JP2003063007A - Ink jet recording head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To resolve the problem of a conventional ink jet recording head and ink jet recorder such as that an ink liquid drop amount to be ejected from channels near both ends of actuator tends to be less than that to be ejected from other channels, and the ink ejection speed is controlled to cope with the situation, when the ink liquid drop amount needs to be uniformalized, but there is a possibility that the ink ejection speed exceeds a stable ejection region to cause a factor for deterioration of the recording quality. SOLUTION: The ink liquid drop amount to be ejected from the whole channels 2 is made even by lengthening the channel length of the channel near both end parts 2a having less ink liquid drop amount longer than that of the channel 2 at the center part 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head having an actuator utilizing shear mode deformation of a piezoelectric element and an ink jet recording apparatus utilizing the recording head.

[0002]

2. Description of the Related Art As a conventional example, JP-A-63-25275
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. 0, an ink jet recording apparatus provided with an ink jet recording head 16 utilizing shear mode deformation of a piezoelectric element as an ink ejection principle (see FIG. 8).
(See) is considered. As shown in FIG. 4, the ink jet recording head 16 is composed of a piezoelectric ceramic actuator member 9, a top sheet 6, a nozzle plate 7, and a printed wiring board 1. The actuator member 9 has a plurality of channels 2 formed by cutting with a diamond blade or the like. The partition walls 3 between the channels 2 are polarized in the groove depth direction. The channels 2 are arranged in parallel with the air chambers and the ink chambers alternately from the end.

The channels 2 have the same depth, the same groove width, and are parallel to each other. The depth of the channels 2 is, as shown in the sectional view of FIG. 5, the rear end surface of the actuator member 9 (nozzle plate 7 and Is shallower as it approaches the opposite surface), and a shallow region of the channel 2 is formed near the rear end surface. The signal electrode 4 is formed on the upper half of the inner wall of each channel 2 by a method such as vapor deposition or sputtering. Further, also in the shallow region of the channel 2, the signal electrode 4 is formed on the side surface and the bottom surface by the same method. As a result, the signal electrodes 4 formed on both side surfaces of the channel 2 are electrically connected by the signal electrodes 4 formed on the bottom surface of the shallow region of the channel 2.

Next, the top sheet 6 is made of a ceramic material, a resin material, or the like. Further, the ink supply port 5 and a manifold (not shown) are formed on the top sheet 6 by grinding or cutting.
The surface of the actuator member 9 on the processed side of the channel 2 and the surface of the top sheet 6 on the processed side of the manifold are adhered by an epoxy-based adhesive (not shown).
In this way, the ink jet recording head is formed with a plurality of ink flow paths having the same spacing in the lateral direction with the upper surface of the channel 2 covered, and a channel 2 serving as a pressure chamber through which ink does not penetrate. The channel 2 has an elongated shape with a rectangular cross section, and all the ink chambers are filled with ink from the ink supply port 5.

Further, as shown in FIG. 6, a nozzle plate 7 is adhered to the end faces of the actuator member 9 and the top sheet 6 so that the nozzles 8 are located at positions corresponding to the positions of the ink chambers. The nozzle plate 7 is made of a plastic such as polyimide, polyetherimide, polyetherketone, polyethersulfone, or polycarbonate. The nozzle plate 7 is attached to the ink discharge surface side of the actuator member 9 and the top sheet 6 by using an epoxy adhesive or the like, and after the center of each channel 2 is positioned by a microscope or the like, an apparatus such as an excimer laser is used. Are making holes.

The printed wiring board 1 is adhered to the surface of the actuator member 9 opposite to the channel 2 with an epoxy adhesive or the like. A conductive pattern 11 is formed on the printed wiring board 1 at a position corresponding to the position of each channel 2. The conductive pattern 11
And signal electrode 4 formed on the bottom of the shallow area of channel 2
Are connected by a bonding wire 10.

