JP3494219B2 - Ink jet recording head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a vibrating plate which constitutes a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets, and a piezoelectric element is provided through the vibrating plate to displace the piezoelectric element. The present invention relates to an ink jet type recording head and an ink jet type recording apparatus for ejecting ink droplets.

[0002]

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

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

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

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

According to this, the work of attaching the piezoelectric element to the diaphragm becomes unnecessary, and not only the piezoelectric element can be built by a precise and simple method such as a lithography method, but also the thickness of the piezoelectric element can be reduced. It has the advantage that it can be made thin and can be driven at high speed.

Further, in such an ink jet recording head, since the pressure generating chamber is formed penetrating in the thickness direction by etching from the surface of the substrate opposite to the piezoelectric element, the dimensional accuracy is improved. The high pressure generating chamber can be relatively easily and densely arranged.

[0008]

However, in such an ink jet recording head, when a relatively large substrate having a diameter of about 6 to 12 inches is used as the substrate for forming the pressure generating chamber, Due to a problem such as handling, the thickness of the substrate has to be increased, and the depth of the pressure generating chamber is accordingly increased. Therefore, unless the thickness of the partition that divides each pressure generating chamber is increased, sufficient rigidity cannot be obtained, crosstalk occurs, and desired ejection characteristics cannot be obtained. Also,
If the thickness of the partition wall is increased, the nozzles cannot be arranged at a high arrangement density, so that there is a problem that high resolution printing quality cannot be achieved.

In view of such circumstances, it is an object of the present invention to provide an ink jet type recording head and an ink jet type recording apparatus capable of improving the rigidity of a partition wall and arranging the pressure generating chambers at a high density. To do.

[0010]

[0011]

[0012]

[Means for Solving the Problems ] The present invention for solving the above problems
A first aspect of the invention is a flow path forming substrate having a silicon layer made of at least single crystal silicon and defining a pressure generating chamber communicating with a nozzle opening, and a vibration plate forming a part of the pressure generating chamber. In an ink jet recording head provided with a piezoelectric element that is provided in a region facing the pressure generating chamber via the piezoelectric element and causes a pressure change in the pressure generating chamber, the ink jet recording head is bonded to the piezoelectric element side of the flow path forming substrate. 1
A bonded substrate made of a single crystal silicon, the nozzle opening is provided in the bonded substrate, and the pressure generating chamber penetrates the flow channel forming substrate on one side of the flow channel forming substrate. In the ink jet recording head, a reservoir which is formed without any means and which supplies ink to the pressure generating chamber is formed on the other surface side of the flow path forming substrate.

In the first aspect, the pressure generating chambers can be formed relatively shallow, and the rigidity of the partition wall that partitions each pressure generating chamber is improved. Further, a reservoir having a volume sufficiently larger than the volume of the pressure generating chamber is provided, and the internal pressure is absorbed by the ink itself in the reservoir.

A second aspect of the present invention, in a first aspect, an ink jet recording head near, characterized in that said reservoir is in direct communication with the pressure generating chamber
It

In the second aspect, ink is directly supplied from the reservoir to each pressure generating chamber.

According to a third aspect of the present invention, in the first aspect, an ink communication path communicating with one longitudinal end of the pressure generating chamber is formed on one surface side of the flow path forming substrate, An ink jet recording head is characterized in that a reservoir is communicated with the ink communication passage.

In the third aspect, since ink is supplied from the reservoir to each pressure generating chamber through the ink communication passage, even if the cross-sectional area of the communication portion between the reservoir and the ink communication passage varies, the ink will remain in the narrow portion. It is possible to control the resistance of the pressure generating chambers, and it is possible to reduce variations in ink ejection characteristics between the pressure generating chambers.

A fourth aspect of the present invention is the ink jet recording head according to the third aspect, characterized in that the ink communication passage is provided for each of the pressure generating chambers.

In the fourth aspect, ink is supplied from the reservoir to each pressure generating chamber via the ink communication passage provided for each pressure generating chamber.

A fifth aspect of the present invention is the ink jet recording head according to the third aspect, characterized in that the ink communication passage is continuously provided in a direction parallel to the pressure generating chambers. It is in.

In the fifth aspect, ink is supplied from the reservoir to each pressure generating chamber via the common ink communication passage.

[0022] A sixth aspect of the present invention, in the first to fifth one embodiment, the longitudinal end portion side opposite to the reservoir of the pressure generating chamber, the nozzle opening and the pressure generating chamber An inkjet recording head is characterized in that a nozzle communication path that communicates with and is provided.

In the sixth aspect, the ink is stably supplied from the reservoir to the pressure generating chamber, and the ink is satisfactorily ejected from the nozzle opening.

A seventh aspect of the present invention is the ink jet recording head according to the sixth aspect, characterized in that the nozzle communication passage is formed by removing the diaphragm.

In the seventh aspect, the nozzle communication passage can be easily formed.

An eighth aspect of the present invention is the ink jet recording head according to the sixth or seventh aspect, characterized in that the inner surface of the nozzle communication passage is covered with an adhesive.

In the eighth aspect, peeling of the diaphragm due to the ink passing through the nozzle communication passage is prevented.

A ninth aspect of the present invention is the ink jet recording head according to any one of the first to eighth aspects, wherein an integrated circuit is integrally formed on the joint substrate.

