JP2002178514A - Ink-jet recording head and ink-jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording head and an ink-jet recorder in which a diaphragm is prevented from being broken by driving a piezoelectric element. SOLUTION: The ink-jet recording head includes pressure generation chambers 12 communicating with nozzle openings, and piezoelectric elements 300 each comprising a lower electrode 60, a piezoelectric layer 70 and an upper electrode 80 set via the diaphragm to a region corresponding to the pressure generation chamber 12. To the region corresponding to the pressure generation chamber 12, the piezoelectric element 300 is provided with a piezoelectric active part 320 which becomes an essential driving part, and piezoelectric non active parts 330 which are formed to both end parts in a longitudinal direction of the piezoelectric element 300 by removing the lower electrode 60 and which are not essentially driven although including the piezoelectric layer 70 continuous from the piezoelectric active part 320. An electrode wiring is extended onto a peripheral wall from the upper electrode 80. Moreover, the diaphragm at regions opposite to at least corners at both sides in the longitudinal direction of the pressure generation chamber 12 are covered with an electrode layer 100 equal to a conductive layer constituting the electrode wiring 90, so that the diaphragm has the rigidity improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure generating chamber which communicates with a nozzle opening for discharging ink droplets, which is constituted by a vibrating plate. TECHNICAL FIELD The present invention relates to an ink jet recording head and an ink jet recording apparatus for ejecting ink droplets by using an ink jet recording head.

[0002]

2. Description of the Related Art A part of a pressure generating chamber communicating with a nozzle opening for discharging ink droplets is constituted by a vibrating plate, and the vibrating plate is deformed by a piezoelectric element to pressurize the ink in the pressure generating chamber to pass through the nozzle opening. Two types of ink jet recording heads that eject ink droplets have been commercialized, one using a longitudinal vibration mode piezoelectric actuator that expands and contracts in the axial direction of the piezoelectric element, and the other using a flexural vibration mode piezoelectric actuator. ing.

In the former method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, so that a head suitable for high-density printing can be manufactured. There is a problem in that a difficult process of cutting into a comb shape in accordance with the arrangement pitch of the openings and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required, and the manufacturing process is complicated.

On the other hand, in the latter, a piezoelectric element can be formed on a diaphragm by a relatively simple process of sticking a green sheet of a piezoelectric material according to the shape of a pressure generating chamber and firing the green sheet. In addition, there is a problem that a certain area is required due to the use of flexural vibration, and that high-density arrangement is difficult.

On the other hand, in order to solve the latter disadvantage of the recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as disclosed in Japanese Patent Application Laid-Open No. 5-286131. A proposal has been made in which the piezoelectric material layer is cut into a shape corresponding to the pressure generating chambers by a lithography method, and a piezoelectric element is formed so as to be independent for each pressure generating chamber.

This eliminates the need for attaching the piezoelectric element to the vibration plate, which not only allows the piezoelectric element to be manufactured by a precise and simple method such as lithography, but also reduces the thickness of the piezoelectric element. There is an advantage that it can be made thin and can be driven at high speed.

Further, in this case, the piezoelectric element corresponding to each pressure generating chamber can be driven by providing at least only the upper electrode for each pressure generating chamber while the piezoelectric material layer is provided on the entire surface of the vibration plate. However, due to the problem of the amount of displacement per unit drive voltage and the stress applied to the piezoelectric layer at the part facing the pressure generating chamber and the part straddling the outside, the piezoelectric active part consisting of the piezoelectric layer and the upper electrode is pressurized. It is desirable to form so as not to go out of the generation chamber.

Therefore, the piezoelectric element corresponding to each pressure generating chamber is covered with an insulating layer, and a window (hereinafter, referred to as a window) for forming a connection portion with a lead electrode for supplying a voltage for driving each piezoelectric element to the insulating layer. , A contact hole) is provided corresponding to each pressure generating chamber, and a connection portion between each piezoelectric element and a lead electrode is formed in the contact hole.

However, in such a structure in which a contact hole is provided to connect the upper electrode and the lead electrode, the entire thickness of the portion where the contact hole is provided becomes large, and the displacement characteristics are reduced. There was a problem.

