JPH11300957A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the operation inferiority of a piezoelectric vibrator formed by film forming technique caused by an external environmental change of humidity or the like. SOLUTION: A recording head is equipped with a flow channel forming substrate 10 having ink emitting nozzle orifices 17 and the pressure generating chambers 12 communicating with the nozzle orifices 17 formed thereto and the piezoelectric vibrators 300 provided to one surface of the flow channel forming substrate 10 to generate a pressure change in the pressure generating chambers. In this case, the cap member bonded to the flow channel forming substrate 10 on the side of the piezoelectric vibrators 300 and ensuring the space not obstructing the motion of the vibrators to seal the space, the heating means 120 provided in the cap member 110 and the moisture absorbing agent 130 absorbing moisture evaporated by the heat of the heating means provided in the cap member 110 are provided to effectively remove moisture in the cap member 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head which expands and contracts a part of a pressure generating chamber communicating with a nozzle opening by an actuator which bends and vibrates to discharge ink droplets from the nozzle opening.

[0002]

2. Description of the Related Art A part of a pressure generating chamber which communicates with a nozzle opening for discharging ink droplets is constituted by a vibrating plate. There are two types of ink-jet recording heads that eject ink droplets from a piezoelectric vibrator, one that uses a longitudinal vibration mode piezoelectric vibrator that expands and contracts in the axial direction of the piezoelectric vibrator, and the other that uses a flexural vibration mode piezoelectric vibrator. Has been put to practical use.

In the former method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric vibrator into contact with the vibrating plate, so that a head suitable for high-density printing can be manufactured. A complicated process of cutting the piezoelectric vibrators into a comb-tooth shape in accordance with the arrangement pitch of the nozzle openings, and a work of positioning and fixing the separated piezoelectric vibrators in the pressure generating chambers, which complicates the manufacturing process. There is.

On the other hand, in the latter, a piezoelectric vibrator 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. However, due to the use of flexural vibration, a certain area is required, and there is a problem that high-density arrangement is difficult.

On the other hand, in order to 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 this piezoelectric material layer is cut into a shape corresponding to the pressure generating chambers by lithography, and a piezoelectric vibrator is formed so as to be independent for each pressure generating chamber.

[0006] According to this, the work of attaching the piezoelectric vibrator to the diaphragm is not required, and the precision of the lithography method is used.
In addition to the fact that the piezoelectric vibrator can be manufactured by a simple and simple method, there is an advantage that the thickness of the piezoelectric vibrator can be reduced and high-speed driving is possible. In this case, the piezoelectric vibrator corresponding to each pressure generating chamber can be driven by providing at least only the upper electrode for each pressure generating chamber while the piezoelectric material layer is provided on the entire surface of the vibration plate.

[0007]

However, when the piezoelectric vibrator is formed by sputtering a piezoelectric material, the piezoelectric vibrator is driven by the same voltage as the piezoelectric vibrator formed by firing a green sheet. When a high electric field is applied by the thickness of the thin film and the moisture in the air is absorbed, the leak current between the drive electrodes tends to increase, eventually leading to dielectric breakdown, causing fatal damage to the piezoelectric active part. There is a problem.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide an ink jet recording head which eliminates a malfunction caused by a change in an external environment such as humidity of a piezoelectric vibrator formed by a film forming technique. .

[0009]

According to a first aspect of the present invention, there is provided a flow path forming substrate having a nozzle opening for discharging ink, a pressure generating chamber communicating with the nozzle opening, and In an ink jet recording head comprising a piezoelectric vibrator provided on one surface of the flow path forming substrate and generating a pressure change in the pressure generating chamber, the piezoelectric recording head is joined to the piezoelectric vibrator side of the flow path forming substrate, A cap member that seals the space while securing a space that does not hinder the movement, a heating means provided in the cap member, and water evaporating due to heat generated by the heating means provided in the cap member. An ink jet recording head, comprising: a moisture absorbing agent that absorbs.

