JP2001225465A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording head in which pressure generating chambers can be arranged at high density. SOLUTION: The ink jet recording head 50 comprises a substrate 10 where at least one and the other side faces are composed of single crystal silicon, and a groove 15 made in one side face of the substrate 10. A first recess 11 communicating with the groove 15 is made in the other side face of the substrate 10 on one side of the groove 15, and a second recess 12 communicating with the groove 15 is made in the other side face of the substrate 10 on the other side of the groove 15. A first diaphragm 13a covers the first recess 11 to form a first pressure generating chamber 21 and a second diaphragm 13b covers the second recess 12 to form a second pressure generating chamber 22. A first piezoelectric element 23 is fixed to cause pressure variation in the first pressure generating chamber 21 and a second piezoelectric element 24 is fixed to cause pressure variation in the second pressure generating chamber 22.

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 for discharging ink by utilizing a change in pressure in a pressure generating chamber, and more particularly to an ink jet recording head which can be reduced in size and easily handled during manufacturing. .

[0002]

2. Description of the Related Art A pressure generating chamber of a conventional ink jet recording head is formed by penetrating a substrate. Accordingly, for example, when a relatively large area substrate having a diameter of about 6 to 12 inches is used, the thickness of the substrate must be increased to some extent due to problems such as handling.
As a result, the depth of the pressure generating chamber also increases.

When the pressure generating chambers are deep, sufficient rigidity cannot be obtained, and crosstalk occurs, so that desired discharge characteristics cannot be obtained unless the thickness of the partition wall that partitions each pressure generating chamber is increased. However, when the thickness of the partition wall is increased, the pressure generating chamber cannot be formed with a high arrangement density, and as a result, high-resolution printing quality cannot be achieved.

In order to overcome such problems, the present inventors have invented an ink jet recording head and a method for manufacturing the same as disclosed in Japanese Patent Application No. 11-324616 prior to the present invention.

This ink jet recording head is opposed to the pressure generating chamber via a silicon single crystal substrate defining a pressure generating chamber communicating with a nozzle opening, and a diaphragm constituting a part of the pressure generating chamber. And a piezoelectric element that is provided in a region where the pressure is generated in the pressure generating chamber, and the pressure generating chamber includes the silicon single crystal substrate on one surface side of the silicon single crystal substrate. A reservoir formed without penetrating and supplying ink to the pressure generating chamber is formed on the other surface side of the silicon single crystal substrate. The specific manufacturing method is described in detail in the aforementioned application.

[0006]

In a conventional ink jet recording head, one groove-shaped ink supply path (called an ink reservoir) is provided for the pressure generating chambers arranged in a line. .

However, in order to arrange the pressure generating chambers and the nozzles at a higher density, it is preferable to share the ink reservoir for the pressure generating chambers using the common ink.

The present invention has been made in view of the above points, and has as its object to provide an ink jet recording head in which pressure generating chambers can be arranged at a higher density.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a substrate having at least one side and another side made of single crystal silicon, a groove formed on one side of the substrate, and a groove formed on the other side of the substrate. A first concave portion formed on one side and communicating with the groove portion, a second concave portion formed on the other side of the substrate with respect to the groove and communicating with the groove portion, and covering the first concave portion. A first diaphragm forming a first pressure generating chamber;
A second diaphragm that covers the recess to form a second pressure generating chamber;
A first piezoelectric element attached to the first diaphragm to cause a pressure change in the first pressure generating chamber, and a second piezoelectric plate attached to the second diaphragm to cause a pressure change in the second pressure generating chamber. And a second piezoelectric element.

According to the present invention, since the first pressure generating chamber and the second pressure generating chamber communicating with the groove are disposed on both sides of the groove, the groove is used as an ink supply path (ink reservoir). By doing so, a higher density arrangement of the ink supply path and the pressure generating chamber is achieved.

The first diaphragm and the second diaphragm can be constituted by a common diaphragm. Further, the first diaphragm and the second diaphragm can be simultaneously formed by a film forming process.

