[0001] The present invention relates to an ink jet head for ejecting ink through nozzles
by exerting pressure on ink in ink channels formed in the ink jet head, and an ink
jet recorder using the ink jet head, and a method for manufacturing the ink jet head.
[0002] A communication device such as a facsimile machine or an information processor such
as a personal computer usually has a recorder capable of recording data, comprising
characters or graphics, onto a sheet of paper so as to store this data as visual information.
The recorder adopts a printing system such as impact system, thermal system or ink
jet system. In recent years, increased attention has been paid to an ink jet recorder
using the ink jet system which is highly quiet and can print on various types of paper.
[0003] The above-described ink jet recorder has an ink jet head with numerous nozzles for
ejecting ink droplets toward a sheet of paper so as to print characters or graphics
thereon. An ink jet head may have a structure as illustrated in Figs. 13 to 15. As
shown there, a plate member 103 is bonded to an actuator base plate 100 to alternately
form ejection channels (ink channels) 111, and dummy channels (blank channels) 110
which accommodate no ink and do not eject ink. A nozzle plate 107 having nozzles 106
formed in correspondence with the respective ejection channels 111 is bonded to an
end face of the actuator base plate 100. A shielding plate 109 having channel holes
108 formed in correspondence with the ejection channels 111 is bonded to the other
end face of the actuator base plate 100. As a result, the dummy channels 110 are spatially
separated from an ink supply path 112, and the ink supply path 112 is caused to communicate
only with the ejection channels 111. Side walls 101 between the ejection channels
111 and the dummy channels 110 are each constituted of a polarized piezoelectric material,
and an electrode 102 is formed on the surface of each side wall. A drive electric
field is applied to the side wall 101 via the electrode 102 to bend the side wall
101 and change the capacity of the ink chamber 110. The resulting increase and decrease
in the ink pressure cause the ink to be discharged (ejected) from and supplied to
the ejection channel 111.
[0004] According to this ink jet head, as noted above, the side walls 101 are bent to increase
or decrease the capacity of the ejection channel 111 so that ink droplets will be
ejected from a predetermined ejection channel 111. On this occasion, the adjacent
dummy channel 110 increases or decreases in capacity. However, this dummy channel
110 is separated from the ink supply path 112 by the shielding plate 109 to be kept
free from ink. Thus, the ink pressure in the adjacent ejection channel 111 is not
affected by the capacity change of the dummy channel 110. Consequently, ink droplets
can be ejected at the desired ink pressure.
[0005] The foregoing structure in which the dummy channels 110 and the ink supply path 112
are separated by the shielding plate 109, however, requires that the dummy channels
110 facing the ink supply path 112 be completely sealed with the shielding plate 109.
This results in a large area of application of an adhesive for bonding the shielding
plate 109. Thus, a bonding failure due to uneven application of the adhesive may occur,
making it difficult to separate the dummy channels 110 from the ink supply path 112
reliably. Furthermore, the need for the shielding plate 109 increases the number of
the parts required, thereby raising the cost of the ink jet head.
SUMMARY OF THE INVENTION
[0006] It is an object of the present invention, therefore, to provide a liquid ejection
head, an ink jet recorder, and an ink jet head manufacturing method, each of which
can separate the dummy channels 110 from the ink supply path 112 reliably without
using the shielding plate 109.
[0007] A first aspect of the present invention provides a liquid ejection head having a
plurality of nozzles for ejecting a liquid and a liquid supply port through which
the liquid is supplied, the liquid ejection head comprising:
a head body;
a plurality of liquid channels each formed inside the head body so as to communicate
at one end thereof with the nozzle and communicate at the other end thereof with the
liquid supply port, the liquid channels each being capable of ejecting the liquid
through the nozzle when at least one of side walls of each liquid channel is deformed;
and
a plurality of blank channels each formed inside the head body so as to be adjacent
to the liquid channel via the side wall, the interior of the blank channel being blocked
so that the blank channel and the liquid supply port will not communicate with each
other.
