JP2000062173A - Ink jet recording head, manufacture thereof and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance deformation and durability of a diaphragm. SOLUTION: In an ink jet recording head having a piezoelectric element 300 formed in a region corresponding to a pressure generating chamber 12 communicating with nozzle opening through a diaphragm forming a part of the chamber 12, a lower electrode 60, a piezoelectric layer 70 and an upper electrode 80 constituting a piezoelectric element are arranged in a region facing the pressure generating chamber 12. The lower electrode 60 and a film 61 having tensile stress arranged continuously at least on the opposite sides of the lower electrode 60 in the breadthwise direction constitute the diaphragm and a tensile force is applied to the lower electrode 60. Since relaxing amount of inner stress of the piezoelectric layer 70 is reduced at the time of forming the pressure generating chamber 12 and initial deformation of the diaphragm is suppressed, deformation of the diaphragm through driving of a piezoelectric active section 320 can be enhanced substantially along with durability of the diaphragm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure in which a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets is composed of a vibrating plate, a piezoelectric element is provided through the vibrating plate, and the displacement of the piezoelectric element The present invention relates to an inkjet recording head that ejects ink droplets by a method, a manufacturing method thereof, and an inkjet recording device.

[0002]

2. Description of the Related Art A part of a pressure generating chamber that communicates with a nozzle opening for ejecting ink droplets is composed of a vibrating plate, and the vibrating plate is deformed by a piezoelectric element to pressurize ink in the pressure generating chamber to eject it from the nozzle opening. Two types of inkjet recording heads for ejecting ink droplets have been put into practical use, one that uses a longitudinal vibration mode piezoelectric element that expands and contracts in the axial direction of the piezoelectric element, and one that uses a flexural vibration mode piezoelectric element. ing.

The former allows the volume of the pressure generating chamber to be changed by bringing the end face of the piezoelectric element into contact with the vibrating plate, and a head suitable for high-density printing can be manufactured. There is a problem in that the manufacturing process is complicated because a difficult process of matching the array pitch of the openings and cutting into comb teeth or a work of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required.

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

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

According to this, the work of attaching the piezoelectric element to the diaphragm becomes unnecessary, and not only the piezoelectric element can be built by a precise and simple method such as a lithography method, but also the thickness of the piezoelectric element can be reduced. It has the advantage that it can be made thin and can be driven at high speed. In this case, it is possible to drive the piezoelectric element corresponding to each pressure generating chamber by providing at least only the upper electrode for each pressure generating chamber while leaving the piezoelectric material layer provided on the entire surface of the vibration plate.

[0007]

However, in the above-mentioned thin film technology and the manufacturing method by the lithographic method,
Although the pressure generating chamber is formed after patterning the thin film, the internal stress of the piezoelectric layer is relaxed at that time, and the diaphragm is bent toward the pressure generating chamber due to the influence of the internal stress of the lower electrode. It remains as the initial deformation of the diaphragm. Therefore, there is a problem that the amount of deformation of the diaphragm due to the driving of the piezoelectric element is substantially reduced, and the durability of the diaphragm is reduced.

In view of the above circumstances, it is an object of the present invention to provide an ink jet recording head, a method of manufacturing the same, and an ink jet recording apparatus, in which the deformation amount and durability of the diaphragm are improved.

[0009]

According to a first aspect of the present invention for solving the above-mentioned problems, a region corresponding to the pressure generating chamber is provided via a vibrating plate forming a part of the pressure generating chamber communicating with the nozzle opening. In an ink jet recording head having a piezoelectric element formed therein, a lower electrode, a piezoelectric layer and an upper electrode forming the piezoelectric element are provided in a region facing the pressure generating chamber, and at least the lower electrode and the lower electrode. An ink jet recording head is characterized in that a tension film having tensile stress continuously provided on both sides in the width direction constitutes at least an upper layer portion of the diaphragm.

In the first aspect, the tension of the tensile film acts on the lower electrode, and the stress relaxation of the diaphragm at the time of forming the pressure generating chamber is reduced.

A second aspect of the present invention is the ink jet recording head according to the first aspect, characterized in that the tensile film is made of a material different from that of the lower electrode.

