JPH11291486A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the amount of deformation and durability of a diaphragm by eliminating initial deformation thereof. SOLUTION: The ink jet recording head comprises a piezoelectric oscillator having an elastic film 50 constituting a part of a pressure generating room 12 communicating with a nozzle opening and serving as a diaphragm, a lower electrode 60 disposed above the elastic film 50, a piezoelectric layer 70 formed the lower electrode 60, an upper electrode 80 formed on the surface of the piezoelectric layer 70, and a piezoelectric active part 320 formed in a region facing the pressure generating room 12. The diaphragm is provided, at least in the regions corresponding to the opposite breadthwise sides of the piezoelectric active part 320, with parts 330 for absorbing deformation of the diaphragm due to internal stress of the piezoelectric layer 70 thus absorbing deformation of the diaphragm at the time of forming the pressure generating room.

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 can be driven by providing at least only the upper electrode for each pressure generating chamber while the piezoelectric material layer is provided on the entire surface of the vibration plate.

[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, the diaphragm undergoes initial deformation, and as a result, there is a problem that the piezoelectric vibrator enters a plastic region when the piezoelectric vibrator is driven. . Therefore, there is a problem that the amount of deformation during driving is substantially reduced, and the durability of the diaphragm is reduced.

In view of such circumstances, an object of the present invention is 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

[0009]

According to a first aspect of the present invention, there is provided an elastic film which constitutes a part of a pressure generating chamber which communicates with a nozzle opening and serves as a diaphragm, and a film on the elastic film. , A piezoelectric layer formed on the lower electrode, a piezoelectric layer formed on the lower electrode, and an upper electrode formed on the surface of the piezoelectric layer, and formed in a region facing the pressure generating chamber. In an ink jet recording head provided with a piezoelectric vibrator comprising an active portion, the vibration plate is formed when the pressure generating chamber is formed at least in regions corresponding to both widthwise sides of the piezoelectric active portion. An ink jet recording head has a stress absorbing portion for absorbing deformation of the diaphragm due to internal stress of the film.

In the first aspect, the stress applied to the diaphragm when the pressure generating chamber is formed is absorbed by the stress absorbing portion, and the amount of deformation of the diaphragm caused by driving the piezoelectric active portion is improved.

According to a second aspect of the present invention, in the first aspect, the stress absorbing portion extends in a direction intersecting a plane direction including at least a main portion of the vibration plate before forming the pressure generating chamber. An ink jet recording head including a stepped portion is provided.

In the second aspect, the stress applied to the diaphragm is absorbed by the step portion and its vicinity being deformed.

According to a third aspect of the present invention, there is provided an ink jet recording head according to the second aspect, wherein a plurality of the step portions are continuously provided, and the vibration plate has an uneven shape. is there.

In the third aspect, the stress applied to the diaphragm is effectively absorbed by deforming the plurality of steps and the vicinity thereof.

According to a fourth aspect of the present invention, in the second or third aspect, the stress absorbing portion projects toward the piezoelectric active portion side as compared with the diaphragm at the peripheral portion of the pressure generating chamber. An ink jet recording head including a stepped portion is provided.

In the fourth aspect, the stress applied to the diaphragm is absorbed by the stepped portion protruding toward the piezoelectric body active portion being displaced toward the pressure generating chamber.

According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the stress absorbing portion is closer to the pressure generating chamber than the diaphragm at the peripheral portion of the pressure generating chamber. An ink jet recording head is characterized in that it includes a projecting step.

In the fifth aspect, the stepped portion protruding toward the pressure generating chamber absorbs the deformation of the diaphragm by displacing the protruding end toward the piezoelectric active portion.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the pressure generating chamber is formed by anisotropic etching on a silicon single crystal substrate, 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 sixth aspect, an ink jet recording head having high-density nozzle openings can be manufactured in a large amount and relatively easily.

[0021]

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

(Embodiment 1) FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention. 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 silicon single crystal 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 0.1 to 2 μm thick elastic film 50 made of silicon dioxide formed by thermal oxidation in advance.