In the ninth aspect, by integrally forming the integrated circuit on the bonded substrate bonded to the flow path forming substrate, the manufacturing process can be simplified, the number of parts can be reduced, and the cost can be reduced. It can be reduced.

A tenth aspect of the present invention is the method according to any one of the first to ninth aspects, in which the bonding substrate has a space in the region facing the piezoelectric element, the space not hindering the movement of the piezoelectric substrate. The inkjet recording head is a sealing substrate having a piezoelectric element holding portion capable of sealing the space.

In the tenth aspect, breakage of the piezoelectric element due to the external environment is prevented.

An eleventh aspect of the present invention is the ink jet recording head according to any one of the first to tenth aspects, characterized in that the flow path forming substrate is composed of only the silicon layer.

In the eleventh aspect, the pressure generating chamber is defined only by the silicon layer.

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

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

(Embodiment 1) FIG. 1 is an exploded perspective view showing an ink jet recording head according to a first embodiment of the present invention, and FIG. 2 is a sectional view of the pressure generating chamber of the ink jet recording head in the longitudinal direction. FIG.

As shown in the figure, the flow path forming substrate 10 in which the pressure generating chamber 12 is formed is, for example, 150 μm to 1 mm.
Of a silicon single crystal substrate having a surface orientation of (100), and a pressure generating chamber 12 partitioned by a plurality of partition walls 11 by anisotropic etching is formed in the surface layer portion on one side thereof. ing.

In addition, an ink communicating portion 13, which is a relay chamber for connecting a reservoir 15 and a pressure generating chamber 12 described later, has a width wider than that of the pressure generating chamber 12 at one longitudinal end of each pressure generating chamber 12. They are communicated with each other through a narrow narrow portion 14. Further, the ink communication portion 13 and the narrow portion 14 are
It is formed together with the pressure generating chamber 12 by anisotropic etching. The narrow portion 14 is for controlling the inflow and outflow of the ink in the pressure generating chamber 12.

This anisotropic etching may be performed by either wet etching or dry etching, but the pressure generating chamber 12 is formed by etching the silicon single crystal substrate halfway in the thickness direction (half etching).
Is formed to be shallow, and its depth can be adjusted by the etching time of half etching.

In this embodiment, the ink communicating portion 13
However, the present invention is not limited to this. For example, as shown in FIG. 2C, the ink communication that communicates with all the pressure generation chambers 12 via the narrow portion 14 is performed. It may be the portion 13A, and in this case, the ink communication portion 13A may form a part of the reservoir 15 described later.

On the other hand, on the other surface side of the flow path forming substrate 10,
A reservoir 15 that communicates with each ink communicating portion 13 and supplies ink to each pressure generating chamber 12 is formed. The reservoir 15 is formed from the other surface side of the flow path forming substrate 10 by anisotropic etching using a predetermined mask, in this embodiment, wet etching. Since the reservoir 15 is formed by wet etching in the present embodiment, it has a shape in which the opening area increases toward the other surface side of the flow path forming substrate 10, and all of the pressure generating chambers 12 that supply ink are covered. The volume is sufficiently larger than the volume.

In this embodiment, the flow path forming substrate 10 is used.
Since a silicon single crystal substrate having a plane orientation of (100) is used as the
Etc. can be formed accurately.

In the vicinity of the end of the flow path forming substrate 10,
A predetermined integrated circuit, in the present embodiment, a drive circuit 16 for driving the piezoelectric element 300 is integrally formed in the pressure generating chamber 12 in the juxtaposed direction.

An elastic film 50 having a thickness of 1 to 2 μm made of an insulating layer such as zirconium oxide (ZrO ₂ ) is provided on the flow path forming substrate 10. The elastic film 50 constitutes one wall surface of the pressure generating chamber 12 on one surface thereof.

Each pressure generating chamber 1 on such an elastic film 50
2 has a thickness of, for example, about 0.5 μm.
The lower electrode film 60, the piezoelectric layer 70 having a thickness of, for example, about 1 μm, and the upper electrode film 80 having a thickness of, for example, about 0.1 μm are laminated in a process described below to form the piezoelectric element 30.
Configures 0. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. Generally, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. Further, here, a portion which is composed of one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the lower electrode film 60 is the common electrode of the piezoelectric element 300, and the upper electrode film 80 is the individual electrode of the piezoelectric element 300.
There is no problem in reversing this due to the driving circuit and wiring.
In any case, the piezoelectric active portion is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and the elastic film that is displaced by the driving of the piezoelectric element 300 are collectively referred to as a piezoelectric actuator.

Further, lead electrodes 90 are respectively extended on the elastic film 50 between the upper electrode film 80 of each piezoelectric element 300 and the drive circuit 16 integrally provided on the flow path forming substrate 10. And each lead electrode 90 and the drive circuit 16 are
The elastic film 50 is electrically connected to each other through connection holes 51 provided in a region facing the drive circuit 16.

Further, by removing the elastic film 50 and the lower electrode film 60 in the vicinity of the end of the pressure generating chamber 12 in the longitudinal direction opposite to the ink communicating portion 13, the elastic film 50 and the lower electrode film 60 are communicated with the nozzle opening 21 described later. The nozzle communication hole 52 is provided for each pressure generating chamber 12.

