JP2002059555A - Ink jet recording head, method of making the same and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording head wherein the ink ejection property is improved and destruction of a diaphragm is prevented and to provide a method of making the same and an ink jet recorder. SOLUTION: This ink jet recording head that comprises a passage forming substrate on which a pressurizing chamber consisting of a monocrystalline silicon and communicating with a nozzle is to be formed and a piezoelectric element which is formed thereon at a region corresponding to the pressurizing chamber with a diaphragm forming a part of the pressurizing chamber therebetween by a thin film and a lithographic method. A passage forming layer is provided between the passage forming substrate and the diaphragm and an opening section is formed on the passage forming layer at a region corresponding to the pressurizing chamber. At least an end section of the pressurizing chamber in a longitudinal direction in a plane shape at the side of the passage forming layer is defined by the outer edge of the opening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric element formed in a part of a pressure generating chamber communicating with a nozzle opening for discharging an ink drop via a vibration plate, and the ink drop is discharged by displacement of the piezoelectric element. The present invention relates to an ink jet recording head, a method for manufacturing the same, and an ink jet recording apparatus.

[0002]

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

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

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

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

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

In such an ink jet recording head, the substrate is generally etched in a thickness direction by etching the substrate from a surface of the substrate opposite to the piezoelectric element using a predetermined mask pattern. A generation chamber is formed.

[0008]

However, in such an ink jet recording head, an error occurs when the mask pattern for forming the piezoelectric element and the mask pattern for forming the pressure generating chamber are aligned. In some cases, exposure deviation may occur due to warpage of the substrate forming the pressure generating chamber, or the like, and the relative positional accuracy between the piezoelectric element and the pressure generating chamber may be reduced, and the ink ejection characteristics may be reduced. There's a problem.

Further, as a substrate, for example, a plane orientation (1)
In the case of using the silicon single crystal substrate of 10), the shape of the pressure generating chamber is restricted by the (111) plane, so that the diaphragm is bent depending on the shape, and cracks are generated by stress due to driving of the piezoelectric element. There are problems such as occurrence.

In view of such circumstances, it is an object of the present invention to provide an ink jet recording head which improves ink ejection characteristics and prevents breakage of a diaphragm, a method for manufacturing the same, and an ink jet recording apparatus.

[0011]

According to a first aspect of the present invention, there is provided a flow path forming substrate formed of single crystal silicon and having a pressure generating chamber communicating with a nozzle opening; An ink jet recording head comprising a thin film and a piezoelectric element formed by a lithography method in a region corresponding to the pressure generating chamber via a vibration plate forming a part of the flow path forming substrate and the vibration plate An opening is formed in a region opposed to the pressure generation chamber in the flow passage formation layer, and at least a longitudinal direction of a planar shape of the pressure generation chamber on the flow passage formation layer side; Is defined by an outer edge of the opening.

In the first aspect, since the longitudinal edge of the pressure generating chamber is defined by the outer edge of the opening of the flow path forming layer, the relative positional accuracy between the pressure generating chamber and the piezoelectric element is improved. . Further, since the stress applied to the diaphragm by driving the piezoelectric element is made uniform by the flow path forming layer, breakage of the diaphragm is prevented.

According to a second aspect of the present invention, in the first aspect, the shape of the opening of the flow path forming layer defines a vibration area of the diaphragm. It is in.

In the second aspect, when the relative positional accuracy between the pressure generating chamber and the piezoelectric element is surely improved, the stress applied to the diaphragm by driving the piezoelectric element becomes more uniform.

According to a third aspect of the present invention, in the second aspect, the opening of the flow path forming layer has a substantially rectangular shape which is included in the flow path forming layer side opening of the pressure generating chamber. An ink jet recording head is characterized in that:

In the third aspect, the relative position accuracy between the pressure generating chamber and the piezoelectric element is improved, and the opening has a substantially rectangular shape, so that the stress applied to the diaphragm is reliably made uniform. .

According to a fourth aspect of the present invention, there is provided an ink jet recording head according to any one of the first to third aspects, wherein the flow path forming layer is made of boron-doped silicon.