In order to solve such a problem, a piezoelectric layer is provided in a region facing the pressure generating chamber, continuously from a piezoelectric active portion which is a substantial driving portion of the piezoelectric element. There has been proposed a structure in which a non-driven piezoelectric inactive portion is provided and a lead electrode is formed without providing a contact hole.

[0011]

However, in such a structure, a sufficient amount of displacement can be obtained in the diaphragm by driving the piezoelectric element. However, cracks and the like are caused in the diaphragm by repeating deformation. There is a problem. This problem is particularly likely to occur in a region facing the longitudinal edge of the pressure generating chamber.

In view of such circumstances, an object of the present invention is to provide an ink jet type recording head and an ink jet type recording apparatus which prevent a diaphragm from being broken by driving a piezoelectric element.

[0013]

According to a first aspect of the present invention for solving the above-mentioned problems, a pressure generating chamber communicating with a nozzle opening and a region corresponding to the pressure generating chamber are provided via a diaphragm. In an ink jet recording head including a lower electrode, a piezoelectric layer, and a piezoelectric element including an upper electrode, the piezoelectric element has a piezoelectric active portion substantially serving as a driving portion in a region opposed to the pressure generating chamber. A piezoelectric non-active portion which is formed by removing the lower electrode at both ends in the longitudinal direction and has the piezoelectric layer continuous from the piezoelectric active portion but is not substantially driven; and The electrode wiring extends from the peripheral wall to the peripheral wall, and a diaphragm in a region facing at least a corner on both sides in the longitudinal direction of the pressure generating chamber is covered with the same electrode configuration layer as the conductive layer forming the electrode wiring. Be In an ink jet recording head according to claim Rukoto.

In the first aspect, the diaphragm in the region opposed to both ends in the longitudinal direction of the pressure generating chamber is covered with the electrode constituting layer, so that the rigidity of the diaphragm is improved. Thus, it is possible to prevent the diaphragm from being broken by the deformation due to the driving of the piezoelectric element.

According to a second aspect of the present invention, there is provided the ink jet recording head according to the first aspect, wherein the piezoelectric layer has crystals preferentially oriented.

In the second aspect, as a result of the piezoelectric layer being formed in the thin film process, the crystals are preferentially oriented.

According to a third aspect of the present invention, there is provided an ink jet recording head according to the second aspect, wherein the piezoelectric layer has a columnar crystal.

In the third aspect, as a result of the piezoelectric layer being formed in the thin film process, the crystals are columnar.

According to a fourth aspect of the present invention, in any one of the first to third aspects, at least the piezoelectric layer constituting the piezoelectric element is independently formed in a region facing the pressure generating chamber. The ink jet recording head is characterized in that:

In the fourth aspect, the amount of displacement of the diaphragm caused by driving the piezoelectric element increases.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the vicinity of both ends in the longitudinal direction of the piezoelectric element is covered with the electrode constituting layer. In the head.

In the fifth aspect, the destruction of the vibration plate in the region facing the both ends in the longitudinal direction of the pressure generating chamber is prevented, and the rigidity near the both ends in the longitudinal direction of the piezoelectric element is improved. Breakage of the piezoelectric layer due to driving is prevented.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the lower electrode is formed over a plurality of piezoelectric elements, and at least the electrode of the pressure generating chamber of the lower electrode is provided. On the end side opposite to the wiring, a lower electrode removing portion from which the lower electrode has been removed is formed for each pressure generating chamber, and the electrode constituent layer is formed only inside the lower electrode removing portion. An ink jet recording head is characterized in that:

In the sixth aspect, since the lower electrode removing portion is provided for each pressure generating chamber, an increase in the resistance value of the lower electrode is suppressed, and a voltage can be applied to the piezoelectric element satisfactorily. .

A seventh aspect of the present invention is the ink jet recording head according to the sixth aspect, wherein the lower electrode removing portion has a substantially rectangular shape.

According to the seventh aspect, the lower electrode removing portion can be easily formed by etching.