In the second aspect, the stress state of the tensile film can be made different from that of the lower electrode.

A third aspect of the present invention is the ink jet recording head according to the first or second aspect, characterized in that the tensile film is made of a material having a Young's modulus larger than that of the lower electrode.

In the third aspect, the tension of the pulling film effectively acts on the lower electrode.

In a fourth aspect of the present invention, the tensile film is platinum, iridium, iridium oxide, zirconium oxide,
The inkjet recording head is characterized by comprising at least one selected from the group consisting of ruthenium oxide, tungsten, and molybdenum.

In the fourth aspect, it is possible to form a tensile film having a tensile stress and effectively applying a tension to the lower electrode.

A fifth aspect of the present invention is the ink jet recording head according to any one of the first to fourth aspects, characterized in that an elastic film is formed under the lower electrode and the tension film. It is in.

In the fifth aspect, the elastic film and the tension film act as a diaphragm.

A sixth aspect of the present invention is the ink jet recording head according to the fifth aspect, characterized in that the portion of the elastic film facing the lower electrode is thicker than other portions.

In the sixth aspect, the tension of the tension film acts on the portion of the elastic film facing the lower electrode, and the initial deflection is reduced.

A seventh aspect of the present invention is the ink jet recording head according to the fifth or sixth aspect, characterized in that the elastic film is made of silicon dioxide.

In the seventh aspect, the elastic film and the tension film made of a silicon dioxide film act as a diaphragm.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, an insulating layer is formed on the upper surface of the piezoelectric element, and a lead electrode for applying a voltage to the piezoelectric element is provided. The inkjet recording head is characterized in that a contact portion serving as a connection portion with the piezoelectric element is formed in a contact hole formed in the insulator layer.

In the eighth aspect, the piezoelectric element and the lead electrode are connected in the contact hole in the region facing the pressure generating chamber.

In a ninth aspect of the present invention according to any one of the first to eighth aspects, at least one longitudinal end of the piezoelectric element is extended to a portion facing a side wall of the pressure generating chamber, and the contact is provided. In the ink jet recording head, the portion is formed in a region facing the side wall.

In the ninth aspect, the contact hole for connecting the piezoelectric element and the lead electrode is provided in the region facing the peripheral wall of the pressure generating chamber, and the influence on the displacement is reduced.

In a tenth aspect of the present invention according to any one of the first to ninth 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 and formed. The inkjet recording head is characterized by being formed by a lithography method.

In the tenth aspect, it is possible to manufacture a large number of ink jet recording heads having high density nozzle openings and relatively easily.

An eleventh aspect of the present invention is an ink jet recording apparatus including the ink jet recording head according to any one of the first to tenth aspects.

According to the eleventh aspect, it is possible to realize an ink jet recording apparatus having improved head durability.

In a twelfth aspect of the present invention, a lower electrode layer, a piezoelectric layer and an upper electrode layer are sequentially laminated on an elastic film provided on one surface of a silicon single crystal substrate forming a pressure generating chamber, and each layer is formed. In the method for manufacturing an ink jet recording head, in which the piezoelectric active part including the lower electrode, the piezoelectric layer and the upper electrode is formed in a region corresponding to the pressure generating chamber by patterning After forming the lower electrode layer, a step of patterning the lower electrode in a region facing the pressure generating chamber, and a tensile film having a tensile stress in a region of the elastic film where the lower electrode is not formed, A step of forming using a mask, and after sequentially stacking the piezoelectric layer and the upper electrode layer on the lower electrode,
And a step of forming the piezoelectric active portion by patterning the upper electrode layer and the piezoelectric layer.

In the twelfth aspect, the diaphragm is composed of the elastic film and the tension film on the elastic film.

A thirteenth aspect of the present invention is the method for producing an ink jet recording head according to the twelfth aspect, characterized in that the film forming conditions are controlled so that the tensile film has a tensile stress during film formation. is there.

In the thirteenth aspect, the tension of the tension film acts on the lower electrode film, and the stress relaxation of the diaphragm at the time of forming the pressure generating chamber is reduced.

