JP2002292871A - Ink-jet recording head and ink-jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording head and an ink-jet recorder in which an integrated circuit and a piezoelectric element are surely connected with each other and a substrate is prevented from deforming and breaking. SOLUTION: The ink-jet recording head is provided with the channel formation substrate 10 formed of a single crystal silicon where pressure generation chambers communicating with nozzle openings 21 are defined, and the piezoelectric element 300 comprising a lower electrode 60, a piezoelectric layer 70 and an upper electrode 80 set via a diaphragm to one face side of the channel formation substrate 10. The ink-jet recording head is provided with the jointing substrate 40 jointed to the side of the piezoelectric element 300 of the channel formation substrate 10 thereby forming a sealing space 43 for sealing the piezoelectric element 300. As an adhesive for jointing the jointing substrate 40 and the channel formation substrate 10 with each other and sealing the sealing space 43, a conductive adhesive 30 containing a conductive filler 31 is used. Moreover, a discrete electrode 90 of the piezoelectric element 300 and a driving system wiring line 42 connected to each terminal of the integrated circuit 41 set to the side of a jointing face of the jointing substrate 40 are electrically connected to each other via the conductive adhesive 30.

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 communicates with a nozzle opening for discharging ink droplets, which is constituted by a vibrating plate. TECHNICAL FIELD The present invention relates to an ink jet recording head and an ink jet recording apparatus for ejecting ink droplets by using an ink jet recording head.

[0002]

2. Description of the Related Art A part of a pressure generating chamber communicating with a nozzle opening for discharging ink droplets is constituted by a vibrating plate, and the vibrating plate is deformed by a piezoelectric element to pressurize the ink in the pressure generating chamber to pass the nozzle opening. Two types of ink jet recording heads that eject ink droplets have been commercialized, one using a longitudinal vibration mode piezoelectric actuator that expands and contracts in the axial direction of the piezoelectric element, and the other using a flexural vibration mode piezoelectric actuator. ing.

[0003] In the former, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, and a head suitable for high-density printing can be manufactured. There is a problem in that a difficult process of cutting into a comb shape in accordance with the arrangement pitch of the openings and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required, and the manufacturing process is complicated.

On the other hand, in the latter, a piezoelectric element 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. 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 over the entire surface of the diaphragm by a film forming technique as disclosed in Japanese Patent Application Laid-Open No. 5-286131. A proposal has been made in which the piezoelectric material layer is cut into a shape corresponding to the pressure generating chambers by a lithography method, and a piezoelectric element is formed so as to be independent for each pressure generating chamber.

This eliminates the need for attaching the piezoelectric element to the vibration plate, which not only allows the piezoelectric element to be manufactured by a precise and simple method such as lithography, but also reduces the thickness of the piezoelectric element. There is an advantage that it can be made thin and can be driven at high speed.

[0007]

In such an ink jet recording head, an integrated circuit for driving a piezoelectric element is integrally provided. The integrated circuit and the lead wiring drawn from the individual electrode of the piezoelectric element are connected by wire bonding or the like, and the substrate is deformed or cracked due to heating at the time of connection or vibration generated at that time. There's a problem.

[0008] In the case of connection by wire bonding, there is a problem that the assembling process is relatively complicated and the manufacturing efficiency is low.

In view of such circumstances, an object of the present invention is to provide an ink jet type recording head and an ink jet type recording apparatus in which an integrated circuit and a piezoelectric element are securely connected and a substrate is prevented from being deformed and cracked. I do.

[0010]

According to a first aspect of the present invention, there is provided a flow path forming substrate made of single-crystal silicon, in which a pressure generating chamber communicating with a nozzle opening is defined; In an ink jet recording head including a lower electrode provided on one surface side of a formation substrate via a vibration plate, and a piezoelectric element including a piezoelectric layer and an upper electrode, the ink jet recording head is joined to the piezoelectric element side of the flow path formation substrate. A bonding substrate that forms a sealing space for sealing the piezoelectric element, and includes a conductive filler as an adhesive for bonding the bonding substrate and the flow path forming substrate and sealing the sealing space. In addition to using a conductive adhesive, the individual electrodes of the piezoelectric element and the drive system wiring connected to each terminal of the integrated circuit provided on the bonding surface side of the bonding substrate via the conductive adhesive are electrically connected. Connected In an ink jet recording head, characterized in that.