An eighth aspect of the present invention is the ink jet recording head according to any one of the first to seventh aspects, wherein the electrode constituting layer has higher rigidity than the lower electrode.

According to the eighth aspect, the rigidity of the diaphragm in the region opposed to both ends in the longitudinal direction of the pressure generating chamber can be reliably improved.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the pressure generating chamber is formed in a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed of a thin film and a lithographic apparatus. An ink jet recording head characterized by being formed by a method.

In the ninth aspect, the pressure generating chambers can be formed relatively easily and with high precision at high density.

According to a tenth aspect of the present invention, there is provided an ink jet recording apparatus including the ink jet recording head according to any one of the first to ninth aspects.

According to the tenth aspect, it is possible to realize an ink jet recording head having improved head durability and reliability.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

(Embodiment 1) FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention, and FIG. 2 is a plan view and a sectional view of FIG.

As shown in the figure, the flow path forming substrate 10 is a single crystal silicon substrate having a plane orientation (110) in this embodiment. One surface of the flow path forming substrate 10 is an opening surface, and the other surface is formed with an elastic film 50 having a thickness of 1 to 2 μm and made of silicon dioxide formed in advance by thermal oxidation.

In the flow path forming substrate 10, pressure generating chambers 12 defined by a plurality of partition walls 11 are arranged in parallel in the width direction by anisotropically etching a silicon single crystal substrate. Is a communication part 13 which forms a part of a reservoir 110 which communicates with a reservoir part of a reservoir forming substrate which will be described later and serves as a common ink chamber of each pressure generating chamber 12.
Are formed, and are communicated with one end in the longitudinal direction of each pressure generating chamber 12 via the ink supply path 14.

Here, in the anisotropic etching, when the silicon single crystal substrate is immersed in an alkaline solution such as KOH, the substrate is gradually eroded and the first (111) plane perpendicular to the (110) plane and the first (111) plane. A second (1) which forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the (110) plane.
11) plane, and the etching rate of the (111) plane is about 1/1 compared to the etching rate of the (110) plane.
This is performed using the property of being 80.
By such anisotropic etching, two first (11
Precision processing can be performed based on depth processing of a parallelogram formed by the 1) plane and two oblique second (111) planes, and the pressure generating chambers 12 can be arranged at high density. it can.

In this embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane, and the short side is formed by the second (111) plane. The pressure generating chamber 12 is provided on the flow path forming substrate 1.
It is formed by etching until it reaches the elastic film 50 almost through 0. Here, the elastic film 50 is
The amount attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small. Each of the ink supply passages 14 communicating with one end of each of the pressure generating chambers 12 is formed shallower than the pressure generating chambers 12 and maintains a constant flow resistance of the ink flowing into the pressure generating chambers 12. That is, the ink supply path 14 is formed by partially etching (half-etching) the silicon single crystal substrate in the thickness direction. Note that the half etching is performed by adjusting the etching time.

The thickness of the flow path forming substrate 10 is selected to be optimal according to the density of the pressure generating chambers 12. For example, when the pressure generating chambers 12 are arranged so as to obtain a resolution of 180 dpi, the thickness of the flow path forming substrate 10 is preferably about 180 to 280 μm, and more preferably about 220 μm. Further, for example, when the pressure generating chambers 12 are arranged so as to obtain a resolution of 360 dpi, the thickness of the flow path forming substrate 10 is
The thickness is preferably 100 μm or less. This is because the arrangement density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.

On the other side of the flow path forming substrate 10,
A nozzle plate 20 provided with a nozzle opening 21 communicating with the pressure supply chamber 12 on the side opposite to the ink supply path 14 is fixed via an adhesive or a heat welding film. The thickness of the nozzle plate 20 is, for example, 0.1 to 1
mm, the coefficient of linear expansion is 300 ° C. or less, for example, 2.5 to
It is made of 4.5 [× 10 ⁻⁶ / ° C.] glass-ceramic or non-rusting steel. The nozzle plate 20 entirely covers one surface of the flow path forming substrate 10 on one surface, and also serves as a reinforcing plate for protecting the silicon single crystal substrate from impact and external force. Further, the nozzle plate 20 is connected to the flow path forming substrate 10.
May be formed of a material having substantially the same thermal expansion coefficient as that of the material. In this case, since the deformation of the flow path forming substrate 10 and the nozzle plate 20 due to heat become substantially the same, it is possible to easily join them using a thermosetting adhesive or the like.