[0010] In the first aspect, the moisture in the cap member is evaporated by the heat generated by the heat generating means and absorbed by the hygroscopic agent, thereby effectively drying the atmosphere in the cap member.

According to a second aspect of the present invention, in the first aspect, the heat generating means is a drive circuit for driving a piezoelectric active portion of the piezoelectric vibrator. It is in.

In the second aspect, the moisture in the cap member is effectively absorbed by the moisture absorbent by evaporating the moisture by the heat generated by the drive circuit.

According to a third aspect of the present invention, in the first aspect, a dummy pressure generating chamber to which ink is not ejected is provided adjacent to the pressure generating chamber, and wherein the heat generating means includes the dummy pressure generating chamber. And a piezoelectric active portion of the piezoelectric vibrator provided in a region facing the ink jet recording head.

In the third aspect, the atmosphere inside the cap member is effectively absorbed by the moisture absorbent by evaporating the water by the heat generated by the piezoelectric active portion.

A fourth aspect of the present invention is the ink jet recording head according to any one of the first to third aspects, wherein the hygroscopic agent is a hygroscopic film coated on an inner surface of the cap member. It is in.

In the fourth aspect, the atmosphere in the cap member is effectively dried by the moisture absorbing film.

According to a fifth aspect of the present invention, in the first aspect, the heat generating means is a heat generating film coated on an inner surface of the cap member, and the moisture absorbent is provided on the flow path forming substrate side. Ink-jet recording head.

In the fifth aspect, the moisture in the cap member is effectively absorbed by the moisture absorbent by evaporating the moisture by the heat generated by the heating film.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the bonding between the cap member and the flow path forming substrate is performed via an adhesive layer. ,
An ink jet recording head is provided continuously from a joining portion to an inner surface of the cap member.

According to the sixth aspect, intrusion of moisture from the interface between the cap member and the adhesive layer is prevented.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the cap member is a resin molded product, and the joining between the cap member and the flow path forming substrate is performed by the resin molded product. And an ink-jet recording head which is formed through an adhesive layer having a composition similar to that of the above-mentioned material.

According to the seventh aspect, intrusion of moisture from the interface between the cap member and the adhesive layer is prevented.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric vibrator is formed by film formation. And an ink jet recording head formed by a lithography method.

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

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, a reservoir communicating with the pressure generating chamber is defined in the flow path forming substrate, and the nozzle having the nozzle opening is defined. An ink jet recording head is characterized in that the plates are joined.

According to the ninth aspect, an ink jet recording head that discharges ink from the nozzle openings can be easily realized.

According to a tenth aspect of the present invention, in any one of the first to eighth aspects, the flow path forming substrate includes a common ink chamber for supplying ink to the pressure generating chamber, A flow path unit for forming a flow path communicating with the nozzle opening is joined to the ink jet recording head.

In the tenth aspect, ink is ejected from the nozzle openings via the flow path unit.

[0029]

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

(Embodiment 1) FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention, and FIG. 2 is a cross section of one of the pressure generating chambers in the longitudinal direction and the width direction. It is a figure showing a structure.

As shown in the figure, the flow path forming substrate 10 is a silicon single crystal substrate having a plane orientation of (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 of 1-2 μm in thickness made of silicon dioxide formed by thermal oxidation in advance.

On the other hand, the opening surface of the flow path forming substrate 10 is anisotropically etched on a silicon single crystal substrate,
Row 1 of pressure generating chambers 12 partitioned by a plurality of partition walls 11
3 are arranged in a substantially U-shape so as to surround three rows of two rows and two rows 13 of the two pressure generating chambers 12, and each pressure generating chamber 12 and the reservoir 14 are communicated with a constant fluid resistance. Ink supply ports 15 are formed. In addition,
The reservoir 1 is located at a substantially central portion of the reservoir 14 from outside.
4 is provided with an ink introduction hole 16 for supplying ink.