The fourteenth aspect of the present invention is the twelfth or thirteenth aspect.
In one aspect, the lower electrode layer is extended from at least one end portion in the longitudinal direction of a region facing the pressure generating chamber to the outside thereof to form a common electrode, which is a common electrode. On the way.

In the fourteenth aspect, the wiring of the head can be formed relatively easily without the need for the interlayer insulating film.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below 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 cross section of one of the pressure generating chambers in the longitudinal direction. It is a figure which shows a structure.

As shown in the figure, the flow path forming substrate 10 is a silicon single crystal substrate having a plane orientation (110) in this embodiment. The flow path forming substrate 10 is usually 150 to 3
A thickness of about 00 μm is used, preferably 18
The thickness is preferably about 0 to 280 μm, more preferably about 220 μm. This is because the array density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.

One surface of the flow path forming substrate 10 serves as an opening surface, and the other surface is provided with an elastic film 50 of 0.1 to 2 μm in thickness made of silicon dioxide formed by thermal oxidation in advance.

On the other hand, the opening surface of the flow path forming substrate 10 is anisotropically etched to form a silicon single crystal substrate.
A nozzle opening 11 and a pressure generating chamber 12 are formed.

In the anisotropic etching, when a silicon single crystal substrate is dipped in an alkaline solution such as KOH, it is gradually eroded to form a first (111) plane perpendicular to the (110) plane and the first (111) plane. Of the second (1) which makes an angle of about 70 degrees with the (111) plane of
The (11) plane appears, and the etching rate of the (111) plane is about 1/1 compared to the etching rate of the (110) plane.
It is performed by utilizing the property of being 80.
By such anisotropic etching, two first (11
Precision machining can be performed on the basis of the depth machining of the parallelogram shape formed by the 1) plane and the two diagonal second (111) planes, and the pressure generating chambers 12 can be arranged at high density. it can.

In the present 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 in the flow path forming substrate 1
It is formed by etching through almost 0 to reach the elastic film 50. Note that the elastic film 50 has a very small amount of being attacked by the alkaline solution that etches the silicon single crystal substrate.

On the other hand, each nozzle opening 11 communicating with one end of each pressure generating chamber 12 is formed narrower and shallower than the pressure generating chamber 12. That is, the nozzle opening 11 is formed by halfway etching the silicon single crystal substrate in the thickness direction. In addition,
Half etching is performed by adjusting the etching time.

Here, the size of the pressure generating chamber 12 that applies the ink droplet ejection pressure to the ink and the size of the nozzle opening 11 that ejects 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, it is necessary to accurately form the nozzle openings 11 with a groove width of several tens of μm.

The pressure generating chambers 12 and the common ink chamber 31 to be described later correspond to the pressure generating chambers 1 of the sealing plate 20 to be described later.
The ink is communicated through an ink supply communication port 21 formed at a position corresponding to one end of each of the two, and the ink is supplied from the common ink chamber 31 through the ink supply communication port 21 and each pressure generation chamber 12 Will be distributed to.

The sealing plate 20 is provided with the ink supply communication port 21 corresponding to each of the pressure generating chambers 12 and has a thickness of, for example, 0.1 to 1 mm and a linear expansion coefficient of 300 ° C. or less. , 2.5-4.5 [× 10 ⁻⁶ / ° C.], for example. The ink supply communication port 21
As shown in FIGS. 3A and 3B, each pressure generation chamber 1
There may be one slit hole 21A crossing the vicinity of the two ink supply side ends, or a plurality of slit holes 21B. The sealing plate 20 has the flow passage forming substrate 10 on one surface.
It also serves as a reinforcing plate that completely covers one surface and protects the silicon single crystal substrate from impact and external force. Also, the sealing plate 2
The other surface 0 forms one wall surface of the common ink chamber 31.

The common ink chamber forming substrate 30 forms the peripheral wall of the common ink chamber 31, and is made by punching out a stainless plate having an appropriate thickness according to the number of nozzle openings and the ink droplet ejection frequency. . In this embodiment, the common ink chamber forming substrate 30 has a thickness of 0.2 mm.

