JP2001150687A - Method for forming piezoelectric actuator and method for producing ink-jet head using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of a piezoelectric actuator and an ink-jet head as much as possible. SOLUTION: A plurality of substrates 41 are prepared, a Pt membrane 42 is formed on all the substrates 41, and a pattern is formed by the membrane 42 to form individual electrodes 24. In this process, the substrates are set to the substrate setting part 51a of a substrate positioning jig 51 to be positioned to each other. Next, PZT membranes and Cr membranes are formed in turn on all the substrates 41 on which the individual electrodes 24 are formed so that piezoelectric elements 23 and common electrodes 22 are formed, and the common electrodes 22 on the substrates 41 and a pressure chamber forming part 55 in which an opening part 55a for the pressure chamber is formed in advance are fixed. In this process, the substrates 41 are positioned to each other by the jig 51. After that, the substrates 41 are removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a method of forming a piezoelectric actuator in which electrodes are provided on both sides in the thickness direction of a piezoelectric element, and a method of manufacturing an ink jet head using the method.

[0002]

2. Description of the Related Art Conventionally, as an ink jet head used in an ink jet printer, a head provided with a piezoelectric actuator has been known. In this piezoelectric actuator, electrodes are provided on both sides in the thickness direction of the piezoelectric element, and are fixed to the pressure chamber components via a vibration plate to form a pressure chamber together with the pressure chamber components. When a voltage is applied between the two electrodes and the piezoelectric element expands and contracts in a direction perpendicular to the thickness direction, the expansion and contraction is restrained by the vibration plate, and the piezoelectric actuator is bent in a convex shape toward the pressure chamber and displaced. I do. Due to this bending deformation, a pressure is generated in the pressure chamber, and the ink in the pressure chamber is discharged to the outside from the nozzle hole communicating with the pressure chamber by the pressure.

As a method of forming a piezoelectric actuator as described above, for example, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-286953, one of two electrodes (an individual electrode film) is formed on an MgO substrate. ), A method of sequentially forming a piezoelectric element film and the other electrode film (common electrode film) by sputtering or the like has been proposed. In the same publication, a diaphragm film is formed on a common electrode film formed on the substrate,
By fixing the common electrode film and the pressure chamber component via the diaphragm film, and then removing the substrate by etching,
It has been proposed to produce an inkjet head. And in this inkjet head,
A plurality of pressure chambers are provided, and in order to form and arrange the individual electrodes and the piezoelectric elements at the positions corresponding to the pressure chambers, the individual electrode film and the piezoelectric element film are separated by a pressure chamber each time the respective films are formed. Patterned into almost the same shape corresponding to
I am trying to do it.

[0004]

In order to improve the productivity of the ink jet head, it is necessary to manufacture as many ink jet heads as possible at one time. For this purpose, one substrate having a size capable of forming individual electrodes (or piezoelectric elements) for a plurality of inkjet heads is prepared, and an electrode film or the like is formed on this substrate and individualized. To form individual electrodes and the like for a plurality of inkjet heads, and further form a common electrode film on the plurality of substrates and one pressure chamber forming component capable of forming a pressure chamber for the plurality of inkjet heads. It is sufficient to fix it and then divide it into individual inkjet heads. However, the size of the substrate has a limit (usually about 20 mm × 20 mm).
It is difficult to increase the number of individual electrodes and the like using only one substrate. Therefore, a plurality of substrates are prepared, a piezoelectric actuator is formed on each of the plurality of substrates, and the common electrode film and one pressure chamber forming component on the plurality of substrates are fixed via the diaphragm film. It can be considered.

However, if the patterning of the individual electrode films and the like is performed independently for each substrate, the efficiency of the patterning process is low, and moreover, when the common electrode film and the component for forming the pressure chamber are fixed, the film is not formed. It is troublesome to accurately arrange the individual electrodes and piezoelectric elements formed by patterning at the positions corresponding to the pressure chambers for each substrate, and there is a problem that the productivity of the inkjet head is rather lowered.

[0006] The present invention has been made in view of such a point, and an object of the present invention is to improve productivity of a piezoelectric actuator and an ink jet head as much as possible.

[0007]

In order to achieve the above object, according to the present invention, a plurality of substrates are positioned with respect to each other when patterning an electrode film or the like.

More specifically, the invention of claim 1 is directed to a method of forming a piezoelectric actuator in which electrodes are provided on both sides in the thickness direction of a piezoelectric element.