Further, on the elastic film 50 and the lower electrode film 60 on which the piezoelectric element 300 is formed, as shown in FIGS. 1 and 2, the nozzles communicating with the respective pressure generating chambers 12 through the nozzle communicating holes 52. A nozzle plate 20 having an opening 21 is provided. This nozzle plate 20 is, for example,
A piezoelectric element holding portion 22 that is made of a single crystal silicon substrate and is capable of sealing the space in a region facing the piezoelectric element 300 is provided in a state where a space that does not hinder the movement of the piezoelectric element 300 is secured. The piezoelectric element 300 is sealed in the piezoelectric element holding portion 22.

Here, the size of the pressure generating chamber 12 that applies the ink droplet ejection pressure to the ink and the size of the nozzle opening 21 that ejects the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized. For example,
When recording 360 ink drops per inch, it is necessary to accurately form the nozzle openings 21 with a diameter of several tens of μm.

The nozzle plate 20 as described above is fixed on the elastic film 50 and the lower electrode film 60 with an adhesive or the like. At this time, the nozzle communication holes 52 formed in the elastic film 50 and the lower electrode film 60 are formed. The inner surface is preferably covered with this adhesive. This protects the inner surface of the ink communication hole 52 and prevents the elastic film 50 or the lower electrode film 60 from peeling off.

As described above, in this embodiment, the nozzle plate 20 having the nozzle openings 21 is formed in the flow path forming substrate 1.
The pressure generating chamber 12 may be formed without penetrating the flow path forming substrate 10, because the pressure generating chamber 12 is provided on the piezoelectric element 300 side of No. 0. Therefore, the pressure generating chambers 12 can be formed relatively thin to increase the rigidity of the partition walls 11 that partition the pressure generating chambers 12, and the plurality of pressure generating chambers 12 can be arranged at high density. Furthermore, the compliance of the partition wall 11 is reduced, and the ink ejection characteristics are improved.

Further, since the flow path forming substrate 10 can be made relatively thick, it becomes easy to handle even a large size wafer. Therefore, the number of chips taken per wafer can be increased, and the manufacturing cost can be reduced. Further, since the chip size can be increased, a long head can be manufactured. Moreover,
The occurrence of warpage of the flow path forming substrate is also suppressed, alignment is facilitated when bonding with other members, and even after bonding, changes in the characteristics of the piezoelectric element are suppressed and ink ejection characteristics are stabilized.

Further, in this embodiment, the flow path forming substrate 1
The pressure generating chamber 12 is formed on the surface layer portion on the one surface side of 0, and the reservoir 15 communicating with each pressure generating chamber 12 is formed on the other surface side. As a result, the volume of the reservoir 15 can be made sufficiently large with respect to the volume of each pressure generating chamber 12, and the ink itself in the reservoir 15 can have compliance. Therefore, it is not necessary to separately provide a substrate or the like for absorbing the pressure change in the reservoir 15, and the structure can be simplified and the manufacturing cost can be reduced.

The method for manufacturing such an ink jet recording head is not particularly limited, but it can be formed by the steps described below.

First, as shown in FIG. 3A, one surface of the silicon single crystal plate which becomes the flow path forming substrate 10 is anisotropically etched using a mask of a predetermined shape made of, for example, silicon oxide. As a result, the pressure generating chamber 12, the ink communicating portion 13, and the narrow portion 14 are formed. The drive circuit 16 for driving the piezoelectric element is previously integrally formed on the flow path forming substrate 10 by, for example, a semiconductor process.

Next, as shown in FIG. 3B, the pressure generating chamber 12 formed in the flow path forming substrate 10 and the ink communicating portion 1 are formed.
3 and the narrow portion 14 are filled with the sacrificial layer 100. For example,
In the present embodiment, after the sacrificial layer 100 is formed over the entire surface of the flow path forming substrate 10 to have a thickness substantially the same as the depth of the pressure generating chamber 12, the pressure generating chamber 12, the ink communicating portion 13, and the narrow portion 14 are excluded. The sacrificial layer 100 was formed by removing it by chemical mechanical polishing (CMP).

The material of such a sacrificial layer 100 is not particularly limited, but polysilicon, phosphorus-doped silicon oxide (PSG) or the like may be used. In this embodiment, PSG having a relatively high etching rate is used. .

The method for forming the sacrificial layer 100 is not particularly limited. For example, ultrafine particles of 1 μm or less can be converted into helium (H
A so-called gas deposition method or jet molding method may be used in which a film is formed by colliding with a substrate at a high speed by the pressure of gas such as e). In this method, the pressure generating chamber 12 and the ink communicating portion 13
Also, the sacrificial layer 100 can be partially formed only in the region corresponding to the narrow portion 14.

Next, as shown in FIG. 3C, the elastic film 50 is formed on the flow path forming substrate 10 and the sacrificial layer 100.
Further, in the present embodiment, the protective film 5 serving as a mask when the reservoir 15 is formed on the other surface side of the flow path forming substrate 10.
5 is formed. For example, in the present embodiment, after forming the zirconium layers on both surfaces of the flow path forming substrate 10, for example, 500
The elastic film 50 and the protective film 55 made of zirconium oxide were thermally oxidized in a diffusion furnace at ˜1200 ° C.

