JPH11300971A - Ink jet recording head and ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the deformation quantity and durability of a vibration plate by excluding the initial deformation of the vibration plate. SOLUTION: In an ink jet recording head equipped with a piezoelectric vibrator consisting of a vibration plate constituting a part of a pressure generation chamber 12 communicating with a nozzle orifice and formed so that at least the upper surface thereof acts as a lower electrode 60 and a piezoelectric element operating part 320 comprising the piezoelectric film 70 formed on the surface of the vibration plate and the upper electrode 80 formed on the surface of the piezoelectric film 70, the initial deformation of the vibration plate is surpressed by providing a recessed part 325 to the inside of the pressure generation chamber 12.

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, and a piezoelectric layer is formed on the surface of the 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 diaphragm, 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 thin film 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 can be performed.

[0007]

However, in the above-described manufacturing method using the thin film technology and the lithography method,
A pressure generating chamber is formed after patterning of the thin film. At that point, initial deformation occurs in the diaphragm, so that stress is concentrated on the so-called arm portion, and the amount of displacement during driving is substantially reduced, and the durability of the diaphragm is reduced. There is a problem that the performance is reduced. In addition, the diaphragm may be plastically deformed, and the displacement efficiency and the durability may be further reduced.

When the lower electrode of the arm is removed to increase the displacement during driving, the initial deformation is twice or more as compared with the case where the lower electrode of the arm is not removed. Therefore, the concentration of stress on the so-called arm portion is further increased, and the above-described problems of a decrease in the displacement amount, a decrease in the displacement efficiency, and a decrease in the durability of the diaphragm are further increased, and plastic deformation of the diaphragm occurs. There is a greater risk of doing so.

In view of such circumstances, it is an object of the present invention to provide an ink jet recording head which eliminates initial deformation of a diaphragm, improves the amount of deformation of the diaphragm, and improves the durability of the diaphragm. And

[0010]

According to a first aspect of the present invention, there is provided a vibration plate which forms a part of a pressure generating chamber communicating with a nozzle opening and at least an upper surface of which functions as a lower electrode. In an ink jet recording head including a piezoelectric vibrator including a piezoelectric layer formed on a surface of the vibration plate and a piezoelectric active portion including an upper electrode formed on the surface of the piezoelectric layer, the vibration plate includes: An ink jet recording head is characterized in that the ink jet recording head has a recess on a part of the pressure generating chamber.

According to the first aspect, the concave portion suppresses the initial deformation of the vibration plate, so that the volume removed by driving the piezoelectric active portion and the durability of the vibration plate can be improved.

According to a second aspect of the present invention, in the ink jet recording head according to the first aspect, the concave portion is provided in a portion of the piezoelectric active portion facing the upper electrode. is there.

In the second aspect, the concave portion is provided in a region facing the upper electrode, and suppresses initial deformation that occurs on the diaphragm when the pressure generating chamber is formed.

According to a third aspect of the present invention, in the ink jet recording head according to the first or second aspect, the concave portion is not provided in a portion where the piezoelectric layer is not formed. is there.

According to the third aspect, the strength of the diaphragm is prevented from being reduced in a region where the piezoelectric layer is not provided.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the concave portion is provided at a substantially central portion in a width direction of the piezoelectric active portion in a longitudinal direction. The feature is the ink jet recording head.

In the fourth aspect, the concave portion relieves the force in the width direction of the piezoelectric active portion, which the diaphragm receives from the substrate when the pressure generating chamber is formed.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the width of the recess is 0.5 to 0.7 times the width of the piezoelectric active portion. And an ink jet recording head.

In the fifth aspect, the initial deformation of the diaphragm during the formation of the pressure generating chamber is suppressed without reducing the durability of the diaphragm.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the diaphragm comprises an elastic film and a lower electrode provided thereon, and the depth of the concave portion is The inkjet recording head is characterized in that the thickness is not less than 0.5 times the thickness of the film and reaches a part of the lower electrode.

In the sixth aspect, the initial deformation of the diaphragm during the formation of the pressure generating chamber is effectively suppressed.

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

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

According to an eighth aspect of the present invention, there is provided an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to seventh aspects.

According to the eighth aspect, it is possible to realize an ink jet recording apparatus having improved head characteristics and improved reliability.

[0026]

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

(Embodiment 1) FIG. 1 is an assembled 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 showing a structure.

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.

On both surfaces of the flow path forming substrate 10, a thickness of 0.1 to 0.1 made of silicon dioxide formed in advance by thermal oxidation.
The elastic films 50 and 55 of 2 μm are formed. The nozzle opening 11 and the pressure generating chamber 12 are formed on one surface of the flow path forming substrate 10 by patterning the elastic film 55 and then anisotropically etching the silicon single crystal substrate.