In such a conventional ink jet recording head, ink is filled from the ink supply port 5 into a plurality of channels 2 which are parallel to each other and are separated by a partition 3 made of a piezoelectric ceramic, while a partition forming the channel 2 is formed. The partition wall 3 is deformed according to the voltage applied to the signal electrode 4 formed on the inner wall of the channel 3, and the ink filled in the channel 2 is selectively selected from the nozzles 8 communicating with the channel 2 according to the deformation. Recording is possible by ejecting.

Further, when this ink jet recording head is used in a color filter manufacturing apparatus, for example, it is necessary to make the amount of droplets to be ejected into each cell of the color filter uniform, so that the number of droplets to be ejected can be changed or the droplets can be ejected. The applied voltage has been changed to change the quantity itself.

[0009]

However, in the above-described conventional structure, the ink flow is less in the both ends of the ink supply port 5 which is also the common ink chamber provided in the ink jet recording head 16 than in the central portion. The amount of ink droplets ejected from the nozzles near both ends of the inkjet recording head 16 tends to be smaller than the amount of ink droplets ejected from other nozzles. When it is necessary to make the droplet amounts uniform, the channel 2 having a small amount of ink droplets has a high ink discharge speed, and the channel 2 having a large amount of ink droplets has a low ink discharge speed. As a result, there is a problem that the ink ejection speed may deviate from the stable ejection area.

In consideration of such a conventional problem, the present invention makes it possible to maintain the ink ejection speed within the stable ejection area by making the ink droplet amounts on both ends and the central portion of the recording head uniform. It is an object of the present invention to provide an inkjet recording head and an inkjet recording device.

[0011]

According to a first aspect of the present invention, there are provided a plurality of channels which are separated from each other by a partition wall of a piezoelectric ceramic on which electrodes are formed and arranged in parallel with each other, and which communicate with the channels, and are connected from an ink supply port. In an inkjet recording head including an actuator having nozzles for ejecting supplied ink, the length of channels at both ends of the actuator is longer than the length of channels at portions other than both ends.

Further, the present invention according to claim 2 is such that the length of the channel is gradually increased stepwise from the channel on the center side of the channel at both ends toward the channel at both ends. It is an inkjet recording head.

Further, according to the invention of claim 3, the width of the ink supply port in the channel length direction is a size according to the length of the channel at the same position. It is a recording head.

According to a fourth aspect of the present invention, a plurality of channels, which are separated from each other by piezoelectric ceramic partition walls on which electrodes are formed and arranged in parallel with each other, and ink which is connected to the channels and is supplied from an ink supply port. In an inkjet recording head including an actuator having a nozzle for ejecting ink, the depth of channels at both ends of the actuator is deeper than the depth of channels at portions other than both ends.

Further, according to the present invention of claim 5, the depth of the channel is gradually increased stepwise from the channel on the center side of the channel at both ends toward the channel at both ends. It is an inkjet recording head.

According to a sixth aspect of the present invention, a plurality of channels, which are separated from each other by piezoelectric ceramic partitions on which electrodes are formed, are arranged in parallel with each other, and ink which communicates with the channels and is supplied from an ink supply port. In an inkjet recording head including an actuator having a nozzle for ejecting ink, the nozzle diameter of the nozzles at both ends of the actuator is larger than the nozzle diameter of the nozzles other than both ends.

Further, according to the present invention of claim 7, the size of the nozzle diameter is increased stepwise from the nozzle on the center side of the channel at both ends toward the nozzles at both ends. Is an inkjet recording head.

Further, the present invention according to claim 8 is the ink jet recording head according to any one of claims 1 to 7, wherein the range of both ends is substantially 10% of the total pitch of the channels in the actuator.

The present invention according to claim 9 provides the invention according to any one of claims 1 to 8.
An ink jet recording apparatus including any one of the ink jet recording heads.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing the embodiments thereof. (First Embodiment) FIG. 1 shows a first embodiment according to the present invention.
3A and 3B are a plan view and a vertical sectional view showing an actuator in the inkjet recording head of FIG. In addition, the same reference numerals are given to the substantially same components as those of the conventional example.