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 ink supply port 15 communicating with one end of each pressure generating chamber 12 is formed shallower than the pressure generating chamber 12. That is, the ink supply port 15
Is formed by etching (half-etching) the silicon single crystal substrate halfway 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 18 in which a nozzle opening 17 communicating with the ink supply port 15 of each pressure generating chamber 12 on the opposite side is formed is fixed via an adhesive or a heat welding film. The thickness of the nozzle plate 18 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 18 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.

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 17 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 17 need to be formed with a diameter of several tens of μm with high precision.

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 0.5 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. (Piezoelectric element) 300 is constituted. Here, the piezoelectric vibrator 300 refers to a portion including the lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80. Generally, the piezoelectric vibrator 30
0 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 vibrator 300, and the upper electrode film 80 is used as an individual electrode of the piezoelectric vibrator 300. Absent. In any case, the piezoelectric active portion is formed for each pressure generating chamber.

Here, a process for forming the piezoelectric film 70 and the like on the flow path forming substrate 10 made of a silicon single crystal substrate will be described with reference to FIGS.

As shown in FIG. 3A, first, a silicon single crystal substrate wafer serving as the flow path forming substrate 10 is
Thermal oxidation is performed in a diffusion furnace at 0 ° C. to form an elastic film 50 made of silicon dioxide.

Next, as shown in FIG. 3B, a lower electrode film 60 is formed by sputtering. Pt or the like is preferable as the material of the lower electrode film 60. This is because a piezoelectric film 70 to be described later, which is formed by sputtering or a sol-gel method, has a thickness of 600 to 100 in an air atmosphere or an oxygen atmosphere after the film formation.
This is because it is necessary to perform crystallization by firing at a temperature of about 0 ° C. That is, the material of the lower electrode film 60 must be able to maintain conductivity at such a high temperature and in an oxidizing atmosphere. In particular, when PZT is used for the piezoelectric film 70, the conductivity of the material by diffusion of PbO is increased. It is desirable that there is little change in sex, and Pt is preferred for these reasons.

Next, as shown in FIG. 3C, a piezoelectric film 70 is formed. Sputtering can be used to form the piezoelectric film 70. In the present embodiment, however, a so-called sol in which a metal organic substance is dissolved and dispersed in a solvent is applied, dried, gelled, and fired at a high temperature. A so-called sol-gel method for obtaining a piezoelectric film 70 made of a metal oxide is used. As a material for the piezoelectric film 70, a lead zirconate titanate (PZT) -based material is suitable when used in an ink jet recording head.

Next, as shown in FIG. 3D, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and can use many metals such as Al, Au, Ni, and Pt, and a conductive oxide. In this embodiment,
Pt is formed by sputtering.

Next, as shown in FIG. 3E, the upper electrode film 80 and the piezoelectric film 70 are patterned so that the piezoelectric vibrators are provided for each of the pressure generating chambers 12, respectively. FIG. 3E shows a case where the piezoelectric film 70 is patterned with the same pattern as the upper electrode film 80. However, as described above, the piezoelectric film 70 does not necessarily need to be patterned. This is because, when a voltage is applied using the pattern of the upper electrode film 80 as an individual electrode, an electric field is applied only between each upper electrode film 80 and the lower electrode film 60 which is a common electrode. This has no effect. However, in this case, it is necessary to apply a large voltage to obtain the same excluded volume. Therefore, it is preferable to pattern the piezoelectric film 70 as well. After that, the lower electrode film 60 may be patterned to remove unnecessary portions, for example, the vicinity of the inside of the edges on both sides in the width direction of the pressure generating chamber 12. The removal of the lower electrode film 60 is not necessarily performed, and when it is removed, the thickness may be reduced without removing all of the lower electrode film 60.

Here, the patterning is performed by forming a resist pattern and then performing etching or the like.

The resist pattern is formed by applying a negative resist by spin coating or the like and performing exposure, development, and baking using a mask having a predetermined shape. In addition,
Of course, a positive resist may be used instead of the negative resist.