[0008] According to the liquid ejection head of the present invention, there is no need
to use the shielding plate employed in the ink jet head shown in Figs. 13 to 15, so
that the number of the constituent parts of the head can be reduced. Moreover, the
sealing of the blank channels, namely, dummy channels, can be achieved by the blockage
of the blank channels. Thus, the reliability of sealing is enhanced compared with
the adhesion of the shielding plate to the opening portions of the blank channels.
[0009] In the liquid ejection head of the present invention, the liquid channels may be
formed so as to pass straight through the head body. Alternatively, when the liquid
is fed through the liquid supply port provided in an upper part of the head, namely
when the liquid is fed from a direction perpendicular to the lengthwise direction
of the channel, as disclosed in the United States Patent No. 5,650,810, the liquid
channel may be curved upwardly midway, without passing through the head body, to communicate
with the liquid supply port. In the present invention, whichever structure the liquid
channel has, the blank channels each have one end thereof blocked inside the head
body.
[0010] The liquid ejection head of the present invention may further include a nozzle plate
having the nozzles formed therein, a member having the liquid supply port formed therein,
and a cover plate for covering channel opening portions open along the lengthwise
direction of the liquid channels and the blank channels. In this case, the bottom
of the blank channel comes into contact with the cover plate at or adjacent to one
end of the blank channel, whereby the one end of the blank channel can be blocked
inside the head body. The side wall may be constituted by laminating piezoelectric
layers polarized in reverse directions.
[0011] The liquid ejection head of the present invention may be a liquid ejection head formed
by a method including the steps of:
forming a plurality of channels parallel and at predetermined spacing in one direction
of a plate material made of a piezoelectric material such that one of the adjacent
channels is blocked at one end thereof to constitute a blank channel, while the other
channel is open at both ends thereof to constitute a liquid channel, whereby the head
body is produced;
securing the nozzle plate having nozzles formed therein to the head body so as to
establish communication between the nozzles and one end of each of the liquid channels;
securing the member having a liquid supply port formed therein to the head body so
as to establish communication between the liquid supply port and the other end of
each of the liquid channels; and
securing the cover plate to the head body so that the plurality of liquid channels
and blank channels formed in the head body are covered in the lengthwise direction.
[0012] A second aspect of the present invention provides an ink jet recorder comprising:
an ink jet head having a plurality of nozzles for ejecting ink onto a recording medium
and an ink supply port through which ink is supplied, and;
an ink supply device connected to the ink jet head for supplying ink thereto;
the ink jet head including:
a head body;
a plurality of ink channels each formed inside the head body so as to communicate
at one end thereof with the nozzle and communicate at the other end thereof with the
ink supply port, the ink channels each being capable of ejecting ink through the nozzle
when at least one of side walls of each ink channel is deformed; and
a plurality of blank channels each formed inside the head body so as to be adjacent
to the ink channel via the side wall, the interior of each blank channel being blocked
so that the blank channel and the ink supply port will not communicate with each other.
[0013] According to the ink jet recorder of the present invention, the constitution of the
ink jet head is so simple that the recorder can be produced at a low cost. Furthermore,
the blank channels of the ink jet head can be sealed without fail, so that the recorder
can be a highly reliable product.
[0014] A third aspect of the present invention provides a method for producing an ink jet
head having a plurality of ink channels and blank channels formed in a head body,
the method comprising the steps of:
forming a plurality of channels parallel and at predetermined spacing in one direction
of a plate material made of a piezoelectric material such that one of the adjacent
channels is blocked at one end thereof to constitute a blank channel, while the other
channel is open at both ends thereof to constitute an ink channel;
securing a nozzle plate having nozzles formed therein to the plate material so as
to establish communication between the nozzles and one end of each of the ink channels;
securing a member having an ink supply port formed therein to the plate material so
as to establish communication between the ink supply port and the other end of each
of the ink channels; and
securing a cover plate to the plate material so that the plurality of ink channels
and blank channels formed are covered in the lengthwise direction.
