JP2002205405A - Ink-jet recording head and ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording head and an ink-jet recording apparatus, capable of preventing destruction of a channel forming substrate by deformation, with an improved ink ejection characteristic. SOLUTION: In an ink-jet recording head comprising a channel forming substrate 10 made of a single crystal silicon, with a pressure generating chamber 12 communicating with a nozzle opening 21 sectioned by a plurality of partition walls, and a piezoelectric element 300 including a lower electrode 60 provided on one side surface of the channel forming substrate 10 via a vibration plate 50, a piezoelectric layer 70 and an upper electrode 80, a nozzle plate 20 having the nozzle opening 21 formed with a material different from that of the channel forming substrate 10 is bonded on the other side surface side of the channel forming substrate 10 as well as a stress alleviating part 23 with the rigidity lowered by partially forming a recess part 22 is provided on the channel forming substrate 10 side surface of the nozzle plate 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure generating chamber which communicates with a nozzle opening for discharging ink droplets, which is constituted by a vibrating plate. TECHNICAL FIELD The present invention relates to an ink jet recording head and an ink jet recording apparatus for ejecting ink droplets by using an ink jet recording head.

[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. Ink jet recording heads that eject droplets use a longitudinal vibration mode piezoelectric actuator that expands and contracts in the axial direction of the piezoelectric element, and a flexural vibration mode piezoelectric actuator.
The types have been put to practical use.

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

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

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

[0006]

A nozzle plate having nozzle openings is joined to such an ink jet recording head. The nozzle plate is made of a material different from that of the flow path forming substrate, for example, a stainless steel plate. When the nozzle plate is joined with a thermosetting adhesive, or when the drive wiring is connected to the piezoelectric element by wire bonding or the like. For example, when the flow path forming substrate to which the nozzle plate is bonded is heated at a high temperature, the nozzle plate is deformed due to a difference in thermal expansion coefficient, and the flow path forming substrate is cracked and broken.

[0007] Such destruction of the flow path forming substrate can be prevented by reducing the thickness of the nozzle plate to suppress the deformation due to thermal expansion. However, since the compliance of the nozzle plate is increased, it is difficult to discharge ink droplets. There is a problem that the pressure causes the nozzle plate to be deformed and the ink ejection characteristics to deteriorate.

Further, if the heating temperature at the time of wire bonding is set to a low temperature in order not to heat the flow path forming substrate to which the nozzle plate is joined at a high temperature, the reliability of the connection is reduced, the connection is time-consuming, and the manufacturing cost is reduced. There is a problem that it becomes expensive.

In view of such circumstances, it is an object of the present invention to provide an ink jet recording head and an ink jet recording apparatus which prevent the flow path forming substrate from being broken due to deformation and have improved ink ejection characteristics.

[0010]

According to a first aspect of the present invention, there is provided a flow path forming substrate made of single crystal silicon, wherein a pressure generating chamber communicating with a nozzle opening is defined by a plurality of partition walls. A lower electrode provided on one surface of the flow path forming substrate via a vibrating plate, a piezoelectric element including a piezoelectric layer and an upper electrode, and the other surface side of the flow path forming substrate. A nozzle plate having the nozzle opening formed of a material different from that of the flow path forming substrate is joined, and a concave portion is partially formed on a surface of the nozzle plate on the flow path forming substrate side. An ink jet recording head is provided with a stress relieving portion having reduced rigidity.

In the first aspect, by providing the nozzle plate with the stress relieving portion composed of the concave portion formed partially, it is possible to prevent deformation due to thermal expansion while maintaining rigidity.

According to a second aspect of the present invention, in the first aspect, the concave portion is formed in a shape selected from a honeycomb shape, a slit shape, a lattice shape, and a column shape. In the head.

In the second aspect, by forming the concave portion in a predetermined shape, it is possible to reliably prevent thermal expansion while maintaining rigidity.

According to a third aspect of the present invention, in the first or second aspect, the concave portion is provided in a region other than the vicinity of the nozzle opening, and the nozzle plate has a residual portion near the nozzle opening. And an ink jet recording head.

In the third aspect, the nozzle opening can be formed in a desired shape.

According to a fourth aspect of the present invention, in the third aspect, a peripheral portion of the nozzle opening has a predetermined thickness and a tapered portion whose inner diameter gradually increases toward the flow path forming substrate. An ink jet recording head comprising:

In the fourth aspect, the bubbles near the nozzle opening can be stopped by the tapered portion, and the ink ejection characteristics are improved.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the concave portion is provided in a region other than a joint surface of the nozzle plate with the flow path forming substrate. And an ink jet recording head.