In the first aspect, the piezoelectric element and the integrated circuit are electrically connected via a conductive adhesive, and the piezoelectric element is sealed between the bonding substrate and the flow path forming substrate with the conductive adhesive. By forming the sealed space for stopping the piezoelectric element, the piezoelectric element and the integrated circuit can be reliably connected, and the piezoelectric element can be prevented from being deteriorated by the external environment.

According to a second aspect of the present invention, in the first aspect, the individual electrode is an extraction electrode extended from the upper electrode of the piezoelectric element onto the flow path forming substrate. In the recording head.

In the second aspect, the integrated circuit and the piezoelectric element can be reliably connected to each other by the conductive adhesive using the lead-out electrode.

According to a third aspect of the present invention, in the first or second aspect, the lead wiring and the drive system wiring are electrically connected to each other by the conductive adhesive provided in a region for sealing the sealing space. An ink jet type recording head characterized by being electrically connected.

In the third aspect, the sealing space is sealed with a conductive adhesive for electrically connecting the lead wiring and the driving system wiring, thereby simplifying the manufacturing process and reducing the manufacturing cost. be able to.

According to a fourth aspect of the present invention, in any one of the first to third aspects, one end of the flow path forming substrate extends outside the sealing space and is connected to an external wiring, An ink jet recording head is characterized in that the other end is provided with an input wiring connected to an input terminal of the integrated circuit and a signal wiring electrically connected through the conductive adhesive.

According to the fourth aspect, the signal wiring provided on the flow path forming substrate and the input wiring can be reliably connected via the conductive adhesive.

According to a fifth aspect of the present invention, in the fourth aspect, the signal wiring and the input wiring are electrically connected by the conductive adhesive provided in a region for sealing the sealing space. An ink jet recording head is characterized by being connected.

According to the fifth aspect, the sealing space is sealed with a conductive adhesive for electrically connecting the signal wiring and the input wiring, thereby simplifying the manufacturing process and reducing the manufacturing cost. Can be.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the diameter of the conductive filler is smaller than the distance between the adjacent lead wires, and the thickness of the integrated circuit and the piezoelectric element are different from each other. An ink jet recording head is characterized by being larger than the sum of the element thicknesses.

According to the sixth aspect, it is possible to prevent a short circuit between the lead wires due to the conductive adhesive and to reliably prevent a short circuit between the integrated circuit and the piezoelectric element in the sealed space.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the base adhesive of the conductive adhesive comprises an epoxy resin, a polyester resin, an acrylic resin, a polyimide resin and a polysulfone resin. Wherein the ink jet recording head is selected from the group consisting of:

In the seventh aspect, by using a predetermined material for the base adhesive of the conductive adhesive, the flow path forming substrate and the bonding substrate are securely bonded to seal the sealing space. Can be.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the conductive filler is selected from the group consisting of gold, copper, silver, lead, an alloy of silver and lead, carbon and nickel. An ink jet recording head is characterized in that:

In the eighth aspect, by using a predetermined material for the conductive filler, electrical conduction between the drive system wiring and the lead wiring can be ensured.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the pressure generating chamber is formed by anisotropic etching, and the respective layers of the diaphragm and the piezoelectric element are formed by lithography. An ink jet recording head characterized by being formed by a method.

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

According to a tenth 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 ninth aspects.

According to the tenth aspect, it is possible to realize an ink jet recording apparatus in which the ink ejection characteristics of the head are improved.

[0030]

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, and FIG. 2 is a top view of a bonding substrate and a top view of a flow path forming substrate. FIG. 3 is a diagram showing a cross-sectional structure of one pressure generating chamber of the ink jet recording head in the longitudinal direction and the juxtaposed direction.

As shown in the figure, the flow path forming substrate 10 is made of, for example, a single crystal silicon substrate having a thickness of 50 to 150 μm, one surface of which is an opening surface, and the other surface of which is formed of a dioxide formed in advance by thermal oxidation. It is made of silicon and has a thickness of 0.
An elastic film 50 having a thickness of 1 to 2 μm is formed.

On the opening surface of the flow path forming substrate 10, a pressure generating chamber 12 partitioned by a plurality of partition walls 11 is formed by anisotropic etching. Further, each pressure generating chamber 12
A communication portion 13 which forms a part of a reservoir 100 which communicates with a reservoir portion of a reservoir forming substrate, which will be described later, and which serves as a common ink chamber of each pressure generation chamber 12 is formed at one end portion in the longitudinal direction. Each of the chambers 12 communicates with one longitudinal end of the chamber 12 via an ink supply path 14.

The communication section 13 and the ink supply path 14 are formed together with the pressure generating chamber 12 by anisotropic etching. The ink supply path 14 is for controlling the flow of ink into and out of the pressure generating chamber 12 and is formed shallower than the pressure generating chamber 12 and the communication portion 13.

Here, in the anisotropic etching, when the single crystal silicon 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 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.

A nozzle plate 20 having a nozzle opening 21 communicating with the pressure supply chamber 12 on the opposite side of the ink supply path 14 is provided on the opening side of the flow path forming substrate 10 with an adhesive or heat welding. It is fixed via a film or the like. The thickness of the nozzle plate 20 is, for example, 0.1 to 1
mm, the coefficient of linear expansion is 300 ° C. or less, for example, 2.5 to
It is made of 4.5 [× 10 ⁻⁶ / ° C.] glass ceramic or non-rusting steel. The nozzle 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. Further, the nozzle plate 20 is connected to the flow path forming substrate 10.
And may be formed of a material having substantially the same thermal expansion coefficient. In this case, since the deformation of the flow path forming substrate 10 and the nozzle plate 20 due to heat become substantially the same, it is possible to easily join them using a thermosetting adhesive or the like.

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 21 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 21 need to be formed with a diameter of several tens of μm with high accuracy.

On the other hand, the lower electrode film 6 having a thickness of, for example, about 0.2 to 0.5 μm is formed on the elastic film 50 of the flow path forming substrate 10.
0, a piezoelectric layer 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 described later to form the piezoelectric element 300. I have. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. In general, 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 patterned for each of the pressure generating chambers 12. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric layer 70 and in which a 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 a common electrode of the piezoelectric element 300, and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. In any case, a piezoelectric active portion is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and the elastic film whose displacement is generated by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 60 function as a diaphragm, but the lower electrode film may also serve as the elastic film.

A lead electrode 90 as a lead electrode extends from the upper electrode film 80, which is an individual electrode of the piezoelectric element 300, to the elastic film 50.
Are electrically connected to respective terminals of the integrated circuit 41 described later.

Further, the piezoelectric element 30 of the flow path forming substrate 10
On the 0 side, in the present embodiment, the bonding substrate 40 is bonded to the elastic film 50 via, for example, an anisotropic conductive adhesive layer 30 made of an anisotropic conductive adhesive containing a substantially spherical conductive filler 31. ing.

The bonding substrate 40 is made of a silicon single crystal substrate, and a predetermined integrated circuit (IC), for example, the piezoelectric element 30 in the present embodiment is provided in a region facing the piezoelectric element 300.
A drive circuit 41 for driving the 0 is integrally formed. In this embodiment, the drive circuit 41 is a semiconductor integrated circuit integrally formed by a semiconductor process on a bonding substrate 40 formed of a silicon single crystal substrate.

The driving circuit 41 and each of the piezoelectric elements 300 are electrically connected via the anisotropic conductive adhesive layer 30 for joining the flow path forming substrate 10 and the joining substrate 40.

More specifically, a conductive filler 31 contained in the anisotropic conductive adhesive layer 30 extends on the bonding substrate 40 from the lead electrodes 90 drawn from the respective piezoelectric elements 300 and the respective terminals of the drive circuit 41. The driving circuit 41 and each of the piezoelectric elements 300 are electrically connected to each other by being sandwiched between the driving system wirings 42. That is, the piezoelectric element 300 and the drive circuit 41 are electrically connected outside the region facing the pressure generating chamber 12.

For this reason, it is preferable that the diameter of the conductive filler 31 is smaller than the gap between the adjacent lead electrodes 90 so that the adjacent lead electrodes 90 are not short-circuited.

Further, by bonding the flow path forming substrate 10 and the bonding substrate 40 via the anisotropic conductive adhesive layer 30 as described above, a space between the two that does not hinder the movement of the piezoelectric element 300 is provided. The piezoelectric element holding portion 43, which is a sealed space capable of sealing this space while ensuring the above, is defined.
That is, the conductive filler 31 contained in the anisotropic conductive adhesive layer 30 is sandwiched between the flow path forming substrate 10 and the bonding substrate 40, so that a predetermined interval is secured between them.
The piezoelectric element holding part 43 is defined.

Therefore, the diameter of the conductive filler 31 is preferably larger than the sum of the thickness of the piezoelectric element 300 and the thickness of the integrated circuit 41.

That is, the diameter r of the conductive filler 31 is larger than the sum of the film thickness t1 of the integrated circuit 41 and the film thickness t2 of the piezoelectric element 300, and the distance w between the adjacent lead electrodes 90 is w.
It is preferably smaller than. Specifically, it is preferable that the diameter r of the conductive filler 31 satisfies the relationship of the following equation (1).

[0049]

(T1 + t2 + 2 [μm]) <r <(w−2 [μm]) (1)

In this embodiment, the film thickness t1 of the drive circuit 41
Is 1.5 μm, and the thickness t2 of the piezoelectric element 300 is 1.
5 μm, and the gap w between the adjacent lead electrodes 90 is 15 μm.
Therefore, the diameter r of the conductive filler 31 is preferably larger than 5 μm and smaller than 13 μm.

The conductive filler 31 is not particularly limited as long as it is a material having high conductivity.
Examples thereof include copper, silver, lead, an alloy of silver and lead, carbon and nickel.

Further, the base adhesive of the anisotropic conductive adhesive layer 30 is not particularly limited, and examples thereof include adhesives such as epoxy resin, polyester resin, acrylic resin, polyimide resin and polysulfone resin.

The piezoelectric element 300 of the flow path forming substrate 10
Are extended with a predetermined width from the lower electrode film 60 formed inside the piezoelectric element holding portion 43 near one end in the juxtaposition direction.
A connection portion 61 connected to an external wiring 110 such as a PC is provided.

Further, a plurality of signal lines 91 connected to the external lines 110 are provided near the connection portions 61 of the lower electrode film 60. Specifically, one end of the signal system wiring 91 is located inside the piezoelectric element holding portion 43, and the other end is extended to near the end of the flow path forming substrate 10. Connection layer 9 made of anisotropic conductive material (AFC) or the like
The external wiring 110 is connected through the connection line 2. In the vicinity of one end of the signal line 91, an external input line 44 extending from the input terminal of the drive circuit 41 to the bonding substrate 40 is electrically connected. That is, the signal system wiring 9
1 and the external input wiring 44 are connected to the driving system wiring 4
Similarly to the electrical connection between the lead 2 and the lead electrode 90, they are electrically connected by the anisotropic conductive adhesive layer 30 containing the conductive filler 31 provided on the signal line 91. Then, a drive signal or the like for driving the piezoelectric element 300 is supplied from the external wiring 110 to the drive circuit 41 via the signal system wiring 91, the anisotropic conductive adhesive layer 30, and the external input wiring 44.

As described above, in the present embodiment, the lead electrode 90, which is a wiring drawn from the upper electrode film 60 of the piezoelectric element 300, and the drive system wiring 42 connected to each terminal of the drive circuit 41 are joined. Since the substrate 40 and the flow path forming substrate 10 are electrically connected by the anisotropic conductive adhesive layer 30 which is an adhesive for bonding, the wiring can be simplified and the connection can be reliably performed. Further, by connecting the respective wirings with the anisotropic conductive adhesive layer 30, the durability of the piezoelectric element 300 against repeated driving can be improved.

Further, since the piezoelectric element holding portion 43 of the flow path forming substrate 10 and the bonding substrate 40 is provided to block the piezoelectric element 300 from the external environment, the piezoelectric element 300 is broken by the external environment such as moisture in the air. Can be prevented, and the environmental resistance can be improved. Further, like the piezoelectric element 300, the drive circuit 41 is also sealed in the piezoelectric element holding section 43, so that the drive circuit 41 can be shielded from light.

Further, in this embodiment, the piezoelectric element 300
Since the lead electrode 90 is extended from the surface to the elastic film 50 and the lead electrode 90 and the drive system wiring 42 are connected in a region corresponding to the ink supply path 14, when the bonding substrate 40 is bonded, The load of the bonding substrate 40 is not directly applied to the piezoelectric element 300 or the diaphragm arm, and the piezoelectric element 30
0 and the diaphragm can be reliably prevented from being damaged.

Further, in a region facing the communication portion 13 of the flow path forming substrate 10, the reservoir forming substrate 13 having a reservoir portion 131 constituting at least a part of the reservoir 100 is provided.
0 is joined. In the present embodiment, the reservoir portion 131 is formed so as to penetrate the reservoir forming substrate 130 in the thickness direction and to extend in the width direction of the pressure generating chamber 12. The reservoir 131 is communicated with the communication part 13 of the flow path forming substrate 10 through the through hole 51 provided through the elastic film 50 and the lower electrode film 60, and
The reservoir 100 is a common ink chamber.

As the reservoir forming substrate 130, it is preferable to use a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10, for example, glass, ceramic material, or the like. It was formed using a silicon single crystal substrate of the same material as that of No. 10. As a result, both can be reliably bonded even when bonding at a high temperature using a thermosetting adhesive. Therefore, the manufacturing process can be simplified.

Further, a compliance substrate 140 including a sealing film 141 and a fixing plate 142 is bonded to the reservoir forming substrate 130. Here, the sealing film 141
Is a material having low rigidity and flexibility (for example, having a thickness of 6
μm polyphenylene sulfide (PPS) film)
And the reservoir 131 is formed by the sealing film 141.
Is sealed on one side. The fixing plate 142 is formed of a hard material such as a metal (for example, stainless steel (SUS) having a thickness of 30 μm). The region of the fixing plate 142 facing the reservoir 100 is an opening 143 completely removed in the thickness direction.
0 is sealed only with a sealing film 141 having flexibility to form a flexible portion 145 that can be deformed by a change in internal pressure.

An ink introduction port 144 for supplying ink to the reservoir 100 is provided on the compliance substrate 140 substantially outside the central portion in the longitudinal direction of the reservoir 100.
Are formed. Further, the reservoir forming substrate 130 is provided with an ink introduction path 136 that communicates the ink introduction port 144 with the side wall of the reservoir 100.

The ink jet recording head of this embodiment takes in ink from an ink inlet 144 connected to an external ink supply means (not shown) and fills the inside from the reservoir 100 to the nozzle opening 21 with ink. According to the recording signal from the driving circuit 41, a voltage is applied between the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generating chamber 12, and the elastic film 50 and the lower electrode film 60 are applied.
By deforming the piezoelectric layer 70 flexibly, the pressure in each pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle openings 21.

Here, the manufacturing process of the ink jet recording head of this embodiment will be described. 4 to 6 are cross-sectional views of the pressure generating chamber 12 in the longitudinal direction.

First, as shown in FIG. 4A, a wafer of a single crystal silicon
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.
The lower electrode film 60 is formed on the entire surface of the substrate 0 by sputtering, and is patterned into a predetermined shape. That is, by patterning, the lower electrode film 60 is basically formed in a region where the piezoelectric element holding portion 43 is defined, and the connection portion 61 (not shown) is formed with a predetermined width.

The material of the lower electrode film 60 is preferably platinum or the like. This is because it is necessary to crystallize a piezoelectric layer 70 described later formed by a sputtering method or a sol-gel method by firing at a temperature of about 600 to 1000 ° C. in an air atmosphere or an oxygen atmosphere after the film formation. Because. That is, the material of the lower electrode film 60 must be able to maintain conductivity under such a high temperature and oxidizing atmosphere. In particular, when the piezoelectric layer 70 is made of lead zirconate titanate (PZT), It is desirable that the change in conductivity due to the diffusion of lead oxide is small, and for these reasons, platinum, iridium, or a multilayer film thereof is preferable.

Next, as shown in FIG. 4C, a piezoelectric layer 70 is formed on the lower electrode film 60. For example, in the present embodiment, a so-called sol in which a metal organic material is dissolved and dispersed in a catalyst is applied and dried to form a gel, and then fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. Formed by using As a material for the piezoelectric layer 70, a PZT-based material is suitable when used in an ink jet recording head. The method for forming the piezoelectric layer 70 is not particularly limited. For example, the piezoelectric layer 70 may be formed by a spin coating method such as a sputtering method or a MOD method (organic metal thermal coating decomposition method).

Further, a method of forming a precursor film of lead zirconate titanate by a sol-gel method, a sputtering method, a MOD method, or the like, and then crystallizing the film at a low temperature by a high-pressure treatment in an alkaline aqueous solution may be used. Good.

In any case, unlike the bulk piezoelectric, the piezoelectric layer 70 formed in this manner has crystals preferentially oriented, and in the present embodiment, the piezoelectric layer 70 has It is formed in a column shape. Note that the preferential orientation refers to a state in which a crystal orientation direction is not disordered and a specific crystal plane is oriented in a substantially constant direction. In addition, a crystal having a columnar thin film refers to a state in which substantially columnar crystals are gathered in a plane direction with their central axes substantially aligned in 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. 4D, an upper electrode film 80 is formed on the piezoelectric layer 70. The upper electrode film 80 only needs to be a material having high conductivity, and many metals such as aluminum, gold, nickel, platinum, and iridium, and a conductive oxide can be used. In the present embodiment, platinum is formed by sputtering.

Next, as shown in FIG. 5A, only the piezoelectric layer 70 and the upper electrode
00 patterning is performed. In the present embodiment, the communication hole 51 is formed by simultaneously etching the region of the elastic film 50 facing the communication portion 13.

Next, as shown in FIG. 5B, a material for the lead electrode 90 is formed over the entire surface of the flow path forming substrate 10 and the lead electrode 90 is provided for each piezoelectric element 300.
Then, the signal system wiring 91 is formed by patterning.

Next, as shown in FIG. 5C, the pressure generating chamber 12, the ink supply path 14, and the communication section 13 are formed by anisotropically etching the flow path forming substrate 10.

Next, as shown in FIG.
A predetermined amount of an anisotropic conductive adhesive 30A, which is a material of the anisotropic conductive adhesive layer 30 having the conductive filler 31, is applied to positions on the lead electrode 90 and the signal system wiring 91 on the zero.

Next, as shown in FIG.
The drive circuit 41 and the bonding substrate 40 on which each wiring is formed are bonded via the anisotropic conductive adhesive layer 30 formed of the anisotropic conductive adhesive 30A on the substrate 0. That is, by applying a predetermined load to the bonding substrate 40 toward the flow path forming substrate 10, the conductive filler 3 contained in the anisotropic conductive adhesive 30 </ b> A is formed.
1 is a lead electrode 90 and each drive system wiring 42 of the drive circuit 41.
To cure the anisotropic conductive adhesive 30A to form the anisotropic conductive adhesive layer 30 and electrically connect the two. Similarly, the signal wiring 91 provided on the flow path forming substrate 10 and the external input wiring 44 of the drive circuit 41 are electrically connected via the anisotropic conductive adhesive layer 30. At the same time, a piezoelectric element holding portion 43 is defined in a region facing the piezoelectric element 300.