[0015] According to the method for producing an ink jet head of the present invention, when
the plurality of ink channels and blank channels are to be formed using, say, a diamond
cutter, the plate material is cut so that the resulting channels will completely cross
(pass through) the head body if the channels serve as ink channels. To form a channel
which will make up a blank channel, the plate material is cut, beginning at one end
thereof, but its cutting is stopped before the cut area extends to the other end,
whereby one of the ends of the channel is blocked. By so forming the blank channel,
it becomes possible to block the blank channel without using a member such as a shielding
plate. Thus, the procedure for the production of the ink jet head can be simplified.
[0016] In the above method of the present invention, blank channels and ink channels can
be formed in another plate material made of a piezoelectric material by the step of
forming a plurality of channels parallel and at predetermined spacing; and
the plate material and the other plate material can be positioned such that the
ink channels of the plate material and the ink channels of the other plate material
are not opposed to each other, and the plate material and the other plate material
can be bonded together via the cover plate such that lengthwise open portions of the
ink channels of the plate material and the other plate material are covered with the
cover plate.
[0017] The present invention will be more clearly understood from the following description,
given by way of example only, with reference to the accompanying drawings in which:
Fig. 1 is an exploded perspective view of an ink jet head according to an embodiment
of the present invention;
Fig. 2 is a longitudinal sectional view of the ink jet head of Fig. 1;
Fig. 3 is an explanatory view showing the state of ink chambers in the ink jet head
of Fig. 1;
Fig. 4 is an exploded perspective view of an ink jet head according to another embodiment
of the present invention;
Fig. 5 is a longitudinal sectional view of the ink jet head of Fig. 4;
Fig. 6 is another longitudinal sectional view of the ink jet head of Fig. 4;
Fig. 7 is an exploded perspective view of an ink jet head according to still another
embodiment of the present invention;
Fig. 8 is a longitudinal sectional view of the ink jet head of Fig. 7;
Fig. 9 is another longitudinal sectional view of the ink jet head of Fig. 7;
Fig. 10 is an exploded perspective view of an ink jet head according to a modified
embodiment of the present invention;
Fig. 11 is a longitudinal sectional view of the ink jet head of Fig. 10;
Fig. 12 is another longitudinal sectional view of the ink jet head of Fig. 10;
Fig. 13 is an exploded perspective view of a conventional ink jet head;
Fig. 14 is a longitudinal sectional view of the ink jet head of Fig. 13; and
Fig. 15 is another longitudinal sectional view of the ink jet head of Fig. 13.
[0018] Embodiments of the present invention will now be described with reference to the
accompanying Figs. 1 to 12.
[0019] An ink jet head related to the embodiment of the invention, as illustrated in Fig.
1, has a first actuator base plate 2U, a second actuator base plate 2L, a plate member
4, a nozzle plate 6, and a manifold member 7. Both actuator base plates 2U, 2L are
each formed of a piezoelectric material comprising a lead zirconate titanate (PZT)
based ceramic material. On one surface of each actuator base plate, a plurality of
two kinds of channels, i.e., first and second channels 14 and 15, formed by cutting
with a diamond blade or the like are alternately provided. As the piezoelectric material,
a lead titanate (PT) based ceramic material may be used.
[0020] The first channel 14, as shown in Fig. 2, mostly has a flat upper (or bottom in 2L)
surface 14a. This surface 14a is formed with a first depth H1 in a region ranging
from the rear end (right end in the drawing) to an intermediate portion near the front
end (left end in the drawing) of the first or second actuator base plate 2U or 2L.
Then, the surface 14a is formed to become shallower from the intermediate portion
toward the front end, and have a second depth H2 at the front end 14b. The second
channel 15, like the first channel 14, mostly has a flat bottom (or upper in 2U) surface
15a. This surface 15a is formed with a depth H3 in a region ranging from the front
end to a site near the rear end of the actuator base plate 2. Then, the surface 15a
is formed to be coplanar, at the rear end 15b, with one surface (the surface on the
open plane side in the longitudinal direction of each channel) of the first and second
actuator base plates 2U and 2L. These first channels 14 and second channels 15, as
shown in Fig. 1, are arranged alternately with side walls 20 therebetween.