The ink chamber side plate 40 is made of a stainless steel substrate, and one surface thereof constitutes one wall surface of the common ink chamber 31. Further, the ink chamber side plate 40 is formed with a thin wall 41 by forming a recess 40a in a part of the other surface by half etching, and further, an ink introduction port 42 for receiving an ink supply from the outside is formed by punching. ing. It should be noted that the thin wall 41 is for absorbing a pressure generated when ink droplets are ejected and directed to the side opposite to the nozzle opening 11, and is unnecessary for another pressure generating chamber 12 via the common ink chamber 31. Prevents the application of positive or negative pressure.
In the present embodiment, the ink chamber side plate 40 has a thickness of 0.2 mm, and a part of the ink chamber side plate 40 has a thickness of 0.02 mm in consideration of the rigidity required when connecting the ink introduction port 42 and an external ink supply means.
However, the thickness of the ink chamber side plate 40 may be 0.02 mm from the beginning in order to omit the formation of the thin wall 41 by half etching.

On the other hand, a thickness of, for example, about 0.5 μm is formed on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10.
The lower electrode film 60, the piezoelectric film 70 having a thickness of, for example, about 1 μm, and the upper electrode film 80 having a thickness of, for example, about 0.1 μm are laminated and formed in a process described later to form the piezoelectric element 30.
Configures 0. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80. In general, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric film 70 are patterned for each pressure generating chamber 12. Further, here, a portion which is composed of one of the patterned electrodes and the piezoelectric film 70 and in which 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 the common electrode of the piezoelectric element 300 and the upper electrode film 80 is the individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed due to the drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. Also here
The piezoelectric element 300 and the vibration plate that is displaced by the driving of the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In this embodiment, since the lower electrode film 60 is patterned as will be described later, the elastic film 50 acts as a diaphragm.

Now, a process of forming the piezoelectric film 70 and the like on the flow path forming substrate 10 made of a silicon single crystal substrate will be described with reference to FIG.

As shown in FIG. 4A, first, a wafer of a silicon single crystal substrate to be the flow path forming substrate 10 is about 110.
An elastic film 50 made of silicon dioxide is formed by thermal oxidation in a 0 ° C. diffusion furnace.

Next, as shown in FIG. 4B, the lower electrode film 60 is formed by sputtering. Platinum or the like is suitable as a material for the lower electrode film 60. This is a piezoelectric film 70 described later, which is formed by sputtering or a sol-gel method.
Is 600 to 600 in an air atmosphere or an oxygen atmosphere after film formation.
This is because it is necessary to fire and crystallize 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 lead zirconate titanate is used as the piezoelectric film 70, the lower electrode film 60 is oxidized. It is desirable that the change in conductivity due to the diffusion of lead is small, and for these reasons platinum is preferred.

Next, as shown in FIG. 4C, the lower electrode film 60 is etched to a region corresponding to the pressure generating chamber 12, and at least both ends in the width direction are opposed to the pressure generating chamber 12. Pattern so that it is located inside.

Next, as shown in FIG. 5A, the tension film 6 is formed on the elastic film in a region where the lower electrode is not formed.
1 is deposited using a mask. For this reason, a material having a large Young's modulus, a material of platinum, iridium, iridium oxide, zirconium oxide, ruthenium oxide, tungsten, or molybdenum is preferable for this portion.

Further, although the tensile film 61 is formed by sputtering in this embodiment, it is necessary to control the film forming conditions so that the tensile film 61 has tensile stress. For example, the argon pressure for sputtering is 3 Pa or more. As a film.

Next, as shown in FIG. 5B, the piezoelectric film 70 and the upper electrode film 80 are formed. Although sputtering can be used to form the piezoelectric film 70, in the present embodiment, a so-called sol in which a metal organic material is dissolved / dispersed in a solvent is applied, dried, gelled, and fired at a higher temperature to form a metal. A so-called sol-gel method for obtaining the piezoelectric film 70 made of an oxide is used. As a material for the piezoelectric film 70, a lead zirconate titanate (PZT) -based material is suitable for use in an inkjet recording head.

