JP2002205394A - 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 pressure generating chambers can be arranged with high density while preventing crosstalk. SOLUTION: The ink jet recording head comprises pressure generating chambers 12 communicating with nozzle openings, and piezoelectric elements 300 each comprising a lower electrode 60, a piezoelectric layer 70 and an upper electrode 80 provided in a region corresponding to the pressure generating chamber 12 through a diaphragm. A plurality of pressure generating chambers 12 each having a part 12a narrower than the major part at one longitudinal end part thereof are juxtaposed as a set of two rows such that the narrow parts 12a are placed on the inside while overlapping alternately in the longitudinal direction thus arranging the nozzle openings at a high density.

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, 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 commercialized, one using a longitudinal vibration mode piezoelectric actuator that expands and contracts in the axial direction of the piezoelectric element, 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 recent years, with such an ink jet recording head, it has been desired to realize higher quality printing by further increasing the density of nozzle openings.

[0008]

However, in order to increase the density of the nozzle openings, it is necessary to arrange the pressure generating chambers at a high density. Since the thickness of the partition between them becomes thin, the rigidity of the partition becomes insufficient, and there is a problem that crosstalk occurs between the adjacent pressure generating chambers.

Also, for example, by reducing the width of the pressure generating chambers and increasing the length in the longitudinal direction, it is possible to arrange the pressure generating chambers of a predetermined volume at a high density while maintaining the rigidity of the partition walls. It is possible. However, in the case of such a structure, there is a problem in that the cross-sectional area of the pressure generating chamber is reduced, so that the flow of ink is hindered, and the attenuation characteristics are reduced.

In view of such circumstances, an object of the present invention is to provide an ink jet recording head and an ink jet recording apparatus which can arrange pressure generating chambers at high density and can prevent crosstalk.

[0011]

According to a first aspect of the present invention for solving the above-mentioned problems, a pressure generating chamber communicating with a nozzle opening and a region corresponding to the pressure generating chamber are provided via a diaphragm. In an ink jet recording head including a piezoelectric element composed of a lower electrode, a piezoelectric layer, and an upper electrode, a plurality of pressure generating chambers each having a narrow portion narrower than a width of a main portion at one longitudinal end thereof. The inkjet recording head is characterized in that the narrow portions are arranged inside and the narrow portions are alternately overlapped in the longitudinal direction in a set of two rows.

In the first aspect, the pressure generating chambers can be arranged at substantially high density without reducing the rigidity of the partition between the pressure generating chambers.

According to a second aspect of the present invention, in the first aspect, the piezoelectric element is provided over an area opposed to a narrow portion of the pressure generating chamber, and is provided in an area opposed to the pressure generating chamber. In the ink jet recording head.

In the second aspect, by driving the piezoelectric element, a sufficient pressure can be applied to the pressure generating chamber, and the ink can be discharged satisfactorily.

According to a third aspect of the present invention, in the first or second aspect, the nozzle opening is provided to face the narrow portion, and the nozzle openings corresponding to the two rows of pressure generating chambers are provided. , Arranged in a line.

In the third aspect, the nozzle openings can be arranged at a high density, and the print quality can be improved.

According to a fourth aspect of the present invention, in any one of the first to third aspects, at least a part of the side surface of the pressure generating chamber in the inner circumferential direction is formed of a curved surface. In the ink jet recording head.

In the fourth aspect, the flow of the ink in the pressure generating chamber becomes smooth, and the ink ejection characteristics and the ink attenuation characteristics are improved.

According to a fifth aspect of the present invention, there is provided an ink jet recording head according to the fourth aspect, wherein the pressure generating chamber has a substantially elliptical planar shape.

In the fifth aspect, the flow of the ink in the pressure generating chamber becomes smoother, and the ink discharge characteristics and the ink attenuation characteristics are surely improved.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the width of the main portion of the pressure generating chamber is the widest at the substantially central portion in the longitudinal direction. In the head.