[0021] The side wall 20, as illustrated in Fig. 3, is formed of a plurality of (e.g., two)
layers of a piezoelectric material that have been laminated in the depth direction
of the channel 14 or 15. The side wall 20 is polarized in a direction perpendicular
to the direction of arrangement, and the longitudinal direction of, these channels
14 and 15, and the respective layers of the side wall 20 are polarized in reverse
directions 27U, 27L to each other. On the wall surfaces of the side wall 20, electrodes
22 are formed by vacuum deposition or plating. The electrodes 22 apply an electric
field in a direction perpendicular to the reverse directions 27U and 27L, thereby
bending the polarized side wall 20 as shown in Fig.3.
[0022] The first and second actuator base plates 2U and 2L constituted as described above
are disposed such that their first channels 14 are not opposed to each other, for
example, that the first channel 14 is opposed to the second channel 15 as shown in
Fig.3. Between the first and second actuator base plates 2U and 2L, the flat plate-shaped
plate member 4 comprising a ceramic material or a resin material is provided. The
plate member 4 is adhered to the aforementioned one surface of the actuator base plates
2U, 2L in a liquid-tight condition by means of an epoxy resin adhesive 24. Thus, the
first channel 14 of the first and second actuator base plates 2U and 2L, as shown
in Fig. 2, is covered with the plate member 4 to define an ejection channel 10 which
serves as an ink (liquid) channel with its front end and rear end open. The second
channel 15 is also covered with the plate member 4 to form a dummy (blank) channel
11 with its front end open and with its rear end 15b being sealed by the contact of
the one surface of the actuator base plates 2U, 2L with the plate member 4.
[0023] To the front ends of the first and second actuator base plates 2U and 2L having the
ejection channels 10 and dummy channels 11 and the plate member 4, the nozzle plate
6 is bonded using the above-mentioned epoxy resin adhesive. The nozzle plate 6 is
formed from a plastic material such as polyalkylene (e.g., polyethylene) terephthalate,
polyimide, polyether imide, polyether ketone, polyether sulfone, polycarbonate or
cellulose acetate.
[0024] In the nozzle plate 6, nozzles 30 are arranged in a staggered manner, as shown in
Fig. 1, in agreement with the ejection channels 10 arranged alternately in two rows,
i.e., upper and lower rows. The nozzle 30, as shown in Fig. 2, is in a nearly truncated
conical shape. Its bore increases from the exit side toward the ejection channel 10
side, reaching nearly the maximum diameter that can be set for the channel cross section
of the ejection channel 10, at the end face of the ejection channel 10. The ejection
channel 10 which the nozzle 30 communicates with is desirably constituted as follows:
The ratio of the second depth H2 of the ejection channel 10 at the end beside the
nozzle 30 to the first depth H1 of the ejection channel 10 at a position distant from
the nozzle 30, i.e. a position at which the bottom of the ejection channel 10 is plane,
is set to be in the range of from 0.1 to 0.8. This is to ensure that air bubbles can
be fully removed through the nozzle 30 by a decreased number of treatments for closely
contacting a suction device with the outside of the nozzle 30 and sucking ink in the
ejection channel 10 under negative pressure. Furthermore, the channel cross section
beside the front end 14b of the ejection channel 10 is desirably constituted as follows:
The ratio of the distance between the side walls 20 to the height of the side wall
20 is set to be in the range of from 0.5 to 2.0 so that the removal of air bubbles
can be performed even more satisfactorily.