The first concave portion and the second concave portion communicate with the groove at an end on the side of the groove, and are respectively provided at ends of the first pressure generating chamber and the second pressure generating chamber on the side remote from the groove. Preferably, holes are formed.

The groove is formed in a substantially straight line, and the first pressure generating chambers extend in a direction orthogonal to the groove, and a plurality of the first pressure generating chambers are formed in parallel with each other along the direction of the groove.
It is preferable that a plurality of the second pressure generating chambers extend in a direction orthogonal to the groove and are formed in parallel with each other along the direction of the groove. In this case, the pressure generating chambers can be arranged more densely and orderly.

Further, in order to protect the first and second piezoelectric elements, a first sealing portion for sealing the first piezoelectric element and a second sealing section for sealing the second piezoelectric element. It is preferable that a sealing plate having a stop portion is fixed to the first diaphragm and the second diaphragm. In this case, it is preferable that a plurality of nozzle portions communicating with the respective nozzle holes are formed in the sealing plate.
The first sealing portion and the second sealing portion may be configured in a communicating mode.

Furthermore, at least one electrode for driving the first piezoelectric element extends toward the nozzle hole of the first pressure generating chamber, and at least one electrode for driving the second piezoelectric element. Preferably extends to the side of the nozzle hole of the second pressure generating chamber. In this case, it is easy to form an electric circuit for driving the first piezoelectric element and the second piezoelectric element.

In addition, preferably, the whole substrate is a single crystal silicon substrate, and the plane orientation of the substrate is (100) plane. Alternatively and preferably, the substrate is a SOI substrate.

In addition to the first and second diaphragms, the first and second piezoelectric elements and their electrodes are preferably formed by a film forming process.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic plan sectional view of a first embodiment of an ink jet recording head according to the present invention.
FIG. 2 is a schematic side sectional view of a pressure generating chamber portion of the ink jet recording head of FIG.

As shown in FIGS. 1 and 2, the ink jet recording head 50 according to the present embodiment includes a substrate 10 made of single crystal silicon. The substrate 10 has a thickness of, for example, 150 μm to 1 mm and a plane orientation of (10
0).

On the lower side surface of the substrate 10, there is formed a groove 15 extending linearly in the vertical direction of FIG. Channel 15
Is designed to function as an ink reservoir,
It communicates with an ink cartridge (not shown). Channel 1
In this case, the reference numeral 5 is formed in a substantially central portion of the substrate 10 in the left-right direction in a tapered cross section (see FIG. 2).

On the other hand, as shown in FIG. 2, a first concave portion is formed on the upper side surface of the 11 are formed. The first concave portion 11 communicates with the groove 15 at an end on the side of the groove 15.

Similarly, a groove 1 is provided on the upper side surface of the substrate 10.
A second recess 12 is formed on the left side of the groove 15 so as to extend in a direction orthogonal to 5, that is, in the left-right direction of FIG. The second recess 12 also communicates with the groove 15 at the end on the side of the groove 15.

As shown in FIG. 1, the first recess 11 and the second
A plurality of the concave portions 12 are formed at equal pitches in parallel with each other along the direction of the groove 15. The first concave portion 11 and the second concave portion 12 are arranged so as to be shifted from each other by a half pitch.

The first concave portion 11 and the second concave portion 12
Prior to the formation of 5, it can be formed by anisotropic etching using a predetermined mask. As the anisotropic etching, any of wet etching and dry etching can be used, and the recesses 11 and 12 can be formed at arbitrary depths by controlling the etching time.

On the other hand, the groove 15 is formed between the first concave portion 11 and the second concave portion 11.
After the formation of the concave portion 12, it can be formed by a predetermined anisotropic etching. Since the plane orientation of the substrate is (100),
Even when wet etching is used as the anisotropic etching, the groove 15 can be formed with high accuracy.