In the sixth aspect, since the thickness of the partition wall between the pressure generating chambers becomes thicker toward the longitudinal end of the pressure generating chamber, the rigidity of the partition wall can be reliably maintained.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the maximum width of the main part of the pressure generating chamber is:
In the ink jet recording head, the maximum width of the narrow portion is twice or more.

In the seventh aspect, since the width of the main portion of the pressure generating chamber is relatively wide, the flow area of the ink is increased, and the flow of the ink is smooth.

According to an eighth aspect of the present invention, there is provided an ink jet recording head according to any one of the first to seventh aspects, wherein a thickness of a partition wall between adjacent pressure generating chambers is 50 μm or more. is there.

In the eighth aspect, the rigidity of the partition wall between the pressure generating chambers is reliably maintained, and the occurrence of crosstalk is suppressed.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, a lead electrode is provided on the peripheral wall from the upper electrode constituting the piezoelectric element, and each of the two adjacent rows is provided with a lead electrode. In an ink jet recording head, a lead electrode provided on a piezoelectric element corresponding to a pressure generating chamber extends in the same direction.

In the ninth aspect, the connection between the lead electrode corresponding to each piezoelectric element and the external wiring is facilitated, so that the structure can be simplified and the head can be downsized.

A tenth aspect of the present invention is the ink jet recording head according to any one of the first to ninth aspects, wherein the nozzle opening is formed in a silicon single crystal substrate.

In the tenth aspect, the nozzle opening can be formed easily and with high precision.

According to an eleventh aspect of the present invention, there is provided an ink jet recording head according to any one of the first to tenth aspects, wherein the pressure generating chamber is formed on a silicon single crystal substrate by dry etching. is there.

In the eleventh aspect, a pressure generating chamber having a desired shape can be easily and accurately formed.

According to a twelfth 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 eleventh aspects.

According to the twelfth aspect, it is possible to realize an ink jet recording apparatus with improved ink ejection characteristics and print quality.

[0035]

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 sectional view thereof.

As shown in FIGS. 1 and 2, the flow path forming substrate 10 in which the pressure generating chamber is formed is a silicon single crystal substrate having a plane orientation (110) in this embodiment. As the flow path forming substrate 10, a substrate having a thickness of about 150 to 300 μm is generally used, and a substrate having a thickness of preferably about 180 to 280 μm, more preferably about 220 μm is suitable. This is because the arrangement density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.

One surface of the flow path forming substrate 10 is an opening surface, and the other surface is formed with an elastic film 50 having a thickness of 1 to 2 μm and made of silicon dioxide previously formed by thermal oxidation.

On the other hand, the opening surface of the flow path forming substrate 10 is dry-etched on the silicon single crystal substrate,
A plurality of pressure generating chambers 12 are formed. In the present embodiment, at one end in the longitudinal direction, a plurality of pressure generating chambers 12 each having a narrow portion 12a narrower than the width of the main portion are formed with the narrow portion 12a inside and the narrow portion 12a. Two rows 13 (13A, 13B) such that 12a alternately overlap in the longitudinal direction
Are arranged side by side as a set. This pressure generating chamber 1
2 will be described later in detail.

On the other side of the flow path forming substrate 10,
A nozzle plate 20 having a nozzle opening 21 communicating with the narrow portion 12a of each pressure generating chamber 12 opposite to the ink supply path 14, that is, a nozzle plate 20 is fixed via an adhesive or a heat welding film. . Further, the pressure generating chambers 1 of each row 13
The nozzle openings 21 corresponding to 2 are arranged in a line.