In FIG. 1, both ends 20a (both ends in the present invention) of a plurality of channels 2 (see FIG. 4) which are parallel to each other and are separated by a partition 3 of piezoelectric ceramics formed on the actuator member 9 are shown. Means not only at both ends but also at both ends or an appropriate range near both ends including both ends) than the channel length of another channel 2 such as the central portion 20b. It has a long structure, and the shape of the ink supply port 5 formed in the top sheet 6 is changed accordingly. That is, the ink supply port in the top sheet 6 attached to the upper surface of the channel 2 having the longer channel length is shortened, and the ink supply port corresponding to the channel 2 having the shorter channel length in the central portion 20b is lengthened. .

With the above structure, the ink can be smoothly supplied into the channel 2, and the ink droplets ejected from the channel 2 near both ends of the actuator, which has been a problem of the conventional ink jet recording head. The problem that the amount is smaller than others is solved.

Here, the channel length is configured to gradually increase in steps from the central portion 20b toward both end portions 20a. According to this structure, it is possible to make the droplet amount of the ejected ink more uniform than when the channel length of the longer channel is constant.

As described above, if the length of the channel 2 as shown in FIG. 1 can be changed, the same amount can be obtained from all channels 2 as compared with the conventional ink jet recording head having the configuration as shown in FIG. It is possible to eject the ink of the above, and it is possible to configure an ink jet recording head capable of ejecting the ink of a stable droplet amount without largely changing the ink ejection speed. The ink jet recording apparatus having the head 16 as shown in FIG. 8 can maintain high recording quality.

In the above embodiment, the channel length is made longer, that is, the range at both ends is set to an appropriate range near both ends, but the present invention is not limited to this, and only the channels at both ends may be made longer. .

Further, in the above-mentioned embodiment, the channel for increasing the channel length, that is, the range of both ends is set to an appropriate range near both ends. However, the present invention is not limited to this, and the amount of ink ejected is small. Since the range of channels is about 10% of the total pitch of the channel, it is optimal to set the range of both ends that lengthens the channel length, and thus the number of channels in both ends to about 10% of the total pitch of the channels. Is. (Second Embodiment) FIG. 2 shows a second embodiment according to the present invention.
FIG. 6 is a cross-sectional view showing an actuator in the inkjet recording head of FIG. In addition, the same reference numerals are given to the substantially same components as those of the conventional example.

As shown in FIG. 2, in the second embodiment,
Among the plurality of channels 2 which are parallel to each other and are separated by the partition walls 3 of the piezoelectric ceramics formed in the actuator member 9, the channel depth of the ink chamber of the channel 2 at both ends 20a is another channel 2 such as the central portion 20b. It is deeper than the channel depth of the ink chamber. In this way, since the channel depth of the ink chambers at both ends 20a of the actuator is deeper than that of the other channels 2, the deformation of the partition walls 3 of the piezoelectric ceramic becomes larger than the deformation of the partition walls 3 of the other ink chambers. The amount of ink droplets ejected is increased. By adopting the above configuration, the problem of the conventional ink jet recording head, that is, the problem that the amount of ink droplets ejected from the channels 2 near both ends of the actuator becomes smaller than others, is solved.

As described above, if the depth of the channel 2 as shown in FIG. 2 can be changed, the same amount can be obtained from all channels 2 as compared with the conventional ink jet recording head having the structure as shown in FIG. It is possible to eject the ink of the above, and it is possible to configure an ink jet recording head capable of ejecting the ink of a stable droplet amount without largely changing the ink ejection speed. The ink jet recording apparatus having the head 16 as shown in FIG. 8 can maintain high recording quality.