In the fourth aspect, the flow path forming layer can be formed relatively easily, and the opening can be formed with relatively high precision.

A fifth aspect of the present invention is the ink jet recording head according to any one of the first to fourth aspects, wherein the pressure generating chamber is formed by anisotropic etching.

In the fifth aspect, the pressure generating chamber can be formed relatively easily and at a high density.

According to a sixth aspect of the present invention, there is provided an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to fifth aspects.

According to the sixth aspect, it is possible to realize an ink jet recording apparatus having improved ink ejection characteristics of the head.

According to a seventh aspect of the present invention, there is provided a flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening made of single crystal silicon is formed, and a diaphragm forming a part of the pressure generating chamber. A method of manufacturing an ink jet recording head comprising a thin film and a piezoelectric element formed by lithography in a region corresponding to the pressure generating chamber, wherein etching selectivity is determined in a predetermined region on one surface side of the flow path forming substrate. And forming a piezoelectric element on the vibration plate while forming the vibration plate on the flow path formation layer, and from the other surface side of the flow path formation substrate Forming the pressure generating chamber by anisotropic etching, and forming an opening in a region of the flow path forming layer facing the pressure generating chamber. In the manufacturing method of the head.

In the seventh aspect, the pressure generating chamber can be formed relatively easily and at a high density, and the vibration region of the diaphragm can be defined with high precision by the opening.

According to an eighth aspect of the present invention, in the seventh aspect, in the step of giving an etching selection to one surface of the flow path forming substrate, the step of forming an opening on the surface layer of the flow path forming substrate is performed. A method of manufacturing an ink jet recording head, wherein the flow path forming layer made of boron-doped silicon is formed by doping boron in a region other than the region.

In the eighth aspect, the opening can be formed with high precision, and the manufacturing process can be simplified.

[0027]

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 plan view and a sectional view of FIG.

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

In the flow path forming substrate 10, pressure generating chambers 12 divided by a plurality of partition walls 11 are arranged in parallel in the width direction by anisotropically etching a silicon single crystal substrate, and outwardly in the longitudinal direction. Is a communication part 13 which constitutes a part of a reservoir 100 which communicates with a reservoir part of a reservoir forming substrate which will be described later and serves as a common ink chamber of each pressure generating chamber 12.
Are formed, and are communicated with one end in the longitudinal direction of each pressure generating chamber 12 via the ink supply path 14.

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

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

On one side of the flow path forming substrate 10,
For example, the flow path forming layer 40 made of boron-doped silicon
Are formed on the flow path forming layer 40.
The elastic film 50 which forms one surface of is formed. In a region of the flow path forming layer 40 facing the pressure generating chamber 12,
An opening 41 having a predetermined shape penetrating in the thickness direction is formed. As will be described in detail later, the outer edge of the opening 41 allows at least the longitudinal direction of the planar shape of the pressure generating chamber 12 on the flow path forming layer 40 side. Is defined.

In this embodiment, the elastic film 50 is formed on the flow path forming layer 40 and is made of silicon oxide (SiO ₂ ).
A first elastic film 50a made of zirconium oxide (ZrO ₂ ) formed on the first elastic film.
And the elastic film 50b. Of course, the elastic film 50
Is not limited to one having a plurality of layers.

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

Here, the size of the pressure generating chamber 12 for applying the ink droplet ejection pressure to the ink and the size of the nozzle opening 21 for ejecting the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized. For example,
When recording 360 ink droplets per inch, the nozzle openings 21 need to be formed with a diameter of several tens of μm with high accuracy.

On the other hand, on the elastic film 50 provided on the side opposite to the opening surface of the flow path forming substrate 10 via the flow path forming layer 40, the thickness is, for example, about 0.2 to 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 to form the piezoelectric element 300. I have. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. Generally, the piezoelectric element 30
0 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric layer 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the lower electrode film 60 is
0, the upper electrode film 80 is an individual electrode of the piezoelectric element 300, and a piezoelectric active portion is formed for each pressure generating chamber 12. Further, here, the piezoelectric element 300 and the elastic film whose displacement is generated by driving the piezoelectric element 300 are referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 60 function as a diaphragm, but the lower electrode film may also serve as the elastic film.