On the other hand, a silicon single crystal substrate is anisotropically etched on the opening surface of the flow path forming 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 are formed. A second (1) which forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the (110) plane.
11) plane, and the etching rate of the (111) plane is about 1/1 compared to the etching rate of the (110) plane.
This is performed using the property of being 80.
By such anisotropic etching, two first (11
Precision processing can be performed based on depth processing of a parallelogram formed by the 1) plane and two oblique second (111) planes, and the pressure generating chambers 12 can be arranged at high density. it can.

In this embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane, and the short side is formed by the second (111) plane. The pressure generating chamber 12 is provided on the flow path forming substrate 1.
It is formed by etching until it reaches the elastic film 50 almost through 0. 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 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.

Further, each pressure generating chamber 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, 2.5-4.5 [× 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 is provided on one side with the flow path forming substrate 10.
, And also serves as a reinforcing plate for protecting the silicon single crystal substrate from impacts and external forces. Also, sealing plate 2
0 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 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 one surface of the ink chamber side plate 40 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 thickness of the elastic film 50 on the opposite side of the opening surface of the flow path forming substrate 10 is, for example, 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 region facing each pressure generating chamber 12, a piezoelectric vibrator is provided independently for each pressure generating chamber 12, and in the present embodiment, the lower electrode film 60 is a common electrode of the piezoelectric vibrator.
Although the upper electrode film 80 is used as an individual electrode of the piezoelectric vibrator, there is no problem even if the upper electrode film 80 is reversed for convenience of a drive circuit and wiring. In the present embodiment, the piezoelectric film 70 is connected to each pressure generating chamber 12.
However, the piezoelectric film may be provided as a whole, and the upper electrode film 80 may be separately provided so as to correspond to each pressure generating chamber 12. In any case, each pressure generating chamber 1
That is, a piezoelectric active portion is formed every two.

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 wafer of a silicon single crystal substrate serving as a 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 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. 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. 4D, 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. 5A, 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. 5B, only the piezoelectric film 70 and the upper electrode film 80 are etched to form the piezoelectric active portion 32.
0 patterning is performed.

As described above, after the entire pattern of the lower electrode film 60 is formed, the patterning is completed by patterning the piezoelectric active portion 320.

As described above, after patterning the lower electrode film 60 and the like, preferably, at least the periphery of the upper surface of each upper electrode film 80, and the piezoelectric film 70 and the lower electrode film 60 are preferably formed.
Is formed so as to cover the side surfaces of the substrate (see FIG. 1).

The respective piezoelectric active portions 3 of the insulator layer 90
A contact hole 90a that exposes a part of the upper electrode film 80 for connecting to a lead electrode 100 described later is formed in a part of the part that covers the upper surface of the part corresponding to one end of 20. One end is connected to each upper electrode film 80 via the contact hole 90a, and the other end is formed with a lead electrode 100 extending to the connection terminal portion. The lead electrode 100 is formed so as to be as narrow as possible so as to reliably supply a drive signal to the upper electrode film 80.

FIG. 6 shows a process for forming such an insulator layer.
Shown in

First, as shown in FIG. 6A, an insulator layer 90 is formed so as to cover the periphery of the upper electrode film 80 and the side surfaces of the piezoelectric film 70 and the lower electrode film 60. This insulator layer 9
The preferred material of 0 is as described above, but in this embodiment, a negative photosensitive polyimide is used.

Next, as shown in FIG. 6B, by patterning the insulator layer 90, each of the pressure generating chambers 12 is formed.
A contact hole 90a is formed in a portion corresponding to the vicinity of the end on the ink supply side. This contact hole 90a
Is for connecting the lead electrode 100 and the upper electrode film 80. In the present embodiment, the contact hole 90a is provided at a position facing the pressure generating chamber 12, but the piezoelectric film 70 and the upper electrode film 80 are extended to the peripheral wall of the pressure generating chamber 12, A contact hole 90a may be provided at a position facing the peripheral wall.