In the above-mentioned embodiment, the channel for deepening the channel depth is applied only to both ends (that is, the range of both ends is only to both ends). The amount of ink droplets ejected more than in the above configuration is set by gradually increasing the channel depth of the channel from the central side channel to the both ends within the range and increasing the channel depth. It becomes possible to achieve uniformization.

In the above embodiment, the channel depth is deepened, that is, the range of both ends is limited to both ends. However, the present invention is not limited to this, and the range of the channel in which the amount of ink droplets ejected is reduced. Is about 10% of the total pitch of the channels, so the range of both ends that deepens the channel depth, and thus the number of channels in both ends, is
The optimum value is about 10% of the total channel pitch.

(Third Embodiment) FIG. 3 is a side view showing a nozzle surface portion of an ink jet recording head according to a third embodiment of the present invention. In addition, the same reference numerals are given to the substantially same components as those of the conventional example.

As shown in FIG. 3, in the third embodiment,
Top sheet 6, actuator member 9, and piezoelectric ceramic partition wall 3 formed in the actuator member 9.
A plurality of parallel channels 2 separated by
(See FIG. 4) The nozzles 8 are attached so as to fit the nozzles 8 and correspond to the channels 2 at both ends 20a.
The nozzle diameter of the other nozzle 8 such as the central portion 20b
Is formed to be larger than the nozzle diameter. When the nozzle diameter of the nozzle 8 is large, the amount of ink droplets ejected from the nozzle 8 is also increased. By adopting the above configuration, the problem of the conventional ink jet recording head, that is, the problem that the amount of ink droplets ejected from the channels 2 near both ends of the actuator becomes smaller than others, is solved.

As described above, if the nozzle diameter of the nozzle 8 as shown in FIG. 3 can be changed, as compared with the conventional ink jet recording head having the structure as shown in FIG.
To configure an inkjet recording head capable of ejecting an equal amount of ink from all channels 2 and capable of ejecting a stable droplet amount of ink without greatly changing the ink ejection speed. FIG. 8 in which the inkjet recording head 16 is mounted is possible.
The inkjet recording apparatus as shown in FIG. 3 can maintain high recording quality.

In the above embodiment, the nozzle for increasing the nozzle diameter is applied only to both ends (that is, the range of both ends is only to both ends), but the present invention is not limited to this, and the both ends should be in an appropriate range near both ends. In addition, by further increasing the size of the nozzle diameter stepwise from the center side of the nozzle surface 7 toward the both ends, it is possible to further uniformize the droplet amount of the ejected ink as compared with the above configuration. It becomes possible to measure.

Further, in the above-mentioned embodiment, the nozzle for increasing the nozzle diameter, that is, the range of both ends is limited to both ends. However, the present invention is not limited to this, and the range of the channel in which the amount of ink ejected drops is small. Since the total pitch of the channels is about 10%, it is optimal that the range of both ends where the shape of the nozzle is changed, that is, the number of channels in both ends is about 10% of the total pitch of the channels. (Fourth Embodiment) FIG. 8 shows a fourth embodiment according to the present invention.
FIG. 3 is a schematic diagram showing the inkjet recording device of FIG. That is, the inkjet recording apparatus according to the fourth embodiment has the inkjet recording head 16 in the direction orthogonal to the recording medium operating direction 15 of the recording medium 17 such as printing paper.
The head scanning direction 14 is set. The inkjet recording head 16 uses any one of the inkjet recording heads described in the first to third embodiments.

With the above arrangement, the amount of ink droplets ejected from the channel 2 near both ends of the actuator can be made approximately the same as the amount of ink droplets ejected from the other channels 2, and the signal electrode It is almost unnecessary to change the drive voltage applied to the drive circuit 4, so that it is possible to realize driving with a lower voltage as compared with the conventional case. Further, as a result, there is almost no need to change the ink ejection speed, so that the ink can be ejected stably and the recording quality can be improved.

[0037]

As is clear from the above description, the present invention can be realized without drastically changing the ink ejection speed.
There is an advantage that the amount of ink droplets ejected from the channels, which are all ink chambers, becomes uniform and the ink ejection performance can be stabilized.