A lead electrode 90 is connected to the upper electrode film 80 which is an individual electrode of each piezoelectric element 300. The lead electrode 90 extends from above the upper electrode film 80 to above the elastic film 50, and is connected to an external wiring (not shown) near its end.

Further, the piezoelectric element 30 of the flow path forming substrate 10
On the 0 side, a reservoir forming substrate 30 having a reservoir portion 26 constituting at least a part of the reservoir 100 is joined. In the present embodiment, the reservoir portion 26 penetrates the reservoir forming substrate 30 in the thickness direction, and
2 and is formed in the width direction of the flow path forming substrate 10.
The communication portion 13 is communicated through an ink communication hole 51 provided through the elastic film 50 and the like and an opening 42 provided in the flow path forming layer 40, and a common ink of each pressure generating chamber 12. A reservoir 100 is formed as a chamber.

As the reservoir forming substrate 30, it is preferable to use a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10, such as glass or ceramic material. It was formed using a silicon single crystal substrate of the same material. As a result, as in the case of the nozzle plate 20 described above, both can be securely bonded to each other even at a high temperature using a thermosetting adhesive.

Further, the reservoir forming substrate 30 includes:
A compliance substrate 35 including a sealing film 36 and a fixing plate 37 is joined. Here, the sealing film 36 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the sealing film 36 seals one surface of the reservoir 26. Has been stopped. The fixing plate 37 is made of a hard material such as a metal (for example, stainless steel (SU) having a thickness of 30 μm).
S) etc.). The reservoir 10 of the fixing plate 37
Since the area facing 0 is the opening 38 completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with the flexible sealing film 36, and the internal pressure changes. Thus, the flexible portion 39 can be deformed.

Further, an ink inlet 27 for supplying ink to the reservoir 100 is formed on the compliance substrate 35 substantially outside the central portion in the longitudinal direction of the reservoir 100. Further, the reservoir forming substrate 30 is provided with an ink introduction path 28 that communicates the ink introduction port 27 with the side wall of the reservoir 100.

On the other hand, the piezoelectric element 3 of the reservoir forming substrate 30
A piezoelectric element holding portion 29 capable of sealing the space is provided in a region opposed to the piezoelectric element 300 while securing a space that does not hinder the movement of the piezoelectric element 300.
Are sealed in the piezoelectric element holding portion 29.

Here, the manufacturing process of the ink jet type recording head of this embodiment, in particular, the flow path forming substrate 1
The step of forming the pressure generating chamber 12 at zero and the step of forming the piezoelectric element 300 in a region corresponding to the pressure generating chamber 12 will be described. 3 to 5 show the pressure generating chamber 12.
It is sectional drawing of the longitudinal direction of FIG.

As shown in FIG. 3A, first, on each surface of the flow path forming substrate 10, a silicon dioxide layer 55A serving as a mask for forming the flow path forming layer 40 having a predetermined pattern is formed.
A silicon dioxide layer 55B serving as a mask when forming the pressure generating chamber 12, the communication section 13, and the ink supply path 14 is formed. That is, specifically, after a single-crystal silicon wafer serving as the flow path forming substrate 10 is thermally oxidized in a diffusion furnace at about 1100 ° C. to form silicon dioxide layers 55A and 55B on each surface, the silicon dioxide layers 55A and 55B are formed. 55B is patterned into a predetermined shape.

Here, by etching the silicon dioxide layer 55B, an etching opening 56 is formed in a region of the flow path forming substrate 10 which becomes the pressure generating chamber 12 and the like. The size of the opening 56 in the region facing the generation chamber 12 is determined by anisotropically etching the flow path forming substrate 10 in a step described later.
At the time of forming, for example, the flow path forming layer 40 is formed in such a size that at least a sharp corner of the opening on the flow path forming layer 40 side is covered by the flow path forming layer 40. That is, the opening of the pressure generating chamber 12 on the side of the flow path forming layer 40 is formed to be larger than the opening 41 of the flow path forming layer 40.