Here, the size of the pressure generating chamber 12 for applying the ink droplet ejection pressure to the ink and the size of the nozzle opening 21 for ejecting the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized. For example,
When recording 360 ink droplets per inch, the nozzle openings 21 need to be formed with a diameter of several tens of μm with high accuracy.

On the other hand, the lower electrode film 60 having a thickness of, for example, about 0.2 μm and the piezoelectric layer 70 having a thickness of, for example, about 1 μm are formed on the elastic film 50 provided on the flow path forming substrate 10. When,
The upper electrode film 80 having a thickness of, for example, about 0.1 μm is laminated and formed by a process described later, and forms the piezoelectric element 300. Here, the piezoelectric element 300 includes the lower electrode film 60,
A portion including the piezoelectric layer 70 and the upper electrode film 80. Generally, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are connected to each of the pressure generating chambers 1.
It is structured by patterning every two. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric layer 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In the present embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element 300, and the upper electrode film 80 is an individual electrode of the piezoelectric element 300.
Even if this is reversed for convenience of the drive circuit and wiring, there is no problem.
In any case, the piezoelectric active portion is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and a diaphragm whose displacement is generated by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator.

Here, the structure of such a piezoelectric element 300 will be described in detail.

As shown in FIG. 2, the lower electrode film 60 constituting a part of the piezoelectric element 300 is provided continuously in a region opposed to the plurality of pressure generating chambers 12 arranged in parallel, and In the vicinity of one longitudinal end of the pressure generating chamber 12, the pressure generating chamber 12 is removed over the width direction. Further, the lower electrode film 60 near the other end in the longitudinal direction of the pressure generation chamber 12 is
Each of the pressure generating chambers 12 is patterned to form, for example, a substantially rectangular lower electrode film removing portion 61, and the elastic film 50 in a region facing the longitudinal edge of each pressure generating chamber 12 is exposed. In the present embodiment, by patterning the lower electrode film 60 in this manner, the piezoelectric active portion 320 that is a substantial driving portion and the piezoelectric active portions 320 provided at both ends in the longitudinal direction and continuous with the piezoelectric active portion 320 are formed. A piezoelectric element 300 comprising a piezoelectric layer inactive portion 330 having a body layer 70 but not being driven
Are formed.

In this embodiment, the piezoelectric layer 70 and the upper electrode film 80 are patterned in the region facing the pressure generating chambers 12, and the piezoelectric element 300 is independent of the region facing each pressure generating chamber 12. It is provided. The upper electrode film 80 is connected to external wiring (not shown) via a lead electrode 90 extending from the vicinity of one end in the longitudinal direction of the piezoelectric element 300 onto the elastic film 50.

Further, in this embodiment, at least the corners on both sides in the longitudinal direction of the pressure generating chamber 12 are covered with the same electrode constituting layer as the conductive layer constituting the lead electrode 90.

Specifically, in the present embodiment, the lead electrode 90 extends outside the boundary between the piezoelectric active portion 320 and the piezoelectric non-active portion 330 and has a wider width than the pressure generating chamber 12. The elastic film 50 in the vicinity of one end in the longitudinal direction of the piezoelectric element 300 and the region facing the edge of the pressure generating chamber 12 is covered with the lead electrode 90, that is, the electrode constituting layer.

On the other hand, a region near the other end in the longitudinal direction of the piezoelectric element 300 and a region facing the edge in the longitudinal direction of the pressure generating chamber 12 are a protective layer which is an electrode constituting layer provided independently of the lead electrode 90. Covered by 100. Here, as described above, the lower electrode film removing portion 61 in which the lower electrode film 60 is removed is formed for each pressure generating chamber 12 on the other end side in the longitudinal direction of the pressure generating chamber 12 so that the elastic film 50 is formed. It is exposed. Then, the protective layer 100 is patterned in the lower electrode removal part 61 so as not to contact the lower electrode film 60.

