JPH11157070A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve displacement characteristics and reliability. SOLUTION: The ink jet recording head includes a piezoelectric vibrator comprising a vibration plate, which partially defines a pressure generating chamber 12 in communication with a nozzle opening and whose upper surface functions at least as a lower electrode 60, and a piezoelectric active part 320, which is composed of a piezoelectric layer 70 formed on the surface of the vibration plate and an upper electrode 80 formed on the surface of the piezoelectric layer 70 and which is formed in a region in opposition to the chamber 12. And the upper electrode 80 extends to a region in opposition to the circumferential wall of the chamber 12 so that a voltage can be directly impressed on the electrode 80, not through a contact hole, to prevent the displacement, lowering and breakage of the contact hole.

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 is in communication with a nozzle opening for discharging ink droplets, and which is constituted by a vibrating plate. The present invention relates to an ink jet recording head that ejects ink droplets by displacement of a layer.

[0002]

2. Description of the Related Art A part of a pressure generating chamber which communicates with a nozzle opening for discharging ink droplets is constituted by a vibrating plate. There are two types of ink-jet recording heads that eject ink droplets from a piezoelectric vibrator, one that uses a longitudinal vibration mode piezoelectric vibrator that expands and contracts in the axial direction of the piezoelectric vibrator, and the other that uses a flexural vibration mode piezoelectric vibrator. Has been put to practical use.

In the former method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric vibrator into contact with the vibrating plate, so that a head suitable for high-density printing can be manufactured. A complicated process of cutting the piezoelectric vibrators into a comb-tooth shape in accordance with the arrangement pitch of the nozzle openings, and a work of positioning and fixing the separated piezoelectric vibrators in the pressure generating chambers, which complicates the manufacturing process. There is.

On the other hand, in the latter, a piezoelectric vibrator 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. 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 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 this piezoelectric material layer is cut into a shape corresponding to the pressure generating chambers by lithography, and a piezoelectric vibrator is formed so as to be independent for each pressure generating chamber.

[0006] According to this, the work of attaching the piezoelectric vibrator to the diaphragm is not required, and the precision of the lithography method is used.
In addition to the fact that the piezoelectric vibrator can be manufactured by a simple and simple method, there is an advantage that the thickness of the piezoelectric vibrator can be reduced and high-speed driving is possible.

In this case, the piezoelectric vibrator corresponding to each pressure generating chamber is 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 driving 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 It is desirable to form so as not to go out of the pressure generating chamber.

Therefore, the piezoelectric vibrators corresponding to the respective pressure generating chambers are covered with an insulating layer, and the insulating layer is formed with a connection portion with a lead electrode for supplying a voltage for driving each piezoelectric vibrator. There is proposed a structure in which a window (hereinafter, referred to as a contact hole) is provided corresponding to each pressure generating chamber, and a connecting portion between each piezoelectric vibrator and a lead electrode is formed in the contact hole.

[0009]

However, in a structure in which a contact hole is provided for connecting 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. Problem.

In the above-described ink jet recording head, a structure has been proposed in which the diaphragms on both sides of the piezoelectric vibrator are thinned in order to improve the displacement efficiency by driving the piezoelectric vibrator. However, such a large displacement promotes the tendency for breakage such as cracks to occur particularly near the contact hole.

Further, these problems tend to occur particularly when the piezoelectric material layer is formed by a film forming technique. Because
This is because the rigidity of the piezoelectric material layer formed by the film forming technique is lower than that of a piezoelectric material layer attached thereto because the piezoelectric material layer is extremely thin.

In view of such circumstances, an object of the present invention is to provide an ink jet recording head capable of improving displacement characteristics and reliability.

[0013]

According to a first aspect of the present invention, there is provided a diaphragm which forms a part of a pressure generating chamber communicating with a nozzle opening, at least an upper surface of which functions as a lower electrode. A piezoelectric vibrator comprising: a piezoelectric layer formed on the surface of the vibration plate; and an upper electrode formed on the surface of the piezoelectric layer, and a piezoelectric active portion formed in a region facing the pressure generating chamber. Wherein the upper electrode extends to a region facing a peripheral wall of the pressure generating chamber.

According to the first aspect, a voltage can be applied directly to the upper electrode without passing through the contact hole, and the displacement of the contact hole can be prevented from being reduced and the contact hole can be prevented from being broken.

