JP2000085122A - Ink jet type recording head and ink jet type recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet type recording head and an ink jet type recording device, the improvement of the bonding strength and of the durability of a board are contrived. SOLUTION: In an ink jet type recording head equipped with a flow passage forming board 10, on which pressure generating chambers 12 each communicating with a nozzle opening, and a piezoelectric element 300 having at least a lower electrode 60, a piezoelectric body layer 7 and an upper electrode 80 provided on one side of the flow passage forming board 10, a bonding member 20 having a piezoelectric element holding part 24, in which a too much space to impede the motion of the piezoelectric element is ensured and which is bonded to the piezoelectric element 300 side of the flow passage forming board, is equipped so as to provide a mixedly existing part 360, in which at least two parts selected from the group consisting of a lower electrode removed part 330, in which the lower electrode 60 is removed a lower electrode exposed part, in which the lower electrode is exposed, and an upper electrode exposed part 350, in which the upper electrode is exposed, in at least some part of the peripheral edge of the piezoelectric element holding part 24 of the bonding surface of the bonding member 20 of the flow passage forming board 10, in order to improve the bonding strength between the board and the bonding member 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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 through 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.

In the former method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, so that 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 by a film forming technique over the entire surface of the diaphragm as disclosed in Japanese Patent Application Laid-Open No. 5-286131. A proposal has been made in which 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. In this case, the piezoelectric element corresponding to each pressure generating chamber can be driven by providing at least only the upper electrode for each pressure generating chamber while the piezoelectric material layer is provided on the entire surface of the vibration plate.

[0007]

Further, a joining member such as a cap member having a space for sealing a piezoelectric element and shutting off the external environment is provided on a flow path forming substrate in which such a pressure generating chamber is formed. May be joined.

However, such a bonding member and the flow path forming substrate are generally bonded by an adhesive or the like, but no special consideration is given to the bonding strength.

In view of such circumstances, an object of the present invention is to provide an ink jet recording head and an ink jet recording apparatus which improve the bonding strength of a substrate and the durability.

[0010]

According to a first aspect of the present invention, there is provided a flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening is defined, and one surface of the flow path forming substrate. And a piezoelectric element having at least a lower electrode, a piezoelectric layer, and a piezoelectric element having an upper electrode, wherein the space is joined to the piezoelectric element side of the flow path forming substrate and does not hinder its movement. The lower electrode is removed on at least a part of the periphery of the piezoelectric element holding portion of the joining surface of the flow path forming substrate with the joining member, the lower electrode being removed. An ink jet type comprising a lower electrode removing portion, a lower electrode exposed portion where the lower electrode is exposed, and a mixed portion where at least two types selected from an upper electrode exposed portion where the upper electrode is exposed are mixed. Record In the head.

In the first aspect, the joint strength between the flow path forming substrate and the joining member is improved by the mixed portion, and the durability of the head is improved.

In a second aspect of the present invention, in the first aspect, the piezoelectric element holding portion of the joining member is divided by a partition wall for each piezoelectric element, and the joining of a portion corresponding to the partition wall is performed. An ink jet recording head having the mixed portion on a surface.

In the second aspect, the strength of the flow path forming substrate at the portion where the partition wall is joined is improved.

According to a third aspect of the present invention, in the first or second aspect, in the mixed portion, at least two of the lower electrode removing portion, the lower electrode exposed portion, and the upper electrode exposed portion are:
An ink jet recording head is characterized in that it is formed in an island shape in a predetermined arrangement.

[0015] In the third aspect, by the mixed portion formed in an island shape, the continuity of the lower electrode can be achieved, or the support portion between the bonding surfaces can be formed, and the bonding strength can be improved.

According to a fourth aspect of the present invention, in the first or second aspect, in the mixed portion, at least two of the lower electrode removing portion, the lower electrode exposed portion, and the upper electrode exposed portion are:
An ink jet recording head is formed in a belt shape.

In the fourth aspect, the band-shaped mixed portion can improve the continuity of the lower electrode or form the support between the bonding surfaces and improve the bonding strength. According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the bonding member is a reservoir forming substrate having a reservoir part that constitutes at least a part of a reservoir that supplies ink to the pressure generating chamber. An ink jet recording head is characterized in that a nozzle forming member for forming the nozzle opening is joined to a surface of the flow path forming substrate opposite to the reservoir forming substrate.

In the fifth aspect, the bonding strength between the flow path forming substrate and the reservoir forming substrate is improved.

According to a sixth aspect of the present invention, in the fifth aspect, at least the upper electrode exposed portion is formed in a strip shape in the mixed portion provided over the entire periphery of the reservoir. And an ink jet recording head.

In the sixth aspect, the bonding strength around the reservoir is improved, and the reservoir is securely sealed by the strip-shaped upper electrode exposed portion.

According to a seventh aspect of the present invention, in any one of the first to fourth aspects, the joining member is a cap member capable of sealing the piezoelectric element holding portion. In the head.

In the seventh aspect, the bonding strength between the flow path forming substrate and the cap member is improved.

According to an eighth aspect of the present invention, in the seventh aspect, at least the piezoelectric element holding portion of the cap member or the mixed portion provided over the entire periphery of each of the piezoelectric element holding portions has the above-mentioned configuration. An ink jet recording head is characterized in that the exposed portion of the upper electrode is formed in a belt shape.

According to the eighth aspect, the piezoelectric element is securely sealed in the piezoelectric element holding portion.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the thermal expansion coefficient of the joining member is substantially the same as the thermal expansion coefficient of the flow path forming substrate. In the ink jet recording head.

In the ninth aspect, the bonding between the flow path forming substrate and the joining member can be performed at a high temperature, and the manufacturing process can be simplified.

According to a tenth aspect of the present invention, in any one of the first to eighth aspects, the material of the joining member is silicon,
An ink jet recording head is selected from the group consisting of glass and ceramics.

In the tenth aspect, the manufacturing process can be simplified by forming the joining member from a specific material.

According to an eleventh aspect of the present invention, in any one of the first to tenth aspects, the pressure generating chamber is formed on a ceramic substrate, and each layer of the piezoelectric element is formed by pasting or printing a green sheet. The ink jet recording head is characterized in that:

In the eleventh aspect, the head can be easily manufactured.

According to a twelfth aspect of the present invention, in any one of the first to tenth aspects, the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed of a thin film and a lithographic apparatus. An ink jet recording head characterized by being formed by a method.

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

A thirteenth aspect of the present invention is the ink jet recording head according to any one of the first to twelfth aspects, wherein an elastic film is formed below the lower electrode. .

In the thirteenth aspect, a voltage is applied to the lower electrode and the upper electrode to deform the piezoelectric layer, whereby the elastic film is deformed and ink is ejected.

According to a fourteenth aspect of the present invention, in the thirteenth aspect, the flow path forming substrate is formed of silicon, the elastic film is formed of silicon dioxide, and a region corresponding to the lower electrode removing portion is formed. An ink jet recording head, wherein the elastic film is exposed.

In the fourteenth aspect, by forming the flow path forming substrate and the elastic film with specific materials, the bonding strength at the lower electrode film removed portion is further improved.

According to a fifteenth 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 fourteenth aspects.

According to the fifteenth aspect, it is possible to realize an ink jet recording apparatus in which the durability of the head is improved and the reliability is improved.

[0039]

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

(Embodiment 1) FIG. 1 is an exploded 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. 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 previously formed by thermal oxidation.

On the other hand, the silicon single crystal substrate is anisotropically etched on the opening surface of the flow path forming substrate
The pressure generating chambers 12 divided by the plurality of partition walls 11 are provided in parallel in the width direction, and on the outside in the longitudinal direction, a common ink chamber of each pressure generating chamber 12 communicates with a reservoir portion of a reservoir forming substrate described later. A communication portion 13 forming a part of the reservoir 100 is formed, and is communicated with one end of each pressure generating chamber 12 in the longitudinal direction via an ink supply path 14.

Here, in the anisotropic etching, when a silicon single crystal substrate is immersed in an alkaline solution such as KOH, the substrate is gradually eroded, and the first (111) plane perpendicular to the (110) plane is formed. A second (1) which forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the (110) plane.
11) plane, and the etching rate of the (111) plane is about 1/1 compared to the etching rate of the (110) plane.
This is performed using the property of being 80.
By such anisotropic etching, two first (11
Precision processing can be performed based on depth processing of a parallelogram formed by the 1) plane and two oblique second (111) planes, and the pressure generating chambers 12 can be arranged at high density. it can.

In this embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane, and the short side is formed by the second (111) plane. The pressure generating chamber 12 is provided on the flow path forming substrate 1.
It is formed by etching until it reaches the elastic film 50 almost through 0. Here, the elastic film 50 is
The amount attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small. Each of the ink supply ports 14 communicating with one end of each of the pressure generating chambers 12 is formed shallower than the pressure generating chambers 12 to maintain a constant flow resistance of the ink flowing into the pressure generating chambers 12. That is, the ink supply port 14 is formed by partially etching (half-etching) the silicon single crystal substrate in the thickness direction. Note that the half etching is performed by adjusting the etching time.

On the opening side of the flow path forming substrate 10,
A nozzle plate 16 provided with a nozzle opening 15 communicating with the pressure supply chamber 12 on the side opposite to the ink supply path 14 is fixed via an adhesive, a heat welding film, or the like. The thickness of the nozzle plate 16 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 16 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 16 is provided with the flow path forming substrate 10.
May be formed of a material having substantially the same thermal expansion coefficient as that of the material. In this case, since the deformation of the flow path forming substrate 10 and the nozzle plate 16 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 15 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 15 need to be formed with a groove width of several tens of μm with high accuracy.

On the other hand, on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10, for example, a thickness of about 0.2 μm
A lower electrode film 60, a piezoelectric film 70 having a thickness of, for example, about 1 μm, and an upper electrode film 80 having a thickness of, for example, about 0.1 μm are formed by lamination in a process to be described later.
0. Here, the piezoelectric element 300 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 300 is used as a common electrode, and the other electrode and the piezoelectric film 70 are patterned for each pressure generating chamber 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 both electrodes is referred to as a piezoelectric active portion 320. 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. However, there is no problem even if the upper electrode film 80 is reversed for convenience of a drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. Also, here
The combination of the piezoelectric element 300 and the vibration plate whose displacement is generated by driving the piezoelectric element 300 is referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 6
Although 0 functions as a diaphragm, the lower electrode film may also serve as an elastic film.

The piezoelectric element 300 of the flow path forming substrate 10
On the side, a reservoir forming substrate 20 having a reservoir portion 21 constituting at least a part of the reservoir 100 is joined. In this embodiment, the reservoir portion 21 penetrates the reservoir forming substrate 20 in the thickness direction, and
Are formed over the width direction. As described above, the reservoir 100 communicates with the communication portion 13 of the flow path forming substrate 10 and serves as a common ink chamber for each pressure generating chamber 12.

As the reservoir forming substrate 20, it is preferable to use a material having substantially the same coefficient of thermal expansion as that of the flow path forming substrate 10, such as glass or ceramic material. It was formed using a silicon single crystal substrate of the same material. As a result, as in the case of the nozzle plate 16 described above, the two can be reliably bonded even when they are bonded at a high temperature using a thermosetting adhesive. Therefore, the manufacturing process can be simplified.

Further, the reservoir forming substrate 20 includes:
The compliance substrate 30 including the sealing film 31 and the fixing plate 32 is joined. Here, the sealing film 31 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and one side of the reservoir 21 is sealed by the sealing film 31. Has been stopped. The fixing plate 32 is made of a hard material such as a metal (for example, stainless steel (SU
S) etc.). The reservoir 10 of the fixing plate 32
Since the region facing 0 is the opening 33 completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with the sealing film 31 having flexibility, and the internal pressure changes. Thus, the flexible portion 22 can be deformed. That is, for example, a change in pressure in the reservoir 100 caused by the flow of ink when the piezoelectric element 300 is driven is absorbed by the deformation of the flexible portion 22, and
The pressure within zero can always be kept substantially constant.

Further, an ink inlet 25 for supplying ink to the reservoir 100 is formed on the compliance substrate 30 substantially outside the longitudinal center of the reservoir 100. Further, the reservoir forming substrate 20 is provided with an ink introduction path 26 that communicates the ink introduction port 25 with the side wall of the reservoir 100. In the present embodiment, the ink is supplied to the reservoir 100 by one ink inlet 25 and the ink inlet path 26. However, the present invention is not limited to this. For example, according to a desired ink supply amount, A plurality of ink introduction ports and ink introduction paths may be provided, or the opening area of the ink introduction ports may be increased to enlarge the ink flow path.

On the other hand, the piezoelectric element 3 of the reservoir forming substrate 20
In a region opposed to the piezoelectric element 300, a piezoelectric element holding portion 24 capable of sealing the space is provided with a space that does not hinder the movement of the piezoelectric element 300, and at least the piezoelectric active portion 320 of the piezoelectric element 300 is provided. Are sealed in the piezoelectric element holding portion 24. Further, in the present embodiment, the piezoelectric element holding portion 24 is provided with a partition wall 27 formed in a region facing the peripheral wall 11 of the pressure generating chamber 12 so that each piezoelectric element 30 is formed.
Each of the piezoelectric elements 300 is sealed in each of the piezoelectric element holding portions 24. That is, the reservoir forming substrate 20 constitutes the reservoir 100 and also serves as a cap member for blocking the piezoelectric element 300 from the external environment.

In the present embodiment, the piezoelectric film 70 and the upper electrode film 80 of the piezoelectric element 300 sealed by the piezoelectric element holding portion 24 are connected to the flow path from one end in the longitudinal direction of the pressure generating chamber 12. The external wiring 40 such as a flexible cable or the like is provided on the surface of the flow path forming substrate 10 that extends on the forming substrate 10 to the outside of the reservoir forming substrate 20 and that is exposed on the surface of the flow path forming substrate 10 on the joining side with the reservoir forming substrate 20. Is connected to

In this embodiment, the lower electrode film removing portion 33 from which the lower electrode film 60 has been removed is provided on the bonding surface of the flow path forming substrate 10.
0, a lower electrode film exposed portion 340 where the lower electrode film is exposed,
By providing a mixed portion 360 in which the upper electrode film exposed portion 350 where the upper electrode film 80 is exposed is provided, and joining the flow path forming substrate 10 and the reservoir forming substrate 20 via the mixed portion 360, the bonding strength is increased. Is being improved.

Hereinafter, the mixed section 360 will be described. FIG. 3 is a plan view showing the arrangement of the mixed section 360 and a cross-sectional view showing the joined state of the mixed section 360.

As described above, the mixed portion 360 of this embodiment includes the lower electrode film removing portion 330, the lower electrode film exposed portion 340, and the upper electrode film exposed portion 350. As shown in FIG. Around, ie, the piezoelectric element holding portion 300
Is provided in a region facing the peripheral edge and the partition wall. In the mixed portion 360, the lower electrode film removing portion 330 and the upper electrode film exposing portion 350 are provided in an island shape, respectively, and these are arranged in series at a predetermined interval. The other portion is a lower electrode film exposed portion 340.

As described above, by providing the mixed portion 360 on the joint surface between the flow path forming substrate 10 and the reservoir forming substrate 20 around the piezoelectric element 300, that is, the lower electrode film 60
By providing the lower electrode film removing portion 330 while maintaining the continuity of the elastic film 50, a part of the elastic film 50 is exposed. Therefore,
The reservoir forming substrate 20 is partially formed with the flow path forming substrate 10.
Since it is directly bonded to the upper elastic film 50, the bonding strength is improved as compared with the case where only the lower electrode film 60 is bonded, and the durability of the head can be improved. This is compared with the bonding strength between the lower electrode film 60 and the reservoir forming substrate 20,
This is because the bonding strength between the elastic film 50 and the reservoir forming substrate 20 is strong.

Further, at the junction between the partition wall 27 for partitioning the piezoelectric element holding portion 24 and the peripheral wall 11 of the pressure generating chamber 12,
By joining the partition walls 27, the rigidity of the peripheral wall of the pressure generating chamber 12 is improved, and the collapse of the peripheral wall when the piezoelectric element 300 is driven is suppressed. Therefore, it is preferable to further improve the bonding strength in the region facing the partition wall 27, and the mixed portion 360 is particularly effective.

The lower electrode film 60 of the piezoelectric element 300 is
Since the common electrode of each piezoelectric element 300 is used, it is preferable that the area of the lower electrode film 60 be kept large. In this embodiment, the lower electrode film removing portion 330 in the mixed portion 360 is formed in an island shape, and the other portions are the lower electrode film exposed portion 340 and the upper electrode film exposed portion 350 where the lower electrode film 60 remains.
Therefore, there is no problem in driving the piezoelectric element 300.

Here, as described above, the piezoelectric element 30
Since the zero piezoelectric layer 70 and the upper electrode film 80 extend from one end in the longitudinal direction to the peripheral wall, the flow path forming substrate 10 and the reservoir forming substrate 20 are connected to the piezoelectric element on the peripheral wall of the pressure generating chamber 12. It is joined in a state where 300 is held. Therefore, the upper electrode exposed portion 350 is provided in the mixed portion 360 serving as a bonding surface in the other region so that the bonding surface between the flow path forming substrate 10 and the reservoir forming substrate 20 is substantially parallel. Have been. Thus, the upper electrode film exposed portion 350 functions as a support, and the reservoir forming substrate 20
The positions of the bonding surfaces are substantially uniform, the bonding surfaces between the flow path forming substrate 10 and the reservoir forming substrate 20 can be made substantially parallel, and variations in the bonding state can be suppressed. Therefore, the characteristics of the head such as the ejection characteristics of the ink by driving the piezoelectric element 300 can be easily made uniform, and the reliability can be improved.