[0025] To the rear ends of the first and second actuator base plates 2U and 2L and the plate
member 4, the manifold member 7 is bonded. In a part of the manifold member 7, an
ink supply port 31 is formed for the supply of ink from an ink tank (not shown). The
manifold member 7 forms an ink supply path 9 communicating with all of the ejection
channels 10. When the ejection channel 10 increases in capacity, the manifold member
7 feeds ink to the expanded ejection channel 10.
[0026] In the foregoing constitution, the actions of the ink jet head will be described.
[0027] When the ink jet recorder is to perform printing, as shown in Fig. 3, a specific
ejection channel is selected in accordance with print data given. For electrodes 22A
and 22D of dummy channels 11A and 11C located on both sides of the selected ejection
channel 10B, a drive voltage is produced. Also, electrodes 22B and 22C of the ejection
channel 10B are grounded to have a GND potential. As a result, the respective layers
of the polarized side walls 20A and 20B on both sides of the ejection channel 10B
deform in reverse directions because of a piezoelectric thickness shear effect, so
that the side walls 20A and 20B bend so as to widen outward at the center. Since the
ejection channel 10B increases in capacity owing to the bending of the side walls
20A, 20B, the ink pressure in the ejection channel 10B decreases. Thus, ink in the
ink supply path 9 is fed into the ejection channel 10B. Then, the drive voltage for
the electrodes 22A and 22D is removed with a predetermined timing with respect to
the supplied ink in the ejection channel 10B, whereupon the side walls 20A, 20B return
to their original straight form. By this return action, the ink in the ejection channel
10B is pressurized at a high pressure, whereby an ink droplet is ejected from the
nozzle 30.
[0028] Alternatively, an ink droplet may be ejected by bending the side walls 20A, 20B so
as to approach each other, and ink may be supplied from the ink supply path 9 into
the ejection channel 10B by restoring the side plates 20A, 20B to the straight form.
It is also permissible to combine these bending actions in a plurality of ways, thereby
stabilizing the ejection of ink droplets or varying the operating characteristics
of ink droplets.
[0029] The above manner of printing varies the capacity of the dummy channels 11A, 11C,
because the side walls 20A, 20B are shared between the ejection channel 10B and the
dummy channels 11A, 11C adjacent to the ejection channel 10B. On this occasion, the
dummy channels 11A, 11C, as shown in Fig. 2, have the rear end thereof sealed by the
contact of one surface of the actuator base plate 2L with the plate member 4. Thus,
the dummy channel is separated spatially from the ink supply path 9 and no ink is
present there. When the capacity of the dummy channels 11A, 11C changes, therefore,
this change in capacity does not affect the ink pressure of the ejection channel 10B
via the ink supply path 9. Hence, printing is carried out with ink droplets in a stable
amount of ejection. Preferably, the sealed portion at the rear end of the dummy channel
is not very large.
[0030] As described above, the ink jet head according to the instant embodiment is constituted
such that a plurality of channels are formed in the first and second actuator base
plates 2U, 2L; of these plural channels, the channels constituting ink channels for
ejection of ink are the ejection channels 10; the channels adjacent to the ejection
channels via the side walls 20 are the dummy channels 11 which do not accommodate
ink; and at the rear end (one end) of the first and second actuator base plates 2U,
2L, the ink supply path 9 is connected for opening the same-side end of the plurality
of ejection channels 10 and supplying ink to the plurality of ejection channels 10,
whereby the dummy channel 11 does not reach the rear end (one end).
[0031] In this manner, the sealing of the dummy channel 11 relative to the ink supply path
9 is completed. Compared with the conventional sealing of the dummy channels relative
to the ink supply path 9 by a shielding plate, therefore, this type of sealing lessens
the adhering procedure for sealing, thereby increasing the reliability of sealing.
Since the shielding plate for sealing is not necessary, moreover, the number of the
parts for forming the dummy channels can be reduced.