In the fifth aspect, deformation due to thermal expansion can be reliably prevented while maintaining the rigidity of the nozzle plate.

According to a sixth aspect of the present invention, there is provided an ink jet recording head according to any one of the first to fifth aspects, wherein the piezoelectric element is formed by film formation and lithography.

According to the sixth aspect, the pressure generating chambers can be formed relatively easily and with high precision at a high density.

According to a seventh aspect of the present invention, there is provided an ink jet recording apparatus including 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 head having improved durability and reliability of the head.

[0024]

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 top view of the ink jet recording head and a longitudinal direction of a pressure generating chamber. FIG.

As shown in the figure, the flow path forming substrate 10 is 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 11 between the adjacent pressure generating chambers.

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

On the other hand, a silicon single crystal substrate is anisotropically etched on the opening surface of the flow path forming substrate
The pressure generating chambers 12 divided by the plurality of partition walls 11 are provided in parallel in the width direction, and on the outside in the longitudinal direction, a common ink chamber of each pressure generating chamber 12 communicates with a reservoir portion of a reservoir forming substrate described later. A communication portion 13 forming a part of the reservoir 100 is formed, and is communicated with one end of each pressure generating chamber 12 in the longitudinal direction via an ink supply path 14.

Here, in the anisotropic etching, when the silicon single crystal substrate is immersed in an alkaline solution such as KOH, the 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. Further, each ink supply path 14 communicating with one end of each pressure generating chamber 12 is
It is formed shallower and keeps the flow resistance of the ink flowing into the pressure generating chamber 12 constant. 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 the opening side of the flow path forming substrate 10,
A nozzle plate 20 having a nozzle opening 21 communicating with each pressure generating chamber 12 on the side opposite to the ink supply path 14 is fixed via a thermosetting adhesive.

In the present embodiment, the thickness of the nozzle plate 20 is set to 50 to 80 μm, and the concave portion 22 which is partially provided in a predetermined pattern is formed on the surface of the nozzle plate 20 on the side of the flow path forming substrate 10. Stress relief part 23
Is configured.

Here, the concave portion 22 is provided only in a predetermined region with respect to the entire nozzle plate 20 as shown in FIG. 3, and in the present embodiment, the concave portion 22 is
, That is, in a region facing the pressure generating chamber 12, the communication portion 13, and the ink supply path 14, the openings are provided in the same size as the openings without penetrating the nozzle plate 20. In the present embodiment, the depth of the concave portion 22 is set so that the thickness of the region of the nozzle plate 20 where the concave portion 22 is formed is approximately 30 μm.

The stress relaxation portion 23 composed of the plurality of recesses 22 provided as described above can reduce the in-plane rigidity of the nozzle plate 20 and maintain the out-of-plane rigidity. Therefore, when the nozzle plate 20 is bonded to the flow path forming substrate 10 with a thermosetting adhesive, or when a drive wiring is connected to a piezoelectric element described later, the flow path forming substrate 10 to which the nozzle plate 20 is bonded is used. Even when heated at a high temperature, the nozzle plate 20 has low rigidity in the in-plane direction, so that deformation due to thermal expansion can be prevented.
It is possible to prevent the occurrence of breakage such as cracks at 0. Further, since the nozzle plate 20 maintains rigidity in an out-of-plane direction, the compliance is low, and the ink ejection characteristics are not deteriorated due to the deformation of the nozzle plate 20 at the time of ejecting ink droplets.

In the present embodiment, the concave portion 22 is provided so as to have substantially the same size as each opening of the flow path forming substrate 10. However, the present invention is not limited to this. The pressure generating chamber 12 may be formed to have a width smaller than the width thereof. As described above, the width and the length of the concave portion 22 are not particularly limited. There is a need. For example, it is preferable to provide the concave portion 22 so as to have an area of about 30 to 70% of a region of the nozzle plate 20 facing the pressure generating chamber 12 and a depth of about 20 to 70% of the nozzle plate 20.

The stress relaxation portion 23 composed of such a concave portion 22 is patterned on a nozzle plate 20 in which the nozzle opening 21 is formed in advance with a photoresist or the like.
By etching, it can be easily formed in a predetermined shape.

The nozzle opening 2 of the nozzle plate 20
1 has a concave portion 2 near the nozzle opening 21 in order to provide a tapered portion 24 whose inner diameter gradually increases toward the flow path forming substrate 10.
2 was formed without forming the remaining portion 25.