As shown in FIG. 2, the upper side of the first recess 11 is covered with a first diaphragm 13a, and a first pressure generating chamber 21 is formed. Similarly, the upper side of the second recess 12 is covered with the second diaphragm 13b, and the first pressure generating chamber 22 is formed. Thereby, as shown in FIG. 1, a plurality of first pressure generation chambers 21 and a plurality of second pressure generation chambers 22 that extend in the direction orthogonal to the groove 15 and are parallel to each other are formed along the direction of the groove 15. Is formed.

As shown in FIG. 2, in the present embodiment, the first diaphragm 13a and the second diaphragm 13b share a common diaphragm 1
3. The vibration plate 13 can be formed of a plate having a thickness of 1 to 2 μm made of an insulating layer such as zirconium oxide. The diaphragm 13 has a nozzle hole 13n at each end of the first pressure generation chamber 21 and the second pressure generation chamber 22 on the side away from the groove 15.

A first piezoelectric element 23 is attached to the first diaphragm 13a in correspondence with each first pressure generating chamber 21 so as to cause a pressure change in each first pressure generating chamber 21. A second piezoelectric element 24 is attached to the second vibration plate 13b so as to generate a pressure change in each second pressure generating chamber 22 so as to correspond to each second pressure generating chamber 22.

More specifically, the first piezoelectric element 23 includes a piezoelectric layer 23a made of a thin film PZT and a piezoelectric layer 2a.
A lower electrode 23d provided on the lower surface side of 3a and an upper electrode 23u provided on the upper surface side of the piezoelectric layer 23a are formed as a three-layer structure.

Similarly, the second piezoelectric element 24 includes a piezoelectric layer 24a made of, for example, a thin film PZT and a piezoelectric layer 24a.
A lower electrode 24d provided on the lower surface side of the
a of the upper electrode 24u provided on the upper surface side of FIG.

The lower electrodes 23d and 24d are, for example, about 0.5 mm.
The upper electrodes 23u and 24u are, for example, about 0.1 μm membrane electrodes, and have a thickness of about 5 μm.
The thickness of 4a is, for example, about 1 μm.

In this case, the lower electrode 23d is configured as a common electrode, and the upper electrodes 23u individually extend toward the nozzle holes 13n of the first pressure generating chamber 21 and are connected to the corresponding lead electrodes 25. Similarly, the lower electrode 24d is configured as a common electrode, and the upper electrodes 24u individually extend toward the nozzle holes 13n of the second pressure generating chamber 22, and are connected to the corresponding lead electrodes 26. FIG. 3 (a)
FIG. 3B is an enlarged plan view of the nozzle hole 13n of the ink jet recording apparatus 50, and FIG.
It is a -b line sectional view. Such lower electrodes 23d, 24
d, piezoelectric layers 23a, 24a and upper electrodes 23u, 24
u can be formed by a film forming process using patterning.

As shown in FIG. 1, the lead electrodes 25, 26
Is connected to the FP via the wire conductor 27 and the driver IC 28.
It is connected to C29. On the other hand, the lower electrodes 23d and 24d as the common electrodes are directly connected to the FPC 29. The FPC 29 is connected to a control unit 30 for applying a predetermined voltage to each electrode.

Other details of the manufacturing process of the recording head are as follows.
This is substantially the same as that described in the aforementioned patent application (Japanese Patent Application No. 11-324616). Japanese Patent Application No. 11-324616
The contents described in the above items are hereby incorporated by reference as such in the description of the present specification.

Further, a sealing plate 40 having a first sealing portion 40a for sealing the first piezoelectric element 23 and a second sealing portion 40b for sealing the second piezoelectric element 24 is provided. , Are fixed to the diaphragm 13. In the present embodiment, the first sealing portion 40a and the second sealing portion 40b are formed independently of each other, but may be in communication with each other. The sealing plate 40 has a plurality of nozzle portions 4 corresponding to the nozzle holes 13n.
0n is formed.