[0032] In the instant embodiment, the side walls 20 are polarized in a direction perpendicular
to the direction of arrangement of, and the longitudinal direction of, the plurality
of channels 10, 11, and a voltage is applied to the electrodes 22 provided along the
side wall 20, whereby the adjacent ejection channel 10 and the adjacent dummy channels
11 can be deformed so that their capacities will be changed. The application of voltage
to the electrodes 22 thus deforms the adjacent ejection channel and dummy channels
in directions in which their capacities are varied. However, ink is absent in the
dummy channels 11 sealed with respect to the ink supply path 9. Thus, ink can be ejected
from the predetermined ejection channel, with no influence exerted on the other ejection
channels 10.
[0033] In the instant embodiment, the ejection channels 10 and the dummy channels 11 are
alternately arranged, and both side walls 20 of the ejection channel are deformable.
Thus, when both side walls 20 of a specific ejection channel are deformed, a great
change in capacity is caused to the predetermined ejection channel with the other
ejection channels being unaffected, since the ejection channels and the dummy channels
are alternately arranged. Consequently, ink can be ejected efficiently.
[0034] In the instant embodiment, the plate member 4 is bonded to the first and second actuator
base plates 2U and 2L so as to cover the open surface (one surface) in the longitudinal
direction of the first channels 14 and second channels 15 corresponding to the plurality
of channels. When the plate member 4 is bonded to the first and second actuator base
plates 2U and 2L, the vicinity of one end 15b of the second channel 15 contacts the
plate member 4, thus reliably sealing the dummy channel 11 relative to the ink supply
path 9.
[0035] In the instant embodiment, a pair of first and second actuator base plates 2U and
2L alternately having the ejection channels 10 and dummy channels 11 are arranged
such that the ejection channels 10 of the first actuator base plate 2U are opposed
to the dummy channels 11 of the second actuator base plate 2L, and the plate member
4 is bonded to and disposed between the pair of first and second actuator base plates
2U and 2L so as to cover the open surface in the longitudinal direction of each channel.
Since the ejection channels 10 are so alternately arranged in two rows, upper row
and lower row, by both actuator base plates 2U and 2L, high density recording becomes
possible. When the pair of first and second actuator base plates 2U and 2L are bonded
together via the plate member 4, the vicinity of one end of each of the dummy channels
11 of the actuator base plates 2U and 2L contacts either surface of the plate member
4, so that the dummy channels 11 can be reliably sealed relative to the ink supply
path 9.
[0036] The ink jet head according to the instant embodiment has the first and second actuator
base plates 2U and 2L bonded together via the plate member 4, thus having channels
comprising the ejection channels 10 and dummy channels 11 in two rows, upper row and
lower row. However, the ink jet head is not restricted to this constitution. That
is, the ink jet head, as shown in Figs. 4 to 6, may be constituted such that a plate
member 4 is bonded to one surface of one actuator base plate 2 via an adhesive layer
24, whereby channels comprising ejection channels 10 and dummy channels 11 are provided
in one row. In this case, the side wall 20 is formed of one layer of a piezoelectric
material polarized in only one direction, and an electrode 22 is formed only in an
upper half of the side wall 20.
[0037] The ink jet head, as shown in Figs. 7 to 9, may also be constituted as follows: To
an actuator base plate 2 polarized in a direction 27L, a piezoelectric member 25 polarized
in the direction 27U opposite to the direction 27L is bonded via an adhesive layer
26. Then, the piezoelectric member 25 and the actuator base plate 2 are cut to form
first channels 14 and second channels 15. Electrodes 22L and 22U are formed on a side
wall 20 comprising the piezoelectric member 25 and the actuator base plate 2 to give
the side wall 20 two layers polarized in reverse directions 27U and 27L. As noted
from this, the ink jet head is configured to comprise a plurality of layers polarized
in reverse directions, a plurality of channels formed along the plurality of layers,
and the plate member 4 bonded to the actuator base plate 2 so as to cover the open
surface in the longitudinal direction of the plurality of channels. According to this
configuration, when voltage is applied to the electrodes 22L, 22U, the plurality of
layers deform in reverse directions in the same manner as in Fig. 3. This causes a
marked change in capacity to the ejection channel, whereby ink can be ejected efficiently.