The upper electrode film 80 may be made of any material having high conductivity, and many metals such as aluminum, gold, nickel, platinum, and conductive oxides can be used. In this embodiment, platinum is deposited by sputtering.

Next, as shown in FIG. 5C, the piezoelectric film 70 and the upper electrode film 80 are etched to etch the piezoelectric active portion 3
20 patterning is performed.

After patterning the piezoelectric film 70 and the upper electrode film 80 as described above, it is preferable to electrically insulate the upper surface of each upper electrode film 80, the piezoelectric film 70 and the tensile film 61. The insulating layer 90 having the property is formed (see FIG. 1).

Then, each piezoelectric active portion 3 of the insulating layer 90.
A contact hole 90a exposing a part of the upper electrode film 80 for connecting to a lead electrode 100 described later is formed in a part of a portion covering an upper surface of a portion corresponding to one end of 20. A lead electrode 100 is formed, one end of which is connected to each upper electrode film 80 through the contact hole 90a and the other end of which extends to the connection terminal portion. The lead electrode 100 is formed to have a width as narrow as possible so that a drive signal can be reliably supplied to the upper electrode film 80.

The process of forming such an insulator layer is shown in FIG.
Shown in.

First, as shown in FIG. 6A, an insulating layer 90 is formed so as to cover the peripheral portion of the upper electrode film 80, the piezoelectric film 70 and the upper surfaces of the tension films 61. This insulator layer 90
In this embodiment, a negative photosensitive polyimide is used as the material.

Next, as shown in FIG. 6B, by patterning the insulating layer 90, each pressure generating chamber 12 is formed.
A contact hole 90a is formed in a portion corresponding to the vicinity of the end portion on the ink supply side. This contact hole 90a
Is for connecting the lead electrode 100 and the upper electrode film 80.

The above is the film forming process. After the film formation is performed in this manner, as shown in FIG. 6C, the pressure generation chamber 12 and the like are formed by anisotropically etching the silicon single crystal substrate with the above-described alkaline solution. The state of the force received by the piezoelectric active part 320 at this time will be described below. FIG. 7 is a diagram schematically showing a state of stress generated in each layer before and after formation of the pressure generating chamber 12 by etching.

As shown in FIG. 7A, the tension film 61,
The lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80 have tensile stresses σ ₄ , σ ₃ , σ ₂ , and σ ₁ , respectively, and the elastic film 50 has a compressive stress σ ₅ . Therefore, as shown in FIG. 7B, when the piezoelectric active part 320 is patterned and the pressure generating chamber 12 is formed below the piezoelectric active part 320, the tensile stress of the piezoelectric film 70 and the upper electrode film 80 is reduced. σ ₂ and σ ₁ are released to become forces F ₂ and F ₁ for compressing the diaphragm, and the compressive stress σ ₅ of the elastic film 50 is released to become force F ₅ to pull the diaphragm. Further, in this embodiment, the tensile force F ₄ acts on the lower electrode film 60 due to the existence of the tensile film 61. Therefore, the compressive forces F ₂ and F ₁ and the tensile forces F ₅ and F ₄ are balanced, and the initial deflection of the diaphragm hardly occurs.

When the tension film 61 is not formed, the lower electrode film 60, the piezoelectric film 70 and the upper electrode film 80 are formed before the pressure generating chamber 12 is formed, as shown in FIG. 8A.
Have tensile stresses σ ₃₁ , σ ₂₁ and σ ₁₁ , respectively, so that when the pressure generating chamber 12 is formed, the tensile stresses σ ₃₁ and σ
₂₁ and σ ₁₁ are released to compressive forces F ₃₁ , F ₂₁ , and F ₁₁ ,
As a result, the elastic film 50 is deformed to be convex downward, and this remains as the initial deformation.