The above is the film forming process. After forming the film in this manner, as shown in FIG. 6C, the silicon single crystal substrate is subjected to anisotropic etching with the above-described alkali solution to form the pressure generating chamber 12 and the like. In addition,
In the series of film formation and anisotropic etching described above, a number of chips are simultaneously formed on one wafer, and after completion of the process, each of the flow path forming substrates 10 having one chip size as shown in FIG. To divide. 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.

In this embodiment, when the pressure generating chamber 12 is formed in the elastic film 50, a stress absorbing portion is provided to absorb the deformation of the elastic film 50 and the lower electrode film 60 due to the internal stress of the piezoelectric film 70. Have been.

FIG. 7 is a plan view and a cross-sectional view showing a main part of such an ink jet recording head of this embodiment.

As shown in FIG. 7, in this embodiment, the piezoelectric active portion 32 composed of the piezoelectric film 70 and the upper electrode film 80 is used.
0 is provided in a region facing the pressure generating chamber 12. Further, the elastic film 50 in a region corresponding to the piezoelectric active portion 320 is provided with a protruding portion 51 protruding toward the piezoelectric active portion 320 from other portions. This protrusion 5
When forming the pressure generation chamber 12, the pressure generation chamber 12
By removing a part from the side to form the concave portion 52,
It is formed to have substantially the same thickness as the other portions of the elastic film 50. In this embodiment, when the pressure generating chamber 12 is formed, the step portion 53 extending in the direction intersecting the surface direction of the diaphragm at the periphery of the projecting portion 51 forms the elastic film 50 due to the residual stress of the piezoelectric film 70.
And a stress absorbing portion 330 for absorbing deformation of the lower electrode film 60.

The method for forming such a stress absorbing portion 330 is not particularly limited, but can be formed, for example, by the following method.

FIG. 8 is a diagram schematically showing a method of forming the stress absorbing portion 330. As shown in FIG.

As shown in FIG. 8A, first, the elastic film 5
0 is formed with a thickness several times as large as a predetermined thickness. Next, as shown in FIG. 8B, a part of the elastic film 50 other than a region corresponding to the piezoelectric active part 320 is removed to a predetermined thickness by etching or the like, so that the piezoelectric active part 320 is removed. In the region to be formed, a convex portion 50a having a thickness greater than that of the other portion of the elastic film 50 is formed. After that, similar to the film formation described above,
After forming the lower electrode film 60 and the like, the piezoelectric active portion 320 is formed by patterning. Then, FIG.
As shown in (c), when forming the pressure generating chamber 12,
A part of the elastic film 50 corresponding to the convex part 50a is partially removed from the pressure generating chamber 12 side to substantially the same thickness as the other part of the elastic film 50 to form the concave part 52. As a result, the protrusion 51 is formed on the elastic film 50 in a region corresponding to the piezoelectric active portion 320.
In the present embodiment, the step portion 53 on the periphery of the protruding portion 51 becomes the stress absorbing portion 330.

Further, as described above, the pressure generating chamber 12 is attached to the head.
FIG. 9 schematically shows the state of the elastic film 50 and the lower electrode film 60 when forming the film.

When the pressure generating chamber 12 is formed by etching or the like, the elastic film 50 and the lower electrode film 60 are deformed downward by the internal stress of the piezoelectric film 70 as described above. However, as shown in FIG. 9A, when the step 53, that is, the stress absorbing section 330 is provided on the elastic film 50, the step 53 is pulled toward the piezoelectric active section 320 and the pressure is reduced. The displacement applied to the generation chamber 12 absorbs the stress applied to the elastic film 50 and the lower electrode film 60. Therefore, the elastic film 50 and the lower electrode film 60 include
Substantially no initial elastic deformation remains.

Meanwhile, as shown in FIG. 9 (b), the case without the stepped portion on the elastic film 50 as in the prior art, the direction of the force f ₁ tensile having the piezoelectric film 70, the elastic film 50
And the lower electrode film 60 will receive a force f ₂ opposite to the force f ₁ on the whole film. As a result, the elastic film 50 and the lower electrode film 60 are deformed convexly downward, and remain as initial deformation.