The material of the elastic film 50 and the protective film 55 is not particularly limited, and may be any material that is not etched in the step of forming the reservoir 15 and the step of removing the sacrificial layer 100. In addition, the elastic film 50 and the protective film 55
May be made of different materials. further,
The protective film 55 may be formed in any step as long as it is before forming the reservoir 15.

Next, the piezoelectric element 300 is formed on the elastic film 50 so as to correspond to each pressure generating chamber 12.

The steps of forming the piezoelectric element 300 include
First, as shown in FIG. 3D, the lower electrode film 60 is formed over the entire surface of the flow path forming substrate 10 on the pressure generating chamber 12 side by sputtering and patterned into a predetermined shape.
Platinum, iridium or the like is suitable as a material for the lower electrode film 60. This is because the piezoelectric layer 70 described later, which is formed by the sputtering method or the sol-gel method, needs to be crystallized by baking at a temperature of about 600 to 1000 ° C. in the air atmosphere or the oxygen atmosphere after the film formation. Because. That is, the material of the lower electrode film 60 must be able to maintain the conductivity under such a high temperature and oxidizing atmosphere, and especially when lead zirconate titanate (PZT) is used as the piezoelectric layer 70. It is desirable that there be little change in conductivity due to diffusion of lead oxide, and for these reasons, platinum and iridium are preferable.

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

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

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

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

Next, as shown in FIG. 4C, only the piezoelectric layer 70 and the upper electrode film 80 are etched to pattern the piezoelectric element 300. Further, in this embodiment,
At the same time, the elastic film 50 in the area facing the drive circuit 16 is removed to form the connection hole 51 to be a connection portion with each piezoelectric element 300, and to connect the ink communication portion 13 in the longitudinal direction of the pressure generating chamber 12. Is an elastic film 5 near the opposite end
0 and the lower electrode film 60 are patterned to form the nozzle communication hole 5
Form 2.

Next, as shown in FIG. 4D, the lead electrode 90 is formed over the entire surface of the flow path forming substrate 10 and is patterned for each piezoelectric element 300 to form the connection hole 51.
The upper electrode film 80 of each piezoelectric element 300 and the drive circuit 16 are electrically connected via the.

Next, as shown in FIG. 5A, the region of the protective film 55 provided on the surface of the flow path forming substrate 10 opposite to the pressure generating chamber 12 and serving as the reservoir 15 is removed by patterning. The opening 56 is formed by the anisotropic etching (wet etching) until the ink communicating portion 13 is reached from the opening 56.
5 is formed. In the present embodiment, the piezoelectric element 300
Although the reservoir 15 is formed after forming the above, the present invention is not limited to this and may be formed in any step.

Next, as shown in FIG. 5B, the sacrificial layer 100 is removed from the reservoir 15 by wet etching or etching with steam. In this embodiment, since PSG is used as the material of the sacrificial layer 100, the sacrificial layer 100 is etched with an aqueous solution of hydrofluoric acid. When polysilicon is used, it can be etched with a mixed aqueous solution of hydrofluoric acid and nitric acid or an aqueous potassium hydroxide solution.

The pressure generating chamber 12 and the piezoelectric element 300 are formed by the steps as described above, and then the nozzle opening 21 is formed on the side of the piezoelectric element 300 of the flow path forming substrate 10 as shown in FIG. 5C. The nozzle plate 20 provided is fixed with an adhesive or the like.

In the ink jet recording head of this embodiment as described above, the ink is taken into the reservoir 15 from the external ink supply means (not shown), and the interior from the reservoir 15 to the nozzle opening 21 is filled with the ink, and then the drive circuit 16 is provided. A voltage is applied between the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generating chamber 12 according to the recording signal from the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70.
By flexurally deforming the ink, the pressure in each pressure generating chamber 12 increases, and an ink droplet is ejected from the nozzle opening 21.

In this embodiment, the ink communicating portion 13 is used.
And each pressure generating chamber 12 and the reservoir 1 via the narrow portion 14.
5 are communicated with each other, but the invention is not limited to this. For example, as shown in FIG.
5 may be directly communicated.

Further, in the present embodiment, the narrow portion 14 is formed to have a width narrower than that of the pressure generating chamber 12 to control the inflow and outflow of the ink into the pressure generating chamber 12, but the invention is not limited to this. For example, as shown in FIG. 7, a narrow portion 14A having the same width as the pressure generating chamber 12 and a depth adjusted may be used.

(Second Embodiment) FIG. 8 is a sectional view of an ink jet recording head according to a second embodiment.

This embodiment is an example using a plurality of layers of flow path forming substrates, and as shown in FIG. 8, an insulating layer 111 and first and second insulating layers 111 provided on both sides of the insulating layer 111. This is an example in which an SOI substrate including silicon layers 112 and 113 is used as the flow path forming substrate 10A.

That is, the first silicon layer 112, which is thinner than the second silicon layer 113, is etched until it reaches the insulating layer 111 to form the pressure generating chamber 12, the ink communicating portion 13 and the narrow portion 14, Second silicon layer 113
Of the reservoir 1 until the insulating layer 111 is reached.
5 is formed, and the penetrating portion 111a is formed in the portion of the insulating layer 111 corresponding to the bottom surface of the reservoir 15,
It is similar to the first embodiment.