In this embodiment, the tensile film 61 is made of a material having a Young's modulus larger than that of the lower electrode film 60 and is formed so as to have a tensile stress. Thereby, the lower electrode film 60
Receives a strong tensile force F ₄ from the tensile films 61 on both sides adjacent to each other. Therefore, the tensile force F ₄ causes the piezoelectric film 70 to move.
Also, the compressive forces F ₂ and F ₁ from the upper electrode film 80 are canceled out, so that the deformation of the elastic film 50 due to the formation of the pressure generating chamber 12 can be reduced or eliminated. Further, since the deformation of the piezoelectric film 70 can be prevented, the piezoelectric characteristics of the piezoelectric film 70 before the pressure generating chamber 12 is formed can be maintained. Therefore, the displacement efficiency of the head can be improved.

In this embodiment, the piezoelectric active portion 320 composed of the piezoelectric layer 70 and the upper electrode 80 has the pressure generating chamber 12
Is provided in a region facing. Further, in the vicinity of the longitudinal end portion of the piezoelectric active portion 320, the contact hole 90 of the insulating layer 90 provided on the piezoelectric active portion 320.
The upper electrode 80 and the lead electrode 100 are connected via a. In the present embodiment, the contact hole 90
As shown in FIG. 2, a is provided at a position facing the pressure generating chamber 12, but the piezoelectric layer 70 and the upper electrode 80 are extended to the peripheral wall of the pressure generating chamber 12 and are provided on this peripheral wall. You may provide the contact hole 90a in the position which opposes.

In the series of film formation and anisotropic etching described above, a large number of chips are simultaneously formed on one wafer, and after the process is completed, a flow path forming substrate of one chip size as shown in FIG. Divide every ten. In addition, the divided flow path forming substrate 10 is sequentially bonded and integrated with the sealing plate 20, the common ink chamber forming substrate 30, and the ink chamber side plate 40 to form an ink jet recording head.

The ink jet head thus constructed takes in ink from the ink introduction port 42 connected to an external ink supply means (not shown) and fills the inside from the common ink chamber 31 to the nozzle opening 11 with ink.
According to a recording signal from an external drive circuit (not shown), a voltage is applied between the lower electrode 60 and the upper electrode 80 via the lead electrode 100, and the elastic film 50, the lower electrode 60 and the piezoelectric layer 7 are formed.
By flexing and deforming 0, the pressure in the pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle openings 11.

(Embodiment 2) FIG. 9 is a sectional view showing a state of a force applied to a piezoelectric active portion according to Embodiment 2 of the present invention when forming a pressure generating chamber.

In this embodiment, when the lower electrode film 60 is etched and patterned, the elastic film 50 is over-etched to a part in the thickness direction to form the elastic film removing portion 350. The film forming process was performed in the same manner as 1.

Therefore, as shown in FIG. 9A, since the elastic film 50 is partially removed, the elastic film 50 is removed.
A part of the compressive stress σ ₅ of is released to σ ₅₂ .

Next, as shown in FIG. 9B, the piezoelectric active portion 320 is patterned, and the piezoelectric active portion 32 is further patterned.
When the pressure generating chamber 12 is formed below 0, the piezoelectric film 70
And the tensile stresses σ ₂₂ and σ ₁₂ of the upper electrode film 80 are released to force F ₂₂ and F ₁₂ that try to compress the diaphragm, and the compressive stress σ ₅₂ of the elastic film 50 is further released to pull the diaphragm. It becomes F ₅₂ . Further, the tensile force F ₄₂ acts on the lower electrode film 60 due to the existence of the tensile film 61.

Even in such a structure, the pressure generating chamber 1
2. When forming 2, the compressive stress σ of the elastic film 50₅₂Is open
Pull the diaphragm Force F₅₂Becomes smaller, but on the other hand, tension
Since the tension film 61 is formed thick, the tension film 61
Tensile force F acting on the lower electrode film 60₄₂Grows. Shi
Therefore, also in the present embodiment, the compression force is the same as in the first embodiment.
F₂, F₁And tensile force F_Five, F_FourAnd become balanced,
The initial deflection of the diaphragm hardly occurs.

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

For example, in addition to the sealing plate 20 described above, the common ink chamber forming plate 30 may be made of glass ceramics, and the thin film 41 may be made of glass ceramics as a separate member. Change is free.

Further, in the above embodiment, the nozzle opening is formed on the end surface of the flow path forming substrate 10, but the nozzle opening may be formed so as to project in the direction perpendicular to the surface.