Further, there is an advantage that the recording quality is improved by stabilizing the ink ejection performance.

[Brief description of drawings]

FIG. 1 is a plan view and a vertical sectional view of an actuator in an inkjet recording head according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an actuator in an inkjet recording head according to a second embodiment of the present invention.

FIG. 3 is a side view of a nozzle surface portion in an inkjet recording head according to a third embodiment of the present invention.

FIG. 4 is an exploded perspective view of a conventional inkjet recording head.

5A and 5B are a plan view and a vertical sectional view of an actuator in a conventional inkjet recording head.

FIG. 6 is a cross-sectional view of an actuator in a conventional inkjet recording head.

FIG. 7 is a side view of a nozzle surface portion of a conventional inkjet recording head.

FIG. 8 is a schematic diagram of an ink jet recording apparatus according to a fourth embodiment of the present invention or a related art.

[Explanation of symbols]

1 printed wiring board 2 channels 3 partitions 4 electrodes 5 Ink supply port 6 top sheet 7 nozzle plate 8 nozzles 9 Actuator member 10 Bonding wire 11 Conductive pattern 14 head scanning direction 15 Recording medium scanning direction 16 inkjet recording head 17 Recording medium

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masao Konishi             1 Juden Matsushita, 1-8 Koshinmachi, Takamatsu City, Kagawa Prefecture             Child Industry Co., Ltd. (72) Inventor Hirofumi Sugimoto             1 Juden Matsushita, 1-8 Koshinmachi, Takamatsu City, Kagawa Prefecture             Child Industry Co., Ltd. (72) Inventor Takayoshi Oga             1 Juden Matsushita, 1-8 Koshinmachi, Takamatsu City, Kagawa Prefecture             Child Industry Co., Ltd. (72) Inventor Masatomo Matsui             1 Juden Matsushita, 1-8 Koshinmachi, Takamatsu City, Kagawa Prefecture             Child Industry Co., Ltd. F-term (reference) 2C057 AF23 AF42 AG13 AG29 AG45                       BA14

Claims (9)

[Claims] 1. A plurality of channels, which are separated from each other by piezoelectric ceramic partitions having electrodes and are arranged in parallel with each other, and nozzles which communicate with the channels and discharge ink supplied from an ink supply port. An ink jet recording head provided with an actuator, wherein the length of channels at both ends of the actuator is longer than the length of channels at portions other than the both ends. 2. The ink jet printer according to claim 1, wherein the length of the channel is gradually increased from the channel on the center side of the channels at both ends toward the channels at both ends. Recording head. 3. The ink jet recording according to claim 1, wherein the width of the ink supply port in the channel length direction is a size corresponding to the length of the channel at the same position. head. 4. A plurality of channels, which are separated from each other by piezoelectric ceramic partitions having electrodes and are arranged in parallel with each other, and nozzles which communicate with the channels and eject ink supplied from an ink supply port. An ink jet recording head provided with an actuator, wherein the depth of channels at both ends of the actuator is deeper than the depth of channels at portions other than the both ends. 5. The inkjet according to claim 4, wherein the depth of the channel is gradually increased stepwise from the channel on the center side of the channel at both ends toward the channel at both ends. Recording head. 6. A plurality of channels, which are separated from each other by piezoelectric ceramic partitions on which electrodes are formed and are arranged in parallel with each other, and nozzles which communicate with the channels and discharge ink supplied from an ink supply port. An inkjet recording head provided with an actuator, wherein nozzle diameters of nozzles at both ends of the actuator are larger than nozzle diameters of nozzles other than the both ends. 7. The size of the nozzle diameter is increased stepwise from the nozzle on the center side of the channel at both ends toward the nozzles at both ends. Inkjet recording head. 8. The ink jet recording head according to claim 1, wherein the range of the both ends is substantially 10% of the total pitch of the channels in the actuator. 9. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.