JPH1178004A - Ink-jet recording head and production method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of improving characteristics for widening the range of selecting the materials for a distortion generating part of a thin film type distortion actuator and a supporting part thereof, and a production method thereof. SOLUTION: On an ink pressure room forming substrate with a pressure room 2, a common channel, and a supply path formed thereon, a pressure generating film 5 laminated so as to provide a wall surface of the pressure room 2 and a nozzle plate with a nozzle communicating with the pressure room 2 formed therein are provided. The pressure generating film 5 comprises a piezoelectric distortion generating part 30 and a supporting part 31, with the supporting part 31 made of a resin material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet used in an ink jet recording apparatus such as an ink jet printer for obtaining a visible image by selectively flying and fixing ink droplets on recording paper in accordance with input print data. The present invention relates to a recording head.

More specifically, the present invention relates to an on-demand type ink jet recording head in which a nozzle plate and an ink pressurizing chamber substrate are laminated and a piezoelectric film formed on the surface of the ink pressurizing chamber substrate is pressurized by bending deformation to fly ink droplets. .

[0003]

2. Description of the Related Art As a prior art relating to the present invention, there is JP-A-5-504740.

In this conventional example, a piezoelectric film is integrally formed on a base material containing an ink pressurizing chamber by a so-called thin-film manufacturing method such as sputtering or a sol-gel method, so that a simple structure and high-definition on-demand type ink jet recording can be performed. The head has been realized. In particular, a silicon single crystal substrate is used as a base material and anisotropic etching can be performed to form a highly accurate ink pressurizing chamber.

FIG. 7 is a cross-sectional view of a conventional actuator for an ink jet recording head using a thin film PZT and a silicon single crystal substrate in the arrangement direction. Reference numeral 20 denotes a silicon single crystal substrate, 2 denotes a pressure chamber formed on the silicon single crystal substrate by anisotropic etching, 18 denotes a partition partitioning the pressure chamber, 21 denotes a silicon dioxide film, 10 denotes a lower drive electrode, 11 is a piezoelectric thin film, 12 is an upper drive electrode, and the thickness of each thin film is several hundred nm to several μm. Numeral 30 denotes a piezoelectric strain generating portion, and 31 denotes a support portion interposed between the partition walls and supporting the piezoelectric strain generating portion.

When a voltage is applied between the lower drive electrode 10 and the upper drive electrode 12, the piezoelectric film 11 tends to contract in the film surface direction. Shrinkage is hindered, and the shrinkage force bends to the lower surface.

[0007]

Focusing on the deformation efficiency of such a unimorph type actuator and the structure of the elastic film and the supporting portion, it is desirable that the elastic film has a higher Young's modulus in the film surface direction, and that the supporting portion has a higher Young's modulus. In order not to hinder the bending stress of the piezoelectric strain portion, it is preferred that the piezoelectric strain portion be easily stretched and have low bending rigidity. However, in the conventional thin film type actuator, since each thin film is formed integrally, the same material must be used for the elastic film and the film constituting the supporting portion.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to propose a means for reducing the manufacturing defect and improving the reliability while increasing the actuator displacement efficiency. An object of the present invention is to provide a high-performance ink jet recording head.

[0009]

An ink jet recording head according to the present invention comprises an ink pressurizing chamber arranged in a row on a silicon single crystal substrate through a partition, and a cover on one side of the pressurizing chamber. A pressure generating film that is suspended and fixed, and is arranged as if forming one wall of the pressure chamber, and an ink discharge nozzle that communicates with each of the pressure chambers, and ink is formed by pressure generated by bending deformation of the pressure generating film. Wherein the pressure-generating film comprises at least a piezoelectric film, lower and upper drive electrodes sandwiching the piezoelectric film, and an elastic film laminated on one of the drive electrodes. It is characterized by comprising a generating section and a supporting section interposed so as to support the piezoelectric strain generating section with respect to the partition wall, and the supporting section is formed of a polymer resin film.