The ink jet recording head of the present embodiment described above takes in ink from the ink inlet 25 connected to external ink supply means (not shown) and fills the inside from the reservoir 100 to the nozzle opening 15 with ink. According to a recording signal from an external driving circuit (not shown), each lower electrode film 6 corresponding to the pressure generating chamber 12 is formed.
0, and a voltage is applied between the upper electrode film 80 and the elastic film 50,
By bending and deforming the lower electrode film 60 and the piezoelectric film 70, the pressure in each pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle openings 15.

(Embodiment 2) FIG. 4 is a plan view and a sectional view of a main part of an ink jet recording head according to Embodiment 2.

In this embodiment, the lower electrode film removing section 330A,
The lower electrode film exposed portion 340A and the upper electrode film exposed portion 350A are formed in a strip shape, and the mixed portions 360A are arranged in parallel.
Is provided over the periphery of the connecting portion between the communication portion 13 of the flow path forming substrate 10 and the reservoir portion 21 of the reservoir forming substrate 20 that constitute the reservoir 100.

More specifically, as shown in FIG. 4, in the present embodiment, the mixing portion 360 A is provided with the ink introduction passage 26 to the reservoir forming substrate 20 in the connection portion between the reservoir portion 21 and the communication portion 13 constituting the reservoir 100. Is formed over the entire circumference except for the part where is formed.

In the mixed portion 360 of this embodiment, the lower electrode film removing portion 330A, the lower electrode film exposing portion 340A, and the upper electrode film exposing portion 350A are formed in a three-row strip shape, and the innermost, that is, the most reservoir portion. On the 100 side, an upper electrode film exposed portion 350A is provided. The lower electrode film exposed portion 340A and the lower electrode film removed portion 330A are formed outside the upper electrode film exposed portion 350A.

As described above, by providing the mixed portion 360 A around the reservoir 100 in addition to the periphery of the piezoelectric element 300, the flow path forming substrate 10 and the reservoir forming substrate 20 are formed.
Can be more reliably joined at a substantially constant position. Further, the reservoir unit 21 constituting the reservoir 100
The connection state between the and the communication part 13 can be always substantially constant. Therefore, the driving of the piezoelectric element 300, and further, the characteristics such as the flow of the ink can be easily made uniform.
The reliability of the head can be further improved.

In this embodiment, the mixed section 360A
Are the lower electrode film removal part 330A and the lower electrode film exposed part 340A
And the upper electrode film exposed portion 350A, but is not limited to this. For example, when a mixed portion is provided around the reservoir 100, the lower electrode film 60 does not particularly function as an electrode. It is not necessary to provide a film exposure part. in this case. Instead of the exposed portion of the lower electrode film, for example, the removed portion of the lower electrode film may be formed wider to further increase the bonding strength.

In this embodiment, the lower electrode film removing section 3
30A, lower electrode film exposed portion 340A and upper electrode film exposed portion 3
The mixed portion 360A formed in a strip shape with 50A is connected to the reservoir 10
0, but of course, this mixed portion 36
0 A may be provided around the piezoelectric element 300. However, in this case, since it is necessary to establish conduction of the lower electrode film 60 constituting the piezoelectric element 300, the lower electrode removing portion 330A cannot be provided so as to surround the entire circumference of the piezoelectric element 300. It is necessary to leave a portion where 60 continues.

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

For example, in the above-described embodiment, the reservoir forming substrate has been described as an example of the joining member to be joined to the flow path forming substrate. However, the present invention is not limited to this. A cap member or the like capable of sealing this space while securing the space may be used.

Further, for example, in each of the above-described embodiments, 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 the embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. FIG.
FIG. 2 is a schematic view illustrating an example of the ink jet recording apparatus.

As shown in FIG. 5, 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.

Then, 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 on which the recording head units 1A and 1B are mounted moves along the carriage shaft 5. Moved. On the other hand, the apparatus main body 4 is provided with a platen 8 along the carriage 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.

[0076]

As described above, according to the present invention, the lower electrode film removing portion, the lower electrode film exposing portion, and the upper electrode film exposing portion are formed on a part of the joint surface between the flow path forming substrate and the reservoir forming substrate. Since the mixed portion is provided, the bonding strength between the flow path forming substrate and the reservoir forming substrate can be improved. Further, the flow path forming substrate and the reservoir forming substrate can always be easily joined at a substantially uniform position, and the characteristics of the head can be easily made uniform. Therefore, there is an effect that the reliability of the head can be improved.