A step of preparing a plurality of substrates, forming a piezoelectric element film and two electrode films on the plurality of substrates, and laminating the plurality of substrates; and forming at least one of the two electrode films on the plurality of substrates. One includes a step of patterning the plurality of substrates in a state where they are positioned with respect to each other.

[0010] This makes it possible to simultaneously pattern electrode films and the like on a plurality of substrates, thereby improving the efficiency of the patterning process. Moreover, since a plurality of substrates are positioned with respect to each other during patterning,
If the electrode film formed on the opposite side of the piezoelectric element film and the one pressure chamber forming part for forming the pressure chamber is fixed on the plurality of substrates while maintaining this positioning state, the pattern on each substrate is fixed. The electrodes and the like formed by the formation can be easily and accurately arranged at positions corresponding to the pressure chambers. Therefore, the productivity of the piezoelectric actuator and the inkjet head can be improved.

According to a second aspect of the present invention, there is provided a pressure chamber filled with ink, and a piezoelectric actuator having electrodes disposed on both sides in the thickness direction of the piezoelectric element, and by applying a voltage between the two electrodes. An invention of a method for manufacturing an ink jet head in which the piezoelectric actuator is deformed so as to reduce the volume of the pressure chamber to discharge ink in the pressure chamber.

According to the present invention, a step of preparing a plurality of substrates, forming a piezoelectric element film and two electrode films on the plurality of substrates and laminating the plurality of substrates, and forming at least the two electrodes on the plurality of substrates. One of the films is patterned with the plurality of substrates positioned with respect to each other, and after both of the steps, an electrode film formed on the plurality of substrates on the opposite side of the piezoelectric element film from the substrate. The method includes a step of fixing one pressure chamber forming component for forming a pressure chamber with the plurality of substrates positioned with respect to each other, and a step of removing the plurality of substrates after the fixing step. Thus, the same function and effect as the first aspect of the invention can be obtained.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an ink jet head to which a method of forming a piezoelectric actuator and a method of manufacturing an ink jet head according to an embodiment of the present invention are applied. The ink jet head discharges ink from a supply port 2a for supplying ink. And a head body 1 in which a plurality of pressure chamber recesses 2 having discharge ports 2b are formed. Each concave portion 2 of the head main body 1 is opened in a substantially rectangular shape on the upper surface of the head main body 1, and is arranged in a plurality of rows (two rows in FIG. 1). The recesses 2 in each row are arranged at predetermined intervals in the width direction.

The side wall of each recess 2 of the head body 1 is
A pressure chamber component 5 made of Si having a thickness of about 200 μm, and a bottom wall portion of each recess 2 is fixed to the pressure chamber component 5 and an ink flow path component 6 formed by bonding a plurality of stainless steel thin plates.
It is composed of In the ink flow path component 6, a supply ink flow path 7 connected to the supply port 2a of each of the concave portions 2 and a discharge ink flow path 8 respectively connected to the discharge port 2b are formed. ing. Each of the supply ink flow paths 7 is provided for each row of the recess 2 and is connected to an ink supply chamber 10 extending in a direction in which the recess 2 of each row is arranged. Connected to the ink tank. Pressure chamber component 5 of the ink flow path component 6
On the opposite side (lower surface), about 20 μm of an electroformed plate of stainless steel or Ni or a polymer resin such as polyimide.
An m-thick nozzle plate 13 is provided, and the nozzle plate 13 is formed with a nozzle hole 14 having a diameter of about 20 μm connected to each of the ejection ink flow paths 8.

On the side (upper surface) of the pressure chamber component 5 of the head body 1 opposite to the ink flow path component 6, a piezoelectric element 2 is provided.
3 are provided with piezoelectric actuators 21 each having an electrode disposed on both surfaces in the thickness direction (a common electrode 22 made of Cr on the lower surface and an individual electrode 24 made of Pt on the upper surface). The common electrode 22 covers all the recesses 2 of the head main body 1 to form a pressure chamber 3 together with the recesses 2 and also serves as a diaphragm, and has a thickness of 1 to 3 μm. ing. The piezoelectric element 23 is made of lead zirconate titanate (PZT) and has a thickness of 2 mm.
５5 μm. The piezoelectric element 23 is provided on substantially the entire side surface (upper surface) of the common electrode 22 opposite to the pressure chamber 3, and is not individualized like the common electrode 22. Then, individual electrodes 24 having a thickness of about 0.1 μm are provided on portions (approximately right above the pressure chambers 3) corresponding to the pressure chambers 3 on the side (upper surface) of the piezoelectric element 23 opposite to the pressure chambers 3. The individual electrodes 24 apply a voltage to the portion corresponding to the pressure chamber 3 of the piezoelectric element 23 together with the common electrode 22. The individual electrode 24 is fitted into a concave portion formed to have the same shape as the individual electrode 24 on the upper surface of the piezoelectric element 23, and the upper surface thereof is substantially the same as the portion of the upper surface of the piezoelectric element 23 except for the concave portion. Surface.