According to a second aspect of the present invention, in the first aspect, the piezoelectric layer of the piezoelectric active portion is formed in a region facing the pressure generating chamber. In the recording head.

In the second aspect, since the piezoelectric layer does not exist in the region facing the vicinity of the end of the pressure generating chamber, the durability is improved.

According to a third aspect of the present invention, in the first or second aspect, the vibrating plate is provided on at least a portion along the edge of the pressure generating chamber on both sides in the width direction of the piezoelectric active portion. An ink jet recording head is characterized in that it has a thin portion thinner than the thickness of the portion corresponding to the body active portion.

In the third aspect, since at least the diaphragm of the arm portion is a thin film portion, the amount of displacement caused by driving the piezoelectric active portion is improved.

According to a fourth aspect of the present invention, in any one of the first to third aspects, an insulator layer is formed to cover a peripheral portion of an upper surface of the piezoelectric film of the piezoelectric active portion and a periphery thereof. An ink jet recording head is characterized in that the upper electrode extends on an insulator layer.

In the fourth aspect, the upper electrode extends on the insulator layer to maintain insulation from the lower electrode.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the upper electrode extends to a region facing at least one peripheral wall in the longitudinal direction of the pressure generating chamber. An ink jet recording head is characterized in that:

In the fifth aspect, the drive voltage can be applied from one end in the longitudinal direction of the piezoelectric active portion.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the upper electrode extends to a region opposed to at least one peripheral wall in the width direction of the pressure generating chamber. Ink-jet recording head.

In the sixth aspect, since the driving voltage can be applied from the vicinity of the center of the piezoelectric active portion, concentration of current at the time of driving can be avoided.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the width in the vicinity of a portion where the upper electrode crosses the boundary between the pressure generating chamber and the peripheral wall is equal to the pressure generating chamber. An ink jet recording head is characterized in that it is narrower than other portions of the opposing region.

In the seventh aspect, the displacement characteristic in the region facing the boundary between the pressure generating chamber and the peripheral wall is improved.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, at least a contact surface of the upper electrode with the piezoelectric layer is formed of a conductive oxide film. The feature is the ink jet recording head.

According to the eighth aspect, it is possible to prevent a decrease in piezoelectric characteristics due to oxygen deficiency in the piezoelectric layer.

According to a ninth aspect of the present invention, in the eighth aspect, the contact surface of the upper electrode with the piezoelectric layer is made of IrO.
x, ReOx, RuOx, SrRuOx, and a conductive oxide material selected from the group consisting of tin oxide and indium oxide-based materials.

According to the ninth aspect, it is possible to prevent a decrease in piezoelectric characteristics due to oxygen deficiency in the piezoelectric layer.

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

In the tenth aspect, an ink jet recording head having high-density nozzle openings can be manufactured in a large amount and relatively easily.

[0033]

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

(Embodiment 1) FIG. 1 is an assembled perspective view showing an ink jet recording head according to an embodiment of the present invention, and FIG. 2 shows a cross-sectional structure of one of the pressure generating chambers in the longitudinal direction. 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. As the flow path forming substrate 10, usually 150 to 3
A thickness of about 00 μm is used.
Those having a thickness of about 0 to 280 μm, more preferably about 220 μm are suitable. This is because the arrangement 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 is an opening surface, and the other surface is formed with a 1-2 μm-thick elastic film 50 made of silicon dioxide formed in advance by thermal oxidation.

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

Here, in the anisotropic etching, when a 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. The second (11) which forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the above (110).
1) plane appears, and the etching rate of the (111) plane is about 1/18 as compared with the etching rate of the (110) plane.
This is performed using the property of being 0. By such anisotropic etching, two first (111)
Precision processing can be performed based on the depth processing of a parallelogram formed by two surfaces and two oblique second (111) surfaces, and the pressure generating chambers 12 can be arranged at high density.

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. The amount of the elastic film 50 that is attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small.

On the other hand, each nozzle opening 11 communicating with one end of each pressure generating chamber 12 is formed to be narrower and shallower than the pressure generating chamber 12. That is, the nozzle opening 11 is formed by partially etching (half-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 for applying the ink droplet ejection pressure to the ink and the size of the nozzle opening 11 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 11 need to be formed with a groove width of several tens of μm with high accuracy.