The etching is performed using a dry etching apparatus, for example, an ion milling apparatus. In addition,
After the etching, the resist pattern is removed using an ashing device or the like.

As a dry etching method, a reactive etching method or the like may be used other than the ion milling method. It is also possible to use wet etching instead of dry etching, but the patterning accuracy is somewhat inferior to the dry etching method, and the upper electrode film 8
Since the material of 0 is also limited, it is preferable to use dry etching.

Next, as shown in FIG. 4A, an insulator layer 90 is formed so as to cover the periphery of the upper electrode film 80 and the side surfaces of the piezoelectric film 70. In this embodiment, a negative photosensitive polyimide is used for the insulator layer 90.

Next, as shown in FIG. 4B, by patterning the insulator layer 90, a contact hole 90a is formed in a portion facing each communication portion 14. This contact hole 90a is provided with a lead electrode 100 described later.
And the upper electrode film 80.

Next, for example, a lead electrode 100 is formed by depositing a conductor such as Cr-Au on the entire surface and then patterning it.

The above is the film forming process. After forming the film in this manner, as shown in FIG. 4C, the silicon single crystal substrate is subjected to anisotropic etching with the above-described alkali solution to form the pressure generating chamber 12 and the like.

The elastic film 50 on the side of the piezoelectric active section 320 formed as described above has a space that does not hinder the driving of the piezoelectric active section 320.
Is provided with a cap member 110 (FIG. 1).
And FIG. 2).

The cap member 110 has a partition wall for partitioning a concave portion 112 made of a space not in contact with the piezoelectric active portion 320 in a region opposed to each row 13 of the pressure generating chambers 12 on the joint side with the elastic film 50. 111. The cap member 110 is fixed to the surface of the elastic film 50 by an adhesive or the like, and seals the piezoelectric active portion 320 in each recess 112. In the present embodiment, the cap member 110 is adhered on the elastic film 50. However, the present invention is not limited to this.
It may be made to adhere to. In any case, the cap member 110 can be securely bonded.

Each recess 1 of the cap member 110
On the elastic film 50 in the inside 12, a heating part 120 for evaporating water in the concave part 112 is provided. This heating part 12
Numeral 0 denotes a drive circuit (IC) for driving the piezoelectric active section 320 by connecting the lead electrodes 100 from the respective piezoelectric active sections 320 in the present embodiment, and generates heat when the drive circuit is driven. The water in the recess 112 evaporates.

In the present embodiment, the heat generating section 120 is
The pressure generating chamber is provided in a region facing the peripheral wall at the longitudinal end portion, but is not limited to this, provided at any position in the recess 112 as long as the position does not hinder the driving of the piezoelectric active portion 320. You may.

On the other hand, each recess 112 of the cap member 110
A moisture absorbing portion 130 made of a moisture absorbing agent that absorbs moisture evaporated by the heat generated by the heat generating portion 120 is provided in a layer on the inner surface.

The moisture absorbing agent used in the moisture absorbing section 130
For example, silica gel, slaked lime, quicklime, polyvinyl chloride
Alcohol, cellulose diacetate, hydroxy lower alcohol
Hydrophilic acrylates such as
Rate polymer, CaF _Two, MgF _TwoOf alkaline earth metals
Boride film, cobalt chloride, and vinyl acetate or
Cellulose plastics and the like can be mentioned.

Although the moisture absorbing portion 130 is formed in a layered form in the present embodiment, the shape is not particularly limited as long as the shape does not hinder the driving of the piezoelectric active portion 320.

In such a configuration, the piezoelectric active section 320
Is sealed by the cap member 110, so that operation failure due to the external environment can be prevented. In addition, moisture remaining in the concave portion 112 after the cap member 110 is joined by evaporating the moisture in the concave portion 112 sealing the piezoelectric active portion 320 by the heat generated by the heat generating portion 120 and absorbing the moisture by the moisture absorbing portion 130. Or the cap member 110
Moisture flowing from a joint between the elastic film 50 and the elastic film 50 can be efficiently removed. Therefore, it is possible to prevent a malfunction of the piezoelectric active section 320 caused by moisture.

In the above-described series of film formation and anisotropic etching, a large number of chips are simultaneously formed on one wafer, and after the process is completed, a flow path of one chip size as shown in FIG. It is divided for each forming substrate 10. Also,
The divided flow path forming substrate 10 is sequentially bonded to the nozzle plate 18 and the cap member 110 to form an ink jet recording head. Then, it is fixed to the holder 105, mounted on a carriage, and incorporated in an ink jet recording apparatus.

The ink-jet head thus configured takes in ink from an ink inlet 16 connected to external ink supply means (not shown), fills the inside from the reservoir 14 to the nozzle opening 17 with ink, and then drives the drive circuit. A voltage is applied between the lower electrode film 60 and the upper electrode film 80 via the lead electrode 100 in accordance with the recording signal of, and the elastic film 50 and the piezoelectric film 70 are bent and deformed. Is increased, and ink droplets are ejected from the nozzle opening 17.

(Embodiment 2) FIG. 5 is a sectional view of a main part of an ink jet recording head according to Embodiment 2.

In this embodiment, instead of the drive circuit, the piezoelectric active portion provided in the region facing the dummy pressure generating chamber is used as the heat generating portion 120A, and the water in the concave portion 112 is evaporated by the heat generated by the driving. Except for this, it is the same as the first embodiment.

That is, as shown in FIG. 5, the pressure generation chamber located at one end of the row of the pressure generation chambers 12 is a dummy pressure generation chamber 12A, and this dummy pressure generation chamber 12A
The piezoelectric active portion 320A, which is the heat generating portion 120A of the present embodiment, is provided in a region opposed to.

In such a configuration, the water in the concave portion 112 can be evaporated by the heat generated by driving the piezoelectric active portion 320A which is the heat generating portion 120A. Therefore, similarly to the first embodiment, there is an effect that an operation failure of the piezoelectric active portion caused by moisture can be prevented.

(Embodiment 3) FIG. 6 is a sectional view of an essential part of an ink jet recording head according to Embodiment 3.

In this embodiment, the heat generating portion 120 B is provided on the inner surface of the concave portion 112 of the cap member 110, and the heat absorbing portion 130 B is provided.
This is an example in which A is provided on the elastic film 50.

As shown in FIG. 6, the heat generating portion 120B of this embodiment is a heat generating layer provided on the inner surface of the concave portion 112 of the cap member 110, and generates heat by flowing an electric current. The material of the heating element is not particularly limited as long as it is a material that generates heat when an electric current flows, and examples thereof include tantalum, tantalum nitride, tantalum silicate, nichrome, and tungsten.

Further, the moisture absorbing portion 130 A is provided between the piezoelectric active portions 320 on the elastic film 50 in a region facing the partition 11 of the flow path forming substrate 10 over the longitudinal direction of the piezoelectric active portions 320. Provided, and the same hygroscopic agent as in the above-described embodiment is used.

In this embodiment, the moisture absorbing portion 130A is provided between the piezoelectric active portions 320, but is not limited to this. For example, the moisture absorbing portion 130A is provided over the entire circumference of the piezoelectric active portion 320. Any configuration may be used as long as the position does not hinder the driving of the piezoelectric body active unit 320.

With such a configuration, the water in the concave portion 112 of the cap member 110 evaporates due to the heat generated by the heat generating portion 120B, and the evaporated water is absorbed by the moisture absorbing portion 130A. Therefore, similarly to the above-described embodiment, it is possible to prevent the malfunction of the piezoelectric active portion caused by moisture.

(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 cap member 110 and the flow path forming substrate 10 are fixed to each other with an adhesive. At this time, as shown in FIG. May be provided continuously to the inner surface of the cap member 110, and the above-described moisture absorbing portion 130 or the heat generating portion 120 may be provided on the adhesive layer 140. Thereby, the cap member 110 and the adhesive layer 140
It is possible to prevent moisture and the like from entering the space from the interface with the interface. In this case, the cap member 110 is most preferably provided on the entire inner surface, but it is needless to say that the effect is obtained even if the cap member 110 is formed in a certain area of the inner surface.

The material of the cap member 110 is not particularly limited. For example, the cap member 110 may be formed of a resin material. In this case, it is preferable that the joining of the cap member 110 and the flow path forming substrate 10 is performed via an adhesive having a composition similar to the material of the cap member 110. Thereby, when the adhesive is cured, the adhesive and the cap member 110 are integrated, and it is possible to prevent moisture from passing through the interface between the adhesive and the cap member 110.

Further, for example, in the above-described embodiment, the reservoir 14 is formed together with the pressure generating chamber 12 in the flow path forming substrate 10, but a member forming the common ink chamber is provided so as to overlap the flow path forming substrate 10. You may.

FIG. 8 shows a partial cross section of the ink jet recording head thus constructed. In this embodiment, the sealing plate 160, the common ink chamber forming plate 170, the thin plate 180, and the ink chamber side plate 190 are sandwiched between the nozzle substrate 18A in which the nozzle openings 17A are formed and the flow path forming substrate 10A. A nozzle communication port 31 that communicates with the pressure generating chamber 12A and the nozzle opening 17A is provided so as to penetrate them. That is, the common ink chamber 32 is defined by the sealing plate 160, the common ink chamber forming plate 170, and the thin plate 180, and each of the pressure generating chambers 3 </ b> A and the common ink chamber 32 are formed in the sealing plate 160. The ink is communicated via the ink communication hole 33. Further, the supply plate 32 is provided in the sealing plate 160.
Also, an ink introduction hole 34 for introducing ink from outside is formed. Also, the thin plate 180 and the nozzle substrate 18
A is formed between the ink chamber side plate 190 and the ink chamber side plate 190 at a position facing each of the supply ink chambers 32. The thin wall 180 is allowed to absorb, thereby preventing unnecessary positive or negative pressure from being applied to the other pressure generating chambers via the common ink chamber 32. it can. The thin plate 18
0 and the ink chamber side plate 190 may be formed integrally.

Also in such an embodiment, the above-mentioned cap member is fixed to the surface of the flow path forming substrate 10A opposite to the opening surface, so that the piezoelectric active portion caused by a change in the external environment can be obtained. Can be prevented from malfunctioning. Further, by providing a heat generating portion for evaporating the internal moisture and a moisture absorbing portion for absorbing the evaporated moisture inside the cap member, the moisture inside the cap member can be removed, and the piezoelectric active material generated by the moisture can be removed. It is possible to prevent malfunction of the unit.

In each of the embodiments described above, a thin-film type ink jet recording head which can be manufactured by applying a film forming and lithography process is described as an example.
Of course, the present invention is not limited to this. For example, a piezoelectric film is formed by laminating substrates to form a pressure generating chamber, or a piezoelectric film is formed by attaching a green sheet or by screen printing, or a piezoelectric film formed by crystal growth. The present invention can be applied to ink jet recording heads having various structures, such as those that form a recording medium.

Further, in each of the above-described embodiments, the connection portion between the upper electrode film and the lead electrode may be provided at any place, and may be at any end or the center of the pressure generating chamber. .

Further, the example in which the insulator layer is provided between the piezoelectric vibrator and the lead electrode has been described. However, the present invention is not limited to this. The conductive film may be thermally welded, and the anisotropic conductive film may be connected to the lead electrode, or may be connected using various bonding techniques such as wire bonding.

As described above, the present invention can be applied to ink-jet recording heads having various structures, as long as the gist of the present invention is not contradicted.