The lead electrode 90 and the protective layer 10
The thickness of the lower electrode film 60 is not particularly limited.
Preferably, the thickness is higher than that of the lower electrode film 60 in this embodiment.

By covering the vibration plate at the longitudinal edge of the pressure generating chamber 12 with the lead electrode 90 and the protective layer 100 as described above, the rigidity of the vibration plate is improved, and the piezoelectric element 300
It is possible to prevent the occurrence of cracks and the like in the diaphragm due to repeated deformation due to the driving of.

Further, in this embodiment, since the vicinity of the longitudinal end of the piezoelectric element 300 is covered by the lead electrode 90 and the protective layer 100, the rigidity near the longitudinal end of the piezoelectric element 300 is increased. The stress applied to the vicinity of the longitudinal end of the piezoelectric element 300 when the piezoelectric element 300 is driven is suppressed. Therefore, when the piezoelectric element 300 is driven, the amount of displacement at the longitudinal end of the piezoelectric element 300 is reduced, so that the piezoelectric layer 70 can be prevented from being broken due to repeated displacement.

Further, since the protective layer 100 is formed in the same layer as the lead electrode 90, there is no need to increase the number of manufacturing steps, and the protective layer 100 can be formed without increasing the manufacturing cost.

Further, in the present embodiment, the pressure generating chamber 12
The lower electrode film 60 on the other end side in the longitudinal direction of the
Each time, the lower electrode film removing portion 61 is formed,
Since the removal area of the lower electrode film 60 is relatively small, the resistance value of the lower electrode film 60 does not increase significantly. Therefore, the piezoelectric layer 7 constituting the piezoelectric element 300
0 can be applied with a favorable voltage. If the resistance value of the lower electrode film 60 does not increase significantly, the lower electrode film removing portion 61 may be provided continuously over a region facing the plurality of pressure generating chambers 12, as a matter of course. .

Hereinafter, a process of forming such a piezoelectric element 300 and the like on the flow path forming substrate 10 made of a silicon single crystal substrate will be described with reference to FIGS. 3 and 4 are cross-sectional views of the pressure generating chamber 12 in the longitudinal direction.

First, as shown in FIG. 3A, a silicon single crystal substrate wafer serving as the flow path forming
Thermal oxidation is performed in a diffusion furnace at 0 ° C. to form an elastic film 50 made of silicon dioxide.

Next, as shown in FIG. 3B, after the lower electrode film 60 is formed on the entire surface of the elastic film 50 by sputtering, the lower electrode film 60 is patterned to form an entire pattern. That is, one longitudinal end of the pressure generating chamber 12 is
The pressure-generating chamber 12 is removed over the width direction of the pressure-generating chamber 12 and
On the other end side in the longitudinal direction of 2, an independent lower electrode film removing portion 61 is formed for each pressure generating chamber 12. As a material of the lower electrode film 60, platinum or the like is preferable. This is because a piezoelectric layer 70 described later formed by a sputtering method or a sol-gel method is formed.
Is from 600 to 600 ° C. in an air atmosphere or an oxygen atmosphere after film formation.
This is because it is necessary to perform crystallization by firing at a temperature of about 1000 ° C. That is, the material of the lower electrode film 60 must be able to maintain conductivity under such a high temperature and oxidizing atmosphere. In particular, when the piezoelectric layer 70 is made of lead zirconate titanate (PZT), It is desirable that the change in conductivity due to the diffusion of lead oxide is small, and for these reasons, platinum is preferred.

Next, as shown in FIG. 3C, a piezoelectric layer 70 is formed. In the piezoelectric layer 70, it is preferable that crystals are oriented. For example, in the present embodiment, a so-called sol-gel method in which a so-called sol in which a metal organic substance is dissolved and dispersed in a catalyst is applied and dried to form a gel, and then fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. To form a piezoelectric layer 70 in which crystals are oriented. As a material for the piezoelectric layer 70, a lead zirconate titanate-based material is suitable when used in an ink jet recording head. The method for forming the piezoelectric layer 70 is not particularly limited, and may be, for example, a sputtering method.