In the method of manufacturing an ink jet recording head according to the present invention, a film forming the piezoelectric strain generating section is formed on one surface of a silicon single crystal substrate, and then the piezoelectric strain generating section is formed by photoetching. A step of forming a film constituting the supporting portion and forming the film into a predetermined shape, and thereafter forming the pressure chamber by etching the silicon single crystal substrate.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on one embodiment.

The structure of the ink jet recording head of the present invention will be described with reference to FIGS.

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

Reference numeral 1 denotes an ink pressurizing chamber substrate, pressurizing chambers 2 arranged in two rows in a staggered manner, and ink (not shown) is provided in each pressurizing chamber.
And a supply path 9 that communicates each pressurizing chamber 2 with the common flow path 3. Array pitch is 180
1 inch, about 141 microns, 64 per row
Elements are arranged to realize a type recording head having a printing density of 360 dots / inch and 128 nozzles in two rows. 8
Is a wiring board for supplying a signal to the displacement element.

Reference numeral 6 denotes a nozzle plate having a plurality of ink discharge nozzles 7 corresponding to the pressure chambers 2. After the pressure chamber substrate 1 and the nozzle plate 6 are bonded, they are fitted to the base 90 to form an ink jet recording head.

FIG. 2 is a sectional view taken along the dashed line AA 'of FIG. 1 in the direction in which the pressure chambers are arranged. The silicon dioxide to form a substantially rectangular pressure generating film 5 on the lower surface of the pressure chamber substrate 1 is shown in FIG. The film 21, the lower drive electrode 10, the piezoelectric film 11, and the upper drive electrode 12 are sequentially laminated to form a piezoelectric strain generating section 30. In this example, the lower drive electrode 10 has a thickness and has a function of an elastic film together with the silicon dioxide film 21.

In this example, the pitch of the pressure chamber was 141 μm, the width of the pressure chamber was 50 μm, the length (in the depth direction in the figure) was 1.2 mm, and the width of the partition was 91 μm.

Numeral 32 denotes a resin film which is adhered to the upper surface of the partition wall 18 and at least the end of the piezoelectric strain generating section 30, and
The pressure generating film 5 composed of the supporting portion 31 and the strain generating portion 30 is formed integrally with the pressure chamber substrate 1.

If the resin film 32 forming the support portion 31 is continuously coated on the end surface of the piezoelectric film 11 and the upper surface of the piezoelectric strain portion 30 as shown in FIG. 2, it can also be used as an environmental film on the end surface and the upper surface. Can also.

If only the end surface of the piezoelectric film 11 is covered as shown in FIG. 6, the end discharge between the upper and lower drive electrodes can be suppressed, and the upper surface of the piezoelectric distortion portion 30 is restrained by the resin film to reduce the displacement. I won't let you.

A method for manufacturing the ink jet recording head of the present invention will be described with reference to FIGS. 3, 4 and 5. FIG. 3 shows a cross section taken along the line AA ′ in FIG. FIG. 4 shows a cross section in the AA ′ direction of FIG. 1 as in FIG. FIG. 5 is a sectional view in the flow channel direction corresponding to each step of FIG.

In the present embodiment, the diameter of 100 mm and the thickness of 220 μm
As shown in FIG. 3 (I), an etching protection layer 2 made of silicon dioxide is formed on the entire surface by a thermal oxidation method using a silicon single crystal substrate 20 which is a pressure chamber substrate having a (110) plane.
1 is formed in a thickness of 1 μm, and platinum on the lower drive electrode 10 is formed on the upper surface by a thin film forming method such as a sputtering film forming method.
A film is formed with a thickness of 00 nm. At this time, in order to increase the adhesion between the platinum layer and the upper and lower layers, ultra-thin titanium, chromium or the like may be interposed as an intermediate layer. The lower drive electrode may be made of a conductive material such as iridium, rubidium, or an oxide thereof, as long as the lower drive electrode has heat resistance to a subsequent heating temperature. The lower drive electrode 10 also serves as an elastic film together with the silicon dioxide film 21.