Even in the structure of the second embodiment,
Of course, the same effect as that of the first embodiment can be obtained.

(Third Embodiment) FIG. 9 is an exploded perspective view showing an ink jet recording head according to a third embodiment.
FIG. 10 is a view showing a cross-sectional structure in the longitudinal direction of one pressure generating chamber of the ink jet recording head and its A-.
It is an A'sectional view.

This embodiment is another example using a flow path forming substrate composed of a plurality of layers. As shown in the figure, the flow path forming substrate 10B includes a polysilicon layer 111A and this polysilicon layer 111A. And the first and second silicon layers 112 and 113 provided on both surfaces of the.

In one of the silicon layers constituting the flow path forming substrate 10B, the first silicon layer 112 in the present embodiment, for example, a pressure generating chamber partitioned by a plurality of partition walls 11 by anisotropic etching. 12 are juxtaposed in the width direction. Further, an ink communicating portion 13 is formed at one longitudinal end of each pressure generating chamber 12, and each pressure generating chamber 12 is formed.
And one end in the longitudinal direction of each of them through the narrow portion 14.

Further, in the other silicon layer, in the present embodiment, the second silicon layer 113, there is provided a reservoir 15 which penetrates the second silicon layer 113 in the thickness direction and communicates with the ink communicating portion 13. Has been formed. Further, boron is doped in a region facing the pressure generating chamber 12, the ink communicating portion 13 and the narrow portion 14 on the side of the surface to be joined to the polysilicon layer 111A and excluding a portion communicating with the reservoir 15. A boron-doped silicon layer 113a is formed.

In the present embodiment, the first and second silicon layers 112 and 113 constituting such a flow path forming substrate 10B are each made of a silicon single crystal substrate having a plane orientation (100). Therefore, the side surface 1 in the width direction of the pressure generating chamber 12
2a is an inclined surface that is inclined so as to become narrower on the piezoelectric element 300 side, and the flow path resistance in the pressure generating chamber 12 is suppressed.

On the other hand, these first and second silicon layers 1
Polysilicon layer 111A sandwiched between 12 and 113
In the present embodiment, a boron-doped polysilicon layer 111a doped with boron is formed in a predetermined region in the present embodiment, and the boron-doped polysilicon layer 111a forms a pressure generation chamber 12 in the first silicon layer 112. It has etching selectivity. That is, substantially only the boron-doped polysilicon layer 111a is sandwiched between the first and second silicon layers 112 and 113. Note that a silicon oxide layer may be provided between the polysilicon layer 111A and the first silicon layer 112, which makes it possible to obtain highly accurate etching selectivity of the polysilicon layer 111A.

In addition, the first constituent of the flow path forming substrate 10B
Of the first silicon layer 11 on the surface of the silicon layer 112 of
A protective film 55A formed by previously thermally oxidizing 2 is formed, and the lower electrode film 60 and the piezoelectric film 7 are formed on the protective film 55A via the elastic film 50 as in the above-described embodiment.
A piezoelectric element 300 including 0 and the upper electrode film 80 is formed.

Then, the piezoelectric element 30 of the flow path forming substrate 10
The nozzle plate 20 is bonded to the 0 side, in the present embodiment, on the elastic film 50 and the lower electrode film 60, as in the above-described embodiments.

Also in the configuration of the third embodiment as described above,
Of course, the same effect as that of the above-described embodiment can be obtained.

In this embodiment, the flow path forming substrate 10 is used.
First and second silicon layers 112 and 113 forming B
Are each made of a silicon single crystal substrate having a plane orientation (100), but are not limited to this.
It may be a silicon single crystal substrate having (0) and a plane orientation (110), or may be a silicon single crystal substrate having a plane orientation (110).

In addition, the first and second silicon layers 112,
In the case where each of 113 is made of a silicon single crystal substrate having a plane orientation (110), as shown in FIG. 11, the inner surface (1
2a) is formed by a surface substantially perpendicular to the surface of the flow path forming substrate 10B. Further, in the case of this configuration, the flow path resistance of the narrow portion 14 can be controlled by, for example, adjusting the width thereof.

Further, the formation position of the drive IC for driving the piezoelectric element 300 is not particularly limited, and the flow path forming substrate 10B or the nozzle plate 2 is the same as in the above embodiment.
It may be provided integrally with 0.

(Embodiment 4) FIG. 12 is an exploded perspective view showing an ink jet recording head according to Embodiment 4, and FIG. 13 is a sectional view of FIG.

In this embodiment, as the flow path forming substrate 10,
This is an example in which a silicon single crystal substrate having a plane orientation (100) is used and a pressure generating chamber is formed without using a sacrificial layer. As shown in the drawing, a plurality of partition walls are provided on one side of the flow path forming substrate 10. Pressure generating chambers 12 each having a substantially triangular cross section defined by 11 are arranged side by side in the width direction, and the flow path forming substrate 10 is anisotropically etched from the other side in the vicinity of one end in the longitudinal direction thereof. A reservoir 15 is formed which serves as a common ink chamber for each pressure generating chamber 12.

