belt 26, is transported in the transport direction. Further,
the control section 1 discharges ink from the discharge head 42 toward the recording
medium 95 while moving the carriage 43 in a direction that intersects the transport
direction of the recording medium 95, by controlling the carriage movement section
41 and the discharge head 42.
[0079] In Step S5, it is determined whether or not there is subsequent line of printing
data. The CPU 3 determines whether or not there is a subsequent line of printing data
by referring to the printing data that is saved in the storage section 5. In a case
in which there is a subsequent line of printing data (Step S5: Yes), the process returns
to Step S3 and the processes from Step S3 to Step S5 are repeated. In a case in which
there is not a subsequent line of printing data (Step S5: No), the control section
1 finishes the printing operation of the printing apparatus 100.
[0080] As a result of the above-mentioned steps, since the movement accuracy of the endless
belt 26 and the transport accuracy of a recording medium 95, which is mounted on the
endless belt 26, is improved, it is possible to improve the printing quality of an
image that is formed on the recording medium 95.
[0081] In the abovementioned manner, according to the printing apparatus 100 of the present
embodiment, it is possible to obtain the following effects.
[0082] The printing apparatus 100 includes a roller correction table acquisition unit that
acquires a roller correction table that corrects a movement error caused by decentering
of the belt driving roller 25, and a belt correction table acquisition unit that acquires
a belt correction table that corrects a movement error caused by the thickness of
the endless belt 26. The control section 1 drives the belt driving roller 25 by calculating
a rotation amount of the belt driving roller 25 on the basis of the roller correction
tables and the belt correction tables that are saved in the storage section 5. As
a result of this, it is possible to correct a movement error of the endless belt 26
caused by decentering of the belt driving roller 25 in addition to a movement error
caused by variations in the thickness of the endless belt 26. Accordingly, it is possible
to provide a printing apparatus 100 that includes a unit that acquires a movement
error of the endless belt 26 caused by decentering of the belt driving roller 25,
and is capable of correcting the movement error.
[0083] Since the printing apparatus 100 includes the roller correction table acquisition
unit and the belt correction table acquisition unit, it is possible to acquire roller
correction tables and belt correction tables based on various printing conditions
that the printing apparatus 100 is provided with, and include the roller correction
tables and the belt correction tables in the storage section 5. The control section
1 selects a roller correction table and a belt correction table that match printing
conditions stipulated at the time of printing, and corrects the movement errors of
the endless belt 26 on the basis of these tables. As a result of this, it is possible
to correct movement errors of the endless belt 26 caused by printing conditions.
[0084] Since the printing apparatus 100 includes roller correction tables and belt correction
tables that are acquired on the basis of printing quality, it is possible to perform
correction that includes a movement error of the endless belt 26 caused by differences
in the printing velocity, which depends on the printing quality.
[0085] Since the printing apparatus 100 includes roller correction tables and belt correction
tables that are acquired on the basis of the type of recording medium 95, it is possible
to perform correction that includes a movement error of the endless belt 26 caused
by differences in the type of recording medium 95.
[0086] Since the printing apparatus 100 includes roller correction tables and belt correction
tables that are acquired on the basis of the condition relating to the tension when
transporting a recording medium 95, it is possible to perform correction that includes
a movement error of the endless belt 26 caused by differences in the condition relating
to the amount of tension of a recording medium 95.
[0087] According to the printing apparatus 100, since the movement accuracy of the endless
belt 26 and the transport accuracy of a recording medium 95, which is mounted on the
endless belt 26, is improved, it is possible to improve the printing quality of an
image that is formed on the recording medium 95.