The precursor 24 of the piezoelectric film is laminated thereon. In this example, a PZT-based piezoelectric film precursor in which the molar mixing ratio of lead titanate and lead zirconate is 55% and 45% is obtained by sol-gel method until the final thickness is 0.9 μm. Coating / drying / degreasing was repeated to form a film. In addition, as a result of various trial experiments, the chemical formula of this piezoelectric film was Pb _C Ti _A Zr
_{Represented by B} O ₃ [A + B = 1], and A and C in the above chemical formula
However, if it was selected within the range of 0.5 ≦ A ≦ 0.6, 0.85 ≦ C ≦ 1.10. Piezoelectric properties that could withstand practical use could be obtained. The film formation method is not limited to this method,
CVD or the like may be used.

Next, as shown in FIG. 3 (II), the entire substrate is heated for crystallization of the piezoelectric film precursor. In this example, the infrared radiation light source 29 is used to apply 70
The piezoelectric film was crystallized by heating at 0 ° C. for 5 minutes and allowing the temperature to decrease naturally. By this step, the piezoelectric film precursor 2
Sample No. 4 was crystallized and sintered with the above-described target composition to form a piezoelectric film 11.

Thereafter, an upper drive electrode film 12 is formed on the piezoelectric film 11, as shown in FIG. In this example, the upper drive electrode 12 was formed of platinum having a thickness of 100 nm by a sputtering film forming method.

Next, as shown in FIGS. 4 (I) and 5 (I), the upper drive electrode 12 and the piezoelectric film 11 are aligned with the position where the pressure chamber 2 is formed, and an appropriate etching mask (not shown) is used. ), And then etching is performed in a predetermined separated shape.

Next, after the lower drive electrode 10 and the silicon dioxide film 21 are similarly subjected to an appropriate etching mask (not shown),
It was formed in a predetermined shape (such as a connection terminal with an external drive circuit).
These etchings were performed by vapor phase etching using an argon gas.

As shown in FIGS. 4 (II) and 5 (II), a resin film is applied on the entire surface after the patterning, an opening such as a contact hole 34 is formed, and wiring electrodes are arranged. . The resin film is coated with a fluorine-based resin to a thickness of 2 μm using a solvent coating method.
It was applied to a thickness of m. Gold was used for the wiring electrode 33.

After forming a protective film (not shown for simplicity) against various chemicals immersed in a later step on the side of the substrate 20 on which the piezoelectric film is formed, at least a pressure chamber or a pressure chamber on the opposite surface is formed. The window 22 is formed by etching the silicon dioxide film 21 with hydrogen fluoride in a region including the chamber partition. Thereafter, an anisotropic etching solution, for example, having a concentration of 17 maintained at 80 ° C.
Anisotropic etching is performed using a potassium hydroxide aqueous solution of about% so as to penetrate the silicon single crystal substrate 20 to the upper surface of the substrate. Since the fluorine-based resin film 32 is hardly soluble in the potassium hydroxide, the support portion is not affected by the etchant from the pressure chamber side. Alternatively, an anisotropic etching method using an active gas such as a parallel plate type reactive ion etching may be used for forming the pressurized chamber. By this process, a flow path such as an ink pressurizing chamber is formed (FIG. 4 (III) and FIG. 5 (III)).

The resin film 32 is preferably made of a resin such as polysulfone in consideration of the resistance to potassium hydroxide.

A separate nozzle plate and the like are bonded and assembled to the pressurized chamber substrate formed by the above steps to complete an ink jet recording head.

When the ink jet recording head formed as described above is compared with the conventional structure, the conventional recording head is
While the maximum deflection amount was 200 nm when a voltage of 20 V was applied, the product of the present invention could obtain a large deformation amount of 300 nm.

Further, as shown in FIG. 6, when the cross section of the piezoelectric film 11 is covered with the resin film 32, the dielectric breakdown electric field of the piezoelectric strain generating portion 30 is 60 V / μm in the past, but 90 V / μm.
improved to μm.

In addition, as shown in FIG. 2, when the cross section of the piezoelectric film 11 and the upper drive electrode 12 are covered with the resin film 32, the durability life in a high humidity environment is improved by 40%.
This is thought to be because the upper drive electrode 12 was as thin as 100 nm and the moisture in the environment had penetrated to the piezoelectric film, but was blocked by the resin film.