Further, after forming a precursor film of lead zirconate titanate by a sol-gel method or a sputtering method,
A method of growing crystals at a low temperature by a high-pressure treatment method in an alkaline aqueous solution may be used.

In any case, in the piezoelectric layer 70 formed in this way, the crystal is preferentially oriented unlike the bulk piezoelectric, and in the present embodiment, the crystal is formed in the piezoelectric layer 70. It is formed in a column shape. Note that the preferential orientation refers to a state in which a crystal orientation direction is not disordered and a specific crystal plane is oriented in a substantially constant direction. In addition, a crystal having a columnar thin film refers to a state in which substantially columnar crystals are gathered in a plane direction with their central axes substantially aligned in the thickness direction to form a thin film. Of course, it may be a thin film formed of preferentially oriented granular crystals. The thickness of the piezoelectric layer manufactured in the thin film process is generally 0.2 to 5 μm.

Next, as shown in FIG. 3D, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and can use many metals such as aluminum, gold, nickel, and platinum, and a conductive oxide. In the present embodiment, platinum is formed by sputtering.

Next, as shown in FIG. 4A, only the piezoelectric layer 70 and the upper electrode film 80 are etched to form a piezoelectric element 3 comprising a piezoelectric active portion 320 and a piezoelectric non-active portion 330.
00 patterning is performed. That is, the pressure generating chamber 12
The region where the lower electrode film 60 is formed in the region opposed to is the piezoelectric active portion 320, and the region where the lower electrode film 60 is removed is the piezoelectric non-active portion 330.

Next, as shown in FIG. 4B, a lead electrode 90 and a protective layer 100 are formed. Specifically, for example, the conductive layer 91 made of gold (Au) or the like is formed on the flow path forming substrate 1.
0 and is patterned for each piezoelectric element 300 to form a lead electrode 90 for connecting the upper electrode film 80 to an external wiring at one end in the longitudinal direction of the piezoelectric element 300 and to form a lead electrode 90 at the other end. Next, a protective layer 100 is formed. The lead electrode 90 and the protective layer 100 are, for example,
You may make it provide through an adhesion layer, such as nickel (Ni), titanium (Ti), and copper (Cu).

The above is the film forming process. After forming the film in this manner, the silicon single crystal substrate was subjected to anisotropic etching using the above-described alkaline solution, and FIG.
As shown in (c), the pressure generating chamber 12, the communication section 13, the ink supply path 14, and the like are formed.

In practice, a number of chips are simultaneously formed on one wafer by such a series of film formation and anisotropic etching, and after the process, one chip as shown in FIG. It is divided for each flow path forming substrate 10 having a size. Then, a reservoir forming substrate 30 and a compliance substrate 40, which will be described later, are sequentially bonded and integrated with the divided flow path forming substrate 10 to form an ink jet recording head.

That is, as shown in FIGS. 1 and 2, a reservoir section 31 constituting at least a part of the reservoir 110 is provided on the piezoelectric element 300 side of the flow path forming substrate 10 in which the pressure generating chambers 12 and the like are formed. The reservoir forming substrate 30 is joined. In the present embodiment, the reservoir portion 31 is formed so as to penetrate the reservoir forming substrate 30 in the thickness direction and to extend in the width direction of the pressure generating chamber 12. Then, the reservoir portion 31 is formed through the elastic film 50 and the lower electrode film 60 through a through hole 51 provided through the flow path forming substrate 10.
And a reservoir 110 that communicates with the communication portion 13 of the pressure generating chamber 12 and serves as a common ink chamber for each pressure generating chamber 12.

As the reservoir forming substrate 30, it is preferable to use a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10, such as glass or ceramic material. It was formed using a silicon single crystal substrate of the same material. As a result, as in the case of the nozzle plate 20 described above, even when bonding is performed at a high temperature using a thermosetting adhesive, both can be reliably bonded. Therefore, the manufacturing process can be simplified.