Next, as shown in FIG. 3B, a flow path forming layer 40 made of boron-doped silicon is formed on one side of the flow path forming substrate 10. Specifically, using the silicon dioxide layer 55A as a mask, on the surface of the flow path forming substrate 10, in the present embodiment, on the surface of the flow path forming substrate 10 in a region other than the portions to be the openings 41 and 42 of the flow path forming layer 40, By doping with boron, a channel forming layer 40 made of boron-doped silicon and having a thickness of 1 to 2 μm was formed. As described above, by forming the flow path forming layer 40 in a predetermined area on one surface side of the flow path forming substrate 10, the flow path forming substrate 10
The surface of the substrate is substantially provided with etching selectivity.

In this embodiment, the openings 41 and 42 are used.
The flow path forming layer 40 made of boron-doped silicon is formed by doping boron in all the areas of the flow path forming substrate 10 except for the area to be formed. However, the present invention is not limited to this. It is sufficient that boron is doped.

Next, the silicon dioxide layer 55A is removed,
As shown in FIG. 3C, the elastic film 5 is formed on the flow path forming layer 40.
0 is formed. In the present embodiment, first, the flow path forming layer 40
Of about 35 by TEOS-CVD, for example.
A first elastic film 50a made of silicon dioxide is formed at a relatively low temperature of 0 to 500C. Next, after forming a zirconium layer on the first elastic film 50a, 500 to 120
The second elastic film 50b made of zirconium oxide was formed by thermal oxidation in a diffusion furnace at 0 ° C.

Here, in this embodiment, the TEOS-CV
Since the first elastic film 50a is formed on the flow path forming layer 40 and the flow path forming substrate 10 at a relatively low temperature by the method D, the flow path forming substrate 10 is formed by the first elastic film 50a.
In addition, the flow path forming layer 40 is protected, and damage due to heat when the second elastic film 50 is thermally oxidized can be prevented.

Next, the piezoelectric element 300 is placed on the elastic film 50.
To form First, as shown in FIG. 3D, the lower electrode film 60 is formed by sputtering and patterned into a predetermined shape. As a material of the lower electrode film 60, platinum or the like is preferable. This is because the piezoelectric layer 70 described below, which is formed by sputtering or a sol-gel method, needs to be crystallized by baking at a temperature of about 600 to 1000 ° C. in an air atmosphere or an oxygen atmosphere after the film formation. It is. That is, the material of the lower electrode film 60 must be able to maintain conductivity under such a high temperature and oxidizing atmosphere. In particular, when lead zirconate titanate is used for the piezoelectric layer 70,
It is desirable that the change in conductivity due to the diffusion of lead oxide is small, and for these reasons, platinum is preferred.

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

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

Next, as shown in FIG. 4B, 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 iridium, aluminum, gold, nickel, and platinum, and a conductive oxide. In the present embodiment, platinum is formed by sputtering.

Next, as shown in FIG. 4C, the piezoelectric layer 70 and the upper electrode
Is performed.

Next, as shown in FIG. 5A, a lead electrode 90 is formed over the entire surface of the flow path forming substrate 10, and is patterned for each piezoelectric element 300.

The above is the film forming process. After forming the film in this manner, as shown in FIG. 5B, the pressure generating chamber 12, the communication section 13, and the ink communication path 14 are formed in the flow path forming substrate 10, and the flow path forming layer 40 is formed. An opening 41 is formed in the opening. That is, the pressure generation chamber 12 is formed by anisotropically etching the flow path forming substrate 10 until the elastic film 50 is reached, using the silicon dioxide layer 55B patterned into a predetermined shape as a mask as described above, thereby forming the pressure generation chamber 12 simultaneously. Openings 41 will be formed in layer 40. In the present embodiment, the communication portion 1 of the flow path forming layer 40 is formed.
An opening 42 is also formed in the region facing 3 at the same time.