The bonding of the bonding substrate 40 is performed by using a nitrogen gas,
By performing the process in an inert gas such as an argon gas, the inside of the piezoelectric element holding unit 43 has a humidity of 5% RH or less (preferably 1% RH or less) at 25 ° C. Can be prevented.

As described above, by adhering the flow path forming substrate 10 and the bonding substrate 40 via the anisotropic conductive adhesive layer 30, the piezoelectric element holding portion 4 for sealing the piezoelectric element therebetween is provided.
3 and the driving circuit 41 and each piezoelectric element 300 or the external wiring 110 are formed by the anisotropic conductive adhesive layer 30.
Is electrically connected, there is no need to separately provide a sealing plate for sealing the piezoelectric element 300 and a circuit board having a drive circuit, thereby reducing the number of parts, simplifying the manufacturing process, and reducing the manufacturing cost. can do.

Further, by connecting the respective wirings by the anisotropic conductive adhesive layer 30, there is no need for heating when connecting the wirings, and no vibration is generated. Can be prevented.

Thereafter, the nozzle plate having the nozzle openings 21 formed on the opening surface side of the flow path forming substrate 10, the reservoir forming substrate 130, and the compliance substrate 140 are joined.

By the series of film formation and anisotropic etching described above, a number of chips are simultaneously formed on one wafer, and after the process is completed, a flow path of one chip size as shown in FIG. The connection layer 9 made of an anisotropic conductive material (ACF) or the like is divided into each of the formation substrates
An external connection 110 such as an FPC is connected through the connection line 2 to form an ink jet recording head.

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

For example, in the first embodiment, the lead electrode 90 and the drive system wiring 41 or the signal system wiring 91 and the external input wiring 44 are simultaneously formed by the anisotropic conductive adhesive layer 30 that seals the piezoelectric element holding portion 43. Are electrically connected, but the sealing of the piezoelectric element holding portion 43 and the connection of each wiring may be performed by separately provided anisotropic conductive adhesive layers.

Further, for example, in the first embodiment described above, the piezoelectric element holding portion 43 is sealed by bonding the bonding substrate 40 via the anisotropic conductive adhesive layer 30. A through-hole is provided to connect the piezoelectric element holding portion 43 to the head external space, and after bonding the bonding substrate 40, the head external space and the piezoelectric element holding portion 43 are evacuated to remove water.
After reducing the temperature to 1% RH or less at 5 ° C., sealing may be performed by introducing an inert gas such as nitrogen or argon gas and closing the above-mentioned through-hole with an adhesive or the like in this state.

Further, for example, in Embodiment 1 described above, a thin-film type ink jet recording head manufactured by applying a film forming and lithography process has been described as an example. However, the present invention is not limited to this. The present invention can also be applied to a thick-film type ink jet recording head formed by a method such as attaching a green 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. FIG.
FIG. 2 is a schematic diagram illustrating an example of the ink jet recording apparatus.

As shown in FIG. 7, the recording head units 1A and 1B having ink jet recording heads are provided with detachable cartridges 2A and 2B constituting ink supply means.
The carriage 3 on which B is mounted is provided movably in the axial direction on a carriage shaft 5 attached to the apparatus main body 4. The recording head units 1A and 1B are, for example,
Each of them ejects a black ink composition and a color ink composition.

The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted moves along the carriage shaft 5. Moved. On the other hand, 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. It is designed to be transported.

[0088]

As described above, according to the present invention, a flow path forming substrate on which a piezoelectric element is formed via a conductive adhesive,
Improves connection durability by joining a bonding substrate with an integrated circuit integrally formed in the area facing the piezoelectric element and electrically connecting the lead wires of the piezoelectric element to each terminal of the integrated circuit. In addition, since there is no need for heating at the time of connection, damage due to deformation of the substrate can be prevented.