As described above, according to the configuration of the present embodiment,
The stress applied to the elastic film 50 and the lower electrode film 60 is absorbed by the step portion 53 provided in the elastic film 50, that is, the stress absorbing portion 330, and does not remain as initial deformation. Therefore, the amount of deformation of the diaphragm due to the driving of the piezoelectric active section 320 can be improved, and the ink ejection characteristics can be maintained in a good state. In addition, durability can be improved.

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.

FIG. 10 shows the relationship between the force applied to the diaphragm and the amount of elastic deformation when the piezoelectric active portion of this embodiment is driven.
(A). As shown in the figure, in the present embodiment, the stress is absorbed by the deformation of the stress absorbing portion 330, and the diaphragm does not undergo any elastic deformation at the initial stage. Therefore, the deformation T with respect to the force F generated when the piezoelectric active portion is driven is elastic. This will occur in the deformation zone.

[0061] On the other hand, as shown in FIG. 10 (b), the case without the stress absorbing portion 330, the force f ₂ which joined the diaphragm initially, the initial deformation t has occurred, the piezoelectric active portion When the force F is applied at the time of driving, the diaphragm enters the plastic deformation region, so that the deformation T corresponding to the force F is not obtained, and the deformation T ′ occurs, and (TT ′) Is a loss of deformation.

(Embodiment 2) FIG. 11 is a plan view and a sectional view showing a main part of an ink jet recording head according to Embodiment 2.

In the present embodiment, instead of providing the elastic film 50 in the region corresponding to the piezoelectric active portion 320 with a protrusion protruding toward the piezoelectric active portion 320 as compared with the elastic film 50 in the other portion, As shown in FIG. 11, a protruding portion 51A protruding toward the pressure generating chamber 12 is provided. Therefore, the step portion 53A on the periphery of the projecting portion 51A is formed by the stress absorbing portion 330.
A.

Further, in the present embodiment, the lower electrode film 60 is removed in a portion corresponding to a so-called diaphragm arm on both sides of the piezoelectric active portion 320, which is a region facing both sides in the width direction of the pressure generating chamber 12. A lower electrode film removing section 350 is provided to improve the amount of displacement by applying a voltage to the piezoelectric body active section 320. The lower electrode film removing portion 350 may be formed by partially removing the lower electrode film 60 by half etching or the like without completely removing the lower electrode film 60. It may be formed by removing a part of the direction.

In such a configuration, as in the first embodiment, the deformation of the stress absorbing portion 330A causes the elastic film 50 to be deformed.
In addition, since the stress applied to the lower electrode film 60 is absorbed, the amount of deformation of the diaphragm caused by driving the piezoelectric active section 320 can be improved.

(Embodiment 3) FIGS. 12A and 12B are a plan view and a sectional view showing a main part of an ink jet recording head according to Embodiment 3. FIG.

In the present embodiment, as described in the above embodiment, the elastic film 5 in the region corresponding to the piezoelectric active portion 320 is provided.
Instead of providing a protruding portion on the elastic film 50, as shown in FIG.
Then, the groove 54 is formed over the entire circumference. Therefore, in the present embodiment, both side surfaces in the width direction of the groove portion 54, that is, the step portion 53B extending in a direction intersecting the surface direction of the elastic film 50 is the stress absorbing portion 330B.

With this configuration, as in the above-described embodiment, when forming the pressure generating chamber 12, the step 53B of the groove 54 formed in the elastic film 50, that is, the stress absorbing portion 330B is deformed. In addition, the stress applied to the elastic film 50 and the lower electrode film 60 is absorbed, and the amount of deformation of the diaphragm caused by driving the piezoelectric active unit 320 can be improved.

In this embodiment, one groove 54 is formed. However, the present invention is not limited to this. For example, a plurality of grooves 54 may be formed. Also, the groove 54 is formed over the entire circumference of the piezoelectric active portion 320,
The present invention is not limited to this, and may be formed at least in regions corresponding to both sides in the width direction of the piezoelectric active portion 320.