Next, the operation of the present embodiment having such a configuration will be described.

The ink reservoir 15 and each pressure generating chamber 2
The insides of 1, 2 are filled with ink supplied from the ink cartridge. A meniscus of ink is formed in each nozzle 40n.

The piezoelectric layer 23 of the first piezoelectric element 23
When a is charged, the first piezoelectric element 23 is deformed and the first pressure generating chamber 21 contracts. The charged piezoelectric layer 2
When discharging 3a, the first pressure generating chamber 21 expands. When the first pressure generation chamber 21 is once expanded and then contracted rapidly, the ink pressure in the first pressure generation chamber 21 rapidly increases, and ink droplets are ejected from the corresponding nozzle 40n.

Similarly, the piezoelectric layer 24 of the second piezoelectric element 24
When a is charged, the second piezoelectric element 24 is deformed and the second pressure generating chamber 22 contracts. The charged piezoelectric layer 2
When discharging 4a, the second pressure generating chamber 22 expands. When the second pressure generating chamber 22 is once expanded and then rapidly contracted, the ink pressure in the second pressure generating chamber 22 rapidly increases, and ink droplets are ejected from the corresponding nozzle 40n.

The first pressure generation chamber 21 and the second pressure generation chamber 22
Means that the ink reservoirs 15 are shared, but that no so-called crosstalk occurs between them. In particular, as in the present embodiment, the first pressure generating chamber 21
When the first pressure generating chamber 21 and the second pressure generating chamber 22 are
Can be more reliably prevented.

As described above, according to the present embodiment, 1
Since the two channels 15 function as ink reservoirs for the first pressure generating chamber 21 and the second pressure generating chamber 22 which are respectively arranged in a row, a further high-density arrangement of nozzles and a small area of the recording head Can be realized. The material cost can be reduced by reducing the area of the recording head.

Further, since the arrangement density of the ink reservoirs 15 relatively decreases, the mechanical strength of the substrate 10 increases,
As a result, handling of the substrate 10 during the manufacturing process or the like becomes easy.

The first diaphragm 13a and the second diaphragm 13
Since “b” is constituted by the common diaphragm 13, manufacture is easy.

Further, the nozzle holes 13n are formed at each end of the first pressure generation chamber 21 and the second pressure generation chamber 22 on the side remote from the groove 15, so that ink droplets can be discharged. The deformation of the first pressure generation chamber 21 and the second pressure generation chamber 22 can be used to the maximum.

The first pressure generating chamber 21 and the second pressure generating chamber 22 each extend in a direction perpendicular to the groove 15 and are formed in parallel with each other along the direction of the groove 15. Therefore, an extremely high-density nozzle arrangement is realized.

The first sealing portion 40a and the second sealing portion 4
Since 0b seals the first piezoelectric element 23 and the second piezoelectric element 24, the first piezoelectric element 23 and the second piezoelectric element 24 are effectively protected. Note that a suitable inert gas or the like can be used as the sealing gas.

The first sealing portion 40a and the second sealing portion 40
When b is in communication, it is easy to form a path for introducing the sealing gas.

Further, since the nozzle portion 40n is formed directly on the sealing plate 40, the formation of the nozzle portion 40n is easy.

Furthermore, since one electrode for driving the first piezoelectric element 23 and the second piezoelectric element 24 extends to the side of each nozzle hole 13n, the first piezoelectric element 23 and the second piezoelectric element 24 can be easily formed.

In addition, according to the present embodiment, since the crosstalk between the first pressure generating chamber 21 and the second pressure generating chamber 22 can be reliably prevented, it is possible to reliably prevent the print quality from deteriorating. .

Next, an ink jet recording head according to a second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic sectional view of an ink jet recording head according to the second embodiment.

