JP2003080706A - Ink jet recording head and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording head and an ink jet recorder in which a channel forming substrate is prevented from being broken. SOLUTION: The ink jet recording head comprises a channel forming substrate 10 in which pressure generating chambers 12 communicating with nozzle openings are defined, and piezoelectric elements 300 provided in regions facing the pressure generating chambers 12 through a diaphragm constituting a part thereof and generating a pressure variation in the pressure generating chambers 12. At the opposite end parts of the channel forming substrate 10 in the array direction of the pressure generating chambers 12, stress relaxing parts 16 are provided to lower the rigidity by forming a plurality of recesses 15 and the channel forming substrate 10 is prevented from cracking by varying the width of the plurality of recesses 15 stepwise thereby varying the rigidity.

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.

[0006]

In such an ink jet recording head, a nozzle plate having a plurality of nozzle openings and the like are joined to the flow path forming substrate in which the pressure generating chamber is formed. Since this nozzle plate is generally made of a material different from that of the flow path forming substrate, wiring is performed by bonding the flow path forming substrate and the nozzle plate with a thermosetting adhesive or by wire bonding to the piezoelectric element. At the time of connection, there is a problem in that the flow path forming substrate and the nozzle plate are deformed due to the difference in thermal expansion coefficient, and breakage such as cracking occurs in the flow path forming substrate.

In particular, since the rigidity in the vicinity of the peripheral portion of the flow path forming substrate is higher than that in the central portion where the pressure generating chamber is provided, stress concentrates near the boundary between the high rigidity region and the low rigidity region. Then, there is a problem that cracks are likely to occur.

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 in which destruction of the flow path forming substrate is prevented.

[0009]

According to a first aspect of the present invention for solving the above problems, a flow path forming substrate defining a pressure generating chamber communicating with a nozzle opening and a part of the pressure generating chamber are provided. In an ink jet recording head, which comprises a piezoelectric element that is provided in a region facing the pressure generating chamber through a vibrating plate that constitutes the pressure generating chamber and causes a pressure change in the pressure generating chamber, the pressure generation of the flow path forming substrate At both ends in the row direction of the chamber, stress relaxation portions whose rigidity is reduced by forming a plurality of recesses are provided, and the rigidity of the flow path forming substrate is increased by changing the width of the recesses stepwise. The inkjet recording head is characterized by being changed.

In the first aspect, the rigidity of the flow path forming substrate is gradually reduced, whereby stress concentration due to deformation of the flow path forming substrate can be prevented and cracking can be prevented.

A second aspect of the present invention is the ink jet recording head according to the first aspect, characterized in that the width of the recess is narrowed toward the end of the flow path forming substrate.

In the second aspect, the rigidity gradually increases toward the end of the flow path forming substrate, and stress concentration due to the deformation of the flow path forming substrate is effectively prevented.

According to a third aspect of the present invention, in the first or second aspect, each pressure generating chamber communicates with the flow path forming substrate, and at least a reservoir serving as a common ink chamber for the pressure generating chambers. A communication part forming a part is formed, and the stress relaxation part is formed inside or outside a region corresponding to an end of the communication part in the row direction of the pressure generating chambers. Inkjet type recording head.

In the third aspect, the rigidity of the flow path forming substrate can be reduced without causing cracks in the flow path forming substrate along the concave portion forming the stress relaxation portion.

According to a fourth aspect of the present invention, the pressure generating chamber is formed via a flow path forming substrate defining a pressure generating chamber communicating with the nozzle opening and a vibrating 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 each other and that causes a pressure change in the pressure generation chamber, a plurality of pressure generating chambers of the flow path forming substrate are provided at both ends in the column direction. A stress relaxation portion whose rigidity is reduced by forming a recess is provided, and the stress relaxation portion is at least one of inside and outside of a region along the end of the communication portion in the column direction of the pressure generating chambers. The inkjet recording head is characterized in that it is formed on one side.

In the fourth aspect, the rigidity of the flow path forming substrate can be reduced without causing cracks in the flow path forming substrate along the concave portion forming the stress relaxation portion.

A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, a width of each recess forming the stress relaxation portion is narrower than a width of the pressure generating chamber. It is in an inkjet recording head.

In the fifth aspect, the rigidity of the flow path forming substrate can be appropriately decreased without being excessively decreased.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the pressure generating chamber is formed in a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed and formed. The inkjet recording head is characterized by being formed by a lithography method.

In the sixth aspect, an ink jet recording head having high density nozzle openings can be manufactured in large quantities and relatively easily.

A seventh aspect of the present invention is an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to sixth aspects.

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

[0023]

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

(Embodiment 1) FIG. 1 is a perspective view of an ink jet recording head according to Embodiment 1 of the present invention.
FIG. 2 is a top view and a sectional view thereof.

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, and one surface side thereof is made of silicon dioxide previously formed by thermal oxidation. Elastic film 50 having a thickness of 1 to 2 μm
Are formed.

In addition, a plurality of pressure generating chambers 12 are formed on the flow path forming substrate 10 by anisotropically etching from the surface opposite to the elastic film 50 and substantially penetrate the flow path forming substrate 10. They are arranged side by side in the width direction. Further, a communication portion 14 is formed outside the pressure generating chambers 12 in the longitudinal direction so that the pressure generating chambers 12 communicate with each other via the ink supply paths 13. The communicating portion 14 communicates with a reservoir portion of a reservoir forming substrate, which will be described later, and constitutes a part of the reservoir 100 that is a common ink chamber of each pressure generating chamber 12.

In this embodiment, the flow path forming substrate 10 is used.
Is provided with two rows of pressure generating chambers 12 arranged side by side in the width direction, and each pressure generating chamber 12 is provided with a slight offset in the width direction so as not to be aligned in a straight line in the longitudinal direction. ing.

Further, the pressure generating chamber 12 of the flow path forming substrate 10
On both outer sides of the row, a stress relaxation portion 16 including a plurality of recesses 15 arranged in parallel in the width direction of the pressure generating chamber 12 is provided.

Recesses 15 constituting the stress relaxation section 16
Like the pressure generating chamber 12, is provided so as to substantially penetrate the flow path forming substrate 10 and has a width narrower than that of the pressure generating chamber 12. Further, in the present embodiment, the width of each recess 15 is narrower toward the end of the flow path forming substrate 10. That is, the rigidity of the flow path forming substrate is changed so as to gradually increase toward the end side by changing the width of each concave portion 15 forming the stress relaxation portion 16 stepwise.

By providing the stress relieving portion 16 as described above, it is possible to prevent the flow path forming substrate 10 from cracking, which will be described in detail later.

Here, the anisotropic etching is performed by utilizing the difference in etching rate of the silicon single crystal substrate. For example, in this embodiment, the silicon single crystal substrate is set to K.
When it is dipped in an alkaline solution such as OH, it is gradually eroded and the first (111) plane perpendicular to the (110) plane and the first (111) plane
Forms an angle of about 70 degrees with the (111) plane of
A second (111) plane that makes an angle of about 35 degrees with the (0) plane appears, and the etching rate of the (111) plane is about 1/180 of the etching rate of the (110) plane. Is done using. By such anisotropic etching, it is possible to perform precision machining based on the depth machining of the parallelogram shape formed by the two first (111) planes and the two diagonal second (111) planes. The pressure generating chambers 12 can be arranged in high density.

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 in the flow path forming substrate 1
It is formed by etching through almost 0 to reach the elastic film 50. Here, the elastic film 50 is
The amount of the alkaline solution that etches the silicon single crystal substrate is extremely small. In addition, each ink supply path 13 communicating with one end of each pressure generating chamber 12 is
It is formed to be shallower and keeps the flow path resistance of the ink flowing into the pressure generating chamber 12 constant. That is, the ink supply path 13 is formed by etching the silicon single crystal substrate halfway in the thickness direction (half etching). The half etching is performed by adjusting the etching time.

On the opening side of the flow path forming substrate 10,
A nozzle plate 20 having a nozzle opening 21 that communicates with each other in the vicinity of the end on the opposite side of each pressure generating chamber 12 and the ink supply path 13 is fixed by, for example, a thermosetting adhesive. In addition, the nozzle plate 20 is made of, for example, non-rust steel having a thickness of 0.1 to 1 mm. Further, the nozzle plate 20 entirely covers one surface of the flow path forming substrate 10 with one surface, and also serves as a reinforcing plate that protects the silicon single crystal substrate from impact and external force.

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.

On the other hand, on the elastic film 50 provided on the flow path forming substrate 10, a lower electrode film 60 having a thickness of, for example, about 0.2 μm and a piezoelectric layer 70 having a thickness of, for example, about 1 μm. When,
The upper electrode film 80 having a thickness of, for example, about 0.1 μm is laminated and formed in a process described later to form the piezoelectric element 300. Here, the piezoelectric element 300 includes the lower electrode film 60,
It refers to a portion including 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 used as the pressure generating chambers 1.
It is configured by patterning every two. 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 serves as a common electrode of the piezoelectric element 300, and the upper electrode film 8
Although 0 is used as the individual electrode of the piezoelectric element 300, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. In addition, here, the piezoelectric element 300
And the diaphragm that is displaced by the driving of the piezoelectric element 300 are collectively referred to as a piezoelectric actuator.

