JPH1178014A - Ink jet recording head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a contact part against crack, breakage, or the like, due to concentration of stress without sacrifice of displacement efficiency. SOLUTION: The ink jet recording head includes a piezoelectric oscillator comprises a resilient board having a resilient film 50 constituting a pressure generation chamber 12 communicating with a nozzle opening 11 and a lower electrode 60, a piezoelectric layer 70, and an upper electrode 80 formed in a region facing the pressure generation chamber 12. An insulator layer 90 having a window, i.e., a contact hole part 90a, for connecting with a conductive pattern 100 applying a voltage to the upper electrode 80 is formed on the upper surface thereof. The part corresponding to the contact hole 90a of the piezoelectric oscillator facing the pressure generation chamber 12 is not deformed easily upon application of voltage as compared with other part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrator formed on the surface of an elastic plate constituting one wall surface of a pressure generating chamber, and the displacement of the piezoelectric vibrator causes ink droplets to flow from a nozzle opening communicating with the pressure generating chamber. TECHNICAL FIELD The present invention relates to an ink jet recording head for discharging ink and an ink jet recording apparatus provided with the recording head.

[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 an elastic plate, and the elastic plate is deformed by a piezoelectric element to pressurize ink in the pressure generating chamber to cause a pressure from the nozzle opening. There are two types of ink jet recording heads that eject ink droplets, one that uses a longitudinal vibration mode piezoelectric vibrator that expands and contracts in the axial direction of the piezoelectric element, and the other that uses a flexural vibration mode piezoelectric vibrator. Has been

[0003] In the former case, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric vibrator into contact with an elastic plate, and 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 element can be formed on an elastic plate by a relatively simple process of sticking a green sheet of a piezoelectric material according to the shape of the pressure generating chamber and firing the green sheet. In addition, there is a problem that a certain area is required due to the use of flexural vibration, and that high-density arrangement is difficult.

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

According to this, the operation of attaching the piezoelectric element to the elastic plate becomes unnecessary, and not only can the piezoelectric vibrator be manufactured by a precise and simple method such as lithography, but also the piezoelectric vibrator can be manufactured. There is an advantage that the thickness can be reduced and high-speed driving becomes 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 elastic plate.

In a recording head using such a flexural mode piezoelectric vibrator, the piezoelectric vibrators corresponding to the respective pressure generating chambers are covered with an insulating layer, and the insulating layers drive the respective piezoelectric vibrators. Windows (hereinafter referred to as contact holes) are provided corresponding to the respective pressure generating chambers so as to form a connection portion with a conductor pattern for supplying a voltage for the piezoelectric vibrator and the conductor pattern. A connection is formed in the contact hole.

[0008]

However, as described above, the contact portion where the connecting portion between the piezoelectric vibrator and the conductor pattern corresponding to each pressure generating chamber is formed has a large stress due to the driving of the piezoelectric vibrator. Are liable to occur, and there is a problem that cracks and destruction may occur.

Further, since the contact portion is connected to the connection portion with the conductive pattern, the displacement due to the application of the voltage is smaller than that of the other portions.
Since the compliance is not small as compared with other parts, there is a problem that a discharge speed is reduced and a driving voltage is increased.

[0010] These problems become a problem particularly when the piezoelectric material layer is formed by a film forming technique. That is, since the piezoelectric material layer formed by the film formation technique is very thin, the rigidity thereof is lower than that of the piezoelectric material layer attached.

In view of such circumstances, an object of the present invention is to provide an ink jet recording head capable of preventing cracks, breakage, and the like due to stress concentration at a contact portion, and preventing a reduction in displacement efficiency of the contact portion. And

[0012]

According to a first aspect of the present invention, there is provided an elastic plate constituting a part of a pressure generating chamber communicating with a nozzle opening, and a piezoelectric member formed on the elastic plate. An ink jet recording head having a piezoelectric vibrator having an element and a piezoelectric active portion of the piezoelectric vibrator facing the pressure generating chamber. A contact portion that is formed to be narrower than the width and that is connected to a lead electrode for applying a voltage to the upper electrode on the upper surface of the upper electrode of the piezoelectric element; An ink jet recording head is characterized in that a portion of the plate corresponding to the contact portion is less likely to be deformed by application of a voltage than other portions.

In the first aspect, since the displacement of the elastic plate in the portion corresponding to the contact portion is smaller than that in the other portions, the stress applied to the piezoelectric layer corresponding to the contact portion is reduced, and the piezoelectric layer may be broken. Is reduced.

According to a second aspect of the present invention, in the first aspect, an insulator layer is formed on an upper surface of the upper electrode, and the contact layer between the lead electrode and the upper electrode is formed on the insulator layer. And a contact hole which is a window for forming the ink jet recording head.

In the second aspect, since the displacement of the piezoelectric vibrator in the portion corresponding to the contact hole portion of the insulator layer is smaller than in other portions, the stress applied to the piezoelectric active portion corresponding to the contact portion is small. Is reduced, and the possibility of destruction is reduced.

According to a third aspect of the present invention, in the first or second aspect, a width of the piezoelectric active portion in a portion corresponding to the contact portion is narrower than other regions. In the ink jet recording head.

In the third aspect, since the width of the piezoelectric active portion in the portion corresponding to the contact portion is small, the displacement caused by driving the contact portion is small as compared with other portions, and as a result, the generation of stress is small. And the risk of destruction is reduced.

According to a fourth aspect of the present invention, in any one of the first to third aspects, a width of the pressure generating chamber at a portion corresponding to the contact portion is narrower than other portions. And an ink jet recording head.

In the fourth aspect, since the width of the pressure generating chamber in the portion corresponding to the contact portion is small, the displacement due to the driving of the contact portion is small as compared with other portions, and as a result, the generation of stress is small. In addition, the risk of breakage and the like is reduced, the compliance of the contact hole portion is reduced, and the discharge speed is improved as a whole.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the thickness of a portion corresponding to the contact portion of the elastic plate made of an elastic film and / or a lower electrode is different from that of the first embodiment. An ink jet recording head characterized in that it is thicker than the part.

In the fifth aspect, since the thickness of the elastic film and / or the elastic plate formed of the lower electrode at the portion corresponding to the contact portion is thicker than other portions, the displacement caused by driving the contact portion is different from that of the other portion. As a result, the generation of stress is reduced, and the risk of breakage and the like is reduced.

According to a sixth aspect of the present invention, in any one of the first to fourth aspects, the thickness of a portion corresponding to the contact portion of the elastic plate comprising the elastic film and / or the lower electrode is the pressure An ink jet recording head is characterized in that it is thicker than a portion near the outer wall of the generation chamber.

In the sixth aspect, since the thickness of the elastic film and / or the elastic plate formed of the lower electrode, which is a displacement portion corresponding to the contact portion, is greater than other portions, the displacement caused by driving the contact portion is different from that of the other portion. The portion is smaller than the portion, and as a result, the generation of stress is reduced, and the risk of breakage and the like is reduced.

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 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, in the ink jet recording head according to the first aspect, a portion corresponding to the contact portion is a piezoelectric inactive portion.

In the eighth aspect, since the portion corresponding to the contact portion does not generate piezoelectric distortion, the displacement due to the driving of the contact portion is small as compared with other portions, and as a result, the generation of stress is small, and And the like are reduced.

According to a ninth aspect of the present invention, in the eighth aspect, the piezoelectric inactive portion is formed by removing a lower electrode of the piezoelectric element at a portion corresponding to the contact portion. Ink-jet recording head.

In the ninth aspect, since the lower electrode corresponding to the contact portion is removed, no piezoelectric distortion occurs in the contact portion, and the displacement caused by driving the contact portion is smaller than that of the other portions. As a result, the generation of stress is reduced, and the risk of breakage and the like is reduced.

According to a tenth aspect of the present invention, in the eighth aspect, the piezoelectric inactive portion is provided between the lower electrode of the piezoelectric element and the piezoelectric layer in a portion corresponding to the contact portion or the piezoelectric layer. An ink jet recording head is characterized in that a low dielectric layer is formed between a piezoelectric layer and an upper electrode of the element.

In the tenth aspect, since the low dielectric layer is formed between the lower electrode and the piezoelectric layer or between the piezoelectric layer and the upper electrode at a portion corresponding to the contact portion, the piezoelectric strain is formed at the contact portion. Does not occur, the displacement due to the driving of the contact portion is small as compared with other portions, and as a result, the generation of stress is reduced, and the risk of breakage and the like is reduced.

According to an eleventh 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 tenth aspects.

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

[0034]

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

(Embodiment 1) FIG. 1 is an assembly 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 made of 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 an elastic film 50 having a thickness of 1 to 2 μm and made of silicon dioxide formed in advance by thermal oxidation.

A nozzle opening 11 and a pressure generating chamber 12 are formed on the opening surface of the flow path forming substrate 10 by anisotropically etching a silicon single crystal substrate.

Here, in the anisotropic etching, when a silicon single crystal substrate is immersed in an alkaline solution such as KOH, it 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 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 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 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 lower electrode film 60 having a thickness of, for example, about 0.5 μm and the piezoelectric film having a thickness of, for example, about 1 μm are formed on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10. Body membrane 7
0 and an upper electrode film 80 having a thickness of, for example, about 0.1 μm are laminated and formed by a process described later, thereby forming a piezoelectric element on the elastic film 50. Here, the piezoelectric element refers to a portion including the lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80. Generally, one of the electrodes of the piezoelectric element is used as a common electrode, and the other electrode and the piezoelectric film 70 are patterned for each of the pressure generating chambers 12. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric film 70 and in which a piezoelectric strain is generated by applying a voltage to the upper electrode and the lower electrode is referred to as a piezoelectric active portion. In the present embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element,
Although the upper electrode film 80 is used as an individual electrode of the piezoelectric element, there is no problem even if the upper electrode film 80 is reversed for convenience of a driving circuit and wiring. In any case, a piezoelectric active portion is formed for each pressure generating chamber.

In the above-described example, the elastic film 50 and the lower electrode film 60 function as an elastic plate.
Only the lower electrode film may serve as an elastic plate, or the lower electrode film may also serve as an elastic film.

Such a portion constituted by the piezoelectric element and the elastic plate is referred to as a piezoelectric vibrator in the present specification.

Here, in the present embodiment, the portions of the piezoelectric film 70 and the upper electrode film 80 corresponding to the contact holes 90a of the insulator layer 90, which will be described later, are narrower than the other portions. It is a narrow portion 80a.

An insulating layer 90 having electrical insulation is formed so as to cover at least the periphery of the upper surface of each of the upper electrode films 80 and the side surfaces of the piezoelectric film 70. The insulator layer 90 is formed of a material that can be formed by a film formation method or shaped by etching, for example, silicon oxide, silicon nitride, or an organic material, preferably photosensitive polyimide having low rigidity and excellent electrical insulation. Is preferred.

The narrow portion 8 of each upper electrode film 80 of the insulator layer 90
A contact hole 90 exposing a portion of the narrow portion 80a of the upper electrode film 80 to be connected to a conductive pattern 100 described later is formed in a part of the part covering the upper surface of the part corresponding to 0a
a is formed. And this contact hole 9
One end is connected to each upper electrode film 80 via Oa, and the other end is formed with a conductive pattern 100 extending to the connection terminal portion. The conductive pattern 100 transmits a drive signal to the upper electrode film 80.
It is formed so as to have a width as narrow as possible so that it can be reliably supplied.

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 FIGS.

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 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 due to the diffusion of PbO 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. 4E, the upper electrode film 80 and the piezoelectric film 70 are patterned so that a piezoelectric vibrator is provided for each of the pressure generating chambers 12. FIG. 4E shows a case where the piezoelectric film 70 is patterned with the same pattern as the upper electrode film 80. However, as described above, the piezoelectric film 70 does not necessarily need to be patterned. This is because, when a voltage is applied using the pattern of the upper electrode film 80 as an individual electrode, an electric field is applied only between each upper electrode film 80 and the lower electrode film 60 which is a common electrode. This has no effect. However, in this case, it is necessary to apply a large voltage to obtain the same excluded volume. Therefore, it is preferable to pattern the piezoelectric film 70 as well. Thereafter, the lower electrode film 60 is patterned to remove unnecessary portions.

Next, as shown in FIG. 5A, an insulator layer 90 is formed so as to cover the periphery of the upper electrode film 80 and the side surface of the piezoelectric film 70. 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. 5B, 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 a conductor pattern 100 as a lead electrode described later.
And a connection portion for connecting the electrode to the upper electrode film 80. The contact hole 90a may be provided in another part of the pressure generating chamber 12, for example, in a central part or an end on the nozzle side.

Next, for example, a conductor such as Cr-Au is formed on the entire surface and then patterned to form a conductor pattern 100.

The above is the film forming process. After forming the film in this manner, as shown in FIG. 5C, the silicon single crystal substrate is anisotropically etched 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.

The ink jet head thus configured takes in ink from an ink inlet 42 connected to 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 interior with ink. In accordance with a recording signal from an external drive circuit, a voltage is applied between the lower electrode film 60 and the upper electrode film 80 via the conductive pattern 100, and the elastic film 50, the lower electrode film 60, and the piezoelectric film 70 are flexibly deformed. By doing so, the pressure generating chamber 1
The pressure in 2 increases, and ink droplets are ejected from nozzle opening 11.

Here, the shapes of the piezoelectric vibrator and the pressure generating chamber 12 in this embodiment are shown in FIG.

As shown in FIG. 6, in the present embodiment, the piezoelectric film 70 and the upper electrode film 80 are
Is formed in a narrow portion 70a narrower than the other portions.
And 80a, and other portions are patterned so as to substantially correspond to the shape of the pressure generating chamber 12. The contact hole 9 of the insulator layer 90 is formed on the narrow portion 80a.
0a is formed, and a connection portion with the conductive pattern 100 is formed in the contact hole 90a.

As described above, in the present embodiment, the width of the piezoelectric body active portion where the piezoelectric film and the upper electrode film are formed in the contact hole 90a forming the connection portion with the conductor pattern 100 as the lead electrode is reduced. Since the width is narrower than the other portions, the amount of deflection of the portion corresponding to the contact hole 90a is small, and the piezoelectric film 70a and the upper electrode film 8
The stress applied to Oa is reduced, and the risk of occurrence of cracks, breakage, and the like is reduced.

(Embodiment 2) FIG. 7 shows the shapes of a piezoelectric vibrator and a pressure generating chamber of an ink jet recording head according to Embodiment 2 of the present invention.

In this embodiment, the piezoelectric film 70 of the first embodiment is used.
Instead of providing a narrow portion 70a of the pressure generating chamber 12 and a narrow portion 80a of the upper electrode film 80.
The configuration is the same as that of the first embodiment, except that a narrow portion 12b is provided in a portion corresponding to.

That is, while the narrow portion 12 b is provided in a part of the pressure generating chamber 12, the piezoelectric film 70 and the upper electrode film 80
Are formed with the same width over the entire pressure generating chamber 12,
The contact hole 90a of the insulator layer 90 is formed in a portion corresponding to the narrow portion 12b.

Therefore, when a voltage is applied to the piezoelectric vibrator through the contact hole 90a, the portion corresponding to the narrow portion 12b of the pressure generating chamber 12, that is, the conductor pattern 100 through the contact hole 90a, The displacement of the portion of the connection portion becomes small. As a result, portions of the piezoelectric film 70 and the upper electrode film 80 corresponding to the contact holes 90a are formed.
Is reduced, and the risk of cracking, breakage and the like is reduced. Further, the compliance at the portion corresponding to the contact hole 90a is reduced, and the discharge speed is improved.

(Embodiment 3) FIG. 8 shows the shapes of a piezoelectric vibrator and a pressure generating chamber of an ink jet recording head according to Embodiment 3 of the present invention.

This embodiment relates to Embodiments 1 and 2.
A narrow portion 12b is provided in a portion corresponding to the contact hole 90a of the pressure generating chamber 12, and narrow portions 70a and 80a are provided in the piezoelectric film 70 and the upper electrode film 80. Yes, the other is the first embodiment described above.
And 2 have the same configuration.

That is, the narrow portion 12b is provided near the ink supply side end of the pressure generating chamber 12, and the piezoelectric film 70 and the upper electrode film 80 corresponding to the narrow portion 12b are made narrower than other portions. Formed into narrow portions 70a and 80a.
A contact hole 90a of the insulator layer 90 is formed in a portion corresponding to 2b.

Therefore, when a voltage is applied to the piezoelectric vibrator through the contact hole 90a, the portion corresponding to the narrow portion 12b of the pressure generating chamber 12, ie, the conductor pattern 100 through the contact hole 90a, The displacement of the connecting portion is further reduced. As a result, stress is reduced in the portions of the piezoelectric film 70 and the upper electrode film 80 corresponding to the contact holes 90a, and the risk of cracking, breakage, and the like is further reduced. Further, the compliance at the portion corresponding to the contact hole 90a is reduced, and the discharge speed is improved.

(Embodiment 4) FIG. 9 shows the shapes of a piezoelectric vibrator and a pressure generating chamber of an ink jet recording head according to Embodiment 4 of the present invention.

In the present embodiment, the thickness of the elastic film 50 and the lower electrode film 60 serving as the elastic plates of the piezoelectric vibrator is made different between the portion corresponding to the contact hole 90a and the other portions. Are relatively difficult to deform.

That is, in the lower electrode film 60 facing the pressure generating chamber 12, the thickness of the lower electrode film 60 other than the portion corresponding to the contact hole 90 a (shown by oblique lines in FIG. 9A) is reduced. A thin portion 60a was formed, on which a piezoelectric film 70 and an upper electrode film 80 were formed. The lower electrode film 60
Can be easily formed by ion milling or the like.

Therefore, by applying a voltage to the piezoelectric vibrator,
Deformation of the portion other than the portion corresponding to the contact hole 90a is facilitated, and conversely, the deformation of the portion corresponding to the contact hole 90a is relatively small, so that the generation of stress is reduced and the risk of cracking, breakage, etc. is reduced. Become. In the present embodiment, the amount of displacement is further increased by removing the insulator layer 90 in a portion other than the contact hole 90a.

In the present embodiment, the thickness of the lower electrode film 60 other than the portion substantially facing the pressure generating chamber 12 and corresponding to the contact hole 90a is reduced. However, the elastic plate is thinned to facilitate deformation. For this reason, as shown in FIG. 10, the thin portion 60b may be formed only in the portion facing the peripheral portion of the pressure generating chamber 12. Also in this case,
The displacement amount is further increased by removing the insulator layer 90 other than the contact hole 90a.

In any case, it is sufficient to make at least the vicinity of the peripheral portion most relevant to deformation by the piezoelectric vibrator thin. Therefore, it is preferable to reduce the thickness from the peripheral edge of the pressure generating chamber 12 to a slightly outer side.
May be continued.

Further, instead of the lower electrode film 60, the elastic film 50
Alternatively, a thin portion may be formed on both the elastic film 50 and the lower electrode 60. Of course, only the lower electrode may be provided as the elastic plate, and a thin portion may be formed on the lower electrode.

(Embodiment 5) FIG. 11 shows the shape of an ink jet recording head according to Embodiment 5 of the present invention.

In the present embodiment, the portion corresponding to the contact hole 90a is a piezoelectric non-active portion, so that the portion corresponding to the contact hole 90a is relatively hard to deform.

That is, at least the contact hole 9
The lower electrode removal portion 60a is formed by removing a part of the lower electrode film 60 corresponding to the portion 0a, and this portion is used as a piezoelectric non-active portion in which piezoelectric distortion does not occur when a voltage is applied.

According to this embodiment, since the portion corresponding to the contact hole 90a does not undergo piezoelectric distortion due to the application of the voltage, the portion corresponding to the contact hole 90a can be relatively hardly deformed.

As a method of forming a piezoelectric inactive portion as in the present embodiment to make it relatively difficult to deform a portion corresponding to the contact hole 90a, FIG.
This can be realized by forming a low dielectric layer in a portion corresponding to the contact hole 90a as shown in FIG.

That is, a low dielectric layer 95a is formed between the lower electrode 60 corresponding to the contact hole 90a and the piezoelectric film 70 as shown in FIG. 12B, a low dielectric layer 95b is formed between the piezoelectric film 70 corresponding to the contact hole 90a and the upper electrode 90 as shown in FIG. By doing so, the portion corresponding to the contact hole 90a can be relatively hardly deformed.

(Other Embodiments) One embodiment of the present invention has 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 for discharging ink in a direction perpendicular to the substrate surface may be formed.

FIG. 13 is an exploded perspective view of the embodiment configured as described above, and FIG. 14 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.

The present embodiment is different from the first embodiment in that
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 embodiment, the contact holes 90a of the insulator layer 90 are formed.
The narrow portions 70a and 80a are provided in the portions of the piezoelectric film 70 and the upper electrode film 80 corresponding to. Thereby, the portion corresponding to the contact hole 90a is less likely to be deformed as compared with the other portions, and the same effect as in the first embodiment described above can be obtained. Of course, the configurations of Embodiments 2 to 4 may be applied.

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 elastic plate, 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 and the contact hole portion is formed has been described. However, the present invention is not limited to this. A configuration in which an anisotropic conductive film is thermally welded to the upper electrode, and the anisotropic conductive film is connected to the lead electrode, or may be connected using various bonding techniques such as wire bonding or the like.

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.

The ink jet recording head of each of the embodiments is used by being mounted on an ink jet recording apparatus so that ink from an ink supply means such as an ink cartridge is supplied through an ink supply path. . FIG. 15 is a schematic view showing an example of such an ink jet recording apparatus.

As shown in FIG. 15, the recording head units 1A and 1B provided with an ink jet recording head and ink supply needles as ink supply passages are provided with detachable ink cartridges 2A and 2B filled with ink. It is configured. The recording head units 1A and 1
B is mounted on the carriage 3 and is configured to be movable in the axial direction of the carriage shaft 5 attached to the apparatus main body 4. The recording head units 1A and 1B discharge, for example, black ink and a plurality of color inks, respectively.

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. Move. On the other hand, a platen 8 is provided on the apparatus main body 4 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is wound around the platen 8 and conveyed. It has become.

Such an ink jet recording apparatus can be widely applied not only to an output apparatus such as a computer but also to a system having a recording apparatus such as a facsimile or a word processor.

[0102]

As described above, in the present invention,
Since the portion corresponding to the contact hole portion of the piezoelectric vibrator facing the pressure generating chamber is less likely to be deformed by voltage application than other portions, there is no danger of cracking, breakage, etc. due to driving. This has the effect.

[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 plan view showing a main part of the first embodiment of the present invention.

FIG. 7 is a plan view of a main part for describing Embodiment 2 of the present invention.

FIG. 8 is a main part plan view for explaining Embodiment 3 of the present invention.

FIG. 9 is a main part plan view for explaining Embodiment 4 of the present invention.

FIG. 10 is a main part plan view showing a modification of the fourth embodiment of the present invention.

FIG. 11 is a cross-sectional view in the longitudinal direction of a pressure generating chamber for explaining a fifth embodiment of the present invention.

FIG. 12 is a cross-sectional view in a longitudinal direction of a pressure generating chamber showing a modification of the fourth embodiment of the present invention.

FIG. 13 is an exploded perspective view of an ink jet recording head according to another embodiment of the present invention.

FIG. 14 is a sectional view showing an ink jet recording head according to another embodiment of the present invention.

FIG. 15 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 12b narrow part 50 elastic film 60 lower electrode film 60a thin part 70 piezoelectric film 70a narrow part 80 upper electrode film 80a narrow part 90 insulator layer 90a contact hole 100 Conductor pattern

Claims (11)

[Claims] 1. A piezoelectric vibrator comprising: an elastic plate constituting a part of a pressure generating chamber communicating with a nozzle opening; and a piezoelectric element formed on the elastic plate. In an ink jet recording head having a body active portion formed so as to face the pressure generation chamber, the piezoelectric body active portion is formed to be narrower than the width of the pressure generation chamber, and the piezoelectric active portion is formed on an upper surface of an upper electrode of the piezoelectric element. It has a contact portion which is a connection portion with a lead electrode for applying a voltage to the upper electrode, and a portion corresponding to the contact portion of the elastic plate facing the pressure generating chamber is compared with other portions. An ink jet recording head, which is hardly deformed by application of a voltage. 2. The ink-jet method according to claim 1, wherein an insulator layer is formed on an upper surface of the upper electrode, and the insulator layer has a contact hole portion serving as a window for forming the contact portion. Type recording head. 3. The ink jet recording head according to claim 1, wherein a width of the piezoelectric active portion at a portion corresponding to the contact portion is narrower than other regions. 4. The ink jet recording head according to claim 1, wherein a width of the pressure generating chamber at a portion corresponding to the contact portion is narrower than other portions. 5. The elastic plate comprising an elastic film and / or a lower electrode according to claim 1, wherein a portion of the elastic plate corresponding to the contact portion is thicker than other portions. An ink jet recording head characterized by the following. 6. The pressure generating chamber according to claim 1, wherein a thickness of a portion corresponding to the contact portion of the elastic plate made of an elastic film and / or a lower electrode is a thickness of a portion near an outer wall of the pressure generating chamber. An ink jet recording head characterized by being thicker than the thickness. 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. The ink jet recording head according to claim 1, wherein a portion corresponding to the contact portion is a piezoelectric non-active portion. 9. The ink jet recording head according to claim 8, wherein the piezoelectric non-active portion is formed by removing a lower electrode of the piezoelectric element at a portion corresponding to the contact portion. 10. The piezoelectric element according to claim 8, wherein the piezoelectric inactive portion is a portion corresponding to the contact portion, between the lower electrode and the piezoelectric layer of the piezoelectric element, or between the piezoelectric layer and the upper electrode of the piezoelectric element. An ink jet recording head characterized by being formed with a low dielectric layer interposed therebetween. 11. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.