The opening 42 is formed with an ink communication hole 51 formed by removing the elastic film 50 and the lower electrode film 60.
In addition, it becomes a flow path that connects the communication portion 13 and the reservoir portion 26.

In the series of film formation and anisotropic etching described above, a number of chips are simultaneously formed on one wafer, and after the process is completed, a flow path forming substrate having one chip size as shown in FIG. Divide every ten. Further, the divided flow path forming substrate 10 is bonded and integrated with the nozzle plate 20 and the reservoir forming substrate 30 to form an ink jet recording head. Then, it is fixed to a holder or the like (not shown), mounted on a carriage, and incorporated in an ink jet recording apparatus.

The ink jet recording head thus configured takes in ink from the ink introduction hole 38 connected to external ink supply means (not shown), and stores the ink in the reservoir 100.
Is filled with ink, a voltage is applied between the lower electrode film 60 and the upper electrode film 80 according to a recording signal from an external driving circuit (not shown), and the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70 are applied. Of the pressure generating chamber 12
The pressure inside increases, and ink droplets are ejected from the nozzle opening 21.

Here, FIG. 6 shows a plan view and a cross-sectional view showing the main part of the ink jet recording head of the present embodiment thus formed.

As shown in FIG. 6, at least the longitudinal end of the planar shape of the pressure generating chamber 12 on the elastic film 50 side is defined by the outer edge of the opening 41 of the flow path forming layer 40 as described above. ing. In the present embodiment, the shape of the opening 41 of the flow path forming layer 40 outside the width direction is formed so as to be substantially the same as the width of the opening of the pressure generating chamber 12.
The width of the pressure generating chamber 12 is also substantially defined by the outer edge of the opening 41. That is, the vibration area of the diaphragm driven by the piezoelectric element 300 is defined by the outer edge of the opening 41.

Specifically, in this embodiment, the plane orientation (1
10) A pressure generating chamber 12 is formed by anisotropically etching a flow path forming substrate 10 made of single crystal silicon having a plane.
Is formed, the opening shape of the pressure generating chamber 12 has a substantially parallelogram. On the other hand, the opening 41 of the flow channel forming layer 40 has a substantially rectangular shape, and the outer edge in the longitudinal direction of the opening 41 is substantially the same as the obtuse corner 12a of the opening of the pressure generating chamber 12 on the flow channel forming layer 40 side. It is provided so as to be located at or at a position inside. That is, the opening 41 is included in the opening of the pressure generating chamber 12, and the opening 41
Defines the vibration area of the diaphragm.

Accordingly, since the stress due to the deformation of the diaphragm due to the driving of the piezoelectric element is dispersed without concentrating on the sharp corners 12b, the destruction of the diaphragm is prevented, and the durability and reliability are improved.

The relative position accuracy between at least the piezoelectric element side region of the pressure generating chamber 12 and the piezoelectric element, that is, the relative position between the vibration region of the diaphragm and the piezoelectric element 300 is determined with high accuracy. Therefore, it is possible to improve the ink ejection characteristics and the print quality.

(Other Embodiments) The embodiments of the present invention have been described above. However, the basic configuration of the ink jet recording head is not limited to the above-described one, and the material, structure, and the like can be freely changed. is there.

For example, in the above-described embodiment, an example in which the pressure generating chamber is provided so as to penetrate the flow path forming substrate has been described. However, the present invention is not limited to this. For example, the pressure generating chamber may penetrate the flow path forming substrate. Alternatively, a structure provided on one surface side may be employed.

Further, for example, in the above-described embodiment, a channel forming layer made of boron-doped silicon is provided by doping boron in a predetermined region on one surface side of the channel forming substrate, thereby improving etching selectivity. However, the present invention is not limited to this. Boron-doped polysilicon is provided by separately providing a polysilicon layer or the like on one surface side of the flow path forming substrate and doping boron or the like into a predetermined region of the polysilicon layer. The flow path forming layer may be made of and may be provided with etching selectivity. In any case, it suffices if etching selectivity can be given to the surface on one side of the flow path forming substrate 10.