As shown in FIG. 4, the ink jet recording head 50 of the present embodiment includes an SOI substrate 10 'having an insulating layer 10m instead of a single-crystal silicon substrate. Except that the bottom surfaces of the first pressure generation chamber 21 and the second pressure generation chamber 22 are defined by the upper surface of 10 m, the configuration is substantially the same as the ink jet recording head of the first embodiment shown in FIGS. 1 to 3. It is. In the second embodiment, the same parts as those in the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description is omitted.

According to the present embodiment, SOI substrate 10 ′
Since the bottom surfaces of the first pressure generation chamber 21 and the second pressure generation chamber 22 are defined by the upper surface of the insulating layer 10m, the formation of the first pressure generation chamber 21 and the second pressure generation chamber 22 is easier.

Next, an ink jet recording head according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic plan view of an ink jet recording head according to the third embodiment.

As shown in FIG. 5, the ink jet recording head 60 of this embodiment is configured by connecting four ink jet recording heads 50 of the first embodiment in parallel. The ink reservoirs 15 of the recording head 50 are BK (black), C
(Cyan), M (magenta), and Y (yellow) ink cartridges (not shown).

Each of the ink jet recording heads 50 has substantially the same configuration as the ink jet recording head of the first embodiment shown in FIGS. In the third embodiment, the same portions as those in the first embodiment shown in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description is omitted.

In the present embodiment, each ink jet recording head 50 operates as described above with reference to the first embodiment. Therefore, for each ink color, high-resolution printing quality can be achieved by nozzles arranged at a higher density.

As is apparent from FIG. 5, the use of the ink reservoir 15 for the two rows of pressure generating chambers 21 and 22 is different from that of the present embodiment in that each ink jet recording is performed for a plurality of color inks. This is extremely effective for downsizing the device when the heads 50 are provided in parallel.

The distance L1 between the nozzle rows of the same color formed in two rows and the distance L2 between the nozzle rows of adjacent colors are determined by various characteristics of the ink jet recording head 50 and the ink jet recording. It can be appropriately determined according to the characteristics of the ink jet recording apparatus on which the head 50 is mounted. For example, the distance L1 between nozzle rows of the same color may be larger or smaller than the distance L2 between adjacent other color nozzle rows.

[0061]

As described above, according to the present invention, since the first pressure generating chamber and the second pressure generating chamber communicating with the groove are arranged on both sides of the groove, the ink is supplied to the groove. By using the passage as an ink reservoir, a denser arrangement of the ink supply passage and the pressure generating chamber is achieved.

Further, since the arrangement density of the ink reservoirs relatively decreases, the mechanical strength of the substrate increases, and as a result, the handling of the substrate during the manufacturing process becomes easy.

Further, when the first diaphragm and the second diaphragm are constituted by a common diaphragm, manufacture is easy.

In the case where nozzle holes are formed at respective ends of the first pressure generation chamber and the second pressure generation chamber remote from the groove, the first pressure generation chamber and the second pressure generation chamber may be provided with nozzle holes. The deformation can be maximally used for drop ejection.

The first pressure generating chamber and the second pressure generating chamber each extend in a direction perpendicular to the groove, and a plurality of pressure generating chambers are formed parallel to each other along the direction of the groove. Thus, a high-density noise arrangement without waste can be realized.

Further, the first sealing part and the second sealing part
When sealing the piezoelectric element and the second piezoelectric element, the first piezoelectric element and the second piezoelectric element can be effectively protected. When the first sealing portion and the second sealing portion communicate with each other, it is easy to form a path for introducing a sealing gas.

When the nozzle portion is formed directly on the sealing plate, the production of the nozzle portion is easy.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a first embodiment of an ink jet recording head according to the present invention.

FIG. 2 is a schematic side sectional view of a pressure generating chamber portion of the ink jet recording head of FIG.

FIG. 3 is a schematic view of a nozzle hole portion of the ink jet recording head of FIG. 1;

FIG. 4 is a schematic cross-sectional view showing a second embodiment of the ink jet recording head according to the present invention.