Embodiment 2
[0088] Fig. 11 is a schematic diagram that schematically shows an overall configuration
of a printing apparatus according to Embodiment 2. Fig. 12 is an enlarged view of
a tension measurement section. A printing apparatus 200 according to the present embodiment
will be described with reference to these drawings. Additionally, constituent sites
that are the same as those of Embodiment 1 will be given the same reference numerals,
and overlapping descriptions thereof will be omitted. The printing apparatus 200 includes
tension measurement sections 110 and 130 that measure an amount of tension that is
applied to a recording medium 95 on at least one of an upstream side and a downstream
side of the endless belt 26 in the movement direction of the recording medium 95.
The printing apparatus 200 of the present embodiment includes the tension measurement
sections 110 and 130 on both the upstream side and the downstream side.
[0089] The recording medium transport section 20 includes a transport roller 21, a movable
roller 122, a transport roller 23, a belt rotation roller 24, a belt driving roller
25, an endless belt 26, a transport roller 27, a movable roller 128 and a transport
roller 29. The transport rollers 21 and 23, and the movable roller 122 relay a recording
medium 95 from the recording medium supply section 10 to the endless belt 26. The
movable roller 122 is provided between the transport roller 21 and the transport roller
23, and is configured so as to be movable in the vertical direction (the Z axis direction).
The movable roller 122 is a constituent component of the tension measurement section
110, which measures an amount of tension of a recording medium 95 that is supplied
to the endless belt 26 from the recording medium supply section 10.
[0090] The transport rollers 27 and 29, and the movable roller 128 relay a recording medium
95 from the endless belt 26 to the recording medium recovery section 30. The movable
roller 128 is provided between the transport roller 27 and the transport roller 29,
and is configured so as to be movable in the vertical direction (the Z axis direction).
The movable roller 128 is a constituent component of the tension measurement section
130, which measures an amount of tension of a recording medium 95 that is recovered
by the recording medium recovery section 30 from the endless belt 26.
[0091] Next, the tension measurement section 130 will be described. Additionally, since
the tension measurement section 110 has the same configuration as the tension measurement
section 130, description thereof will be omitted.
[0092] The tension measurement section 130 is provided with the movable roller 128 and an
optical sensor 140. The movable roller 128 has a predetermined mass, and the position
of the movable roller 128 moves along the vertical direction (the Z axis direction)
as a result of the amount of tension that is applied to a recording medium 95. That
is, the movable roller 128 is positioned in the +Z axis direction in a case in which
the amount of tension of a recording medium 95 is high, and the movable roller 128
is positioned in the -Z axis direction in a case in which the amount of tension of
a recording medium 95 is low.
[0093] A plurality of optical sensors 140 are provided along the Z axis direction in which
the movable roller 128 moves. In the present embodiment, three optical sensors 140a,
140b and 140c are provided from the +Z axis direction toward the -Z axis direction.
The optical sensors 140a, 140b and 140c detect the position of a lower end of the
movable roller 128. The optical sensors 140a, 140b and 140c are configured to include
a light emission section, which includes a light emitting element, or the like, that
emits light, and a light reception section, which includes a light receiving element,
or the like, that receives light emitted from the light emission section. Optical
axes of the light emission sections are directed toward the movable roller 128, which
is movable in the Z axis direction.
[0094] Light that is emitted from the light emission sections is received by the light reception
sections in a case in of being reflected by a recording medium 95 that is latched
onto the movable roller 128. The optical sensors 140a, 140b and 140c output an "ON"
signal when reflected light that is reflected by a recording medium 95 is received,
and an "OFF" signal when it is not possible to receive reflected light. For example,
in a case in which the movable roller 128 is positioned in a first position 128a,
the optical sensor 140a outputs the "ON" signal, and the optical sensors 140b and
140c output the "OFF" signal. In addition, in a case in which the movable roller 128
is positioned in a third position 128c, the optical sensors 140a, 140b and 140c output
the "ON" signal.