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 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 (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.
0, and is formed by etching a part of the elastic film 50 as described later. The amount of the elastic films 50 and 55 affected by the alkali 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 described later are connected to each pressure generating chamber 1 of the sealing plate 20 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 to 4.5 [× 10 ⁻⁶ / ° C.]. The ink supply communication port 2
Reference numeral 1 may be a single slit or a plurality of slits crossing the vicinity of the ink supply side end of each pressure generating chamber 12. 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. Also,
The sealing plate 20 forms one wall surface of the common ink chamber 31 on the other surface.

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 in accordance with 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 one surface thereof constitutes 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, the pressure generating chamber 12 of the flow path forming substrate 10
The lower electrode film 60 having a thickness of, for example, about 0.5 μm and a thickness of, for example, about 1 μm
The piezoelectric film 70 and the upper electrode film 80 having a thickness of, for example, about 0.1 μm are laminated and formed by a process described later to constitute a piezoelectric vibrator (piezoelectric element). As described above, in the region of the elastic film 50 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 The upper electrode film 80 is used as a common electrode of the piezoelectric vibrator, and the upper electrode film 80 is used as an individual electrode of the piezoelectric vibrator. In the present embodiment, the piezoelectric films 70 are individually provided corresponding to the respective pressure generating chambers 12. However, the piezoelectric films are provided entirely, and the upper electrode film 80 is provided corresponding to each of the pressure generating chambers 12. They may be provided individually. In any case, a piezoelectric active portion is formed for each pressure generating chamber 12.

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. 3A, 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 elastic films 50 and 55 made of silicon dioxide on both surfaces of the flow path forming substrate 10 at one time. In the present embodiment, the elastic film 55 is formed to be thicker than the elastic film 50 in order to form the pressure generating chamber 12 into a predetermined shape as described later.

Next, as shown in FIG. 3B, 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 in an air atmosphere or an oxygen atmosphere after the film formation.
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. 3C, 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. 3D, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and many metals such as Al, Au, Ni, and Pt, and a conductive oxide can be used. In the present embodiment, P
t is formed by sputtering.

Next, as shown in FIG.
The piezoelectric film 70 and the upper electrode film 80 are patterned.

First, as shown in FIG. 4A, the lower electrode film 60, the piezoelectric film 70 and the upper electrode film 80 are etched together to pattern the entire pattern of the lower electrode film 60. Next, as shown in FIG. 4B, only the piezoelectric film 70 and the upper electrode film 80 are etched to
0 patterning is performed. Next, as shown in FIG. 4C, the piezoelectric active region is a region opposed to both sides in the width direction of each pressure generating chamber 12 (in FIG. 4, the pressure generating chamber 12 is before being formed, 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. Thus, the lower electrode film removing section 3
By providing 50, the amount of displacement due to application of a voltage to the piezoelectric body active section 320 is improved. Note that the lower electrode film removing portion 350 may be formed by removing a part of the lower electrode film 60 in the thickness direction by half etching or the like, or may be formed up to a part of the elastic film 50 in the thickness direction. It may be formed by removing. Of course, it goes without saying that the lower electrode film removing section 350 need not be provided at all.

The above is the film forming process. After forming the film in this manner, as shown in FIG. 5, the silicon single crystal substrate is anisotropically etched with the above-described alkali solution to form the pressure generating chamber 12 and the like. At this time, in the present embodiment, a concave portion described later is formed at a position on the pressure generating chamber 12 side of the diaphragm facing the piezoelectric active portion 320.

First, as shown in FIG. 5A, a portion of the elastic film 55 corresponding to the position where the pressure generating chamber 12 is formed is patterned to form an opening 55a and a step 55b having a relatively thin film thickness. Form. The opening 55a is a portion corresponding to a concave portion described later, and in the present embodiment, the piezoelectric active portion 3
20 and a step 55b.
Is provided in a portion corresponding to the pressure generating chamber 12 around the opening 55a. Note that the step portion 55a may be formed by half etching or the like.

Next, as shown in FIG. 5B, anisotropic etching of the silicon single crystal substrate is performed using the above-described alkaline solution. With this etching, the opening 5
While the silicon single crystal substrate in the region 5a is attacked, the surrounding step 55b is also attacked. Therefore,
The step portion 55b is completely removed, and the portion of the silicon single crystal substrate covered by the step portion 55b is attacked with a delay. Thereafter, the silicon single crystal substrate in the region of the opening 55a is completely removed, but etching is performed until the silicon single crystal substrate in the region of the step 55b is completely removed, that is, until the pressure generating chamber 12 is formed. To continue. As a result, the elastic film 50 in the area of the opening 55a is eroded, and the recess 325 is formed.