The nozzle plate 20 is preferably formed of a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10. For example, in the present embodiment, the nozzle plate 20
The nozzle opening 21 is formed by dry etching using a silicon single crystal substrate. Since the nozzle plate 20 is formed of a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10 as described above, the deformation of the flow path forming substrate 10 and the nozzle plate 20 due to heat becomes substantially the same. The channel forming substrate and the nozzle plate can be easily joined using a curable 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, the lower electrode film 60 having a thickness of, for example, about 0.2 μm and the piezoelectric film having a thickness of, for example, about 1 μm are formed on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10. Body layer 7
0 and an upper electrode film 80 having a thickness of about 0.05 μm, for example,
0. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. 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. 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 a common electrode of the piezoelectric element 300, and the upper electrode film 80 is an individual electrode of the piezoelectric element 300.
Even if this is reversed for convenience of the drive circuit and wiring, there is no problem.
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 this embodiment, the piezoelectric element 300
Is provided in a region facing the pressure generating chamber 12 and is formed over a region facing the narrow portion 12 a of the pressure generating chamber 12. That is, the piezoelectric element 300 is placed in a region facing the narrow portion 12a of the pressure generating chamber 12.
00 has a tip portion 300a narrower than the main portion.

Here, the process of forming the piezoelectric layer 70 and the like on the flow path forming substrate 10 made of a silicon single crystal substrate will be described with reference to FIGS. 2 and 3 are cross-sectional views of the pressure generating chamber 12 in the longitudinal direction.

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

Next, as shown in FIG. 3B, a lower electrode film 60 is formed by sputtering. As a material of the lower electrode film 60, platinum (Pt), a platinum (Pt) / titanium (Ti) multilayer film, or the like is preferable. This is because a piezoelectric layer 70 described later, which is formed by a sputtering method or a sol-gel method,
After film formation, 600 to 10 in an air atmosphere or an oxygen atmosphere
This is because it is necessary to perform crystallization by firing at a temperature of about 00 ° 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, when the piezoelectric layer 70 is made of lead zirconate titanate (PZT), 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. 3C, a piezoelectric layer 70 is formed. In the piezoelectric layer 70, it is preferable that crystals are oriented. For example, in the present embodiment, a so-called sol-gel method in which a so-called sol in which a metal organic substance is dissolved and dispersed in a catalyst is applied and dried to form a gel, and then fired at a high temperature to obtain a piezoelectric layer 70 made of a metal oxide. To form a piezoelectric layer 70 in which crystals are oriented. As a material for the piezoelectric layer 70, a lead zirconate titanate-based material is suitable when used in an ink jet recording head. The method for forming the piezoelectric layer 70 is not particularly limited, and may be, for example, a sputtering method.

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

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

Next, as shown in FIG. 3D, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and can use many metals such as aluminum, gold, nickel, and platinum, and a conductive oxide. In the present embodiment, platinum is formed by sputtering.

Thereafter, as shown in FIG. 4A, only the piezoelectric layer 70 and the upper electrode film 80 are etched to pattern the piezoelectric active portion 320. At the same time, the elastic film 50 and the lower electrode film 60 are etched to form a communication hole 51 for communicating each pressure generating chamber 12 with a reservoir 41 described later.
To form

The above is the film forming process. After forming the film in this manner, as shown in FIG. 4B, the silicon single crystal substrate is dry-etched with the above-described alkali solution to form the pressure generating chamber 12 and the like. In addition,
After that, it is preferable that the inner surface of the pressure generating chamber 12 and the like, that is, the etched surface is further light-etched with, for example, a mixed solution of fluorine and nitric acid to flatten the etched surface.

In practice, a large number of chips are simultaneously formed on one wafer by such a series of film formation and dry etching, and after completion of the process, a chip of one chip size as shown in FIG. It is divided for each flow path forming substrate 10.

Here, the structure of the pressure generating chamber and the piezoelectric element thus formed will be described in detail. In addition,
FIG. 5 is a plan view showing the structures of the pressure generating chamber and the piezoelectric element.

As shown in FIG. 5, the pressure generating chamber 12 includes a row 13A in which a plurality of pressure generating chambers 12 (12A) are arranged in the width direction and a plurality of pressure generating chambers 12 (12B) in the width direction. The rows 13B provided are formed as a set on the flow path forming substrate 10. Further, each of the pressure generating chambers 12A and 12B has a narrow portion 12a at one longitudinal end.
The pressure generating chambers 12A and 12B are alternately arranged such that the narrow portions 12a overlap each other in the longitudinal direction of the pressure generating chamber 12 with the narrow portions 12a inside. And
As described above, the nozzle opening 21 is connected to each pressure generating chamber 12.
A and 12B are provided in regions corresponding to the narrow portions 12a, and are arranged in a line.