[0095] The control section 1 can determine the position of the movable roller 128 in the
Z axis direction by analyzing the signals that are output from the optical sensors
140a, 140b and 140c. In addition, since the position of the movable roller 128 in
the Z axis direction is proportionate to the amount of tension that is applied to
a recording medium 95, the control section 1 can detect the amount of tension that
is being applied to a recording medium 95 by determining the position of the movable
roller 128 in the Z axis direction. Additionally, in the present embodiment, a configuration
example that uses three optical sensors is shown, but configurations that use one
or two optical sensors or four or more optical sensors, may also be used. It is possible
to reduce the cost of the tension measurement sections in a case of a configuration
using one or two optical sensors. It is possible to improve the measuring accuracy
of the amount of tension that is applied to a recording medium 95 in a case of a configuration
using four or more optical sensors. In addition, a method that uses the optical sensors
140 is illustrated by way of example as a method for determining the position of the
movable roller 128 in the Z axis direction, but a method that uses a laser length
measurement machine may also be used. For example, it is possible to determine the
position of the movable roller 128 in the Z axis direction by providing a laser length
measurement machine, which emits laser light toward the movable roller 128 from vertically
above or vertically below the movable roller 128.
[0096] The printing apparatus 200 includes a roller correction table acquisition unit that
acquires a roller correction table, and a belt correction table acquisition unit that
acquires a belt correction table. Roller correction tables and belt correction tables
that are acquired using the acquisition units by including amounts of tension that
can be measured by the tension measurement sections 110 and 130 as a parameter, are
saved in the storage section 5.
[0097] The control section 1 of the printing apparatus 200 selects a roller correction table
and a belt correction table that match amounts of tension that are measured by the
tension measurement sections 110 and 130 at the time of printing.
[0098] To explain in more detail, in a case in which amounts of tension that are measured
by the tension measurement sections 110 and 130 fluctuate at the time of printing,
the control section 1 selects a roller correction table and a belt correction table
that match the amounts of tension that are measured by the tension measurement sections
110 and 130, from the plurality of roller correction tables and the plurality of belt
correction tables that are saved in the storage section 5 by performing acquisition
including the tension as a parameter. As a result of this, it is also possible to
obtain correction values α and σ that include movement errors of the endless belt
26 caused by amounts of tension of a recording medium 95 in a case in which there
are fluctuations in the amount of tension of a recording medium 95 at the time of
printing. The control section 1 calculates a feed out amount (a rotation amount) of
the belt driving roller 25 using the correction values α and σ.
[0099] The control section 1 moves the endless belt 26 by rotating the belt driving roller
25 by the calculated feed out amount, as a result of controlling the belt driving
roller 25. As a result of this, a recording medium 95, which is mounted on the endless
belt 26, is transported in the transport direction.
[0100] In the abovementioned manner, according to the printing apparatus 200 of the present
embodiment, it is possible to obtain the following effects.
[0101] The printing apparatus 200 is provided with the tension measurement sections 110
and 130 that measure the amount of tension of a recording medium 95. Since the control
section 1 selects a roller correction table and a belt correction table that match
the amount of tension that is measured by the tension measurement sections 110 and
130, it is even possible to obtain correction values α and σ that include a movement
error of the endless belt 26 caused by amounts of tension of a recording medium 95
in a case in which there are fluctuations in the amount of tension of a recording
medium 95 during printing. As a result of this, since the movement accuracy of the
endless belt 26 and the transport accuracy of a recording medium 95, which is mounted
on the endless belt 26, is improved, it is possible to improve the printing quality
of an image that is formed on the recording medium 95.
[0102] Where there are two tension measurement sections 110 and 130 provided, their outputs
may be used as separate tension parameters for the tables or as a combined tension
parameter.
[0103] Once the correction tables have been acquired and stored, it is no longer necessary
to use or retain the acquisition unit or the movement amount detection sensor 70 unless
the tables are to be updated or new tables are to be added. It is sufficient just
to store the tables.
[0104] The foregoing description has been given by way of example only and it will be appreciated
by a person skilled in the art that modifications can be made without departing from
the scope of the present invention as defined by the claims.