Further, in the above-described embodiment, the reservoir forming substrate 30 having the reservoir 26 constituting the reservoir 100 for supplying the ink to the pressure generating chamber 12 is provided on the piezoelectric element side of the flow path forming substrate 10. However, the structure of the reservoir 100 or the like is not particularly limited. For example, a member forming the reservoir is
Alternatively, it may be provided on the flow path forming substrate 10.

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.

The ink jet recording head of each of these embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. FIG.
FIG. 2 is a schematic diagram illustrating an example of the ink jet recording apparatus.

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

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

[0074]

As described above, in the present invention, the flow path forming layer is provided on the vibration plate side of the flow path forming substrate, and the outer edge of the opening of the flow path forming layer is formed at least in the longitudinal direction of the pressure generating chamber. Is defined, the stress applied to the diaphragm by driving the piezoelectric element is made uniform. Thereby, generation of cracks and deformation of the diaphragm can be prevented,
Reliability can be improved. Further, the relative position accuracy between the piezoelectric element and the pressure generating chamber can be improved, and the ink ejection characteristics can be improved.

[0075]

[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 plan view and a cross-sectional view of a main part of FIG. 1, showing the ink jet recording head according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a manufacturing process according to the first embodiment of the present invention.

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

FIG. 5 is a cross-sectional view illustrating a manufacturing process according to the first embodiment of the present invention.

FIG. 6 is a plan view and a cross-sectional view illustrating a main part of the inkjet recording head according to the first embodiment of the present invention.

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 flow path forming substrate 11 partition wall 12 pressure generating chamber 13 communication portion 14 ink supply path 20 nozzle plate 21 nozzle opening 30 reservoir forming substrate 35 compliant substrate 40 flow path forming layer 41 opening 50 elastic film 60 lower electrode film 70 piezoelectric layer 80 Upper electrode film 300 Piezoelectric element

Claims (8)

[Claims] 1. A flow path forming substrate formed of single crystal silicon and having a pressure generating chamber communicating with a nozzle opening, and a pressure plate corresponding to the pressure generating chamber via a diaphragm constituting a part of the pressure generating chamber. An ink jet recording head including a thin film and a piezoelectric element formed by a lithography method in a region, comprising: a flow path forming layer between the flow path forming substrate and the vibration plate; An opening is formed in a region facing the pressure generating chamber, and at least an end in the longitudinal direction of the planar shape of the pressure generating chamber on the side of the flow path forming layer is defined by an outer edge of the opening. Inkjet recording head. 2. The ink jet recording head according to claim 1, wherein the shape of the opening of the flow path forming layer defines a vibration area of the vibration plate. 3. The ink jet recording head according to claim 2, wherein the opening of the flow path forming layer has a substantially rectangular shape included in the opening of the pressure generating chamber on the side of the flow path forming layer. . 4. An ink jet recording head according to claim 1, wherein said flow path forming layer is made of boron-doped silicon. 5. The ink jet recording head according to claim 1, wherein the pressure generating chamber is formed by anisotropic etching. 6. An ink jet recording apparatus comprising the ink jet recording head according to claim 1. 7. A flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening made of single-crystal silicon is formed, and a pressure generating chamber corresponding to the pressure generating chamber via a diaphragm constituting a part of the pressure generating chamber. What is claimed is: 1. A method for manufacturing an ink jet recording head, comprising: a thin film and a piezoelectric element formed by a lithography method in a region; Forming a piezoelectric element on the vibration plate while forming the vibration plate on the flow path formation layer, and performing anisotropic etching from the other surface side of the flow path formation substrate Forming the pressure generating chamber and forming an opening in a region of the flow path forming layer facing the pressure generating chamber. 8. The method according to claim 7, wherein, in the step of giving etching selection to one surface side of the flow path forming substrate, boron is doped into a surface layer of the flow path forming substrate other than the region to be the opening. Forming the flow path forming layer made of boron-doped silicon by the method described above.