By using the manufacturing method according to the present embodiment, the material of the elastic film constituting the piezoelectric strain generating section 30 and the material of the supporting section 31 can be selected to be different from each other. Can be expanded. In particular, since the support member is formed after the piezoelectric film firing step, high temperature heat resistance is not required.

In this embodiment, the PZT-based material has been described as the piezoelectric film. However, a material obtained by adding other metal oxides such as niobium oxide, nickel oxide, magnesium oxide, or a material other than the PZT-based material to this system. The present invention is effective.

In this embodiment, an application example of the ink jet recording head has been described. However, in addition to the above, the displacement of other small elements utilizing the characteristics of a thin film piezoelectric material such as a micro optical device and a micro pressure detector or a pressure generator and a detector. The present invention is effective in all cases.

[0038]

According to the present invention, by using a resin film for the support portion of the pressure generating film, it is possible to solve the problems of displacement characteristics and reliability and to realize a highly reliable and high performance ink jet recording head. it can.

[Brief description of the drawings]

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

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

FIG. 3 is a diagram illustrating a manufacturing process of the ink jet recording head according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a manufacturing process of the ink jet recording head according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating a manufacturing process of the ink jet recording head according to the embodiment of the present invention.

FIG. 6 is a cross-sectional view of an ink jet recording head according to an embodiment of the present invention.

FIG. 7 is a diagram illustrating the structure of a conventional ink jet recording head.

[Explanation of symbols]

 Reference Signs List 1 pressure chamber substrate 2 pressure chamber 3 common flow path 5 pressure generation film 6 nozzle plate 7 ink discharge nozzle 8 wiring board 9 supply path 10 lower drive electrode 11 piezoelectric film 12 upper drive electrode 14 drive voltage source 18 pressurization Room partition 20 Silicon single crystal substrate 21 Silicon dioxide film 24 Piezoelectric film precursor 29 Radiation light source 30 Piezoelectric strain generator 31 Support for piezoelectric strain generator 32 Resin film 33 Wiring electrode 34 Contact hole 90 Base

Claims (8)

[Claims] An ink pressurizing chamber arranged in a row on a silicon single crystal substrate via a partition, one side of the pressurizing chamber is covered and suspended and fixed by the partition to form one wall of the pressurizing chamber. An ink jet recording head, comprising: a pressure generating film arranged in a similar manner, and an ink discharge nozzle communicating with each of the pressurizing chambers, and discharging ink by a pressure generated by bending deformation of the pressure generating film, The generating film includes at least a piezoelectric film, a lower and upper drive electrode sandwiching the piezoelectric film, and a piezoelectric strain generating portion composed of an elastic film laminated on one of the drive electrodes. An ink jet recording head comprising: a support portion interposed so as to support the support portion; and the support portion is formed of a polymer resin film. 2. An ink jet recording head according to claim 1, wherein one of said drive electrodes also functions as said elastic film. 3. The ink jet recording head according to claim 1, wherein said support portion is made of a fluorine resin film. 4. An ink jet recording head according to claim 1, wherein said support portion is made of a polyolefin film. 5. The ink jet printer according to claim 1, wherein a polymer resin film forming the supporting portion covers at least a cross section of the piezoelectric film of the piezoelectric strain generating portion. Type recording head. 6. The method according to claim 1, wherein a polymer resin film constituting the supporting portion covers a cross section of the piezoelectric film of the piezoelectric strain generating portion and a surface of the upper drive electrode. Item 7. An ink jet recording head according to item 1. 7. A wiring for connecting an upper drive electrode and an external drive circuit on an upper surface of a polymer resin film constituting the supporting portion covers at least a part of a cross section of the piezoelectric film of the piezoelectric strain generating portion. 7. The ink jet recording head according to claim 1, further comprising an electrode. 8. A step of forming a film constituting the piezoelectric strain generating part on one surface of a silicon single crystal substrate, a step of forming the piezoelectric strain generating part by photoetching, and then forming a film forming the supporting part. A method for manufacturing an ink jet recording head, comprising: a step of forming a film and forming it into a predetermined shape; and a step of forming the pressure chamber by etching the silicon single crystal substrate.