(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, as shown in FIG. 13, a projection 51C is formed on the elastic film 50 in a region corresponding to the piezoelectric active section 320, and the piezoelectric active section 3 on the projection 51C is further formed.
A plurality of grooves 54 </ b> A may be formed around 20. Accordingly, the plurality of steps 53C, that is, the stress absorbing portions 330C are provided, so that the deformation of the elastic film 50 and the lower electrode film 60 can be more effectively absorbed.

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 further, the thin film 41 may be made of glass ceramic as a separate member, and the material, structure and the like can be freely changed.

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 so as to project in a direction perpendicular to the surface.

FIG. 14 is an exploded perspective view of the embodiment constructed as described above, and FIG. 15 is a 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 the present 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, similarly to the above-described embodiment, by providing a stress absorbing portion,
The deformation of the elastic film and the lower electrode film due to the formation of the pressure generating chamber can be reduced or eliminated, and the deformation amount of the diaphragm and the durability of the diaphragm can be improved.

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 diaphragm, but 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.

[0082]

As described above, according to the present invention,
By providing the stress absorbing portion in the elastic film, it is possible to substantially suppress deformation of the diaphragm that occurs when forming the pressure generating chamber. Therefore, the amount of deformation of the diaphragm and the durability can be improved by driving the piezoelectric active portion.

[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.

FIGS. 7A and 7B are a plan view and a cross-sectional view illustrating a main part of the inkjet recording head according to the first embodiment of the invention.

FIG. 8 is a view showing a step of forming a protrusion of the elastic film.

FIG. 9 is a diagram showing a state of a diaphragm at the time of forming a pressure generating chamber.

FIG. 10 is a graph showing the relationship between the force applied to the diaphragm and the amount of elastic deformation when driving the piezoelectric active portion.

FIGS. 11A and 11B are a plan view and a cross-sectional view illustrating a main part of an ink jet recording head according to a second embodiment of the invention.

12A and 12B are a plan view and a cross-sectional view illustrating a main part of an inkjet recording head according to Embodiment 3 of the present invention.

FIG. 13 is a cross-sectional view illustrating a main part of an ink jet recording head according to another embodiment of the present invention.

FIG. 14 is an exploded perspective view of an ink jet recording head according to another embodiment of the present invention.

FIG. 15 is a cross-sectional view illustrating 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 51 projecting part 52 concave part 53, 53A, 53B, 53C step part 54 groove part 60 lower electrode film 70 piezoelectric film 80 upper electrode film 90 insulator layer 100 lead electrode 320 Active part of piezoelectric element 330 Stress absorbing part 350 Lower electrode film removing part

Claims (6)

[Claims] An elastic film which constitutes a part of a pressure generating chamber communicating with a nozzle opening and functions as a vibration plate, a lower electrode provided on the elastic film, and a piezoelectric formed on the lower electrode An ink jet recording head comprising a piezoelectric vibrator comprising a body layer 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, The vibrating plate has a stress absorbing portion that absorbs deformation of the vibrating plate due to internal stress of the piezoelectric layer when forming the pressure generating chamber, at least in a region corresponding to both widthwise sides of the piezoelectric active portion. An ink jet recording head, characterized in that: 2. The method according to claim 1, wherein the stress absorbing portion includes:
An ink jet recording head according to claim 1, wherein before the pressure generating chamber is formed, the vibration plate includes a step portion extending in a direction intersecting a plane direction including at least a main portion thereof. 3. The ink jet recording head according to claim 2, wherein a plurality of the step portions are continuously provided, and the vibration plate has an uneven shape. 4. The stress absorbing portion according to claim 2, wherein the stress absorbing portion includes a step portion projecting toward the piezoelectric active portion side as compared with the vibration plate at a peripheral portion of the pressure generating chamber. Inkjet recording head. 5. The pressure-absorbing member according to claim 2, wherein the stress absorbing portion includes a step portion protruding toward the pressure-generating chamber as compared with the diaphragm at a peripheral portion of the pressure-generating chamber. Characteristic inkjet recording head. 6. 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: