JP2000127379A - 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 the structure is simplified and the manufacturing cost is reduced. SOLUTION: The ink jet recording head comprises a nozzle forming member 16 having a plurality of nozzle openings 15 for ejecting ink, a channel forming substrate 10 being bonded to the nozzle forming member 16 and pressure generating chambers 12 communicating with the nozzle openings 15 are defined therein, and piezoelectric elements 300 arranged on the side of the channel forming substrate 10 not bonded with the nozzle forming member 16 and generating a pressure variation in the pressure generating chambers 12. Structure of the head is simplified by bonding a reservoir forming substrate 20 having a reservoir part 21 constituting at least a part of a reservoir 100 communicating with the pressure generating chambers 12 and supplying ink thereto to the side of the channel forming substrate 10 where the piezoelectric elements 300 are formed.

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. The present invention relates to an ink jet recording head that ejects 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.

[0006] According to this, the operation of attaching the piezoelectric element to the diaphragm becomes unnecessary, and not only can the piezoelectric element be manufactured by a precise and simple method called lithography, but also the thickness of the piezoelectric actuator can be reduced. There is an advantage that it can be made thin and can be driven at high speed. In this case,
By providing at least only the upper electrode for each pressure generating chamber while keeping the piezoelectric material layer on the entire surface of the diaphragm, the piezoelectric actuator corresponding to each pressure generating chamber can be driven.

[0007] In such an ink jet recording head, a reservoir serving as a common ink chamber for each pressure generating chamber is generally formed by laminating a plurality of substrates. Is supplied with ink. Further, the reservoir is provided with a compliance section for absorbing a pressure change at the time of driving the piezoelectric element in order to keep the internal pressure of the reservoir constant.

[0008]

However, the number of substrates used to form the reservoir is large, and in particular, the number of substrates laminated to form the compliance section is large, resulting in high material and assembly costs. There is.

Further, when silicon is used for the substrate defining the pressure generating chamber, it is difficult to adhere at a high temperature due to a difference in thermal expansion coefficient from other substrates, and there are also problems such as an increase in the number of assembly steps. is there.

In view of such circumstances, an object of the present invention is to provide an inkjet recording head and an inkjet recording apparatus whose structure is simplified and whose manufacturing cost is reduced.

[0011]

According to a first aspect of the present invention, there is provided a nozzle forming member having a plurality of nozzle openings for discharging ink, the nozzle forming member being joined to the nozzle forming member and being provided with the nozzle opening. A flow channel forming substrate defining a pressure generating chamber communicating with the nozzle, and a pressure change chamber provided on a surface of the flow channel forming substrate opposite to a surface to which the nozzle forming member is joined, to change pressure in the pressure generating chamber. In the ink jet type recording head having a piezoelectric element to be generated, ink is supplied to each pressure generating chamber by communicating with the pressure generating chamber on a surface of the flow path forming substrate on which the piezoelectric element is formed. An ink jet recording head is characterized in that a reservoir forming substrate having a reservoir portion constituting at least a part of the reservoir is joined.

In the first aspect, the number of stacked substrates for forming the reservoir can be reduced, and the structure can be simplified.

According to a second aspect of the present invention, in the first aspect, there is provided a communication system in which the flow path forming substrate communicates with the reservoir portion of the reservoir forming substrate to form a part of the reservoir together with the reservoir portion. And an ink jet recording head comprising:

[0014] In the second aspect, the reservoir is constituted by the reservoir portion and the communication portion, and the reservoir having a relatively large volume can be easily formed.

According to a third aspect of the present invention, in the first or second aspect, the reservoir and each of the pressure generating chambers are communicated with each other via an ink supply path having a flow path relatively narrower than the reservoir. Ink-jet recording head.

In the third aspect, since the ink is supplied from the reservoir to the pressure generating chamber via the ink supply path having a relatively narrow flow path, the amount of bubbles mixed into the ink is suppressed.

According to a fourth aspect of the present invention, in any one of the first to third aspects, ink is introduced into the reservoir portion of the reservoir forming substrate so as to communicate with the outside and supply ink to the reservoir. An ink jet type recording head characterized in that the mouth is communicated.

In the fourth aspect, ink is supplied from the ink inlet to the reservoir.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the reservoir forming substrate has a space secured in a region facing the piezoelectric element so as not to hinder its movement. And a piezoelectric element holding part capable of sealing the space.

According to the fifth aspect of the present invention, the piezoelectric element is hermetically sealed in the piezoelectric element holding portion, thereby preventing the piezoelectric element from being broken due to an external environment.

According to a sixth aspect of the present invention, in the fifth aspect, the piezoelectric element holding section is partitioned by partition walls for each piezoelectric element, and the partition walls are joined to the flow path forming substrate. An ink jet recording head is characterized in that:

In the sixth aspect, the rigidity of the peripheral wall that partitions the pressure generating chamber is increased, and the peripheral wall is prevented from falling down when the piezoelectric element is driven.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, a part of the reservoir portion of the reservoir forming substrate has a flexible portion having flexibility. In the ink jet recording head.

In the seventh aspect, the change in the internal pressure of the reservoir is absorbed by the deformation of the flexible portion,
The pressure inside the reservoir is always kept constant.

According to an eighth aspect of the present invention, there is provided an ink jet recording head according to the seventh aspect, wherein the flexible portion is provided by joining a flexible member.

In the eighth aspect, the flexible portion can be easily provided by joining the flexible member to the reservoir forming substrate.

A ninth aspect of the present invention is the ink jet recording head according to the eighth aspect, wherein the flexible member is made of a thin film of metal or ceramic.

In the ninth aspect, the flexible portion can be easily formed by forming a thin film on the flow path forming substrate.

A tenth aspect of the present invention is the ink jet recording head according to the eighth aspect, wherein the flexible member is made of a resin material.

In the tenth aspect, since the flexible portion is made of a resin member, it can be easily formed.

According to an eleventh aspect of the present invention, there is provided the ink jet recording head according to the tenth aspect, wherein the resin material is selected from the group consisting of a fluororesin, a silicone resin and a silicone rubber. .

In the eleventh aspect, the use of the specific resin material allows the flexible portion to be reliably formed.

According to a twelfth aspect of the present invention, in any one of the eighth to eleventh aspects, another substrate having a through hole at least in a region facing the flexible portion is joined to the flexible member. An ink jet recording head is characterized in that:

In the twelfth aspect, the strength of the portion other than the flexible portion is improved, and the durability of the head is improved.

According to a thirteenth aspect of the present invention, in any one of the first to twelfth aspects, a displacement of the piezoelectric element is detected in at least a part of a region of the reservoir forming substrate facing the piezoelectric element. An ink jet type recording head is provided with a through hole for detection.

In the thirteenth aspect, the displacement of the piezoelectric element can be easily detected from outside the reservoir forming substrate.

According to a fourteenth aspect of the present invention, in the thirteenth aspect, the piezoelectric element holding portion is provided so as to penetrate the reservoir forming substrate and is sealed with a transparent member.
An ink jet recording head characterized in that it also serves as the detection through-hole.

In the fourteenth aspect, the displacement of the piezoelectric element can be detected with the piezoelectric element sealed.

A fifteenth aspect of the present invention is the ink jet recording head according to the fourteenth aspect, wherein the transparent member forms the flexible portion.

In the fifteenth aspect, the change in the internal pressure of the piezoelectric element holding section is absorbed by the deformation of the permeable member, and the internal pressure of the piezoelectric element holding section is kept constant.

According to a sixteenth aspect of the present invention, in any one of the first to fifteenth aspects, the wiring on the flow path forming substrate drawn from the piezoelectric element and the flow path forming substrate of the reservoir forming substrate A connection wiring for connecting to a wiring provided in a region on the opposite side to the wiring, and an external wiring is connected to the wiring provided in a region on the opposite side of the reservoir forming substrate. In the recording head.

In the sixteenth aspect, the wiring drawn from the piezoelectric element and the external wiring are connected in the region on the opposite side of the reservoir forming substrate, so that the size of the head can be reduced.

A seventeenth aspect of the present invention is the ink jet recording head according to the sixteenth aspect, wherein the connection wiring is formed by wire bonding.

According to the seventeenth aspect, the connection wiring can be easily formed.

An eighteenth aspect of the present invention is the ink jet recording head according to the sixteenth aspect, wherein the connection wiring is formed of a thin film.

According to the eighteenth aspect, the connection wiring can be easily formed.

According to a nineteenth aspect of the present invention, in any one of the sixteenth to eighteenth aspects, the reservoir forming substrate communicates with the outside through a region corresponding to the piezoelectric element through the reservoir forming substrate. Wherein the connection wiring is provided through the communication hole.

In the nineteenth aspect of the present invention, since the connection wiring can be provided in the reservoir forming substrate, the head can be reduced in size.

A twentieth aspect of the present invention is the ink jet recording head according to the nineteenth aspect, wherein the communication hole is provided in a region of the pressure generating chamber facing the peripheral wall on the reservoir side. It is in.

In the twentieth aspect, the connection wiring is provided through the communication hole on the reservoir side.

According to a twenty-first aspect of the present invention, in the nineteenth aspect, the communication hole is provided in a region facing the peripheral wall of the pressure generating chamber on the nozzle opening side. In the head.

In the twenty-first aspect, the connection wiring is provided through the communication hole on the nozzle opening side.

According to a twenty-second aspect of the present invention, in any one of the sixteenth to twenty-first aspects, a driving circuit for driving the piezoelectric element is mounted on the reservoir forming substrate, and the connection wiring is connected to the driving circuit. An ink jet recording head is connected to a circuit.

In the twenty-second aspect, the drive circuit is mounted on the reservoir forming substrate, so that space can be saved.

A twenty-third aspect of the present invention is the ink jet recording head according to the twenty-second aspect, wherein the driving circuit is a semiconductor integrated circuit.

In the twenty-third aspect, the drive circuit can be easily mounted on the reservoir forming substrate, and the space can be surely saved.

According to a twenty-fourth aspect of the present invention, in any one of the first to twenty-third aspects, the nozzle plate is formed of substantially the same material as the flow path forming substrate and the reservoir forming substrate. In the recording head.

In the twenty-fourth aspect, the joining of the nozzle plate is facilitated, and the manufacturing process can be simplified.

According to a twenty-fifth aspect of the present invention, there is provided an ink jet recording head according to any one of the first to twenty-fourth aspects, wherein the nozzle forming member is a nozzle plate having a nozzle opening.

In the twenty-fifth aspect, an ink jet recording head that discharges ink from nozzle openings can be easily realized.

According to a twenty-sixth aspect of the present invention, in any one of the first to twenty-fifth aspects, the thermal expansion coefficient of the reservoir forming substrate is substantially the same as the thermal expansion coefficient of the flow path forming substrate. Ink-jet recording head.

In the twenty-sixth aspect, the reservoir forming substrate and the flow path forming substrate can be bonded at a high temperature, and the manufacturing process can be simplified.

According to a twenty-seventh aspect of the present invention, in any one of the first to twenty-sixth aspects, the material of the reservoir forming substrate is
An ink jet recording head is selected from the group consisting of silicon, glass and ceramics.

In the twenty-seventh aspect, the manufacturing process can be reliably simplified by forming the reservoir forming substrate with a specific material.

According to a twenty-eighth aspect of the present invention, in any one of the first to twenty-seventh 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 twenty-eighth aspect, the head can be easily manufactured.

According to a twenty-ninth aspect of the present invention, in any one of the first to twenty-eighth 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 lithography. An ink jet recording head characterized by being formed by a method.

In the twenty-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 thirtieth 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 twenty-ninth aspects.

According to the thirtieth aspect, it is possible to realize an ink jet recording apparatus in which the structure of the head is simplified and the manufacturing cost is reduced.

[0071]

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 formed of a silicon single crystal substrate having a plane orientation (110) in this embodiment. As the flow path forming substrate 10, usually 150 to 3
A thickness of about 00 μm is used.
Those having a thickness of about 0 to 280 μm, more preferably about 220 μm are suitable. This is because the arrangement density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.

One surface of the flow path forming substrate 10 is an opening surface, and the other surface is formed with a 1-2 μm-thick elastic film 50 made of silicon dioxide previously formed by thermal oxidation.

On the other hand, the opening surface of the flow path forming substrate 10 is anisotropically etched on a silicon single crystal 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 the silicon single crystal substrate is immersed in an alkaline solution such as KOH, it is gradually eroded and the first (111) plane perpendicular to the (110) plane and the first (111) plane 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 passages 14 communicating with one end of each of the pressure generating chambers 12 is formed shallower than the pressure generating chambers 12 and maintains a constant flow resistance of the ink flowing into the pressure generating chambers 12. That is, the ink supply path 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.

Further, 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
4.5 [× 10 ⁻⁶ / ° C.] glass-ceramic,
Or made of 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. In addition, the nozzle plate 16 is used for the passage forming substrate 1.
It may be made of a material having a thermal expansion coefficient substantially equal to 0. 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, the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10 has a thickness of about 0.2 μm, for example.
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.

Further, an ink inlet 25 for supplying ink to the reservoir 100 is formed on the compliance substrate 30 substantially outside the central portion in the longitudinal direction 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.

Normally, the reservoir 10 is
When the ink is supplied to 0, a pressure change occurs in the reservoir 100 due to, for example, a flow of the ink when the piezoelectric element 300 is driven or ambient heat. However, as described above, one surface of the reservoir 100 is
1 to form a flexible portion 22
The flexible portion 22 flexes and absorbs the pressure change. Therefore, the inside of the reservoir 100 is always maintained at a constant pressure. The other parts are held by the fixing plate 32 with sufficient strength. In the present embodiment,
Since the number of substrates constituting the reservoir 100 and the like can be reduced, material costs, assembly costs, and the like can be reduced.

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. Note that, in the present embodiment, the piezoelectric element holding section 24 includes a plurality of piezoelectric elements 3 arranged in parallel in the width direction.
It is formed in a size to cover 00.

As described above, the reservoir forming substrate 20 constitutes the reservoir 100 and also serves as a cap member for shutting off the piezoelectric element 300 from the external environment. Can be prevented. In the present embodiment, the piezoelectric element holding unit 2
Although the inside of the piezoelectric element holding part 4 is merely sealed, for example, the inside of the piezoelectric element holding part 24 is kept at a low humidity by evacuating the space inside the piezoelectric element holding part 24 or setting it to a nitrogen or argon atmosphere. The piezoelectric element 30
0 can be more reliably prevented from being destroyed.

In this embodiment, the piezoelectric film 70 and the upper electrode film 80 of the piezoelectric element 300 which are sealed by the piezoelectric element holding section 24 are connected to one end in the longitudinal direction of the pressure generating chamber 12 in the flow path. An exposed portion 10 extending on the formation substrate 10 to the outside of the reservoir formation substrate 20 and exposing a surface of the flow path formation substrate 10 on the joining side with the reservoir formation substrate
a, an external wiring 4 such as a flexible cable
0 is connected. That is, by extending the wiring from the piezoelectric element 300 to the outside of the reservoir forming substrate 20, the piezoelectric element 300 and the external wiring can be easily connected.

The ink jet recording head of this embodiment takes in ink from the ink inlet 25 connected to an external ink supply means (not shown),
After filling the inside with ink from 00 to the nozzle opening 15, each lower electrode film 60 corresponding to the pressure generating chamber 12 is made according to a recording signal from an external driving circuit (not shown).
A voltage is applied between the pressure generating chamber 12 and the upper electrode film 80 to deflect and deform the elastic film 50, the lower electrode film 60, and the piezoelectric film 70.
5 ejects ink droplets.

In the present embodiment, the piezoelectric element holding portions 24 of the reservoir forming substrate 20 are formed so as to cover all the piezoelectric elements 300 arranged in parallel in the width direction. However, the present invention is not limited to this. For example, as shown in FIG. 3, the piezoelectric element holding portions 24 are formed as independent piezoelectric element holding portions 24A for the respective piezoelectric elements 300 by the partition walls 27, and the piezoelectric elements 300 are sealed in the respective piezoelectric element holding portions 24A. It may be. As a result, the partition walls 27 are respectively joined to portions of the flow path forming substrate 10 corresponding to the side walls 12a of the pressure generating chambers 12, and the rigidity of the peripheral walls of the pressure generating chambers 12 is improved, and the piezoelectric element The fall of the peripheral wall when the 300 is driven can be suppressed. Needless to say, even with such a configuration, it is possible to prevent the piezoelectric element 300 from being broken, as in the above-described embodiment.

In this embodiment, the flow path forming substrate 10
Is formed to be larger than the reservoir forming substrate 20, and the connection between the piezoelectric element 300 and the external wiring 40 is performed on the exposed portion 10a of the flow path forming substrate 10. However, the present invention is not limited to this. As shown in FIG. 4, the reservoir forming substrate 2
0 is formed to be larger than the flow path forming substrate 10 to form an exposed portion 20a that exposes the surface of the reservoir forming substrate 20 on the joint side with the flow path forming substrate 10. On the exposed portion 20a, the piezoelectric element 300 and the outside are formed. You may make it connect with wiring.

Further, in the present embodiment, the flow path forming substrate 1
On the other end side of the zero pressure generation chamber 12 opposite to the nozzle opening 15, the communication portion 13 forming a part of the reservoir 100 is provided via the ink supply path 14. However, the present invention is not limited to this. For example, as shown in FIG. 5, the reservoir 100 is basically composed of only the reservoir portion 21 of the reservoir forming substrate 20, and each pressure generating chamber 1
The reservoir 2 and the reservoir 100 may be communicated with each other through a communication passage 18 having a narrower flow path than the reservoir 100. With such a configuration, when the ink is supplied to the pressure generating chamber 12, the flow velocity of the ink is maintained, so that the incorporation of bubbles can be prevented and good ink ejection can be performed.

(Embodiment 2) FIG. 6 is a plan view and a sectional view of an ink jet recording head according to Embodiment 2.

In the present embodiment, as shown in FIG. 6, the compliance substrate 30 is not provided on a part of the reservoir forming substrate 20 opposite to the reservoir 100, and the surface of the reservoir forming substrate 20 is exposed. Have been. And
Piezoelectric element 3 extended to outside of reservoir forming substrate 20
The wiring 28 is extended from the upper electrode film 80 to the surface of the reservoir forming substrate 20 by wire bonding, and the end of the extended wiring 28 is connected to the mounting portion 90 for connecting the piezoelectric element 300 and the external wiring 40. And Further, the structure is the same as that of the first embodiment, except that the outside is molded by an insulating member 95 such as epoxy to achieve electrical insulation.

Here, as in the conventional case, the flow path forming substrate 10
When the piezoelectric element 300 and the external wiring 40 are connected on the exposed portion 10a, the width of the exposed portion 10a is about 2.2 to 2.2.
About 3 mm is required, and the size of the head is slightly increased. On the other hand, in the present embodiment, the wiring 28 is extended from the exposed portion 10a of the flow path forming substrate 10 to above the exposed portion 20a of the reservoir forming substrate 20 by wire bonding, and is connected to the external wiring 40. Therefore, the width of the exposed portion 10a of the flow path forming substrate 10 can be reduced to about 0.2 mm, and the size of the recording head can be further reduced. Further, needless to say, the same effect as in the first embodiment can be obtained by such a configuration.

Third Embodiment FIG. 7 is a plan view and a sectional view of an ink jet recording head according to a third embodiment.

This embodiment is an example in which a through groove is provided in the reservoir forming substrate 20, and the piezoelectric element 300 and an external wiring are connected through the through groove. More specifically, as shown in FIG. 7, in the present embodiment, the piezoelectric film 70 and the upper electrode film 80 of the piezoelectric element 300 are extended to the longitudinal peripheral wall on the nozzle opening 15 side of the pressure generating chamber 12, It is sandwiched between the formation substrate 10 and the reservoir formation substrate 20. Further, similarly to the second embodiment, a part of the joint surface of the reservoir forming substrate 20 with the compliance substrate 30 is an exposed portion 20b whose surface is exposed, and corresponds to the exposed portion 20b and the piezoelectric element 300 is formed. In a region facing the upper electrode film 80,
A through groove 35 extending over the row of the pressure generating chambers 12 is formed. Then, the wiring 28 is extended from the upper electrode film 80 of each piezoelectric element 300 through the through groove 35 to the surface of the reservoir forming substrate 20 by wire bonding,
An end of the wiring 28 serves as a mounting part 90 for connecting the piezoelectric element 300 to an external wiring 40 such as a flexible cable.

In such a configuration, since the wiring 28 extends through the through groove 35, the above-described flow path forming substrate 10
Alternatively, there is no need to provide the exposed portions 10a and 20a of the reservoir forming substrate 20, and the head can be further reduced in size.

In this embodiment, the through-grooves 35 are formed in a groove shape over the rows of the pressure generating chambers 12. However, the present invention is not limited to this. A through hole may be provided.

In the above-described embodiment, the wiring 28 is extended from the upper electrode film 80 by wire bonding. However, the present invention is not limited to this. For example, as shown in FIG. ) And other conductive thin films
The wiring 28 </ b> A may be formed by forming a film on the inner peripheral surface of the substrate 5 and the upper surface of the compliance substrate 30 and patterning this conductive thin film for each piezoelectric element 300.

(Embodiment 4) FIG. 9 is a plan view and a sectional view of a main part of an ink jet recording head according to Embodiment 4.

In this embodiment, as shown in FIG. 9, the flow path forming substrate 10 is provided with two rows in which the pressure generating chambers 12 are arranged in the width direction so that the ends on the nozzle opening 15 side face each other. The piezoelectric element 300 is formed in a region corresponding to each pressure generating chamber 12. In addition, reservoirs 100 are provided in each of the rows of the pressure generating chambers on the outside of the pressure generating chambers 12 in the longitudinal direction, and the ink introduction ports 25 and the ink introduction paths 26 communicate with the reservoirs 100, respectively. ing. The structures of the reservoir, the ink inlet, and the like are the same as in the above-described embodiment.

The piezoelectric elements 300 extend from the areas facing the pressure generating chambers 12 to the peripheral wall on the reservoir 100 side, respectively.
0. In a region facing the upper electrode film 80 of the piezoelectric element 300, a through groove 35A is provided for each row of the pressure generating chambers 12, as in the above-described embodiment. Further, for example, the piezoelectric element 300 is provided on the reservoir forming substrate 20 in a region corresponding to the space between the rows of the pressure generating chambers 12.
Is mounted with a drive circuit 110 for driving. The drive circuit 110 may be a circuit board or a semiconductor integrated circuit (IC) including the drive circuit. The upper electrode film 80 of each piezoelectric element 300 and the drive circuit 110 are connected to each other by the wiring 28 extended by wire bonding or the like via the through groove 35A. Further, a wiring for supplying a signal to the drive circuit 110 is provided on the reservoir substrate 20, and one end of this wiring is connected to the drive circuit 110, and the other end is connected to the external wiring 40. It is 90.

According to such a configuration, the head can be downsized as in the third embodiment. Further, in the present embodiment, since the through groove 35A is provided on the reservoir 100 side, the piezoelectric element 300 and the driving means 110 can be more efficiently connected between the plurality of rows of the pressure generating chambers 12. it can.

In the present embodiment, the driving means 110 is provided on the reservoir forming substrate 20. However, the present invention is not limited to this. For example, as in Embodiment 1, the reservoir forming substrate 2
Needless to say, the wiring extending from the piezoelectric element 300 and the external wiring such as a flexible cable may be connected on the exposed portion 10a of zero.

(Embodiment 5) FIG. 10 is a sectional view of an essential part of an ink jet recording head according to Embodiment 5.

The present embodiment is an example in which a compliance substrate 30A composed of one member is provided on the flow path forming substrate 10. In the present embodiment, as shown in FIG. 10, a portion in the thickness direction of a region facing the reservoir 100 is removed to form a flexible portion 22 </ b> A having flexibility, and a penetrating hole that becomes an ink inlet 25 outside the flexible portion 22 </ b> A. It is the same as Embodiment 1 except that the holes were formed. As a material of such a compliance substrate 30A, a material having flexibility, for example, a fluororesin,
It is preferable to use a resin material such as a silicone resin or a silicone rubber.
OA can be easily formed.

The method of manufacturing the compliance substrate 30A is not particularly limited. For example, a resin layer having a predetermined thickness is formed on a silicon single crystal substrate constituting the reservoir forming substrate 20, and then the reservoir forming substrate 20 is formed. The reservoir 100 and the like can be formed by etching or the like, and further, a part of the region of the resin layer facing the reservoir 100 in the thickness direction can be etched.

In this embodiment, the compliance substrate 30A is formed of a resin material. However, the present invention is not limited to this. For example, as shown in FIG. It may be made of a thin film of metal or ceramic of about 10 to 10 μm. In this case, the region facing the reservoir 100 can be a flexible portion 22B having flexibility without removing a part in the thickness direction. Therefore, the head can be manufactured more easily.

(Embodiment 6) FIG. 12 is a sectional view of an essential part of an ink jet recording head according to Embodiment 6.

In the present embodiment, as shown in FIG. 12, the piezoelectric element 300 extends in the column direction of the pressure generating chamber 12 in a portion of the reservoir forming substrate 20 corresponding to the piezoelectric element 300 in a region opposed to the piezoelectric element holding portion 24. Embodiment 3 is the same as Embodiment 1 except that a detection through hole 29 for detecting the displacement of 300 is provided.

In such a configuration, the reservoir forming substrate 2
Before bonding the compliance substrate 30 on the zero, the displacement of the piezoelectric element 300 can be checked using, for example, a laser or the like. Therefore, a defect of the piezoelectric element 300 can be found before the head is completed, and the manufacturing efficiency can be improved. Also, this detection through hole 29
Is sealed by the compliance substrate 30, the piezoelectric element holding portion 24 can be held in a sealed state as in the first embodiment.

The size of the detection through-hole 29 is as follows.
There is no particular limitation, as long as it is formed at least in a region facing the piezoelectric element 300. Therefore, in the present embodiment, the pressure generating chambers 12 are provided in a groove shape in the row direction. However, for example, a round hole for each piezoelectric element 300 may be used.
Alternatively, the entire piezoelectric element holding portion may be a through hole.

In this embodiment, the detection through-hole 29 is used.
Is sealed with the compliance substrate 30, but is not limited to this. For example, as shown in FIG. 13, the detection through-hole 29 is sealed only with the sealing film 31 having flexibility, that is, detection is performed. The fixing plate 32 in the region facing the through hole 29 may be removed to form the flexible portion 24a. Thereby, when a pressure change occurs in the piezoelectric element holding portion 24, the flexible portion 24
Due to the deformation of a, the pressure change is absorbed, and the inside of the piezoelectric element holding portion 24 can be always maintained at a constant pressure.

The flexible portion 24a of the piezoelectric element holding portion 24
The sealing film 31 may be formed of, for example, a light-transmitting member such as an acrylic resin, so that displacement can be detected while the piezoelectric element 300 is sealed in the piezoelectric element holding portion 24. it can. That is, the inspection of the piezoelectric element 300 can be always performed.

(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 nozzle plate 16 is joined to one surface of the flow path forming substrate 10 as a nozzle forming member having the nozzle openings 15, but the present invention is not limited to this. The nozzle forming member may have a multilayer structure including another substrate having a nozzle communication hole or the like for communicating the nozzle opening with the pressure generating chamber.

In each of the above embodiments, the thin film type ink jet recording head manufactured by applying the film forming and lithography processes is 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 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 and the like, and is mounted on an ink jet recording apparatus. FIG.
FIG. 1 is a schematic view showing an example of the ink jet recording apparatus.

As shown in FIG. 14, the recording head units 1A and 1B having the ink jet recording heads are
Cartridges 2A and 2B constituting ink supply means are detachably provided. A carriage 3 on which the recording head units 1A and 1B are mounted is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. I have. 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, 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.

[0122]

As described above, according to the present invention, the reservoir is formed by joining the reservoir forming substrate constituting at least a part of the reservoir on the flow path forming substrate. Simplification can be achieved, and the number of manufacturing steps can be reduced and the manufacturing cost can be improved. In addition, since the reservoir forming substrate also functions as a cap member that blocks the piezoelectric element from the outside, it is possible to prevent the piezoelectric element from being broken due to an external environment, and to improve durability. Further, by connecting the piezoelectric element and the external wiring on the reservoir forming substrate, there is an effect that the head can be reduced in size.

[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.

FIG. 3 is a plan view and a cross-sectional view illustrating a modification of the ink jet recording head according to the first embodiment of the present invention.

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

5A and 5B are a plan view and a cross-sectional view illustrating a modified example of the inkjet recording head according to the first embodiment of the present invention.

FIG. 6 is a plan view and a side view of an ink jet recording head according to a second embodiment of the present invention.

FIG. 7 is a plan view and a cross-sectional view of an ink jet recording head according to Embodiment 3 of the present invention.

FIG. 8 is a plan view and a cross-sectional view illustrating a modification of the ink jet recording head according to Embodiment 3 of the present invention.

FIG. 9 is a plan view and a cross-sectional view of an ink jet recording head according to Embodiment 4 of the present invention.

FIG. 10 is a sectional view of a main part of an ink jet recording head according to a fifth embodiment of the invention.

FIG. 11 is a sectional view showing a modified example of the ink jet recording head according to Embodiment 5 of the present invention.

FIG. 12 is a plan view and a cross-sectional view of an ink jet recording head according to Embodiment 6 of the present invention.

FIG. 13 is a cross-sectional view showing a modification of the ink jet recording head according to Embodiment 6 of the present invention.

FIG. 14 is a schematic view 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 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 30, 30A compliance substrate 31 sealing film 32 fixing plate Reference Signs List 60 lower electrode film 70 piezoelectric film 80 upper electrode film 100 reservoir 300 piezoelectric element

Claims (30)