The upper electrode film 80, which is an individual electrode of the piezoelectric element 300, is connected to a drive wiring (not shown) through a lead electrode 90 extending from the upper electrode film 80 to the elastic film 50.

Further, the piezoelectric element 300 of the flow path forming substrate 10
On the side, a reservoir portion 3 forming a part of the reservoir 100
The reservoir forming substrate 30 having No. 1 is bonded. In this embodiment, the reservoir portion 31 penetrates the reservoir forming substrate 30 in the thickness direction and is formed in the row direction of the pressure generating chambers 12, and as described above, the flow passage forming substrate 10 is formed.
The reservoir 100 is formed by being communicated with the communication portion 14 of FIG.

As the reservoir forming substrate 30, it is preferable to use a material having substantially the same coefficient of thermal expansion as that of the passage forming substrate 10, such as glass or a ceramic material. In the present embodiment, the passage forming substrate is used. A silicon single crystal substrate of the same material as 10 was used. As a result, both can be reliably bonded by high-temperature bonding using a thermosetting adhesive, and the manufacturing process can be simplified.

Further, the piezoelectric element 3 of the reservoir forming substrate 30
In a region facing 00, a piezoelectric element holding portion 32 that can seal the space is provided in a state where a space that does not hinder the movement of the piezoelectric element 300 is secured, and the piezoelectric element 300 includes the piezoelectric element holding portion 32. It is sealed inside.

Further, on the reservoir forming substrate 30, a lead electrode 90 connected to the upper electrode film 80 of the piezoelectric element 300.
A through groove 37 penetrating in the thickness direction is provided in a region facing the vicinity of the end of the pressure generating chamber 12 in the direction in which the pressure generating chambers 12 are arranged in parallel. Then, a drive wiring connected to a drive circuit (not shown) is extended in the through groove 37 by, for example, wire bonding or the like, and is electrically connected to each lead electrode 90.

Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded to the reservoir forming substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm),
One surface of the reservoir section 31 is sealed by the sealing film 41. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm).
Etc.). The area of the fixing plate 42 facing the reservoir 100 is the opening 4 completely removed in the thickness direction.
Therefore, the one surface of the reservoir 100 is sealed by only the flexible sealing film 41, and is a flexible portion 45 that can be deformed by a change in internal pressure.

The ink jet recording head of the present embodiment as described above takes in ink from an external ink supply means (not shown), and the nozzle opening 2 from the reservoir 100.
After filling the inside up to 1 with ink, 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 a recording signal from an external drive circuit (not shown). By deforming the elastic film 50, the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70 by bending, each pressure generating chamber 1
The pressure inside 2 rises and ink droplets are ejected from the nozzle openings 21.

The manufacturing process of such an ink jet recording head will be described below with reference to FIGS. 3 and 4 are cross-sectional views of the pressure generating chamber 12 in the width direction.

First, as shown in FIG. 3A, about 110 wafers of a silicon single crystal substrate to be the flow path forming substrate 10 are prepared.
An elastic film 50 made of silicon dioxide is formed by thermal oxidation in a 0 ° C. diffusion furnace.

Next, as shown in FIG. 3B, 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. The material of the lower electrode film 60 is platinum,
Iridium and the like are preferable. This is because the piezoelectric layer 70 described later, which is formed by the sputtering method or the sol-gel method, is 600 to 1000 in the air atmosphere or the oxygen atmosphere after the film formation.
This is because it is necessary to crystallize by firing at a temperature of about ° C. 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, as the piezoelectric layer 70, lead zirconate titanate (PZ
When T) is used, it is desirable that the change in conductivity due to diffusion of lead oxide is small, and for these reasons, platinum and iridium are preferable.

Next, as shown in FIG. 3C, the piezoelectric layer 70 and the upper electrode film 80 are sequentially laminated, and only the piezoelectric layer 70 and the upper electrode film 80 are etched to form the piezoelectric element 300. Perform patterning.

This piezoelectric layer 70 is, for example, in the present embodiment, a so-called sol in which a metal organic material is dissolved / dispersed in a catalyst is applied and dried to be gelled, and is further baked at a high temperature to form a piezoelectric body made of a metal oxide. The layer 70 was formed by using a so-called sol-gel method. 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, for example, a spin coating method such as a sputtering method or a MOD method (organic metal thermal coating decomposition method).

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

The upper electrode film 80 may be made of any material having high conductivity, and many metals such as aluminum, gold, nickel and platinum, and conductive oxides can be used. In this embodiment, platinum is deposited by sputtering.

Next, as shown in FIG. 3D, 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.

The above is the film forming process. After the film formation is performed in this way, as shown in FIG. 4A, the pressure forming chamber 12 is formed by anisotropically etching the flow path forming substrate 10 made of the silicon single crystal substrate by the above-mentioned alkaline solution. And so on. In addition, in the present embodiment, at the same time, the concave portion 15 that constitutes the stress relaxation portion 16 is formed in the flow path forming substrate 10.

Next, as shown in FIG. 4B, the reservoir forming substrate 30 is provided on the piezoelectric element 300 side of the flow passage forming substrate 10.
Then, as shown in FIG. 4C, the nozzle plate 20 is adhered to the surface of the flow path forming substrate 10 where the pressure generating chamber 12 is opened.

Here, as described above, the nozzle plate 20 is formed of the flow path forming substrate 1 by the thermosetting adhesive.
It adheres to 0. Therefore, each of the substrates such as the flow channel forming substrate 10, the reservoir forming substrate 30, the nozzle plate 20 and the like expands due to the heat of adhesion, and a warp occurs due to the difference in the thermal expansion coefficient of each substrate. Board 10
May crack.

That is, the flow path forming substrate 10 has relatively low rigidity in the region where the pressure generating chamber 12 is provided, and its peripheral portion has higher rigidity than the region where the pressure generating chamber 12 is provided. Therefore, regions on both outer sides of the row of the pressure generating chambers 12 serve as boundaries between regions having high rigidity and regions having low rigidity, and stress due to warpage concentrates on the boundary portions, so that pressure generation occurs on the flow path forming substrate 10. Breakage such as cracking may occur along the side surface of the chamber 12.

However, in the present invention, as described above, since the stress relaxation portions 16 composed of the plurality of concave portions 15 are provided on both outer sides of the row of the pressure generating chambers of the flow path forming substrate 10,
The stress due to the warpage generated in each substrate is not concentrated in a part, and it is possible to prevent the flow path forming substrate 10 from being broken or broken.

In the present embodiment, the rigidity of the flow path forming substrate 10 is gradually increased by gradually narrowing the width of each recess 15 toward the end of the flow path forming substrate 10. Therefore, stress concentration on a part of the flow path forming substrate 10 can be surely eliminated.

After that, the connection wiring is connected to the lead electrode 90 by wire bonding, and at that time, each substrate is heated at, for example, 100 ° C. to 120 ° C. By providing the stress relaxation portion 16, it is possible to prevent the occurrence of cracks or the like due to the flow path forming substrate 10 warping.

Further, the stress relaxation portion 1 is formed on the flow path forming substrate 10.
By providing 6, the rigidity of the flow path forming substrate becomes substantially uniform, so that it is possible to suppress variations in the displacement amount of the elastic film 50 and improve ink ejection characteristics.

(Second Embodiment) FIG. 5 is a plan view showing a main part of an ink jet recording head according to a second embodiment.

As shown in FIGS. 5 (a) and 5 (b), in this embodiment, the stress relaxation portion 16 composed of a plurality of recesses 15A is formed.
A is provided inside or outside of a region (a region in the vicinity of the line BB ′ in the drawing) along the end of the communicating portion 14 that constitutes a part of the reservoir. Further, each recess 15A forming the stress relaxation portion 16A is formed with the same width, and the pressure generating chamber 12
Is formed with a width narrower than the width.

In this way, by providing the stress relaxation portion on the flow path forming substrate, as in the first embodiment, the stress due to the warp generated on each substrate does not concentrate on a part, and the flow path forming substrate 10 It is possible to prevent the occurrence of breakage such as cracking.

If the recess 15A is provided in the region along the end of the communicating portion 14, the rigidity of this region is significantly reduced,
The stress due to the warp of the substrate concentrates and cracks are likely to occur. However, in the present embodiment, since the concave portion 15A is not provided in the region along the end of the communicating portion 14 but is provided inside or outside the region, the flow path forming substrate 10 is not cracked. It can be prevented more reliably.

Further, the width of the concave portion 15A constituting the stress relaxation portion 16A is not particularly limited, but it is preferable that the width is narrower than that of the pressure generating chamber 12 as in the present embodiment. Thereby, it is possible to prevent the rigidity of the flow path forming substrate 10 from being lowered more than necessary.

In this embodiment, the stress relaxation portion 16A
The widths of the recesses 15A constituting the above are substantially the same, but the widths of the recesses 15A are not limited to this. May be narrowed.

Further, in the present embodiment, the stress relieving portions 16A are provided only on one side inside or outside the region along the end of the communicating portion 14, but of course they may be provided on both sides.

(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-mentioned embodiment, the thin film type ink jet recording head manufactured by applying the film formation and the lithographic process is taken as an example, but the present invention is not limited to this, for example, a green sheet. The present invention can be applied to a thick film type ink jet recording head formed by a method such as sticking.

Further, 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 6
It is a schematic diagram showing an example of the ink jet type recording device.

As shown in FIG. 6, in the recording head units 1A and 1B having an ink jet recording head, the cartridges 2A and 2B constituting the ink supply means are detachably provided, and the recording head units 1A and 1B are provided.
The carriage 3 on which B is mounted is provided on a carriage shaft 5 attached to the apparatus body 4 so as to be movable in the axial direction. 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 drive 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 main 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 conveyed on the platen 8. It is like this.

[0071]

As described above, according to the present invention, the flow path forming substrate is provided with the stress relaxation portion whose rigidity is reduced by forming a plurality of recesses, and the widths of these recesses are changed stepwise. Since the rigidity of the flow path forming substrate is changed by doing so, it is possible to effectively suppress the concentration of the stress due to the warp on a part of the flow path forming substrate, and the flow path forming substrate is cracked or the like. Can be prevented. Further, since the rigidity of the flow path forming substrate is substantially uniform, the variation in the displacement amount of the diaphragm provided on the flow path forming substrate is suppressed, and the effect of improving the ink ejection characteristics is achieved.

[Brief description of drawings]

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

2A and 2B are a plan view and a cross-sectional view showing the ink jet recording head according to the first embodiment of the invention.

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 plan view showing an ink jet recording head according to a second embodiment of the invention.

FIG. 6 is a schematic diagram of an inkjet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

10 Flow path forming substrate 12 Pressure generation chamber 13 ink supply path 14 Communication 15,15A recess 16, 16A stress relaxation section 20 nozzle plate 21 nozzle opening 30 Reservoir forming substrate 31 Reservoir section 32 Piezoelectric element holder 40 compliance board 50 elastic membrane 60 Lower electrode film 70 Piezoelectric layer 80 Upper electrode film 100 reservoir 300 Piezoelectric element

Claims (7)

[Claims] 1. A flow path forming substrate which defines a pressure generating chamber communicating with the nozzle opening, and a region which is opposed to the pressure generating chamber via a vibration plate forming a part of the pressure generating chamber. In the ink jet recording head including a piezoelectric element that causes a pressure change in the pressure generating chamber, a plurality of concave portions are formed at both ends of the flow path forming substrate in the column direction of the pressure generating chamber, thereby providing rigidity. The ink jet recording head is characterized in that a stress relaxation portion having a reduced pressure is provided, and the rigidity of the flow path forming substrate is changed by changing the width of the concave portion stepwise. 2. The ink jet recording head according to claim 1, wherein the width of the recess is narrower toward the end of the flow path forming substrate. 3. The flow path forming substrate according to claim 1, wherein each pressure generating chamber communicates with each other, and a communicating portion that constitutes at least a part of a reservoir serving as a common ink chamber of the pressure generating chamber is provided. An ink jet recording head, wherein the stress relieving portion is formed inside or outside a region corresponding to an end of the communicating portion in the column direction of the pressure generating chambers. 4. A flow passage forming substrate that defines a pressure generating chamber communicating with the nozzle opening, and a region that faces the pressure generating chamber via a diaphragm that forms a part of the pressure generating chamber. In the ink jet recording head including a piezoelectric element that causes a pressure change in the pressure generating chamber, a plurality of concave portions are formed at both ends of the flow path forming substrate in the column direction of the pressure generating chamber, thereby providing rigidity. Is provided, and the stress relaxation portion is formed on at least one of the inside and the outside of the region along the end of the communication portion in the row direction of the pressure generating chambers. Inkjet recording head characterized by 5. The ink jet recording head according to claim 1, wherein the width of each recess forming the stress relaxation portion is narrower than the width of the pressure generating chamber. 6. The pressure generating chamber according to claim 1, wherein the pressure generating chamber is formed in a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by film formation and a lithography method. An ink jet recording head characterized by being present. 7. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.