Each of the pressure generating chambers 12 and a common ink chamber 31 to be described later are connected to each of the pressure generating chambers 1 of the sealing plate 20 to be described later.
The ink is supplied from a common ink chamber 31 through the ink supply communication port 21 formed at a position corresponding to one end of the pressure generation chamber 12. Distributed to

The sealing plate 20 is provided with an ink supply communication port 21 corresponding to each of the pressure generating chambers 12 described above, and has a thickness of, for example, 0.1 to 1 mm and a linear expansion coefficient of 300 ° C. or less. , For example, 2.5-4.5 [× 10 ⁻⁶ / ° C.]. In addition, the ink supply communication port 21
Each of the pressure generating chambers 1 is, as shown in FIGS.
It may be one slit hole 21A crossing the vicinity of the second ink supply side end or a plurality of slit holes 21B. The sealing 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. In addition, the sealing plate 20
The other surface constitutes 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 formed by punching a stainless steel plate having an appropriate thickness according to the number of nozzles and the ink droplet ejection frequency. . In the present embodiment, the thickness of the common ink chamber forming substrate 30 is 0.2 mm.

The ink chamber side plate 40 is made of a stainless steel substrate, and has one surface constituting one wall surface of the common ink chamber 31. In the ink chamber side plate 40, a thin wall 41 is formed by forming a concave portion 40a by half etching on a part of the other surface, and an ink introduction port 42 for receiving ink supply from the outside is punched and formed. ing. The thin wall 41 is for absorbing pressure generated at the time of ink droplet ejection toward the side opposite to the nozzle opening 11, and is unnecessary for the other pressure generating chambers 12 via the common ink chamber 31. Prevents positive or negative pressure from being applied.
In the present embodiment, the ink chamber side plate 40 is made 0.2 mm in consideration of rigidity required at the time of connection between the ink introduction port 42 and an external ink supply means, and a part of the thickness is 0.02 mm.
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, on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10, for example, a thickness of about 0.5 μm
A lower electrode film 60, a piezoelectric film 70 having a thickness of, for example, about 1 μm, and an upper electrode film 80 having a thickness of, for example, about 0.1 μm are formed by lamination in a process to be described later. (Piezoelectric element). Thus, the elastic film 50
In the area facing each pressure generating chamber 12, a piezoelectric vibrator is provided independently for each pressure generating chamber 12, but in the present embodiment, the lower electrode film 60 is a common electrode of the piezoelectric vibrator. The upper electrode film 80 is used as an individual electrode of the piezoelectric vibrator to form a piezoelectric active portion. Therefore, an insulator layer 9 having electrical insulation is provided around the piezoelectric film 70 of each piezoelectric vibrator.
0 is formed on the lower electrode film 60, and the upper electrode film 80 extends on the insulator layer 90 to the connection terminal portion.

The insulator layer 90 is provided on each of the piezoelectric films 7 in order to reliably prevent a short circuit between the lower electrode film 60 and the upper electrode film 80.
It is formed so as to cover at least the peripheral edge of the upper surface from the side surface of the zero. That is, on the upper surface of each piezoelectric film 70, a connection hole 90a that exposes substantially the entire piezoelectric film 70 for connection with the upper electrode film 80 is formed. This insulator layer 9
0 is preferably formed of a material that can be formed by a film forming method or shaped by etching, for example, silicon oxide, silicon nitride, an organic material, preferably photosensitive polyimide having low rigidity and excellent electrical insulation. .

Here, a process for 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 silicon single crystal substrate wafer serving as the flow path forming substrate 10 is
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. 4B, a lower electrode film 60 is formed by sputtering. Pt or the like is preferable as the material of the lower electrode film 60. This is because a piezoelectric film 70 to be described later, which is formed by sputtering or a sol-gel method, has a thickness of 600 to 100
This is because it is necessary to perform crystallization by firing at a temperature of about 0 ° C. That is, the material of the lower electrode film 70 must be able to maintain conductivity at such a high temperature and in an oxidizing atmosphere. In particular, when PZT is used as the piezoelectric film 70, the conductivity of the material by diffusion of PbO is increased. It is desirable that there is little change in sex, and Pt is preferred for these reasons.

Next, as shown in FIG. 4C, a piezoelectric film 70 is formed. The piezoelectric film 70 can be formed by sputtering, but in this embodiment, a so-called sol in which a metal organic substance is dissolved and dispersed in a solvent is applied, dried and gelled, and further baked at a high temperature. A so-called sol-gel method for obtaining a 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 when used in an ink jet recording head.