[0083]

As described above, according to the present invention, by providing a cap member having a concave portion having such a space that does not hinder the driving of the piezoelectric active portion, the piezoelectric active portion caused by the external environment is provided. An operation failure can be prevented. Further, by providing a heat generating means for evaporating water in the concave portion of the cap member and a moisture absorbent for absorbing the evaporated water, the water in the concave portion can be effectively removed, and generated by the water. This has the effect of preventing operation failure of the piezoelectric active portion.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a cross-sectional structure of an ink jet recording head according to an embodiment of the present invention in a longitudinal direction of pressure generating chambers and an arrangement direction of the pressure generating chambers.

FIG. 3 is a view showing a thin film manufacturing process according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a thin film manufacturing process according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a cross-sectional structure of an ink jet recording head according to a second embodiment of the present invention in a direction in which pressure generating chambers are arranged.

FIG. 6 is a diagram showing a cross-sectional structure of an ink jet recording head according to a third embodiment of the present invention in a direction in which pressure generating chambers are arranged.

FIG. 7 is a cross-sectional view showing a main part of an ink jet recording head according to another embodiment of the present invention.

FIG. 8 is a diagram showing a cross-sectional structure in a longitudinal direction of a pressure generating chamber of an ink jet recording head according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 flow path forming substrate 12 pressure generating chamber 14 reservoir 18 nozzle plate 50 elastic film 60 lower electrode film 70 piezoelectric film 80 upper electrode 90 insulating layer 90a contact hole 100 lead electrode 105 holder 110 cap member 112 recess 120, 120A, 120B Heating part 130, 130A Moisture absorbing part 140 Adhesive layer 320 Piezoelectric active part

Claims (10)

[Claims] 1. A flow path forming substrate having a nozzle opening for discharging ink, a pressure generating chamber communicating with the nozzle opening, and a pressure generating chamber provided on one surface of the flow path forming substrate. An ink jet recording head comprising a piezoelectric vibrator that causes a change, wherein the space is joined to the flow path forming substrate on the side of the piezoelectric vibrator, and the space is sealed so as not to hinder its movement. An ink jet recording head, comprising: a cap member; a heat generating means provided in the cap member; and a moisture absorbent provided in the cap member for absorbing moisture evaporated by heat generated by the heat generating means. 2. An ink jet recording head according to claim 1, wherein said heating means is a drive circuit for driving a piezoelectric active portion of said piezoelectric vibrator. 3. A pressure generating chamber according to claim 1, further comprising a dummy pressure generating chamber to which ink is not discharged, adjacent to said pressure generating chamber, wherein said heat generating means is provided in a region opposed to said dummy pressure generating chamber. An ink jet recording head, which is a piezoelectric active portion of the piezoelectric vibrator. 4. The ink jet recording head according to claim 1, wherein the moisture absorbing agent is a moisture absorbing film coated on an inner surface of the cap member. 5. The ink-jet system according to claim 1, wherein said heat generating means is a heat generating film coated on an inner surface of said cap member, and said moisture absorbent is provided on said flow path forming substrate side. Recording head. 6. The cap member according to claim 1, wherein the cap member and the flow path forming substrate are joined via an adhesive layer. An ink jet recording head, which is provided continuously to the inner surface. 7. The cap member according to claim 1, wherein the cap member is a resin molded product, and a joining between the cap member and the flow path forming substrate has a composition similar to a material of the resin molded product. An ink jet recording head, wherein the recording is performed via an adhesive layer. 8. The pressure generating chamber according to claim 1, wherein the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric vibrator is formed by film formation and lithography. An ink jet recording head, characterized in that: 9. The flow path forming substrate according to claim 1, wherein a reservoir communicating with the pressure generating chamber is defined in the flow path forming substrate, and a nozzle plate having the nozzle opening is joined thereto. Inkjet recording head. 10. The flow path forming substrate according to claim 1, wherein the flow path forming substrate has a common ink chamber for supplying ink to the pressure generating chamber, and a flow path communicating between the pressure generating chamber and the nozzle opening. An ink jet recording head, wherein a flow path unit forming a path is joined to the ink jet recording head.