The pressure generating chambers 12 are preferably arranged such that the thickness of the partition 11 between the pressure generating chambers 12 is 50 μm or more. For example, in the present embodiment, the pressure generating chambers 12 are arranged such that the thickness of the partition wall 11 between the narrow portions 12a of the pressure generating chambers 12A and 12B is the narrowest, and the width of this portion is about 50 μm. ing.

In such a configuration, each row 13A, 13B
Pressure generating chambers 12A and 12B are arranged such that narrow portions 12a narrower than the main portion overlap each other.
The pitch between the pressure generating chambers 12A and 12B, that is, the pitch between the nozzle openings 21 communicating with the narrow portions 12a can be reduced. In addition, the partition 11 between the pressure generating chambers 12A in each row, for example, the row 12A, can secure a sufficient thickness, and can reliably obtain desired rigidity. That is, with the configuration of the present embodiment, the nozzle openings 21 can be arranged at a high density without reducing the rigidity of the partition walls 11 between the pressure generating chambers 12. For example,
If the width of the main part of the pressure generating chamber 12 is 49 μm, 51
It is possible to arrange the nozzle openings 21 at a high density of about 2 dpi.

The maximum width of the main part of the pressure generating chamber 12 is preferably at least twice the maximum width of the narrow part 12a. That is, it is preferable that the width of the main part of the pressure generating chamber 12 be relatively wide and the length of the pressure generating chamber 12 in the longitudinal direction be relatively short. In the present embodiment, the inner surface of the pressure generating chamber 12 is formed as a flat surface,
The width of the main part of the pressure generating chamber 12 and the width of the narrow part 12a are:
Each is uniform.

As a result, the cross-sectional area of the pressure generating chamber 12 in the width direction, that is, the flow path area of the ink is increased, so that the damping characteristic at the time of discharging the ink is improved. Therefore,
The ink ejection characteristics and print quality are improved.

Each of the piezoelectric elements 300 is provided in a region facing each of the pressure generating chambers 12 formed as described above, and each of the piezoelectric elements 300 faces each of the pressure generating chambers 12 as described above. The piezoelectric element 30 is provided in a region facing the narrow portion 12 a of the pressure generating chamber 12.
0 has a tip portion 300a narrower than the main portion.

As described above, in this embodiment, the piezoelectric element 3
Since the piezoelectric element 300 has a tip portion 300a and is formed over a region opposed to the narrow portion 12a of the pressure generation chamber 12, the pressure required for ink ejection into the pressure generation chamber 12 by driving the piezoelectric element 300 is formed. Can be reliably provided. Of course, the piezoelectric element 300 may be provided only in a region facing the main part of the pressure generating chamber 12.

In this embodiment, each piezoelectric element 300
A lead electrode 90 extends on the peripheral wall from the upper electrode film 80, which is an individual electrode, and is connected to an external terminal (not shown) near the end of the lead electrode 90. This lead electrode 9
The extending direction of the pressure generating chambers 0A, 0B is not particularly limited, but as shown in FIG.
12B corresponding to the lead electrode 90 (9
0A, 90B) extend in the same direction. In the present embodiment, the lead electrode 90A of the piezoelectric element 300 corresponding to the pressure generating chamber 12A is
A from the end opposite to the narrow portion 12a of A
The lead electrode 90B of the piezoelectric element 300 extending to the vicinity of the zero end and corresponding to the pressure generation chamber 12B is connected to the pressure generation chamber 12B.
B extends from the end on the narrow portion 12a side to the vicinity of the end of the flow path forming substrate 10 via the partition 11 between the pressure generating chambers 12A.

As described above, if each of the lead electrodes 90A and 90B of each piezoelectric element 300 is extended in the same direction, it is easy to take out the external wiring and the size of the head can be reduced.