The depth of the recess 325 thus formed can be adjusted by the thickness of the step 55b. That is, as the step portion 55b is left thicker, the concave portion 32
5 will be formed deeply. Further, in the present embodiment, since the elastic film 55 is formed thicker than the elastic film 50 as described above, the depth of the concave portion 325 can be adjusted within a range reaching a part of the lower electrode film 60. .

FIG. 6 shows the positional relationship among the thus formed concave portion 325, the piezoelectric active portion 320 and the pressure generating chamber 12. 6A is a plan view, and FIGS. 6B and 6C are a sectional view taken along line BB ′ and a line taken along line CC ′, respectively.

As shown in FIG.
Is formed on the elastic film 50 in a region opposed to the pressure generating chamber 12 at a substantially central portion in the width direction of the piezoelectric active portion 320 with a width smaller than the width of the piezoelectric active portion 320 over the longitudinal direction. . Further, the depth of the concave portion 325 is formed to be 0.5 times or more the thickness of the elastic film 50.

Here, the deformation of the elastic film 50 and the lower electrode film 60 when the recess 325 is formed as described above will be described. FIG. 7 is a diagram schematically illustrating deformation of the elastic film 50 and the lower electrode film 60.

As shown in FIG. 7A, when the piezoelectric film 70 and the upper electrode film 80 are patterned, the piezoelectric film 70 and the lower electrode film 60 have residual stress in the contracting direction. The elastic film 50 has a residual stress in the extending direction. Here, if the pressure generating chamber 12 is formed as before, the neutral surface of the bending of the piezoelectric active portion 320 is formed by the lower electrode film 60.
Since the piezoelectric active portion 320 is located in a lower layer portion which is considerably lower than half of the thickness of the piezoelectric member, as shown in FIG.
It deforms convexly downward, causing a large initial deformation.

On the other hand, as described above, the pressure generating chamber 1
When forming the piezoelectric element 2, the concave portion 325 is formed in the diaphragm, so that the neutral plane of the bending moves upward, for example, into the piezoelectric film 70. As shown, the amount of deformation at the substantially central portion of the pressure generating chamber 12 is reduced, and the entire initial displacement can be kept small.

Although the size of the concave portion 325 reduces the initial deformation of the diaphragm satisfactorily, it is necessary to design the concave portion 325 so as not to greatly affect the durability of the diaphragm. The range and width up to a part of the lower electrode film 60 with a thickness of 0.5 times or more of the film thickness of the 50
Is preferably in the range of 0.5 to 0.7 times the width of

In any case, the design of the concave portion 325 depends on the internal stress and thickness remaining in the piezoelectric film 70, the lower electrode film 60, and the elastic film 50, and the piezoelectric active portion 32.
0, the width of the pressure generating chamber 12, etc.
It is necessary to determine the optimum value in consideration of these.

As described above, according to the present invention, the pressure generating chamber 12
By forming the concave portion 325 at the same time as the formation of the pressure generating chamber 12, it is possible to move the bending neutral surface of the piezoelectric active portion 320 upward, thereby reducing the initial displacement amount generated when the pressure generating chamber 12 is formed. it can. Therefore, the excluded volume at the time of driving can be improved.

In the above description, the pressure generating chamber 12 is formed after the formation of the piezoelectric active portion 320. However, in practice, as shown in FIG. And an insulating layer 90 having electrical insulation properties so as to cover the side surfaces of the piezoelectric film 70 and the lower electrode film 60, and further correspond to one end of each piezoelectric active portion 320 of the insulating layer 90. A contact hole 90a exposing a part of the upper electrode film 80 for connecting to the lead electrode 100 is formed in a part of the part covering the upper surface of the part, and one end is formed in each upper electrode film 80 through the contact hole 90a. The pressure generating chamber 12 may be formed after the lead electrodes 100 are connected and the other end is formed to extend to the connection terminal portion. Here, it is preferable that the lead electrode 100 be formed to have a width as narrow as possible so that a drive signal can be reliably supplied to the upper electrode film 80.

In the present embodiment, the contact hole 90 a is provided at a position facing the peripheral wall of the pressure generating chamber 12. However, the piezoelectric active portion 320 is patterned in a region facing the pressure generating chamber 12. Alternatively, a contact hole 90a may be provided at a position facing the pressure generating chamber 12.