Next, as shown in FIG. 5, the lower electrode film 60 and the piezoelectric film 70 are patterned.

First, as shown in FIG. 5A, the lower electrode film 60 and the piezoelectric film 70 are etched together to pattern the entire pattern of the lower electrode film 60. Then, FIG.
As shown in (b), only the piezoelectric film 70 is etched to pattern the piezoelectric active part 320. Next, as shown in FIG. 5 (c), the piezoelectric active region is a region opposed to both sides in the width direction of each pressure generating chamber 12 (in FIG. 5, the pressure generating chamber 12 has not been formed yet but is indicated by a broken line). By removing portions of the lower electrode film 60 corresponding to the arms of the diaphragm on both sides of the portion 320, a lower electrode film removing portion 350 is formed. By providing the lower electrode film removing section 350 in this manner, the amount of displacement due to voltage application to the piezoelectric active section 320 is improved.

It should be noted that the lower electrode film removing section 350 may have a reduced thickness without completely removing the lower electrode film 60.
Further, the lower electrode film removing portion 350 is formed at a portion corresponding to the arm portion of the piezoelectric active portion 320, but is not limited thereto. The pressure generating chamber 1 may be formed.
2 may be formed over substantially the entire periphery. Needless to say, the lower electrode removing section 350 is not necessarily provided.

Next, as shown in FIG.
Then, patterning of the upper electrode film 80 is performed.

First, as shown in FIG. 6A, an insulator layer 90 is formed so as to cover the upper and side surfaces of the piezoelectric film 70 and the lower electrode film 60. Suitable materials for the insulator layer 90 are as described above, but in the present embodiment, a negative photosensitive polyimide is used. Next, as shown in FIG. 6B, a connection hole 90a for connection with the upper electrode film 80 is patterned in a portion of the insulator layer 90 corresponding to the piezoelectric film 70. Next, as shown in FIG.
0 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and many metals such as Al, Au, Ni, Pt, and Pd, and a conductive oxide can be used. In this embodiment,
Pt is formed by sputtering.

In particular, when PZT is used as the piezoelectric layer 70, it is preferable to use a conductive oxide for the upper electrode film 80 instead of Pt. This is because Pt may take in oxygen from PZT, which may cause a decrease in piezoelectric characteristics. In this case, a conductive oxide material may be used when the upper electrode film 80 is formed, or a conductive material that forms a conductive oxide film on the interface after being formed on the piezoelectric layer 70 may be used. You may. Such a conductive oxide material, for example, IrOx, ReOx, RuOx, SrRu
Ox and, for example, tin oxide / indium oxide based materials such as ITO can be used. Further, examples of the conductive material include Ir, Re, and Ru. When the upper electrode film 80 is formed using these materials, IrOx, ReOx, and Ru are respectively provided at the interface with the piezoelectric layer 70.
An Ox layer is formed, and the same effect is obtained. Of course, a conductive film such as Pt may be further laminated on the layer formed of these materials to form the upper electrode film 80.

Then, as shown in FIG. 6D, the entire pattern of the piezoelectric film 80 and the insulator layer 90 is patterned.

The above is the film forming process. After forming the film in this manner, as shown in FIG. 6E, the silicon single crystal substrate is anisotropically etched with the above-described alkali solution to form the pressure generating chamber 12 and the like.

The patterning procedure described above is not particularly limited.

The thus formed piezoelectric active part 320
FIG. 7 shows a planar positional relationship and a cross section between the pressure generating chamber 12 and the pressure generating chamber 12.

As shown in FIG. 7A, the piezoelectric active part 320 composed of the piezoelectric film 70 and the upper electrode film 80 basically has the pressure generating chamber 1 in a region facing the pressure generating chamber 12.
It is formed with a width slightly smaller than the width of No. 2. The upper electrode film 80 extends continuously from a region facing the pressure generating chamber 12 to a region facing the peripheral wall at one end in the longitudinal direction of the pressure generating chamber 12, and in the present embodiment, A connecting portion 85 is formed in a region facing one end of the pressure generating chamber 12 in the longitudinal direction.

In the region facing one end of the pressure generating chamber 12 in the longitudinal direction and the peripheral wall, the insulating layer 90 is
As shown in FIG. 2B, the upper electrode film 80 is formed to have a thickness substantially equal to that of the piezoelectric active portion 320, and extends on the insulator layer 90 to a connection terminal portion (not shown). .