[0038] The ink jet head, as shown in Figs. 10 to 12, may also be constituted as follows:
First and second actuator base plates 2U, 2L having electrodes 22U, 22L formed on
side walls 20U, 20L of first channels 14U, 14L and second channels 15U, 15L are vertically
bonded together as a pair. As a result, ejection channels 10 and dummy channels 11
are defined by the side walls 20U, 20L polarized in one direction 27U and in another
direction 27L. In this manner, the pair of first and second actuator base plates 2U,
2L having a plurality of channels are bonded together so that the open surfaces in
the longitudinal direction of the channels of the base plates 2U, 2L are opposed to
the others. This brings the vicinity of one end 15b of the second channel 15 of the
dummy channels into contact with the vicinity of the counterpart. Thus, the dummy
channel 11 can be reliably sealed with respect to the ink supply path 9.
[0039] The ink jet head of the present invention that has been described is useful for an
ink jet recorder such as ink jet printer and facsimile. The ink jet printer usually
has the ink jet head, an ink supply device such as an ink cartridge for feeding ink
to the ink jet head, and a carriage for holding the ink jet head and moving it along
and over a recording medium such as printing paper. Thereby, the ink jet printer ejects
the ink from the ink jet head onto a certain printing place on the recording medium.
An example of the ink jet printer to which the present invention can be applied is
disclosed in the United States Patent No. 5,639,220, the disclosure of which is incorporated
herein by reference.
[0040] According to the above-described embodiments, the rear end of the dummy channel is
not cut, but left intact for use as a sealed portion. However, the rear end of the
dummy channel may be cut similar to the ejection channel, and a filler may be filled
into the rear end portion of the dummy channel to form a sealed portion.
[0041] The present invention has been described with an ink jet head for use in an ink jet
printer being taken as the example. However, the invention may be applied to not only
ink jet printer, but any types of recorder such as a facsimile using an inkjet head.
Also, the invention is not restricted thereto, and may be applied, for example, to
any types of apparatus for ejecting molten solder, or a decorative liquid for foods
and cosmetics.
1. A liquid ejection head having a plurality of nozzles for ejecting a liquid and a liquid
supply port through which the liquid may be supplied, the liquid ejection head comprising:
a head body;
a plurality of liquid channels each formed inside the head body so as to communicate
at one end thereof with one of the nozzles and communicate at the other end thereof
with the liquid supply port, each liquid channel being capable of ejecting the liquid
through the one of the nozzles when at least one of side walls of the liquid channel
is deformed; and
a plurality of blank channels each formed inside the head body so as to be adjacent
to the liquid channel via the side wall, the interior of each blank channel being
blocked so that the blank channel and the liquid supply port will not communicate
with each other.
2. The liquid ejection head as claimed in claim 1, wherein the liquid channel is formed
so as to pass straight through the head body, while the blank channel has one end
thereof blocked inside the head body.
3. The liquid ejection head as claimed in claim 1 or 2, wherein the side wall is formed
of a piezoelectric element.
4. The liquid ejection head as claimed in claim 3, which has an electrode formed on the
side wall, and wherein the side wall is polarized in a direction perpendicular to
the direction of arrangement of, and the longitudinal direction of, the plurality
of channels, such that a voltage may be applied to the electrode to deform the liquid
channel.
5. The liquid ejection head as claimed in any preceding claim, wherein the liquid channels
and the blank channels are arranged alternatively.
6. The liquid ejection head as claimed in any preceding claim, wherein the side wall
is constituted by laminating piezoelectric layers polarized in reverse directions.
7. The liquid ejection head as claimed in any preceding claim, wherein the head body
has a set of head members each having a plurality of liquid channels, and the head
members are bonded together such that their respective liquid channels are opposed
to each other.