Further, the reservoir forming substrate 30 includes:
The compliance substrate 40 including the sealing film 41 and the fixing plate 42 is joined. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the sealing film 41 seals one surface of the reservoir 31. Has been stopped. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SU) having a thickness of 30 μm.
S) etc.). The reservoir 11 of the fixing plate 42
Since the region opposing to 0 is the opening 43 completely removed in the thickness direction, one surface of the reservoir 110 is sealed only with the sealing film 41 having flexibility, and the internal pressure changes. Thus, the flexible portion 32 is deformable.

Further, an ink introduction port 35 for supplying ink to the reservoir 110 is formed on the compliance substrate 40 substantially outside the central portion in the longitudinal direction of the reservoir 110. Further, the reservoir forming substrate 30 is provided with an ink introduction path 36 that communicates the ink introduction port 35 with the side wall of the reservoir 110.

On the other hand, the piezoelectric element 3 of the reservoir forming substrate 30
A piezoelectric element holding portion 33 that seals the space is provided in a region opposed to 00 while securing a space that does not hinder the movement of the piezoelectric element 300. At least the piezoelectric active portion 320 of the piezoelectric element 300 is sealed in the piezoelectric element holding portion 33 to prevent the piezoelectric element 300 from being destroyed due to an external environment such as moisture in the atmosphere.

The ink jet recording head thus configured takes in ink from an ink inlet 42 connected to an external ink supply means (not shown) and fills the interior from the common ink chamber 31 to the nozzle opening 11 with ink. After that, a voltage is applied between the upper electrode film 80 and the lower electrode film 60 in accordance with a recording signal from an external drive circuit (not shown), and the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70 are flexibly deformed. As a result, the pressure in the pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle opening 11.

In the present embodiment, the piezoelectric layer 70 and the upper electrode film 80 are patterned in the region facing each pressure generating chamber 12 so that the piezoelectric element 300 is independent of the region facing each pressure generating chamber 12. However, the present invention is not limited to this. For example, the longitudinal end of the piezoelectric element 300, that is, the piezoelectric inactive portion 330 may extend to the outside of the pressure generating chamber 12.

(Other Embodiments) The embodiments of the present invention have been described above, but the basic configuration of the ink jet recording head is not limited to the above.

The ink jet recording head of each of the embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. FIG.
FIG. 2 is a schematic diagram illustrating an example of the ink jet recording apparatus.

As shown in FIG. 6, the recording head units 1A and 1B having the ink jet recording heads are provided with detachable cartridges 2A and 2B constituting ink supply means.
The carriage 3 on which B is mounted is provided movably in the axial direction on a carriage shaft 5 attached to the apparatus main body 4. The recording head units 1A and 1B are, for example,
Each of them ejects a black ink composition and a color ink composition.

Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears (not shown) and the timing belt 7, so that the carriage 3 on which the recording head units 1A and 1B are mounted moves along the carriage shaft 5. Moved. On the other hand, a platen 8 is provided on the apparatus main body 4 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is wound around the platen 8. It is designed to be transported.

[0076]

As described above, according to the present invention, the piezoelectric element having the piezoelectric active portion and the piezoelectric non-active portion formed by removing the lower electrode film is provided in the region facing the pressure generating chamber. The electrode wiring is formed on the peripheral wall from the upper electrode, and at least the corner in the longitudinal direction of the pressure generating chamber is covered with the same electrode configuration layer as the conductive layer constituting the electrode wiring. In addition, the rigidity of the diaphragm at the longitudinal edge of the pressure generating chamber is improved, and it is possible to prevent cracks and the like from occurring in the diaphragm due to deformation due to driving of the piezoelectric element.

[Brief description of the drawings]

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

FIG. 2 is a plan view and a cross-sectional view of the inkjet recording head according to the first embodiment of the present invention.

FIG. 3 is a sectional view illustrating a manufacturing process of the ink jet recording head according to the first embodiment of the invention.

FIG. 4 is a cross-sectional view illustrating a manufacturing process of the ink jet recording head according to the first embodiment of the present invention.

FIG. 5 is a plan view and a cross-sectional view of an ink jet recording head according to Embodiment 2 of the present invention.