FIG. 5 is a schematic plan view showing a third embodiment of the ink jet recording head according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Single crystal silicon substrate 10 'SOI substrate 10m Insulating layer 11 1st recessed part 12 2nd recessed part 13 Vibration plate 13a 1st diaphragm 13b 2nd diaphragm 13n Nozzle hole 15 Groove (ink reservoir) 21 1st pressure generation chamber 22 Second pressure generating chamber 23 First piezoelectric element 23a Piezoelectric layer 23d Lower electrode 23u Upper electrode 24 Second piezoelectric element 24a Piezoelectric layer 24d Lower electrode 24u Upper electrode 25, 26 Lead electrode 27 Wire lead 28 Driver IC 29 FPC 30 Control part 40 Sealing plate 40a First sealing part 40b Second sealing part 40n Nozzle part 50 Inkjet recording head 60 Inkjet recording head

Claims (13)

[Claims] 1. A substrate having at least one side surface and another side surface made of single crystal silicon, a groove formed on one side surface of the substrate, and a groove formed on one side of the other side surface of the substrate, A first concave portion communicating with the groove, a second concave portion formed on the other side of the substrate with respect to the groove, and communicating with the groove, and a first pressure generating chamber covering the first concave portion; A first diaphragm, a second diaphragm covering the second recess to form a second pressure generating chamber, and a first diaphragm attached to the first diaphragm to cause a pressure change in the first pressure generating chamber. An ink jet recording head, comprising: a piezoelectric element; and a second piezoelectric element attached to the second diaphragm so as to generate a pressure change in the second pressure generating chamber. 2. The ink jet recording head according to claim 1, wherein the first diaphragm and the second diaphragm are constituted by a common diaphragm. 3. The first concave portion and the second concave portion communicate with the groove at an end on the side of the groove, and each end of the first pressure generating chamber and the second pressure generating chamber on the side remote from the groove. 3. The ink jet recording head according to claim 1, wherein each of the ink jet recording heads has a nozzle hole. 4. The groove is formed in a substantially linear shape, and each of the first pressure generating chambers extends in a direction orthogonal to the groove, and a plurality of first pressure generating chambers are formed in parallel with each other along the direction of the groove. And a plurality of second pressure generating chambers each extending in a direction orthogonal to the groove and being formed in parallel with each other along the direction of the groove. 3. The ink jet recording head according to item 1. 5. A sealing plate having a first sealing portion for sealing a first piezoelectric element and a second sealing portion for sealing a second piezoelectric element is a first diaphragm. 5. The ink jet recording head according to claim 1, wherein the ink jet recording head is fixed to the second diaphragm. 6. The first pressure generating chamber and the second pressure generating chamber on the side remote from the groove.
A nozzle hole is formed at each end of the pressure generating chamber, and the sealing plate has a plurality of nozzle portions communicating with each nozzle hole. The ink jet recording head according to the above. 7. The ink jet recording head according to claim 5, wherein the first sealing portion and the second sealing portion communicate with each other. 8. A nozzle hole is formed at each end of the first pressure generation chamber and the second pressure generation chamber on the side remote from the groove, and at least one of the holes for driving the first piezoelectric element is provided. One electrode extends to the nozzle hole side of the first pressure generating chamber, and at least one electrode for driving the second piezoelectric element extends to the nozzle hole side of the second pressure generating chamber. The ink jet recording head according to any one of claims 1 to 7, wherein 9. The ink jet recording head according to claim 1, wherein the substrate is a single crystal silicon substrate as a whole. 10. The ink jet recording head according to claim 9, wherein the plane orientation of the substrate is a (100) plane. 11. The ink jet recording head according to claim 1, wherein the substrate is an SOI substrate. 12. The method according to claim 1, wherein the first diaphragm, the second diaphragm, the first piezoelectric element, and the second piezoelectric element are each formed by a film forming process. Inkjet recording head. 13. An ink jet recording apparatus comprising: the ink jet recording head according to claim 1; and a control unit for driving the first piezoelectric element and the second piezoelectric element. apparatus.