In the present embodiment, the insulator layer 90 is provided at the longitudinal end of the pressure generating chamber 12 in the piezoelectric active section 3.
20 is formed, but is not limited to this. For example, as shown in FIG.
May be formed thin along the side surface of the lower electrode film 60 and the upper surface of the lower electrode film 60, as long as the lower electrode film 60 and the upper electrode film 80 are substantially insulated. As described above, photosensitive polyimide or the like is exemplified as a suitable material for the insulator layer 90. However, in the present embodiment, since it is not necessary to substantially cover the upper surface of the piezoelectric film 70, for example, SiO 2 may be used. _A hard material having low moisture permeability such as ₂ may be used to improve the environmental resistance.

In such a configuration, the upper electrode film 80 also serves as a lead electrode. However, since the insulator layer 90 prevents short circuit with the lower electrode film 60, the upper electrode film 80 extends from the connection terminal portion to the upper electrode film. By supplying a voltage directly to the film 80, the lower electrode film 60
And a voltage between the upper electrode film 80.

Therefore, there is no need to form a contact hole, so that there is no reduction in displacement due to a thicker film in the contact hole portion.
Since 0 is provided in a region facing the pressure generating chamber 12, cracks and the like near the connecting portion 85 can be prevented, and displacement characteristics and reliability can be improved. Further, since the upper electrode film 80 also functions as a lead electrode, the number of manufacturing steps can be reduced, and costs can be reduced.

In the above-described series of film formation and anisotropic etching of the piezoelectric active portion 320 and the pressure generating chamber 12, etc., a large number of chips are simultaneously formed on one wafer.
After the process is completed, the substrate is divided into each of the flow path forming substrates 10 having one chip size as shown in FIG. Further, the divided flow path forming substrate 10 is divided into a sealing plate 20 and a common ink chamber forming substrate 3.
0 and the ink chamber side plate 40 are sequentially bonded and integrated to form an ink jet recording head.

The ink jet head thus configured takes in ink from an ink inlet 42 connected to an external ink supply means (not shown), fills the interior from the common ink chamber 31 to the nozzle opening 11 with ink, and then fills the inside with ink (not shown). According to a recording signal from an external drive circuit, a voltage is applied between the upper electrode film 80 and the lower electrode film 60, and the elastic film 5
0, the lower electrode film 60 and the piezoelectric film 70 are flexibly deformed, so that the pressure in the pressure generating chamber 12 is increased and ink droplets are ejected from the nozzle opening 11.

(Embodiment 2) FIG. 8 shows a planar positional relationship between the piezoelectric active section 320 and the pressure generating chamber 12 according to Embodiment 2.

In this embodiment, as shown in FIG. 8, the region facing the longitudinal end of the pressure generating chamber 12, that is, the upper electrode film 80 and the insulating layer 90 of the connecting portion 85A are formed narrow. Other than the above, it is the same as the first embodiment.

By adopting such a configuration, in addition to the same effects as in the first embodiment, it is possible to improve the displacement near the connecting portion 85A.

In the present embodiment, the upper electrode film 80 and the insulator layer 90 of the connecting portion 85A are formed narrow, but only the upper electrode film 80 may be formed narrow.

(Embodiment 3) FIG. 9 shows a planar positional relationship between the piezoelectric active section 320 and the pressure generating chamber 12 according to Embodiment 3.

This embodiment is different from the embodiment shown in FIG. 9 in that a connecting portion 85 B is provided at the center of the piezoelectric active portion 320, and the upper electrode film 80 is extended to a region facing the side wall of the pressure generating chamber 12. Is the same as in the first embodiment.

With such a configuration, in addition to the same effects as in the first embodiment, the concentration of current near the connecting portion 85B during driving can be suppressed, and the piezoelectric film 70 and the like can be prevented from being broken. be able to.

(Other Embodiments) The embodiments of the present invention have been described above. However, the basic configuration 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 ceramic, and the thin film 41 may be made of glass ceramic as a separate member. Changes are free.

In the above-described embodiment, the nozzle openings are formed on the end surface of the flow path forming substrate 10. However, the nozzle openings may be formed to project in a 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-sectional view of the flow path. In this embodiment, the nozzle openings 11 are drilled in the nozzle substrate 120 opposite to the piezoelectric vibrator, and these nozzle openings 11
A nozzle communication port 22 for communicating the pressure generating chamber 12 with the pressure generating chamber 12 is provided so as to penetrate the sealing plate 20, the common ink chamber forming plate 30, the thin plate 41A, and the ink chamber side plate 40A.