[Claims] A nozzle forming member having a plurality of nozzle openings for discharging ink; a flow passage forming substrate joined to the nozzle forming member and defining a pressure generating chamber communicating with the nozzle openings, respectively; A piezoelectric element provided on a surface of the flow path forming substrate opposite to a surface to which the nozzle forming member is joined and causing a pressure change in the pressure generating chamber; A reservoir forming substrate having a reservoir portion that forms at least a part of a reservoir that communicates with the pressure generation chambers and supplies ink to each pressure generation chamber is joined to a surface of the substrate on which the piezoelectric element is formed. An ink jet recording head characterized in that: 2. The communication device according to claim 1, wherein the flow path forming substrate has a communicating portion that communicates with the reservoir portion of the reservoir forming substrate and forms a part of the reservoir together with the reservoir portion. Ink jet recording head. 3. The ink-jet system according to claim 1, wherein the reservoir and each of the pressure generating chambers are connected to each other via an ink supply path having a flow path relatively narrower than the reservoir. Recording head. 4. The ink supply device according to claim 1, wherein the reservoir portion of the reservoir forming substrate is connected to an ink introduction port for supplying ink to the reservoir by communicating with the outside. Characteristic inkjet recording head. 5. The piezoelectric device according to claim 1, wherein the reservoir forming substrate has a space in a region facing the piezoelectric element, the space being such that the movement of the reservoir forming substrate is not hindered. An ink jet recording head having an element holding portion. 6. The ink jet recording apparatus according to claim 5, wherein the piezoelectric element holding section is partitioned by partition walls for each piezoelectric element, and the partition walls are joined to the flow path forming substrate. head. 7. The ink jet recording head according to claim 1, wherein a part of the reservoir portion of the reservoir forming substrate has a flexible portion having flexibility. 8. The ink jet recording head according to claim 7, wherein the flexible portion is provided by joining a flexible member. 9. The method according to claim 8, wherein the flexible member comprises:
An ink jet recording head comprising a metal or ceramic thin film. 10. The ink jet recording head according to claim 8, wherein said flexible member is made of a resin material. 11. The ink jet recording head according to claim 10, wherein the resin material is selected from the group consisting of a fluororesin, a silicone resin and a silicone rubber. 12. The flexible member according to claim 8, wherein another substrate having a through hole is joined to the flexible member at least in a region facing the flexible portion. Ink jet recording head. 13. A detection through-hole according to claim 1, wherein at least a part of a region of said reservoir forming substrate facing said piezoelectric element is provided with a detection through-hole for detecting a displacement of said piezoelectric element. An ink jet recording head. 14. The piezoelectric element holding portion according to claim 13, wherein the piezoelectric element holding portion is provided so as to penetrate the reservoir forming substrate, is sealed with a transparent member, and also serves as the detection through hole. Inkjet recording head. 15. The ink jet recording head according to claim 14, wherein the transparent member forms the flexible portion. 16. The wiring according to claim 1, wherein the wiring on the flow path forming substrate drawn from the piezoelectric element is provided in a region of the reservoir forming substrate opposite to the flow path forming substrate. An ink-jet recording head, comprising: a connection wiring for connecting the wiring provided with the wiring; and an external wiring connected to the wiring provided in a region on the opposite side of the reservoir forming substrate. 17. An ink jet recording head according to claim 16, wherein said connection wiring is formed by wire bonding. 18. An ink jet recording head according to claim 16, wherein said connection wiring is formed of a thin film. 19. The method according to claim 16, wherein
In the reservoir forming substrate, in a region corresponding to the piezoelectric element, a communication hole that penetrates the reservoir forming substrate and communicates with the outside is provided, and the connection wiring is provided through the communication hole. Characteristic inkjet recording head. 20. The ink jet recording head according to claim 19, wherein the communication hole is provided in a region of the pressure generating chamber facing the peripheral wall on the reservoir side. 21. The ink jet recording head according to claim 19, wherein the communication hole is provided in a region of the pressure generating chamber facing a peripheral wall on the nozzle opening side. 22. The method according to claim 16, wherein
An ink jet recording head, wherein a drive circuit for driving the piezoelectric element is mounted on the reservoir forming substrate, and the connection wiring is connected to the drive circuit. 23. An ink jet recording head according to claim 22, wherein said drive circuit is a semiconductor integrated circuit. 24. The ink jet recording head according to claim 1, wherein the nozzle forming member is formed of substantially the same material as the channel forming substrate and the reservoir forming substrate. 25. An ink jet recording head according to claim 1, wherein said nozzle forming member is a nozzle plate having a nozzle opening. 26. The ink jet recording head according to claim 1, wherein a thermal expansion coefficient of the reservoir forming substrate is substantially the same as a thermal expansion coefficient of the flow path forming substrate. 27. The ink jet recording head according to claim 1, wherein a material of the reservoir forming substrate is selected from the group consisting of silicon, glass, and ceramics. 28. An ink jet printer according to claim 1, wherein said pressure generating chamber is formed on a ceramic substrate, and each layer of said piezoelectric element is formed by pasting or printing a green sheet. Type recording head. 29. 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: 30. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.