The elastic film 5 is formed on the flow path forming substrate 10.
The lower electrode film 60, the piezoelectric film 70, and the upper electrode film 8
A piezoelectric element 300 of 0 is formed. Further, in the present embodiment, the elastic film 50 has the protruding portion 50 a that protrudes toward the flow path forming substrate 10 side in the region facing each pressure generating chamber 15.
Are formed along the longitudinal direction of the pressure generating chamber 15.

Then, the piezoelectric element 30 of the flow path forming substrate 10
The nozzle plate 20 is bonded to the 0 side, in the present embodiment, on the elastic film 50 and the lower electrode film 60, as in the above-described embodiments.

Here, a method of manufacturing the ink jet recording head of the present embodiment, particularly a process of forming the pressure generating chamber 12 in the flow path forming substrate 10 will be described with reference to FIGS. 14 and 15.
Will be described with reference to.

First, as shown in FIGS. 14A and 14B, the region of the flow path forming substrate 10 made of a silicon single crystal substrate in which the pressure generating chambers 12 are formed is narrower than the pressure generating chambers 12. A substantially rectangular groove 120 having a width of, for example, a depth of about 50 to 100 μm is formed. The width of the groove 120 is preferably about 0.1 to 3 μm, and in the present embodiment, it is formed to be about 1 μm. The method of forming the groove 120 is not particularly limited, and may be formed by dry etching or the like, for example.

Next, as shown in FIGS. 14C and 14D, the elastic film 50 and the protective film 55 are formed on both surfaces of the flow path forming substrate 10, respectively.

Here, the elastic film 50 formed on the groove portion 120 side of the flow path forming substrate 10 is formed so as to partially penetrate into the groove portion 120, and therefore faces the pressure generating chambers 12 of the elastic film 50. In the region to be formed, a protruding portion 50a having substantially the same shape as the groove 120 and protruding toward the flow path forming substrate 10 side is formed.

Next, as shown in FIGS. 14E and 14F, the lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80 are sequentially laminated and patterned to form the piezoelectric element 300.

Thereafter, the silicon single crystal substrate which is the flow path forming substrate 10 is anisotropically etched with an alkaline solution or the like to form the pressure generating chamber 12 and the like.

Specifically, first, FIG. 15A and its B
As shown in FIG. 7B which is a cross-sectional view taken along the line B ′, the lower electrode film 60 and the elastic film 50 in the region that becomes one end in the longitudinal direction of each pressure generating chamber 12 are removed to communicate with the nozzle opening 21. The hole 52 is formed. Thereby, the flow path forming substrate 10
And the one end in the longitudinal direction of the groove 120 is exposed.
At the same time, the protective film 55 in the region where the reservoir 15 is formed is removed to form the opening 56.

After that, as shown in FIG. 15C and its sectional view taken along the line BB ′, FIG. 15D, the flow path forming substrate 10 is treated with an alkaline solution such as KOH through the nozzle communication hole 52. Pressure generation chamber 12 by anisotropic etching
To form. Here, during the anisotropic etching, the alkaline solution flows into the groove 120 through the nozzle communication hole 52, and the flow path forming substrate 10 is gradually eroded from the groove 120 to form the pressure generating chamber 12. . Further, since the flow path forming substrate 10 is a silicon single crystal substrate having a crystal plane orientation (100), the inner side surface of the pressure generating chamber 12 is inclined by about 54 ° with respect to the surface of the flow path forming substrate 10 ( 111) surface. That is, the (111) plane is a substantial bottom surface of the pressure generating chamber 12, and also serves as an etching stop surface during anisotropic etching.
Is formed so that its cross section has a substantially triangular shape.

After the pressure generating chamber 15 and the like are formed in this manner, FIG. 15 (e) and its sectional view taken along the line CC ′ (f).
As shown in FIG. 5, the flow path forming substrate 10 is anisotropically etched by etching from the surface of the flow path forming substrate 10 opposite to the piezoelectric element 300 using the protective film 55 as a mask. By etching, the reservoir 15 communicating with the pressure generating chamber 12 is formed.

As described above, in the present embodiment, the pressure generating chambers 12 are formed so that the cross section has a substantially triangular shape, so that the strength of the partition wall 11 between the pressure generating chambers 12 is significantly increased. Therefore, even if the pressure generating chambers 12 are arranged at a high density, crosstalk does not occur and the ink ejection characteristics can be kept good.

Further, since the pressure generating chamber 12 can be formed without penetrating the flow path forming substrate 10 by etching, the thickness of the flow path forming substrate 10 is set to about 220 μm in the present embodiment. It may be thicker than. Therefore, even if the wafer forming the flow path forming substrate 10 has a relatively large diameter, it can be easily handled and the cost can be reduced.

Of course, with the configuration of this embodiment, the same effect as that of the above-described embodiments can be obtained.

In the present embodiment, the protruding portion 50a is formed in the portion of the elastic film 50 corresponding to each pressure generating chamber 12, but this protruding portion 50a is, for example, the pressure generating chamber 1
It may be removed simultaneously with the second etching. Further, for example, as shown in FIG. 16, on the elastic film 50,
A second elastic film 50A made of zirconium oxide or the like is provided so that the elastic film 50 in the region facing the pressure generating chamber 12 is completely removed when the pressure generating chamber 12 is formed by anisotropic etching. May be.