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

Here, also in this embodiment, as in the first to third embodiments, a voltage can be directly applied to the upper electrode film without passing through the contact hole, and the displacement efficiency can be improved.

Of course, it is needless to say that the above-described embodiments can be more effective when implemented in combination as appropriate.

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

Further, in each of the above-described embodiments, the elastic film is provided separately from the lower electrode film as the vibration plate. However, the lower electrode film may also serve as the elastic film.

As described above, the present invention can be applied to ink-jet recording heads having various structures, as long as the spirit of the present invention is not contradicted.

[0086]

As described above, according to the present invention, it is possible to apply a voltage to the piezoelectric active portion without forming a contact hole, and to place the piezoelectric active portion in a region facing the pressure generating chamber. Because of the provision, the displacement characteristics and the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an ink jet recording head according to an 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, showing the same.

FIG. 3 is a view showing a modification of the sealing plate of FIG. 1;

FIG. 4 is a diagram showing a thin film manufacturing process according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a thin film manufacturing process according to the first embodiment of the present invention.

FIG. 6 is a view showing a thin film manufacturing process according to the first embodiment of the present invention.

7A and 7B are a plan view and a cross-sectional view illustrating a main part of the first embodiment of the present invention.

FIG. 8 is a plan view of a principal part for explaining a second embodiment of the present invention.

FIG. 9 is a main part plan view for explaining Embodiment 3 of the present invention.

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 cross-sectional view showing an ink jet recording head according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 flow path forming substrate 11 nozzle opening 12 pressure generating chamber 50 elastic film 60 lower electrode film 70 piezoelectric film 85, 85A, 85B connecting portion 80 upper electrode film 90 insulating layer 320 piezoelectric active portion 350 lower electrode removing portion

Claims (10)

[Claims] 1. A vibrating plate constituting a part of a pressure generating chamber communicating with a nozzle opening, at least an upper surface of which functions as a lower electrode, a piezoelectric layer formed on a surface of the vibrating plate, and a piezoelectric layer formed on the surface of the vibrating plate. An ink jet recording head comprising a piezoelectric vibrator comprising an upper electrode formed on a surface thereof and a piezoelectric active portion formed in a region facing the pressure generating chamber, wherein the upper electrode is a peripheral wall of the pressure generating chamber. An ink jet recording head extending to a region facing the ink jet recording head. 2. The ink jet recording head according to claim 1, wherein the piezoelectric layer of the piezoelectric active section is formed in a region facing the pressure generating chamber. 3. The piezoelectric element according to claim 1, wherein the vibrating plate has a portion corresponding to the piezoelectric active portion at least along the edge of the pressure generating chamber on both sides in the width direction of the piezoelectric active portion. An ink jet recording head having a thin portion thinner than the thickness. 4. The piezoelectric device according to claim 1, wherein an insulating layer is formed to cover a periphery of an upper surface of the piezoelectric film of the piezoelectric active portion and a periphery thereof, and the upper electrode is provided on the insulating layer. An ink jet type recording head, wherein is extended. 5. The ink-jet recording method according to claim 1, wherein the upper electrode extends to a region facing at least one peripheral wall in a longitudinal direction of the pressure generating chamber. head. 6. The ink jet type according to claim 1, wherein the upper electrode extends to a region facing at least one peripheral wall in a width direction of the pressure generating chamber. Recording head. 7. The pressure generating chamber according to any one of claims 1 to 6, wherein a width near a portion where the upper electrode crosses a boundary between the pressure generating chamber and a peripheral wall thereof is larger than that of another portion in a region facing the pressure generating chamber. An ink jet recording head characterized by being narrow. 8. An ink jet recording head according to claim 1, wherein at least a contact surface of said upper electrode with said piezoelectric layer is formed of a conductive oxide film. 9. The method according to claim 8, wherein the contact surface of the upper electrode with the piezoelectric layer is formed of IrOx, ReOx, RuOx,
An ink jet recording head formed of a conductive oxide material selected from the group consisting of SrRuOx and tin oxide / indium oxide based materials. 10. 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 vibrator is formed by film formation and lithography. An ink jet recording head, characterized in that: