JP2003237076A - Ink-jet recording head and ink-jet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet recording head capable of always maintaining the ink ejecting characteristic preferably and achieving miniaturization, and an ink-jet recording apparatus. <P>SOLUTION: In an ink-jet recording head comprising a channel forming substrate 10 of a silicon single crystal substrate with a pressure generating chamber 12 communicating with a nozzle opening formed, and a piezoelectric element 300 provided on one surface side of the channel forming substrate 10 via a diaphragm for generating pressure change in the pressure generating chamber 12, a plurality of recessed parts 51 are provided in the diaphragm in the area facing the peripheral wall of the pressure generating chamber 12 for exposing the surface of the channel forming substrate 10 such that a connection wiring 65 for electrically connecting a common electrode 60 provided commonly for a plurality of the piezoelectric elements 300 and the channel forming substrate 10 is provided in the recessed parts 51 so as to substantially lower the resistance value of the common electrode 60. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

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

[0002]

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

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

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

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

According to this, the work of attaching the piezoelectric element to the diaphragm becomes unnecessary, and not only the piezoelectric element can be densely formed by a precise and simple method such as a lithography method, but also the piezoelectric element. The advantage is that the thickness can be reduced and high speed driving is possible.

[0007]

However, in the ink jet recording head in which the piezoelectric elements are arranged in high density, when a large number of piezoelectric elements are simultaneously driven to eject a large number of ink droplets, a voltage drop occurs. As a result, the amount of displacement of the piezoelectric element becomes unstable and the ink ejection characteristics deteriorate.

Although such a problem can be solved by increasing the thickness of the common electrode and lowering the resistance value of the common electrode, the displacement of the vibrating plate due to the driving of the piezoelectric element is hindered and the ink droplets are prevented. There is a problem that the discharge amount of

This can also be solved by widening the area of the common electrode to lower the resistance value of the common electrode. However, in order to widen the area of the common electrode, it is necessary to widen the area of the head itself. There is a problem that it becomes large.

In view of such circumstances, it is an object of the present invention to provide an ink jet recording head and an ink jet recording apparatus which can always maintain good ink ejection characteristics and can be downsized.

[0011]

A first aspect of the present invention for solving the above-mentioned problems is to provide a flow channel forming substrate in which a pressure generating chamber is formed which is made of a silicon single crystal substrate and communicates with a nozzle opening, and the flow channel. In an ink jet recording head including a piezoelectric element that is provided on one surface side of a formation substrate via a vibration plate to generate a pressure change in the pressure generating chamber, the vibration in a region facing a peripheral wall of the pressure generating chamber. The flow path forming substrate has a plurality of recesses that penetrate the plate and expose the surface of the flow path forming substrate, and electrically connects the common electrode common to the plurality of piezoelectric elements to the flow path forming substrate. The inkjet recording head is characterized by having a connection wiring.

In the first aspect, since the common electrode of the piezoelectric element is electrically connected to the flow path forming substrate made of the silicon single crystal substrate by the connection wiring, the substantial resistance value of the common electrode is lowered. To do. As a result, even if a voltage is applied to a plurality of piezoelectric elements at the same time, a voltage drop does not occur, and it is possible to always maintain good ink ejection characteristics.

A second aspect of the present invention is the ink jet recording head according to the first aspect, wherein the connection wiring is made of the same material as the common electrode.

In the second aspect, the common electrode and the flow path forming substrate can be reliably electrically connected by the wiring electrode,
Moreover, the wiring electrode can be easily formed.

A third aspect of the present invention is the ink jet recording head according to the second aspect, characterized in that the connection wiring is formed continuously with the common electrode.

In the third aspect, the connection wiring can be formed simultaneously with the common electrode, and the connection wiring can be formed without complicating the manufacturing process.

A fourth aspect of the present invention is the ink jet recording head according to the first aspect, characterized in that the connection wiring is made of the same material as that of the lead wiring drawn from the individual electrode of the piezoelectric element. .

In the fourth aspect, the connection wiring can be formed simultaneously with the lead-out wiring, and the connection wiring can be formed without complicating the manufacturing process.

A fifth aspect of the present invention is the ink jet recording head according to any one of the first to fourth aspects, characterized in that each of the recesses is arranged at intervals of about 1 mm or less. .

In the fifth aspect, the resistance value of the common electrode can be surely reduced.

A sixth aspect of the present invention is the ink jet recording head according to any one of the first to fifth aspects, characterized in that the inner diameter of the recess is larger than the depth of the recess.

In the sixth aspect, the connection wiring can be formed relatively easily, and the common electrode and the flow path forming substrate can be electrically connected reliably.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the common electrode is formed by film formation and a lithographic method, and the film thickness is 0.1 to 0.5 μm. It is a characteristic inkjet recording head.

In the seventh aspect, stable ink ejection characteristics can be obtained without hindering the displacement of the diaphragm by the common electrode.

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

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

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on embodiments.

(Embodiment 1) FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention, and FIG. 2 is a plan view and a sectional view of FIG.

As shown in the figure, the flow path forming substrate 10 is a silicon single crystal substrate having a plane orientation (110) in this embodiment. The flow path forming substrate 10 is usually 50 to 30.
A film having a thickness of about 0 μm is used. For example, when the array density of the pressure generating chambers is 180 per inch,
The flow path forming substrate 10 is preferably 180 to 280.
It is preferable to use a substrate having a thickness of about μm, more preferably about 220 μm. This is because the array density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.

One surface of the flow path forming substrate 10 is an opening surface, and the other surface is provided with an elastic film 50 made of silicon dioxide formed by thermal oxidation in advance and having a thickness of 1 to 2 μm.

On the other hand, the opening surface of the flow path forming substrate 10 is anisotropically etched to form a silicon single crystal substrate.
The pressure generating chambers 12 partitioned by the plurality of partition walls 11 are arranged side by side in the width direction, and on the outer side in the longitudinal direction, the pressure generating chambers 12 communicate with the reservoir portion 31 of the reservoir forming substrate 30 described later, and the common ink of each pressure generating chamber 12 is provided. A communication portion 13 that forms a part of the reservoir 100 that serves as a chamber is formed, and communicates with one end portion in the longitudinal direction of each pressure generation chamber 12 via an ink supply passage 14.

Here, the anisotropic etching is carried out by utilizing the difference in etching rate of the silicon single crystal substrate. For example, in this embodiment, the silicon single crystal substrate is set to K.
When it is dipped in an alkaline solution such as OH, it is gradually eroded and the first (111) plane perpendicular to the (110) plane and the first (111) plane
Forms an angle of about 70 degrees with the (111) plane of
A second (111) plane that makes an angle of about 35 degrees with the (0) plane appears, and the etching rate of the (111) plane is about 1/180 of the etching rate of the (110) plane. Is done using. By such anisotropic etching, it is possible to perform precision machining based on the depth machining of the parallelogram shape formed by the two first (111) planes and the two diagonal second (111) planes. The pressure generating chambers 12 can be arranged in 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 in the flow path forming substrate 1
It is formed by etching through almost 0 to reach the elastic film 50. Here, the elastic film 50 is
The amount of the alkaline solution that etches the silicon single crystal substrate is extremely small. Further, each ink supply passage 14 communicating with one end of each pressure generation chamber 12 is formed shallower than the pressure generation chamber 12, and keeps the flow resistance of the ink flowing into the pressure generation chamber 12 constant. That is, the ink supply path 14 is formed by etching the silicon single crystal substrate halfway in the thickness direction (half etching). The half etching is performed by adjusting the etching time.

On the opening side of the flow path forming substrate 10,
A nozzle plate 20 having a nozzle opening 21 that communicates with the pressure generating chamber 12 on the side opposite to the ink supply path 14 is fixed via an adhesive or a heat-welding film. The nozzle plate 20 has a thickness of, for example, 0.05 to
1 mm, linear expansion coefficient of 300 ℃ or less, for example 2.5
Glass ceramics of up to 4.5 [× 10 ⁻⁶ / ° C.],
Or made of non-rust steel. The nozzle plate 20 entirely covers one surface of the flow path forming substrate 10 with one surface, and also serves as a reinforcing plate that protects the silicon single crystal substrate from impact and external force. In addition, the nozzle plate 20 is the flow path forming substrate 1
It may be made of a material whose coefficient of thermal expansion is substantially the same as that of the material. In this case, since the flow path forming substrate 10 and the nozzle plate 20 have substantially the same deformation due to heat, they can be easily joined using a thermosetting adhesive or the like.

Here, the size of the pressure generating chamber 12 that applies the ink droplet ejection pressure to the ink and the size of the nozzle opening 21 that ejects the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized. For example,
When recording 180 ink droplets per inch, it is necessary to accurately form the nozzle opening 21 with a diameter of several tens of μm.

On the other hand, the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10 has a thickness of, for example, about 0.1 to
An insulating film 55 having a thickness of 2 μm is formed, and a lower electrode film 60 having a thickness of, for example, about 0.1 to 0.5 μm and a thickness of, for example, about 0.01 are formed on the insulating film 55. The piezoelectric layer 70 having a thickness of about 2 μm 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 form the piezoelectric element 300. Here, the piezoelectric element 300
Indicates a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. Generally, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are used.
Is patterned for each pressure generating chamber 12. Further, here, a portion which is composed of one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the lower electrode film 60 is used as the common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as the individual electrode of the piezoelectric element 300, but there is no problem even if this is reversed due to the convenience of the drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and the vibration plate that is displaced by the driving of the piezoelectric element 300 are collectively referred to as a piezoelectric actuator.

Here, a lead electrode 90 made of, for example, gold (Au) is connected to each upper electrode film 80, which is an individual electrode of the piezoelectric element 300, in the vicinity of the end portion on the ink supply path 14 side. The lead electrode 90 is extended to above the elastic film 50 in a region facing the ink supply path 14.

On the other hand, the lower electrode film 60, which is the common electrode of the piezoelectric element 300, is continuously extended in the direction in which the pressure generating chambers 12 are arranged in parallel, and is patterned near one end of the piezoelectric element 300. . That is, the lower electrode film 60 is continuously provided over the area other than the area where the lead electrode 90 extends.

The vibrating plate in the region facing the peripheral wall of the pressure generating chamber 12, that is, the elastic film 50 and the insulating film 5 in this embodiment.
5 and the lower electrode film 60 are provided with a plurality of recesses 51 penetrating through them and exposing the flow path forming substrate 10 at predetermined intervals.

A connection wiring 65 made of a conductive material is provided in each of the recesses 51, and the connection wiring 65 is provided.
The lower electrode film 60 and the flow path forming substrate 10 are electrically connected by.

In such a configuration, since the lower electrode film 60, which is the common electrode of the piezoelectric element 300, is electrically connected to the flow path forming substrate 10 via the connection wiring 65, the resistance of the lower electrode film 60 is reduced. The value drops substantially. That is, since the flow path forming substrate 10 is made of a silicon single crystal substrate and has conductivity, the resistance value of the lower electrode film 60 electrically connected to the flow path forming substrate 10 is substantially reduced.

As a result, no voltage drop occurs even if a large number of piezoelectric elements are driven at the same time. Therefore, the size of the ink droplets ejected from the nozzle openings 21 can be stabilized, and the ink ejection characteristics can always be kept good. Further, since it is not necessary to increase the area of the lower electrode film 60, the ink ejection characteristics can be stabilized without increasing the size of the head. Furthermore, since the resistance value of the lower electrode film 60 is substantially reduced, the thickness of the lower electrode film 60 can be made relatively thin, and the displacement amount of the diaphragm due to the driving of the piezoelectric element 300 can be improved. .

Here, the interval between the recesses 51 is, for example, 1
It is preferable that they are formed at relatively narrow intervals of not more than mm. As a result, the substantial resistance value of the lower electrode film 60 can be significantly reduced to about 5Ω or less.

The material of the connection wiring 65 is not particularly limited as long as it is a material having conductivity.
In this embodiment, the lower electrode film 60 is made of the same material and is continuously provided with the lower electrode film 60. With such a configuration, as will be described in detail later, the lower electrode film 60 and the connection wiring 65 can be formed simultaneously, and the connection wiring 65 can be formed relatively easily without increasing the manufacturing process.

The piezoelectric element 300 of the flow path forming substrate 10
On the side, a reservoir section 31 that constitutes at least a part of the reservoir 100 that serves as a common ink chamber for each pressure generating chamber 12 is provided.
The reservoir forming substrate 30 having the is bonded. In the present embodiment, the reservoir portion 31 is formed to penetrate the reservoir forming substrate 30 in the thickness direction and extend in the width direction of the pressure generating chamber 12, and as described above, the communicating portion of the flow passage forming substrate 10. A reservoir 100 that communicates with the pressure generating chamber 12 and serves as a common ink chamber for the pressure generating chambers 12 is configured.

As the reservoir forming substrate 30, it is preferable to use a material having substantially the same coefficient of thermal expansion as that of the passage forming substrate 10, such as glass or a ceramic material. It was formed using a silicon single crystal substrate of the same material.

Further, the piezoelectric element 3 of the reservoir forming substrate 30
In a region facing 00, a piezoelectric element holding portion 32 that can seal the space is provided in a state where a space that does not hinder the movement of the piezoelectric element 300 is secured, and the piezoelectric element 300 includes the piezoelectric element holding portion 32. It is sealed inside.

The reservoir forming substrate 30 is located between the reservoir portion 31 of the reservoir forming substrate 30 and the piezoelectric element holding portion 32, that is, in the region corresponding to the ink supply passage 14.
Is provided with a through hole 33 penetrating in the thickness direction. Then, the lead electrode 9 extracted from each piezoelectric element 300
Reference numeral 0 extends to the through hole 33 and is connected to an external wiring (not shown) by wire bonding or the like.

A compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded on the reservoir forming substrate 30. The sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the sealing film 41 seals one surface of the reservoir portion 31. There is. Further, the fixing plate 42 is made of a hard material such as metal (for example, stainless steel having a thickness of 30 μm (SU
S) and the like). The reservoir 10 of this fixed plate 42
Since the region facing 0 is the opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with the flexible sealing film 41.

The ink jet recording head of the present embodiment as described above takes in ink from the external ink supply means (not shown) and fills the interior from the reservoir 100 to the nozzle openings 21 with ink, and then from the drive circuit (not shown). Pressure generation chamber 1 via external wiring according to the recording signal
2 is applied to each of the lower electrode film 60 and the upper electrode film 80 to flexibly deform the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70. And the ink droplets are ejected from the nozzle openings 21.

Here, a method of manufacturing the ink jet recording head of this embodiment will be described with reference to FIGS.
Will be described with reference to. 3 and 4 are cross-sectional views showing a part of the pressure generating chamber 12 in the width direction.

First, as shown in FIG. 3A, about 110 wafers of a silicon single crystal substrate to be the flow path forming substrate 10 are prepared.
An elastic film 50 made of silicon dioxide is formed by thermal oxidation in a 0 ° C. diffusion furnace.

Next, as shown in FIG. 3B, the elastic film 5
An insulating film 55 made of zirconium dioxide is formed on the insulating film 55. Specifically, after forming a zirconium layer on the elastic film 50, for example, thermal oxidation is performed in a diffusion furnace at about 1150 ° C. to form an insulator film 55 made of zirconium dioxide.

Next, as shown in FIG. 3C, the elastic film 5
By etching the insulating film 55 and the insulating film 55 until reaching the flow path forming substrate 10, a plurality of recesses 51 are formed at predetermined intervals in the region facing the peripheral wall of the pressure generating chamber 12.

The size of the recess 51 is not particularly limited, but the inner diameter is preferably larger than the depth. Thereby, the connection wiring 65 can be favorably formed in the recess 51 in the step described later.

The recess 51 may be provided so as to penetrate the elastic film 50 and the insulating film 55 so that the surface of the flow path forming substrate 10 is exposed. However, in the thickness direction of the flow path forming substrate 10. The recess 51 may be formed by partially etching.

Next, as shown in FIG. 3D, after the lower electrode film 60 is formed on the entire surface of the elastic film 50 by sputtering,
The entire pattern of the lower electrode film 60 is formed. At this time, the lower electrode film 60 is also formed in each recess 51, and these recesses 5 are formed.
In the present embodiment, the lower electrode film 60 in 1 is the piezoelectric element 30.
Connection wiring 6 continuous with the lower electrode film 60 which is a common electrode of 0
It becomes 5.

As described above, if the inner diameter of the recess 51 is larger than the depth, the lower electrode film 60 is formed by sputtering, so that the connection wiring 6 is formed.
5 (lower electrode film 60) is reliably and continuously formed up to the bottom surface of the recess 51, that is, the surface of the flow path forming substrate 10.

As the material of the lower electrode film 60,
Platinum (Pt) or the like is suitable. This is because the piezoelectric layer 70 described later, which is formed by the sputtering method or the sol-gel method, is 600 to 100 in the air atmosphere or the oxygen atmosphere after the film formation.
This is because it is necessary to fire and crystallize at a temperature of about 0 ° C. That is, the material of the lower electrode film 60 must be able to maintain the conductivity under such a high temperature and oxidizing atmosphere, and especially when lead zirconate titanate (PZT) is used as the piezoelectric layer 70. It is desirable that the change in conductivity due to the diffusion of lead oxide is small, and platinum is preferable for these reasons.

Next, as shown in FIG. 3E, the piezoelectric layer 70 is formed. The piezoelectric layer 70 preferably has crystals oriented. For example, in the present embodiment, a so-called sol-gel method is used in which a so-called sol in which a metal organic material is dissolved and dispersed in a catalyst is applied, dried, gelled, and fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. To form a piezoelectric layer 70 in which crystals are oriented. As a material for the piezoelectric layer 70, a lead zirconate titanate-based material is suitable for use in an inkjet recording head. The method for forming the piezoelectric layer 70 is not particularly limited, and may be formed by, for example, a sputtering method.

Further, after forming a precursor film of lead zirconate titanate by a sol-gel method or a sputtering method,
A method of growing crystals at a low temperature by a high-pressure treatment method in an alkaline aqueous solution may be used.

In any case, in the piezoelectric layer 70 thus formed, the crystals are preferentially oriented unlike the bulk piezoelectric body, and in the present embodiment, the piezoelectric layer 70 has the crystals. It has a columnar shape. Note that the preferential orientation means that the crystal orientation direction is not disordered, and a specific crystal plane is oriented in a substantially constant direction. Further, a thin film having a columnar crystal means a state in which crystals having a substantially columnar body are aggregated in a plane direction with the central axes substantially aligned with the thickness direction to form a thin film. Of course, it may be a thin film formed of preferentially oriented granular crystals. The thickness of the piezoelectric layer manufactured in the thin film process is generally 0.2 to 5 μm.

Next, as shown in FIG. 4A, the upper electrode film 80 is formed. The upper electrode film 80 may be made of a material having high conductivity, and many metals such as aluminum, gold, nickel and platinum, and a conductive oxide can be used. In this embodiment, platinum is deposited by sputtering.

Next, as shown in FIG. 4B, only the piezoelectric layer 70 and the upper electrode film 80 are etched to remove the piezoelectric element 3.
00 patterning is performed.

Next, as shown in FIG. 4C, the lead electrode 90 is formed. Specifically, for example, the lead electrode 90 made of gold (Au) or the like is formed over the entire surface of the flow path forming substrate 10, and is patterned for each piezoelectric element 300.

The above is the film forming process. After the film formation is performed in this manner, anisotropic etching of the silicon single crystal substrate with the above-mentioned alkaline solution is performed, and the result of FIG.
As shown in (d), the pressure generating chamber 12 and the like are formed.

After that, the reservoir forming substrate 30 and the compliance substrate 40 are sequentially bonded to the surface of the flow passage forming substrate 10 on the side of the piezoelectric element 300 by an adhesive or the like, and the reservoir forming substrate 30 of the flow passage forming substrate 10 is further bonded. Nozzle plate 2 having a nozzle opening 21 on the surface opposite to
The ink jet recording head of the present embodiment is formed by joining 0s.

In practice, a large number of chips are simultaneously formed on one wafer by the above-described series of film formation and anisotropic etching, and after the process is completed, one chip size as shown in FIG. The flow path forming substrate 10 is divided. Then, the ink jet recording head is formed by sequentially adhering the reservoir forming substrate 30 and the compliance substrate 40 to the divided flow path forming substrate 10 and integrating them.

(Second Embodiment) FIG. 5 is a sectional view of an ink jet recording head according to a second embodiment.

In the present embodiment, as shown in FIG. 5, the connection wiring 65A for electrically connecting the lower electrode film 60, which is the common electrode of the piezoelectric element 300, and the flow path forming substrate 10 is not called the lower electrode film 60. This connection wiring 6 is an example formed of another material.
The configuration is the same as that of the first embodiment except that 5A is made of the same material as the lead electrode 90.

Of course, even with the structure of this embodiment, the resistance value of the lower electrode film 60 is substantially reduced by the connection wiring 65A. Therefore, the size of the ink droplets ejected from the nozzle openings 21 can be stabilized, and the print quality can always be kept good.

The ink jet recording head of this embodiment can be formed by the following procedure. The method of forming and patterning each layer of the vibration plate and the piezoelectric element 300 is the same as in the first embodiment.

First, as shown in FIG. 6A, the elastic film 50, the insulator film 55 and the lower electrode film 6 are formed on the flow path forming substrate 10.
0s are sequentially formed.

Next, as shown in FIG. 6B, the piezoelectric layer 70 and the upper electrode film 80 are sequentially laminated on the lower electrode film 60 and patterned to form the piezoelectric element 300.

Next, as shown in FIG. 6C, the recess 51A is formed by etching the elastic film 50, the insulator film 55 and the lower electrode film 60.

Next, as shown in FIG. 6D, the lead electrode 90 is formed over the entire surface of the flow path forming substrate 10 and is patterned so as to be independent for each piezoelectric element 300. At this time, the lead electrode 90 in the region facing the recess 51A is left without being removed. As a result, the connection wiring 65A made of the same material as the lead electrode 90 is formed in the recess 51A.

After that, the ink jet recording head of this embodiment is formed by the same procedure as that of the first embodiment.

Thus, the connection wiring 65A of this embodiment is
Can be formed at the same time when the lead electrode 90 is formed, and thus can be easily formed without complicating the manufacturing process as in the first embodiment.

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

For example, in each of the above-described embodiments, the thin film type ink jet recording head manufactured by applying the film formation and the lithographic process is taken as an example. However, the present invention is not limited to this and, for example, green. The present invention can also be applied to a thick film type ink jet recording head formed by a method such as attaching a sheet.

The ink jet recording head of each of these embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. Figure 7
It is a schematic diagram showing an example of the ink jet type recording device.

As shown in FIG. 7, in the recording head units 1A and 1B having an ink jet recording head, the cartridges 2A and 2B constituting the ink supply means are detachably provided, and the recording head units 1A and 1B are attached.
The carriage 3 on which B is mounted is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. The recording head units 1A and 1B are, for example,
The black ink composition and the color ink composition are respectively discharged.

The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears (not shown) and the timing belt 7, so that the carriage 3 having the recording head units 1A and 1B mounted thereon extends along the carriage shaft 5. Be moved. On the other hand, a platen 8 is provided on the apparatus main body 4 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a feed roller (not shown), is conveyed on the platen 8. It is like this.

[0084]

As described above, according to the present invention, a concave portion is provided in the vibrating plate in a region facing the peripheral wall of the pressure generating chamber, and a flow path formed by the common electrode of the piezoelectric element and the silicon single crystal substrate is formed in the concave portion. Since the connection wiring for electrically connecting to the substrate is provided, the resistance value of the common electrode can be substantially reduced. Therefore, even if a large number of piezoelectric elements are driven at the same time, a voltage drop does not occur, and stable ink ejection characteristics can always be obtained.

[Brief description of drawings]

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

2A and 2B are a plan view and a sectional view of the ink jet recording head according to the first embodiment of the invention.

FIG. 3 is a cross-sectional view showing the manufacturing process of the ink jet recording head according to the first embodiment of the invention.

FIG. 4 is a cross-sectional view showing the manufacturing process of the inkjet recording head according to the first embodiment of the invention.

FIG. 5 is a sectional view of an ink jet recording head according to a second embodiment of the invention.

FIG. 6 is a cross-sectional view showing the manufacturing process of the ink jet recording head according to the second embodiment of the invention.

FIG. 7 is a schematic diagram of an inkjet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

10 Flow path forming substrate 12 Pressure generation chamber 20 nozzle plate 21 nozzle opening 30 Reservoir forming substrate 31 Reservoir section 32 Piezoelectric element holder 40 compliance board 50 elastic membrane 51,51A recess 55 Insulator film 60 Lower electrode film 65, 65A connection wiring 70 Piezoelectric layer 80 Upper electrode film 100 reservoir 300 Piezoelectric element

Claims (8)

[Claims] 1. A flow path forming substrate comprising a silicon single crystal substrate in which a pressure generating chamber communicating with a nozzle opening is formed; and a pressure generating member provided on one surface side of the flow path forming substrate via a vibrating plate. In an ink jet recording head including a piezoelectric element that causes a pressure change in a chamber, a plurality of ink jet recording heads that are provided to penetrate the vibrating plate in a region facing a peripheral wall of the pressure generating chamber and expose a surface of the flow path forming substrate 2. An ink jet recording head, characterized in that it has a concave portion and a connecting wiring for electrically connecting a common electrode common to a plurality of piezoelectric elements and the flow path forming substrate in the concave portion. 2. The ink jet recording head according to claim 1, wherein the connection wiring is made of the same material as the common electrode. 3. The ink jet recording head according to claim 2, wherein the connection wiring is formed continuously with the common electrode. 4. The ink jet recording head according to claim 1, wherein the connection wiring is made of the same material as the lead wiring drawn from the individual electrode of the piezoelectric element. 5. The ink jet recording head according to claim 1, wherein each of the recesses is arranged at an interval of about 1 mm or less. 6. The ink jet recording head according to claim 1, wherein an inner diameter of the recess is larger than a depth of the recess. 7. The ink jet recording according to claim 1, wherein the common electrode is formed by a film forming method and a lithographic method and has a film thickness of 0.1 to 0.5 μm. head. 8. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.