FIG. 10 is an exploded perspective view of the embodiment configured as described above, and FIG. 11 is a cross section of the flow path. In this embodiment, the nozzle openings 11 are formed in the nozzle substrate 120 opposite to the piezoelectric element, and the nozzle communication openings 22 that connect the nozzle openings 11 and the pressure generating chambers 12 are the sealing plate 20 and the common ink chamber. It is arranged so as to penetrate the forming plate 30, the thin plate 41A, and the ink chamber side plate 40A.

In this embodiment, the thin plate 41 is also used.
A and the ink chamber side plate 40A are separate members, and basically the same as the above-described embodiment except that the opening 40b is formed in the ink chamber side plate 40. Is omitted.

Also in this embodiment, similarly to the above-described embodiment, the lower electrode 60 and the tension film 61 are provided on the diaphragm to suppress the deflection of the diaphragm and improve the deformation amount and durability of the diaphragm. You can

Of course, the invention can be similarly applied to an ink jet recording head of the type in which the common ink chamber is formed in the flow path forming substrate.

Further, in each of the embodiments described above, the thin film type ink jet recording head which can be manufactured by applying the film formation and the lithography process is taken as an example.
Of course, the present invention is not limited to this. For example, one in which substrates are laminated to form a pressure generating chamber, one in which a piezoelectric film is formed by attaching a green sheet or screen printing, or a piezoelectric film by crystal growth. The present invention can be applied to ink jet type recording heads having various structures such as those for forming ink.

Further, although the example in which the insulating layer is provided between the piezoelectric element and the lead electrode has been described, the present invention is not limited to this. For example, without providing the insulating layer, anisotropic conductivity is provided to each upper electrode. The film may be heat-welded, and the anisotropic conductive film may be connected to the lead electrode, or may be connected using various bonding techniques such as wire bonding.

As described above, the present invention can be applied to ink jet type recording heads having various structures as long as it does not violate the gist thereof.

The ink jet recording head of each of these 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. 12
FIG. 3 is a schematic view showing an example of the inkjet recording apparatus.

As shown in FIG. 12, the recording head units 1A and 1B having the ink jet recording head are
Cartridges 2A and 2B forming an ink supply unit are detachably provided, and a carriage 3 having the recording head units 1A and 1B mounted thereon is provided on a carriage shaft 5 attached to an apparatus main body 4 so as to be axially movable. There is. The recording head units 1A and 1B are, for example,
The black ink composition and the color ink composition are respectively discharged.

The driving force of the drive 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 having the recording head units 1A and 1B mounted thereon extends along the carriage shaft 5. Be moved. On the other hand, a platen 8 is provided on the apparatus body 4 along the carriage 3. The platen 8 can be rotated by the driving force of a paper feed motor (not shown), and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller or the like, is wound around the platen 8 and conveyed. It has become so.

[0090]

As described above, according to the present invention,
The amount of relaxation of the internal stress of the piezoelectric film when forming the pressure generating chamber is reduced, and the initial deformation of the diaphragm is suppressed accordingly,
It is possible to substantially improve the amount of deformation of the diaphragm caused by driving the piezoelectric active portion.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an ink jet recording head according to a first embodiment of the invention, and is a plan view and a sectional view of FIG.

FIG. 3 is a perspective view showing a modified example of the sealing plate of FIG.

FIG. 4 is a cross-sectional view showing the thin film manufacturing process of Embodiment 1 of the present invention.

FIG. 5 is a cross-sectional view showing the thin film manufacturing process of Embodiment 1 of the present invention.

FIG. 6 is a cross-sectional view showing the thin film manufacturing process of Embodiment 1 of the present invention.

FIG. 7 is a sectional view showing a state of a force applied to the piezoelectric active portion according to the first embodiment of the present invention when the pressure generating chamber is formed.

FIG. 8 is a cross-sectional view showing a state of a force applied to a conventional piezoelectric active portion when forming a pressure generating chamber.

FIG. 9 is a cross-sectional view showing a state of a force applied to the piezoelectric active portion according to the second embodiment of the present invention when the pressure generating chamber is formed.