FIG. 6 is a schematic diagram of an ink jet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 flow path forming substrate 11 partition wall 12 pressure generating chamber 13 communication section 14 ink supply path 20 nozzle plate 30 reservoir forming substrate 40 compliant substrate 50 elastic film 60 lower electrode film 70 piezoelectric layer 80 upper electrode film 90 lead electrode 100 protective layer 300 Piezoelectric element 320 Piezoelectric active part 330 Piezoelectric non-active part

[Procedure amendment]

[Submission date] February 12, 2002 (2002.2.1
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 9

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the pressure generation chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by film formation. An ink jet recording head is formed by a lithography method.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0070

[Correction method] Change

[Correction contents]

The ink jet recording head thus configured takes in ink from an ink inlet 35 connected to an external ink supply means (not shown) and fills the interior from the common ink chamber 110 to the nozzle opening 21 with ink. After that, a voltage is applied between the upper electrode film 80 and the lower electrode film 60 in accordance with a recording signal from an external drive circuit (not shown), and the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70 are flexibly deformed. As a result, the pressure in the pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle openings 21 .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0071

[Correction method] Change

[Correction contents]

In the present embodiment, the piezoelectric layer 70 and the upper electrode film 80 are patterned in the region facing each pressure generating chamber 12 so that the piezoelectric element 300 is independent of the region facing each pressure generating chamber 12. However, the present invention is not limited to this . For example, as shown in FIG. 5, the longitudinal end of the piezoelectric element 300, that is, the piezoelectric inactive portion 330 extends to the outside of the pressure generating chamber 12. It may be.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5 is a plan view and a cross-sectional view illustrating another example of the inkjet recording head according to the first embodiment of the present invention.

[Procedure amendment 6]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

Continued on the front page F-term (reference) 2C057 AF68 AF69 AF93 AG12 AG41 AG42 AG44 AG60 AP02 AP14 AP34 AP52 AP57 AQ02 BA04 BA14

Claims (10)

[Claims] 1. An ink jet type comprising: a pressure generating chamber communicating with a nozzle opening; and a piezoelectric element including a lower electrode, a piezoelectric layer, and an upper electrode provided in a region corresponding to the pressure generating chamber via a diaphragm. In the recording head, the piezoelectric element is located in a region facing the pressure generating chamber,
A piezoelectric element which has a piezoelectric active part serving as a substantial driving part and the piezoelectric layer formed by removing the lower electrode at both ends in the longitudinal direction and continuous from the piezoelectric active part, but is not substantially driven A body non-active portion, electrode wiring is extended from the upper electrode on the peripheral wall, and a diaphragm in a region opposed to at least a corner on both sides in the longitudinal direction of the pressure generating chamber connects the electrode wiring. An ink jet recording head, which is covered with the same electrode constitution layer as a conductive layer to constitute. 2. The ink jet recording head according to claim 1, wherein crystals of the piezoelectric layer are preferentially oriented. 3. The ink-jet recording head according to claim 2, wherein the piezoelectric layer has a columnar crystal. 4. The ink-jet apparatus according to claim 1, wherein at least the piezoelectric layer constituting the piezoelectric element is formed independently in a region facing the pressure generating chamber. Type recording head. 5. The ink jet recording head according to claim 1, wherein the vicinity of both ends in the longitudinal direction of the piezoelectric element is covered with the electrode constituting layer. 6. The lower electrode according to claim 1, wherein the lower electrode is formed over a plurality of piezoelectric elements, and at least an end of the lower electrode opposite to the electrode wiring of the pressure generating chamber. An ink jet recording head, wherein a lower electrode removing portion from which the lower electrode is removed is formed for each pressure generating chamber, and the electrode constituent layer is formed only in the lower electrode removing portion. . 7. The ink jet recording head according to claim 6, wherein the lower electrode removing section has a substantially rectangular shape. 8. An ink jet recording head according to claim 1, wherein said electrode constituting layer has higher rigidity than said lower electrode. 9. The pressure generating chamber according to claim 1, wherein the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by a thin film and a lithography method. An ink jet recording head, characterized in that: 10. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.