According to the tapered portion 24, the nozzle opening 2
Air bubbles generated when the ink is ejected from No. 1 stay in the tapered portion 24, so that the air bubbles are easily sucked by a suction operation 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 on the side opposite to the opening surface of the flow path forming substrate 10, the thickness is, for example, about 0.2 μm.
A lower electrode film 60, a piezoelectric layer 70 having a thickness of, for example, about 1 μm, and an upper electrode film 80 having a thickness of, for example, about 0.1 μm are formed by film formation and lithography to form a laminate.
The piezoelectric element 300 is constituted. Here, the piezoelectric element 30
0 is the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80
Means the part containing In general, 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 of the pressure generating chambers 12. In this case, the piezoelectric active layer 320 is composed of one of the patterned electrodes and the piezoelectric layer 70, and the portion where the piezoelectric strain is generated by the application of the voltage to both the electrodes is formed.
That. In the present embodiment, the lower electrode film 60 is
Although the common electrode is 0 and the upper electrode film 80 is an individual electrode of the piezoelectric element 300, it does not matter if the configuration is reversed for convenience of a drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and a diaphragm whose displacement is generated by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the example described above, the elastic film 50
The lower electrode film 60 functions as a diaphragm, but the lower electrode film may also serve as an elastic film.

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. The connection of the driving wires is performed by wire bonding or the like. In this wire bonding, the flow path forming substrate 10 to which the nozzle plate 20 is bonded at the time of connection is heated to a high temperature, for example, 100 ° C. to 120 ° C.
However, in the present embodiment, since the nozzle plate 20 is provided with the stress relaxation portion 23 composed of the concave portion 22 partially formed in a predetermined shape,
Even when the flow path forming substrate 10 bonded to the above is heated at a high temperature, the flow path forming substrate 10 is not deformed by thermal expansion, and the flow path forming substrate 10 is not broken or broken. Therefore, the connection by wire bonding can be performed at a high temperature, and the time required for the connection can be shortened, so that the manufacturing cost can be reduced and the drive wiring can be reliably connected.

The piezoelectric element 300 of the flow path forming substrate 10
On the side, a reservoir forming substrate 30 having a reservoir part 31 constituting at least a part of the reservoir 100 is joined. In this embodiment, the reservoir portion 31 penetrates the reservoir forming substrate 30 in the thickness direction, and
Each of the pressure generating chambers 12 is communicated with the communicating portion 13 of the flow path forming substrate 10 as described above.
Constitute a reservoir 100 serving as a common ink 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, for example, glass, ceramic material, or the like. A silicon single crystal substrate of the same material as 10 was used. As a result, the two can be securely bonded by high-temperature bonding using a thermosetting adhesive, and the manufacturing process can be simplified.

The piezoelectric element 3 of the reservoir forming substrate 30
A piezoelectric element holding portion 32 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. Sealed inside. In this embodiment, the piezoelectric element holding portion 32 is formed to have a size that covers each row of the plurality of piezoelectric elements 300 arranged in the width direction.

As described above, the reservoir forming substrate 30 has the piezoelectric element holding portion 32 that seals the piezoelectric element 300 together with the reservoir portion 31 that constitutes a part of the reservoir 100, and is used to shut off the piezoelectric element 300 from the external environment. The piezoelectric element 30 which also serves as a sealing member and is formed by an external environment such as atmospheric moisture.
0 is prevented from being destroyed.

Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is joined 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 31 is sealed by the sealing film 41. The fixing plate 42 is made of a hard material such as a 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, one surface of the reservoir 100 is sealed with only the sealing film 41 having flexibility, thereby forming a flexible portion 45 that can be deformed by a change in internal pressure.

Further, an ink inlet 44 for supplying ink to the reservoir 100 is formed on the compliance substrate 40 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 36 that communicates the ink introduction port 44 with the side wall of the reservoir 100. In the present embodiment, the ink is supplied to the reservoir 100 by one ink introduction port 44 and the ink introduction path 36. However, the present invention is not limited to this. For example, according to a desired ink supply amount, A plurality of ink introduction ports and ink introduction paths may be provided, or the opening area of the ink introduction ports may be increased to enlarge the ink flow path.

The ink jet recording head of this embodiment takes in ink from the ink inlet 44 connected to external ink supply means (not shown),
After the inside is filled with ink from 00 to the nozzle opening 21, each lower electrode film 60 corresponding to the pressure generating chamber 12 is formed according to a recording signal from an external driving circuit (not shown).
By applying a voltage between the upper electrode film 80 and the elastic film 50, the lower electrode film 60 and the piezoelectric layer 70 are flexed and deformed, the pressure in each pressure generating chamber 12 increases, and the nozzle opening 2
An ink droplet is ejected from 1.

As described above, in the ink jet recording head of the present embodiment, the thermal expansion of the flow path forming substrate 10 and the nozzle plate 20 during high-temperature heating is achieved by providing the nozzle plate 20 with the stress alleviating portion 23 composed of the concave portion 22. Thus, the flow path forming substrate 10 can be prevented from being broken due to cracks and the like. Also,
Rather than making the nozzle plate 20 thinner as a whole, the compliance of the nozzle plate 20 is reduced by providing a stress relaxation portion 23 composed of a concave portion 22 partially formed in a predetermined shape, so that the nozzle plate 20 can discharge ink droplets. By preventing deformation, the ink ejection characteristics are not reduced.

In this embodiment, the nozzle plate 2
The recess 22 is formed in a region facing the opening of the
Although the stress relieving portion 23 made of is provided, the present invention is not limited to this. For example, a concave portion may be provided in a region facing the joint surface with the flow path forming substrate 10. Such an example is shown in FIG. FIG. 4 is a plan view of a nozzle plate and an enlarged cross-sectional view of a main part in a direction in which nozzle openings are juxtaposed.

As shown in FIG. 4, the nozzle plate 20A
The surface on the side of the flow path forming substrate 10 is provided with a stress relaxation portion 23A composed of a concave portion 22A in a region to be joined to the flow path forming substrate 10. That is, the nozzle plate 20A is provided with the stress relaxation portion 23A formed of the concave portion 22A by etching a region other than the region corresponding to the pressure generating chamber 12, the communication portion 13, and the ink supply passage 14 of the flow path forming substrate 10.

The stress relaxing portion 23A composed of the recess 22A can also reduce the in-plane rigidity of the nozzle plate 20A and maintain the out-of-plane rigidity. Therefore, when the flow path forming substrate 10 to which the nozzle plate 20A is bonded is heated at a high temperature, deformation due to thermal expansion can be prevented, and the flow path forming substrate 10 can be prevented from being broken or otherwise broken. . In addition, by maintaining the rigidity in the out-of-plane direction, the ink ejection characteristics are not reduced.

(Embodiment 2) In Embodiment 1 described above,
Although one concave portion 22 of the stress relaxation portion 23 is provided with a size substantially equal to the opening of the flow path forming substrate 10, the present embodiment is an example in which a plurality of hole-shaped or groove-shaped concave portions are provided.

In this embodiment, a concave portion formed in a honeycomb shape, a column shape, a slit shape and a lattice shape as the concave portion of the stress relaxation portion will be described with reference to FIGS. FIGS. 5 and 6 are plan views of the nozzle plate according to the second embodiment.

The example shown in FIG. 5A is an example of the concave portion 22B formed in a honeycomb shape. More specifically, the nozzle plate 20B has the pressure generating chambers 12, the communication section 13, and the ink supply path. A plurality of hexagonal concave portions 22A are arranged side by side in a region facing 14 to form a honeycomb-shaped stress relaxation portion 23B.

The example shown in FIG. 5B is an example of a concave portion 22C formed in a columnar shape. In the nozzle plate 20C, each pressure generating chamber 12, communication portion 13, and ink supply passage 14 are provided. A plurality of cylindrical recesses 22
A stress relaxation portion 23C made of C is provided.

The example shown in FIG. 6A is an example of a concave portion 22D formed in a slit shape. Each of the pressure generating chambers 12, the communication section 13, and the ink supply path 14 is provided in the nozzle plate 20D. A plurality of slit-shaped recesses 22D provided along the width direction of the pressure generating chamber 12 in a region facing the
Is formed.

Further, the example shown in FIG. 6B is an example of a concave portion 22E formed in a lattice shape. Each of the pressure generating chambers 12, the communication portion 13, and the ink supply passage 14 is provided in the nozzle plate 20E. Is formed in a region opposed to the stress relief portion 23E composed of a lattice-shaped concave portion 22E.

As described above, as shown in FIGS.
Regardless of the shape of the stress relaxing portions 23B to 23E, the in-plane rigidity of the nozzle plates 20B to 20E can be reduced and the out-of-plane rigidity can be maintained. Therefore, when the flow path forming substrate 10 to which the nozzle plates 20B to 20E are joined is heated at a high temperature, it is possible to prevent deformation due to thermal expansion and prevent breakage such as cracks from occurring. Further, since the out-of-plane rigidity of the nozzle plates 20B to 20E is maintained, the ink ejection characteristics are not reduced without lowering the compliance.

In this embodiment, the nozzle plate 2
The recesses 22B to 22E of the flow path forming substrate 10
It is needless to say that the regions where the concave portions 22B to 22E are formed are not limited to the same as in the first embodiment described above.

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

In Embodiments 1 and 2 described above, as the stress relaxing portions 23 to 23D, the concave portion 22 having substantially the same size as the opening of the flow path forming substrate, the honeycomb-shaped concave portion 22A, the columnar concave portion 22B, the slit-shaped The concave portion 22C and the lattice-shaped concave portion 22D have been exemplified, but the shape of the concave portion is not limited to this.

Further, for example, in the above-described first and second embodiments, the pressure generating chamber 12 is formed so as to penetrate the flow path forming substrate 10, but the shape of the pressure generating chamber is not particularly limited. Instead, for example, it may be formed on one surface side of the flow path forming substrate without penetrating the flow path forming substrate.

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 and 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 the 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.

[0067]

As described above, according to the present invention, the rigidity of the flow path forming substrate is maintained by providing a stress relaxation portion formed of a partially formed concave portion on the surface of the nozzle plate on the flow path forming substrate side. As a result, deformation due to thermal expansion can be prevented. Therefore, when the flow path forming substrate to which the nozzle plate is bonded is heated at a high temperature, it is possible to prevent the flow path forming substrate from being cracked or the like and destroyed.
In addition, since the flow path forming substrate to which the nozzle plate is bonded can be heated at a high temperature, the time required for connecting the wires can be reduced, the manufacturing cost can be reduced, and the connection can be reliably performed. Further, since the rigidity of the nozzle plate can be maintained, the ink ejection characteristics do not deteriorate.

[Brief description of the drawings]

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

FIG. 2 is a top view and a cross-sectional view illustrating the ink jet recording head according to the first embodiment of the present invention.

FIG. 3 is a top view of a nozzle plate according to Embodiment 1 of the present invention and a cross-sectional view in which main parts are enlarged.

FIG. 4 is a top view showing a modified example of the nozzle plate according to the first embodiment of the present invention and a cross-sectional view in which main parts are enlarged.

FIG. 5 is a top view of a nozzle plate according to a second embodiment of the present invention.

FIG. 6 is a top view of a nozzle plate according to a second embodiment of the present invention.

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

[Explanation of symbols]

 Reference Signs List 10 flow path forming substrate 12 pressure generating chamber 13 communication part 14 ink supply path 15, 15A to 15H concave part 16, 16A to 16H stress relieving part 20, 20A to 20E nozzle plate 21 nozzle opening 22, 22A to 22E concave part 23, 23A to 23E Stress relaxation part 24 Tapered part 25 Residual part 30 Reservoir forming substrate 31 Reservoir part 32 Piezoelectric element holding part 40 Compliance substrate 50 Elastic film 60 Lower electrode film 70 Piezoelectric layer 80 Upper electrode film 100 Reservoir 300 Piezoelectric element

Claims (7)

[Claims] A pressure generating chamber made of single-crystal silicon and communicating with a nozzle opening is provided on a flow path forming substrate defined by a plurality of partition walls and on one surface of the flow path forming substrate via a diaphragm. In an ink jet recording head including a lower electrode, a piezoelectric layer, and a piezoelectric element including an upper electrode, the nozzle opening formed of a material different from the flow path forming substrate is provided on the other surface side of the flow path forming substrate. And a stress relieving portion whose rigidity is reduced by partially forming a concave portion is provided on the surface of the nozzle plate on the side of the flow path forming substrate. Inkjet recording head. 2. The ink jet recording head according to claim 1, wherein the recess is formed in a shape selected from a honeycomb shape, a slit shape, a lattice shape, and a column shape. 3. The ink jet recording head according to claim 1, wherein the recess is provided in a region other than the vicinity of the nozzle opening, and the nozzle plate has a residual portion near the nozzle opening. 4. The ink jet type according to claim 3, wherein a peripheral portion of the nozzle opening has a predetermined thickness and a tapered portion whose inner diameter gradually increases toward the flow path forming substrate. Recording head. 5. The ink jet recording head according to claim 1, wherein the recess is provided in a region other than a joint surface of the nozzle plate with the flow path forming substrate. 6. An ink jet recording head according to claim 1, wherein said piezoelectric element is formed by film formation and lithography. 7. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.