In the above-described series of film formation and anisotropic etching, a large number of chips are simultaneously formed on one wafer, and after the process is completed, a flow path of one chip size as shown in FIG. It is divided for each forming substrate 10. Further, the divided flow path forming substrate 10 is sequentially adhered 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 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
In accordance with a recording signal from an external drive circuit (not shown), a voltage is applied between the lower electrode film 60 and the upper electrode film 80 via the lead electrode 100, and the elastic film 50, the lower electrode film 60, and the piezoelectric film 70 The pressure generating chamber 1 is deformed by bending.
The pressure in 2 increases, and ink droplets are ejected from nozzle opening 11.

(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.

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. 8 is an exploded perspective view of the embodiment constructed as described above, and FIG. 9 is a sectional view of the flow path. In this embodiment, the nozzle opening 11 is formed in the nozzle substrate 120 opposite to the piezoelectric vibrator, and the nozzle communication port 22 that connects the nozzle opening 11 and the pressure generating chamber 12 is formed with the sealing plate 20 and the common ink. It is arranged so as to penetrate the 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 above-described embodiment, the initial deformation of the vibration plate can be suppressed by providing a concave portion on the vibration plate inside the pressure generating chamber.

Further, needless to say, the present invention can be similarly applied to an ink jet recording head of a type in which a common ink chamber is formed in a flow path forming substrate.

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.

Further, the example in which the insulator layer is provided between the piezoelectric vibrator and the lead electrode has been described. However, the present invention is not limited to this. The conductive film may be thermally 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 recording heads having various structures, as long as the gist of the present invention is not contradicted. Further, 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 the ink jet recording apparatus. FIG. 10 is a schematic view showing an example of the ink jet recording.

As shown in FIG. 10, the recording head units 1A and 1B having ink jet recording heads are provided with detachable cartridges 2A and 2B constituting ink supply means, and are equipped with these recording head units 1A and 1B. The carriage 3 is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B respectively discharge, for example, a black ink composition.

The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), 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, the apparatus main body 4 is provided with a platen 8 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 as a recording medium such as paper fed by a paper feed roller is wound around the platen 8 and conveyed. It has become so.

[0075]

As described above, according to the present invention,
Since the concave portion is formed in the diaphragm on the pressure generating chamber side, the initial deformation of the diaphragm is reduced, and the displacement amount of the diaphragm can be improved. In addition, the effect of suppressing stress concentration on the arm portion of the diaphragm and improving the durability is achieved.

[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 thin film manufacturing process according to the first embodiment of the present invention.

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 process of manufacturing a pressure generating chamber and a concave portion according to the first embodiment of the present invention.

FIG. 6 is a plan view and a cross-sectional view illustrating a main part of the inkjet recording head according to the first embodiment of the present invention.

FIG. 7 is a schematic view showing deformation of a diaphragm.

FIG. 8 is an exploded perspective view of an ink jet recording head according to another embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating an ink jet recording head according to another embodiment of the present invention.

FIG. 10 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 nozzle opening 12 pressure generating chamber 50 elastic film 60 lower electrode film 70 piezoelectric film 80 upper electrode film 90 insulating layer 100 lead electrode 320 piezoelectric active portion 325 concave portion 350 lower electrode removing portion

Claims (8)

[Claims] 1. A vibrating plate constituting a part of a pressure generating chamber communicating with a nozzle opening and having at least an upper surface serving as a lower electrode, a piezoelectric layer formed on the surface of the vibrating plate, and a piezoelectric layer An ink jet recording head comprising a piezoelectric vibrator comprising a piezoelectric active portion comprising an upper electrode formed on a surface thereof, wherein the vibration plate has a concave portion in a part on the pressure generating chamber side. Type recording head. 2. The ink jet recording head according to claim 1, wherein the concave portion is provided in a portion of the piezoelectric active portion facing the upper electrode. 3. The method according to claim 1, wherein the recess is
An ink jet recording head, wherein the ink jet recording head is not provided in a portion where the piezoelectric layer is not formed. 4. The ink jet recording head according to claim 1, wherein the concave portion is provided at a substantially central portion in a width direction of the piezoelectric active portion in a longitudinal direction. 5. The ink jet recording head according to claim 1, wherein the width of the recess is 0.5 to 0.7 times the width of the piezoelectric active portion. 6. The vibration plate according to claim 1, wherein the diaphragm comprises an elastic film and a lower electrode provided thereon, and the depth of the concave portion is 0.5% of the thickness of the elastic film. More than twice,
An ink jet recording head, which is located in a range up to a part of the lower electrode. 7. 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: 8. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.