The sealing substrate 30, the reservoir forming substrate 40, and the compliance substrate 45 are sequentially adhered to the flow path forming substrate 10 in which the pressure generating chambers 12, the piezoelectric elements 300, and the like are formed. It becomes a recording head.

More specifically, as shown in FIGS. 1 and 2, a space is secured on the piezoelectric element 300 side of the flow path forming substrate 10, that is, on the elastic film 50, so as not to hinder the movement of the piezoelectric element 300. In this state, the sealing substrate 30 having the piezoelectric element holding portion 31 capable of sealing the space is joined. The piezoelectric element 300 is hermetically sealed in the piezoelectric element holding portion 31 to prevent breakage of the piezoelectric element 300 due to an external environment such as atmospheric moisture.

Further, on the sealing substrate 30, a reservoir forming substrate 40 defining a reservoir 41, which is a common ink chamber of each pressure generating chamber 12, and a sealing plate 45 are joined. Substantially the entire upper surface is a reservoir 41. The sealing plate 45 is provided with an ink introduction port 46 for supplying ink from an external ink supply unit to the reservoir 41.

The reservoir 31 defined as above
In the present embodiment, two adjacent rows 13A and 13B
Are common to each of the pressure generating chambers 12A and 12B.
Each of the pressure generating chambers 12A and 12B of each row 13A and 13B and the reservoir 31 are connected to each of the pressure generating chambers 12A and 12A of the sealing substrate 30.
The ink supply passages 32A and 32B provided at positions corresponding to the ends of the 12B opposite to the narrow portion 12a and the communication holes 51 provided through the elastic film 50 and the lower electrode film 60 are provided. The ink is supplied from the reservoir 41 to each of the pressure generating chambers 12 through the ink supply communication ports 32A and 32B.

The ink jet recording head thus constructed takes in ink from an ink inlet 35 connected to an external ink supply means (not shown), and fills the interior from the reservoir 110 to the nozzle opening 21 with ink. By applying a voltage between the upper electrode film 80 and the lower electrode film 60 in accordance with a recording signal from an external drive circuit (not shown), the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70 are flexibly deformed. Then, the pressure in the pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle opening 21.

(Embodiment 2) FIG. 6 is a plan view showing a main part of an ink jet recording head according to Embodiment 2.

The present embodiment is an example in which the shape of the pressure generating chamber 12 is changed. As shown in FIG. 6, the inner peripheral surface of the pressure generating chamber 12 is formed as a curved surface in the circumferential direction, Embodiment 1 differs from Embodiment 1 in that the planar shape of the generation chamber 12 is formed to be substantially elliptical, and the outer shape of the piezoelectric element 300 is formed by a curve along the opening shape of the pressure generation chamber 12. The same is true.

Also in such an embodiment, it is preferable that the pressure generating chambers 12 are arranged such that the thickness of the partition walls 11 is 50 μm or more. Further, the maximum width of the main part of the pressure generating chamber 12 is two times the maximum width of the narrow part 12a.
It is preferably at least two times.

In the present embodiment, the outer shape of the piezoelectric element 300 is formed so as to be substantially elliptical along the opening shape of the pressure generating chamber 12. May be formed.

In the configuration of this embodiment, the flow of ink in the pressure generating chamber 12 becomes smooth,
The ink ejection characteristics are improved. In addition, since the ink attenuation characteristics are improved, high-speed printing can be realized by shortening the ink ejection interval.

Further, since the inner peripheral surface of the pressure generating chamber 12 is formed as a curved surface, bubbles hardly accumulate in the pressure generating chamber 12 and printing defects such as missing dots can be prevented.

In the present embodiment, the surface shape of the pressure generating chamber 12 is substantially elliptical, and the main part of the pressure generating chamber 12 has the largest width at the substantially central portion in the longitudinal direction. That is, the thickness of the partition 11 between the pressure generating chambers 12 is
Since the pressure generating chamber 12 has the narrowest portion at the substantially central portion in the longitudinal direction and becomes wider toward the end portion in the longitudinal direction, the rigidity of the partition wall 11 is ensured more reliably. Therefore, crosstalk can be reliably prevented.