(Fifth Embodiment) FIG. 17 is a sectional view of an ink jet recording head according to a fifth embodiment.

The present embodiment is an example in which a drive circuit for driving the piezoelectric element is integrally provided on the nozzle plate.
As shown in FIG. 17, the drive circuit 16A is provided in a region of the nozzle plate 20A other than the piezoelectric element holding portion 22 on the joint surface side with the flow path forming substrate 10, in the present embodiment, in the vicinity of one end of the flow path forming substrate 10. It is formed integrally.

Further, the drive circuit 16A and the piezoelectric element 30
The upper electrode film 80 of 0 is connected via the lead electrode 90. For example, in the present embodiment, the lead electrode 90
Is extended from above the upper electrode film 80 to above the elastic film 50 to the vicinity of the discontinuous lower electrode film 61 which is discontinuous with the lower electrode film 60, and its end and the drive circuit 16A are anisotropically conductive. Material ( A
The second embodiment is the same as the first embodiment except that it is electrically connected via the connection layer 110 made of CF 4 ) or the like.

In this embodiment, as shown in FIG. 18, the drive circuit 16A and the external wiring 120 such as the FPC are provided on the flow path forming substrate 10 near the end portion of the pressure generating chamber 12 in the arranging direction. The connection wiring 130 for connecting the
The drive circuit 16A and the connection wiring 130 form the lead electrode 90.
Similarly, the electrical connection is made through the connection layer 110.

Even with such a configuration of this embodiment, the same effects as those of the above-described embodiments can be obtained. Further, in the present embodiment, the nozzle plate 20 and the flow path forming substrate 10 are
Since the lead electrodes 90 and the connection wirings 130 can be electrically connected to the drive circuit 16A by joining with, the number of the connection wirings 130 can be reduced, and the nozzle openings 21 can be increased to achieve high density. Even if it is installed in
It can be taken out with a PC or the like.

For example, as shown in FIG. 19, a plurality of drive circuits 16A are provided on a bonding substrate bonded to the piezoelectric element 300 side of the flow path forming substrate 10, and both drive circuits 16A of the flow path forming substrate 10 are provided on both sides. The rows of the pressure generating chambers 12 and the piezoelectric elements 300 may be provided in the corresponding regions, respectively. With such a configuration, the wiring from the piezoelectric elements 300 arranged at high density can be easily taken out by the external wiring 120 such as an FPC.

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

For example, in the above embodiment, the piezoelectric element 3
Although the drive circuit 16 or 16A for driving 00 is integrally provided on the flow path forming substrate 10 or the nozzle plate 20A, it is separately provided near the flow path forming substrate 10,
For example, the piezoelectric element 300 may be electrically connected by wire bonding or the like.

Further, for example, in each of the above-described embodiments, an example in which the pressure generating chamber is formed without penetrating the flow path forming substrate has been described. However, of course, the pressure generating chamber penetrates the flow path forming substrate. May be. FIG. 20 shows an example thereof.

In this embodiment, as shown in FIG.
The sealing substrate 140 is bonded to the surface of the flow path forming substrate 10 opposite to the piezoelectric element 300, and the sealing substrate 140 forms one surface of the pressure generating chamber 12. A reservoir forming substrate 150, in which a reservoir 15A for supplying ink to the pressure generating chamber 12 is formed, is joined on the sealing substrate 140, and the pressure generating chamber 12 and the reservoir 15A are sealed substrates. They are communicated with each other via a through hole 141 provided in a region of the 140 which faces the pressure generating chamber 12.

Further, a compliance substrate 160 including a sealing film 161 and a fixing plate 162 is bonded to the reservoir forming substrate 150. The sealing film 161 is made of a material having low rigidity and flexibility.
The one surface of the reservoir 15A is sealed by. Further, the fixing plate 162 is formed of a hard material such as metal. Since the region of the fixing plate 162 facing the reservoir 15A is the opening 163 completely removed in the thickness direction, one surface of the reservoir 15A is sealed with only the flexible sealing film 161. The flexible portion 164 is deformable by the change in the internal pressure.

An ink introducing port 165 for supplying ink to the reservoir 15A is provided on the compliance substrate 160 outside the central portion in the longitudinal direction of the reservoir 15A.
The reservoir forming substrate 150 is provided with an ink introducing passage 151 that connects the ink introducing port 165 and the side wall of the reservoir 15A.

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

The ink jet recording head of each of these embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. Figure 21
FIG. 3 is a schematic view showing an example of the inkjet recording apparatus.

As shown in FIG. 21, the recording head units 1A and 1B having the ink jet recording head are
Cartridges 2A and 2B forming an ink supply unit are detachably provided, and a carriage 3 having the recording head units 1A and 1B mounted thereon is provided on a carriage shaft 5 attached to an apparatus main body 4 so as to be axially movable. There is. The recording head units 1A and 1B are, for example,
The black ink composition and the color ink composition are respectively discharged.

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

[0153]

As described above, in the present invention, since the nozzle opening is provided in the bonding substrate provided on the piezoelectric element side of the flow path forming substrate, the pressure generating chamber penetrates the flow path forming substrate. It may be formed without. Therefore, since the pressure generating chambers can be formed to be relatively thin, the rigidity of the partition wall that partitions each pressure generating chamber can be increased. Thereby, a plurality of pressure generating chambers can be arranged at high density. In addition, since the bonded substrate serves multiple roles, the number of components can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing an inkjet recording head according to a first embodiment of the invention.