FIG. 10 is an exploded perspective view of an ink jet recording head according to another embodiment of the present invention.

FIG. 11 is a sectional view showing an ink jet recording head according to another embodiment of the present invention.

FIG. 12 is a schematic diagram of an inkjet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

10 Flow path forming substrate 11 nozzle opening 12 Pressure generation chamber 50 elastic membrane 60 Lower electrode film 61 Tensile film 70 Piezoelectric film 80 Upper electrode film 90 Insulator layer 100 lead electrode 320 Piezoelectric active part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Mari Sakai             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation F-term (reference) 2C057 AF52 AF65 AF93 AG12 AG44                       AG90 AG92 AG93 AP02 AP31                       AQ02 BA03 BA14

Claims (14)

[Claims] 1. An ink jet recording head in which a piezoelectric element is formed in a region corresponding to the pressure generating chamber via a vibration plate forming a part of the pressure generating chamber communicating with the nozzle opening, and the piezoelectric element is constituted. The lower electrode, the piezoelectric layer and the upper electrode are provided in a region facing the pressure generating chamber, and the lower electrode and a tensile film continuously provided on both sides in at least the width direction of the lower electrode and having a tensile stress. An ink jet recording head comprising at least an upper layer portion of the diaphragm. 2. The ink jet recording head according to claim 1, wherein the tensile film is made of a material different from that of the lower electrode. 3. The ink jet recording head according to claim 1, wherein the tensile film is made of a material having a Young's modulus larger than that of the lower electrode. 4. The tensile film according to claim 1, wherein the tensile film is made of at least one selected from the group consisting of platinum, iridium, iridium oxide, zirconium oxide, ruthenium oxide, tungsten, and molybdenum. Inkjet recording head. 5. The ink jet recording head according to claim 1, wherein an elastic film is formed below the lower electrode and the tension film. 6. The ink jet recording head according to claim 5, wherein a portion of the elastic film facing the lower electrode has a larger film thickness than other portions. 7. The ink jet recording head according to claim 5, wherein the elastic film is made of silicon dioxide. 8. The insulating layer according to claim 1, wherein an insulating layer is formed on an upper surface of the piezoelectric element, and a lead electrode for applying a voltage to the piezoelectric element and a connecting portion with the piezoelectric element. An ink jet recording head, wherein the contact portion is formed in a contact hole formed in the insulating layer. 9. The region according to claim 1, wherein at least one longitudinal end of the piezoelectric element is extended to a portion facing a side wall of the pressure generating chamber, and the contact portion is a region facing the side wall. An ink jet recording head characterized in that it is formed on the. 10. The pressure generating chamber according to claim 1, wherein the pressure generating chamber is formed in a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by film formation and a lithography method. An ink jet recording head characterized by being present. 11. An ink jet recording apparatus comprising the ink jet recording head according to claim 1. 12. The pressure is obtained by sequentially laminating a lower electrode layer, a piezoelectric layer and an upper electrode layer on an elastic film provided on one surface of a silicon single crystal substrate forming a pressure generating chamber and patterning each layer. In a method of manufacturing an ink jet recording head, wherein a piezoelectric active portion including the lower electrode layer, the piezoelectric layer, and the upper electrode layer is formed in a region corresponding to the generation chamber, the lower electrode layer is formed on the elastic film. After forming the film, patterning the lower electrode in a region facing the pressure generating chamber, and forming a tensile film having a tensile stress in a region of the elastic film where the lower electrode is not formed using a mask And a step of sequentially stacking the piezoelectric layer and the upper electrode on the lower electrode layer, and then patterning the upper electrode and the piezoelectric layer to form the piezoelectric active portion. A method for manufacturing an ink jet recording head, comprising: 13. The method for manufacturing an ink jet recording head according to claim 12, wherein the film forming conditions are controlled so that the tensile film has a tensile stress during film formation. 14. The common electrode according to claim 12, wherein the lower electrode layer extends from at least one longitudinal end of a region facing the pressure generating chamber to the outside thereof. And a method for manufacturing an ink jet recording head.