In this embodiment, almost the entire inner peripheral surface of the pressure generating chamber 12 is formed as a curved surface.
A part thereof may be a curved surface.

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

For example, in each of the embodiments described above, a thin-film type ink jet recording head which can be manufactured by applying a film forming and lithography process is exemplified. However, the present invention is not limited to this. To form a piezoelectric layer by laminating a green sheet, forming a piezoelectric layer by pasting or screen printing a green sheet, or forming a piezoelectric layer by crystal growth such as a hydrothermal method. The present invention can be applied to an inkjet recording head having a structure.

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 the 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 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, the apparatus main body 4 is provided with a platen 8 along the carriage 3. The platen 8 can be rotated by a driving force of a paper feed motor (not shown), and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller, is wound around the platen 8 and conveyed. It has become so.

[0084]

As described above, according to the present invention, two rows of a plurality of pressure generating chambers are provided adjacent to each other, and the narrow portions of the pressure generating chambers in each row are arranged in the longitudinal direction. Since the pressure generating chambers are arranged alternately so as to overlap with each other, the intervals between the substantially adjacent pressure generating chambers can be shortened so that the nozzle openings can be arranged at a high density, and the rigidity of the partition wall between the pressure generating chambers is maintained and crosstalk is achieved. Can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view of 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 plan view showing a configuration of a pressure generating chamber and a piezoelectric element of the ink jet recording head according to the first embodiment of the present invention.

FIG. 6 is a plan view showing a configuration of a pressure generating chamber and a piezoelectric element of an ink jet recording head 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 11 nozzle opening 12 pressure generating chamber 13 row 50 elastic film 60 lower electrode film 70 piezoelectric layer 80 upper electrode film 300 piezoelectric element 300a tip

Claims (12)

[Claims] An ink jet type comprising: a pressure generating chamber communicating with a nozzle opening; and a piezoelectric element including a lower electrode, a piezoelectric layer, and an upper electrode provided via a diaphragm in a region corresponding to the pressure generating chamber. In the recording head, a plurality of pressure generating chambers each having a narrow portion narrower than the width of the main portion at one longitudinal end portion, the narrow portion being inward and the narrow portion being in the longitudinal direction. An ink jet recording head characterized in that it is arranged in two rows and one set so as to alternately overlap. 2. The method according to claim 1, wherein the piezoelectric element is provided over a region opposed to a narrow portion of the pressure generation chamber, and is provided in a region opposed to the pressure generation chamber. Characteristic ink jet recording head. 3. The nozzle opening according to claim 1, wherein the nozzle openings are provided to face the narrow portion, and the nozzle openings corresponding to the two rows of pressure generating chambers are arranged in one row. An ink jet recording head characterized by the following. 4. The ink jet recording head according to claim 1, wherein at least a part of the side surface of the pressure generating chamber in the inner circumferential direction is formed of a curved surface. 5. The ink jet recording head according to claim 4, wherein the pressure generating chamber has a substantially elliptical planar shape. 6. The ink jet recording head according to claim 1, wherein a width of a main portion of the pressure generating chamber is widest at a substantially central portion in a longitudinal direction. 7. The pressure generating chamber according to claim 1, wherein a maximum width of a main part of the pressure generating chamber is two times a maximum width of the narrow part.
An ink jet recording head characterized in that the number is twice or more. 8. The ink jet recording head according to claim 1, wherein a thickness of a partition wall between adjacent pressure generating chambers is 50 μm or more. 9. The piezoelectric element according to claim 1, wherein a lead electrode extends from an upper electrode constituting the piezoelectric element on a peripheral wall and corresponds to each of two adjacent rows of the pressure generating chambers. Wherein the lead electrodes provided in the ink jet recording head extend in the same direction. 10. An ink jet recording head according to claim 1, wherein said nozzle opening is formed in a silicon single crystal substrate. 11. The ink jet recording head according to claim 1, wherein the pressure generating chamber is formed in a silicon single crystal substrate by dry etching. 12. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.