8. The liquid ejection head as claimed in any one of claims 1 to 6, wherein the head
body has a set of head members each having a plurality of liquid channels, the head
members are positioned such that their respective liquid channels are not opposed
to each other, and the head members are bonded together via a cover plate which covers
lengthwise open portions of their respective liquid channels.
9. The liquid ejection head as claimed in any preceding claim, further including a nozzle
plate having the nozzles formed therein, a member having the liquid supply port formed
therein, and a cover plate for covering channel opening portions open along the lengthwise
direction of the liquid channels and the blank channels.
10. The liquid ejection head as claimed in claim 9, wherein the bottom of the blank channel
comes into contact with the cover plate, whereby one end of the blank channel is blocked
inside the head body.
11. The liquid ejection head as claimed in any one of claims 1 to 8, further including
a nozzle plate having the nozzles formed therein, and a cover plate for covering channel
opening portions open along the lengthwise direction of the liquid channels and the
blank channels, the cover plate having the liquid supply port formed therein.
12. The liquid ejection head as claimed in claim 9 or 10, which has been formed by a method
including the steps of:
forming a plurality of channels parallel and at predetermined spacing in one direction
of a plate material made of a piezoelectric material such that one of the adjacent
channels is blocked at one end thereof to constitute a blank channel, while the other
channel is open at both ends thereof to constitute a liquid channel, whereby a head
body is produced;
securing the nozzle plate having nozzles formed therein to the head body so as to
establish communication between the nozzles and one end of each of the liquid channels;
securing the member having a liquid supply port formed therein to the head body so
as to establish communication between the liquid supply port and the other end of
each of the liquid channels; and
securing the cover plate to the head body so that the plurality of liquid channels
and blank channels formed in the head body are covered in the lengthwise direction.
13. An ink jet recorder comprising:
an ink jet head comprising a liquid ejection head according to any preceding claim;
and
an ink supply device connected to the ink jet head for supplying ink thereto; wherein
the nozzles are for ejecting ink onto a recording medium and the liquid supply port
is an ink supply port through which ink is supplied.
14. The ink jet recorder as claimed in claim 13 including an ink jet head which has been
formed by a method including the steps of:
forming a plurality of channels parallel and at predetermined spacing in one direction
of a plate material made of a piezoelectric material such that one of the adjacent
channels is blocked at one end thereof to constitute a blank channel, while the other
channel is open at both ends thereof to constitute an ink channel, whereby a head
body is formed;
securing the nozzle plate having nozzles formed therein to the plate material so as
to establish communication between the nozzle and one end of each ink channel;
securing the member having an ink supply port formed therein to the plate material
so as to establish communication between the ink supply port and the other end of
each ink channel; and
securing the cover plate to the plate material so that the plurality of ink channels
and blank channels formed are covered in the lengthwise direction.
15. A method for producing an ink jet head having a plurality of ink channels and blank
channels formed in a head body, the method comprising the steps of:
forming a plurality of channels parallel and at predetermined spacing in one direction
of a plate material made of a piezoelectric material such that one of the adjacent
channels is blocked at one end thereof to constitute a blank channel, while the other
channel is open at both ends thereof to constitute an ink channel;
securing a nozzle plate having nozzles formed therein to the plate material so as
to establish communication between the nozzle and one end of each ink channel;
securing a member having an ink supply port formed therein to the plate material so
as to establish communication between the ink supply port and the other end of each
ink channel; and
securing a cover plate to the plate material such that the plurality of ink channels
and blank channels formed are covered in the lengthwise direction.
16. The method as claimed in claim 15 wherein the plurality of ink channels and blank
channels are formed using a cutter.
17. The method as claimed in claim 15 or 16 wherin blank channels and ink channels are
formed in another plate material made of a piezoelectric material by the step of forming
a plurality of channels parallel and at predetermined spacing; and
the plate material and the other plate material are positioned such that their respective
ink channels are not opposed to each other, and the plate material and the other plate
material are bonded together via the cover plate such that lengthwise open portions
of their respective ink channels are covered with the cover plate.