Further, since the bonding substrate also serves as the sealing plate for the piezoelectric element and the integrated circuit substrate, the wiring and sealing steps are simplified, and the manufacturing cost can be reduced.

Further, it is possible to reduce the size and the density of the ink jet recording head.

[Brief description of the drawings]

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

FIG. 2 is a top view of a bonding substrate and a top view of a flow path forming substrate according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of the pressure generating chamber of the inkjet recording head according to the first embodiment of the present invention in the longitudinal direction and the juxtaposed direction.

FIG. 4 is a cross-sectional view illustrating a manufacturing process of the ink jet recording head according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a manufacturing process of the ink jet recording head according to Embodiment 1 of the present invention.

FIG. 6 is a cross-sectional view illustrating a manufacturing process of the ink jet recording head according to Embodiment 1 of the present invention.

FIG. 7 is a schematic view of an ink jet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flow path forming substrate 11 Partition wall 12 Pressure generating chamber 13 Reservoir 14 Ink supply path 20 Nozzle plate 21 Nozzle opening 30 Anisotropic conductive adhesive layer 30A Anisotropic conductive adhesive 31 Conductive filler 40 Joining substrate 41 Drive circuit 42 Drive system wiring 43 piezoelectric element holding section 44 external input wiring 50 elastic film 60 lower electrode film 70 piezoelectric layer 80 upper electrode film 90 lead electrode 91 signal system wiring 92 connection layer 100 reservoir 110 external wiring 130 reservoir forming substrate 140 compliance substrate 300 piezoelectric element

Claims (10)

[Claims] 1. A flow path forming substrate made of single crystal silicon defining a pressure generating chamber communicating with a nozzle opening, a lower electrode provided on one surface side of the flow path forming substrate via a diaphragm, and a piezoelectric element. An ink jet recording head comprising a body layer and a piezoelectric element comprising an upper electrode, comprising: a bonding substrate which is bonded to the piezoelectric element side of the flow path forming substrate to form a sealing space for sealing the piezoelectric element. And, as an adhesive for joining the joining substrate and the flow path forming substrate and sealing the sealing space, a conductive adhesive containing a conductive filler is used, and the conductive adhesive is used via the conductive adhesive. An ink jet recording head, wherein an individual electrode of a piezoelectric element is electrically connected to a drive system wiring connected to each terminal of an integrated circuit provided on a bonding surface side of the bonding substrate. 2. The ink jet recording head according to claim 1, wherein the individual electrode is a lead electrode drawn from the upper electrode of the piezoelectric element onto the flow path forming substrate. 3. The method according to claim 1, wherein the lead wiring and the drive system wiring are electrically connected by the conductive adhesive provided in a region for sealing the sealing space. Characteristic inkjet recording head. 4. The integrated circuit according to claim 1, wherein one end of the flow path forming substrate extends outside the sealed space and is connected to an external wiring, and the other end is an input of the integrated circuit. An ink jet recording head, comprising: an input wiring connected to a terminal; and a signal wiring electrically connected through the conductive adhesive. 5. The signal line according to claim 4, wherein the signal wiring and the input wiring are electrically connected by the conductive adhesive provided in a region for sealing the sealing space. Inkjet recording head. 6. The conductive filler according to claim 1, wherein a diameter of the conductive filler is smaller than an interval between the adjacent lead wires, and is larger than a sum of a thickness of the integrated circuit and a thickness of the piezoelectric element. An ink jet recording head characterized by being large. 7. The method according to claim 1, wherein the base adhesive of the conductive adhesive is selected from the group consisting of an epoxy resin, a polyester resin, an acrylic resin, a polyimide resin and a polysulfone resin. Inkjet recording head. 8. The ink jet type according to claim 1, wherein the conductive filler is selected from the group consisting of gold, copper, silver, lead, an alloy of silver and lead, carbon and nickel. Recording head. 9. The pressure generating chamber according to claim 1, wherein the pressure generating chamber is formed by anisotropic etching, and each layer of the vibration plate and the piezoelectric element is formed by film formation and a lithography method. An ink jet recording head, characterized in that: 10. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.