FIG. 2 is a diagram showing an ink jet recording head according to a first embodiment of the invention, and is a cross-sectional view and a plan view of FIG.

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

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

FIG. 5 is a cross-sectional view showing the manufacturing process of the ink jet recording head according to the first embodiment of the invention.

FIG. 6 is a cross-sectional view showing a modified example of the ink jet recording head according to the first embodiment of the invention.

FIG. 7 is a cross-sectional view showing a modified example of the ink jet recording head according to the first embodiment of the invention.

FIG. 8 is a cross-sectional view showing an ink jet recording head according to a second embodiment of the invention.

FIG. 9 is a perspective view schematically showing an ink jet recording head according to a third embodiment of the invention.

FIG. 10 is a sectional view showing an ink jet recording head according to a third embodiment of the invention.

FIG. 11 is a cross-sectional view showing a modified example of the ink jet recording head according to the third embodiment of the invention.

FIG. 12 is a perspective view showing an outline of an ink jet recording head according to a fourth embodiment of the invention.

FIG. 13 is a cross-sectional view showing an ink jet recording head according to a fourth embodiment of the invention.

FIG. 14 is a cross-sectional view showing the manufacturing process of the inkjet recording head according to the fourth embodiment of the invention.

FIG. 15 is a cross-sectional view showing the manufacturing process of the ink jet recording head according to the fourth embodiment of the invention.

FIG. 16 is a cross-sectional view showing a modified example of the ink jet recording head according to the fourth embodiment of the invention.

FIG. 17 is a sectional view showing an ink jet recording head according to a fifth embodiment of the invention.

FIG. 18 is a top view schematically showing an ink jet recording head according to a fifth embodiment of the invention.

FIG. 19 is a top view showing a modified example of the ink jet recording head according to the fifth embodiment of the invention.

FIG. 20 is a cross-sectional view showing an ink jet recording head according to another embodiment of the invention.

FIG. 21 is a schematic diagram of an ink jet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

10, 10A, 10B Channel forming substrate 11 partitions 12 Pressure generation chamber 13 Ink communication part 14 narrow space 15 Reservoir 16,16A drive circuit 20,20A nozzle plate 21 nozzle opening 50 elastic membrane 60 Lower electrode film 70 Piezoelectric layer 80 Upper electrode film 300 Piezoelectric element

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Matsuzawa 3-5 Yamato, Suwa City, Nagano Seiko Epson Corporation (56) References JP-A-9-57981 (JP, A) JP-A 10-304685 (JP, A) JP 10-226071 (JP, A) JP 2000-158645 (JP, A) JP 2000-289201 (JP, A) JP 11-198375 (JP, A) JP-A-9-323415 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/16 B41J 2/045 B41J 2/055

Claims (11)

(57) [Claims] 1. A flow path forming substrate having a silicon layer made of at least single crystal silicon and defining a pressure generating chamber communicating with a nozzle opening, and a vibration plate forming a part of the pressure generating chamber. An ink jet recording head, comprising: a piezoelectric element that is provided in a region facing the pressure generating chamber and that causes a pressure change in the pressure generating chamber, wherein one sheet is bonded to the piezoelectric element side of the flow path forming substrate. Of the single crystal silicon, the nozzle opening is provided in the bonding substrate, and the pressure generating chamber does not penetrate the flow channel forming substrate on one side of the flow channel forming substrate. An ink jet recording head, wherein a reservoir that is formed and supplies ink to the pressure generating chamber is formed on the other surface side of the flow path forming substrate. 2. The ink jet recording head according to claim 1 , wherein the reservoir directly communicates with the pressure generating chamber. 3. The ink communication passage according to claim 1 , wherein an ink communication passage communicating with one longitudinal end of the pressure generating chamber is formed on one surface side of the flow passage formation substrate, and the reservoir is connected to the ink communication passage. An ink jet recording head characterized by being communicated. 4. The ink jet recording head according to claim 3 , wherein the ink communication passage is provided for each of the pressure generating chambers. 5. The ink jet recording head according to claim 3 , wherein the ink communication passage is continuously provided in a direction in which the pressure generating chambers are arranged in parallel. 6. In any one of claims 1 to 5, and the reservoir of the pressure generating chamber in the longitudinal end side of the opposite side, a nozzle communicating path communicating with said nozzle opening and the pressure generating chamber An inkjet recording head characterized in that it is provided. 7. The ink jet recording head according to claim 6 , wherein the nozzle communication passage is formed by removing the diaphragm. 8. The ink jet recording head according to claim 6 or 7 , wherein an inner surface of the nozzle communication passage is covered with an adhesive. 9. The claim 1-8, an ink jet recording head to the bonding substrate integrated circuit is characterized in that it is formed integrally. 10. In any one of claims 1 to 9, wherein the bonding substrate, the a region facing the piezoelectric element, a piezoelectric element capable sealing the space while securing a space so as not to inhibit the movement An ink jet recording head, which is a sealing substrate having a holding portion. 11. The claim 1-10, wherein the passage forming substrate, an ink jet recording head characterized by comprising only the silicon layer.