[Brief description of the drawings]

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

3A and 3B are diagrams illustrating a mixed portion according to the first embodiment of the present invention, wherein FIG. 3A is a plan view of a main portion thereof, and FIG.
It is -A 'sectional drawing.

4A and 4B are diagrams illustrating a mixed portion according to a second embodiment of the present invention, wherein FIG. 4A is a plan view of a main portion thereof, and FIG.
FIG. 14 is a sectional view taken along the line B-B '.

FIG. 5 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 side wall 12 pressure generating chamber 13 communication part 14 ink supply path 15 nozzle opening 16 nozzle plate 20 reservoir forming substrate 21 reservoir part 22 flexible part 24 piezoelectric element holding part 25 ink introduction port 26 ink introduction path 27 section Wall 30 compliance substrate 31 sealing film 32 fixing plate 60 lower electrode film 70 piezoelectric film 80 upper electrode film 100 reservoir 110 adhesive layer 300 piezoelectric element

Claims (15)

[Claims] 1. A flow path forming substrate defining a pressure generating chamber communicating with a nozzle opening, and a piezoelectric element provided on one surface of the flow path forming substrate and having at least a lower electrode, a piezoelectric layer, and an upper electrode. An ink jet recording head comprising: a joining member that is joined to the piezoelectric element side of the flow path forming substrate and has a piezoelectric element holding portion that secures a space that does not hinder the movement; At least part of the periphery of the piezoelectric element holding portion of the bonding surface of the forming substrate with the bonding member, a lower electrode removal portion from which the lower electrode has been removed, and a lower electrode exposed portion where the lower electrode is exposed, An ink jet recording head having a mixed portion in which at least two types selected from an upper electrode exposed portion where the upper electrode is exposed are mixed. 2. The piezoelectric element holding portion of the bonding member according to claim 1, wherein the piezoelectric element holding portion of the bonding member is partitioned by partition walls for each piezoelectric element, and the mixed portion is provided on a portion of the bonding surface corresponding to the partition wall. An ink jet recording head, characterized in that: 3. The mixed portion according to claim 1, wherein at least two of the lower electrode removing portion, the lower electrode exposed portion, and the upper electrode exposed portion are formed in an island shape in a predetermined arrangement. An ink jet recording head characterized in that: 4. The device according to claim 1, wherein at least two of the lower electrode removing portion, the lower electrode exposed portion, and the upper electrode exposed portion are formed in a strip shape in the mixed portion. Inkjet recording head. 5. The reservoir according to claim 1, wherein the joining member is a reservoir forming substrate having a reservoir part that constitutes at least a part of a reservoir that supplies ink to the pressure generating chamber, An ink jet recording head, wherein a nozzle forming member for forming the nozzle opening is joined to a surface of the forming substrate opposite to the reservoir forming substrate. 6. The ink jet recording head according to claim 5, wherein at least the upper electrode exposed portion is formed in a strip shape in the mixed portion provided around the entire periphery of the reservoir. 7. An ink jet recording head according to claim 1, wherein said joining member is a cap member capable of sealing said piezoelectric element holding portion. 8. The at least one upper electrode exposed portion of the cap member according to claim 7, wherein at least the upper electrode exposed portion is formed in a strip shape over the entire piezoelectric element holding portion of the cap member or over the entire periphery of each piezoelectric element holding portion. An ink jet recording head characterized in that: 9. The ink jet recording head according to claim 1, wherein the thermal expansion coefficient of the joining member is substantially the same as the thermal expansion coefficient of the flow path forming substrate. 10. The ink jet recording head according to claim 1, wherein a material of the bonding member is selected from the group consisting of silicon, glass, and ceramics. 11. The ink jet printer according to claim 1, wherein the pressure generating chamber is formed on a ceramic substrate, and each layer of the piezoelectric element is formed by pasting or printing a green sheet. Type recording head. 12. 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 element is formed by a thin film and a lithography method. An ink jet recording head, characterized in that: 13. The ink jet recording head according to claim 1, wherein an elastic film is formed below the lower electrode. 14. The flow path forming substrate according to claim 13, wherein the flow path forming substrate is formed of silicon, the elastic film is formed of silicon dioxide, and the elastic film in a region corresponding to the lower electrode removal portion is exposed. An ink jet recording head, characterized in that: 15. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.