The piezoelectric actuator 21 deforms a portion corresponding to the pressure chamber 3 of the piezoelectric actuator 21 by applying a voltage to the piezoelectric element 23 via the common electrode 22 and the individual electrode 24 to thereby deform the portion. The ink in the pressure chamber 3 is ejected from the ejection port 2b. That is, when a pulse-like voltage is applied between the common electrode 22 and the individual electrode 24, the rising of the pulse voltage causes the piezoelectric element 23 to contract in the width direction perpendicular to the thickness direction. Since the individual electrode 24 does not shrink, the portion corresponding to the pressure chamber 3 of the piezoelectric actuator 21 is bent and deformed toward the pressure chamber 3 by the so-called bimetal effect. This bending deformation causes the pressure chamber 3
A pressure is generated in the nozzle hole 14, and the pressure causes the ink in the pressure chamber 3 to pass through the ejection port 2 b and the ejection ink flow path 8.
The ink is further discharged to the outside and adheres to the paper surface in a dot shape. When the pulse voltage falls, the piezoelectric element 23 expands, and the portion of the piezoelectric actuator 21 corresponding to the pressure chamber 3 returns to the original state. The ink is filled through the supply ink flow path 7 and the supply port 2a. In addition, 1
In addition to color inks, for example, black, cyan, magenta, and yellow inks may be ejected from different nozzle holes 14, respectively, to perform color printing.

Next, a schematic procedure of the method for manufacturing the ink jet head will be described with reference to FIG.
In FIG. 4, the vertical relationship between the ink jet head and FIGS. 2 and 3 is reversed.

First, a plurality (four in this embodiment: FIG. 4)
In this case, only two of them are shown), and a Pt film 42 (individual electrode film) is formed on the entire four substrates 41 by sputtering (FIG. 4A).
reference). The size of the film formation surface of one substrate 41 is 1
It is almost the same as the upper surface of one ink jet head.

Thereafter, the Pt film 42 is patterned by dry etching or the like and finished in a predetermined shape (divided into individual pieces) to form individual electrodes 24 (FIG. 4).
(B)). This patterning makes the four substrates 41
The setting is performed on the substrate positioning jig 51 shown in FIG. The substrate positioning jig 51 has four concave substrate setting portions 51a on which the four substrates 41 can be set, respectively. An air suction port 51b connected to a vacuum pump (not shown) is provided at the bottom of each substrate setting section 51a, and the substrate 41 is held by the substrate setting section 51a by the vacuum pump and the air suction port 51b. In this holding state, the four substrates 41 are positioned with respect to each other. The board positioning jig 51 has two positioning pins 51c.
A mask plate (not shown) used at the time of patterning is set in c.

Subsequently, a PZT film (piezoelectric element film) is formed on the entire substrate 41 on which the individual electrodes 24 are formed by sputtering to form a piezoelectric element 23, and thereafter,
A common electrode 22 is formed by forming a Cr film (common electrode film) on the entire piezoelectric element 23 by sputtering (see FIG. 4C). At this stage, the formation of the piezoelectric actuator 21 is completed. When forming each film, each substrate 4
1 is not set in each of the substrate setting portions 51a of the substrate positioning jig 51, but may be set as long as a film can be formed.

Next, the four substrates 41 are set on the respective substrate setting portions 51a of the substrate positioning jig 51 (the same substrate setting portions 51a as those at the time of patterning), and then the common electrodes on the four substrates 41 are set. 22 (common electrode film) and the pressure chamber opening 55a (pressure chamber recess 2).
The pressure chamber forming part 55 for forming the pressure chamber, in which the four substrates 41 are positioned with respect to each other, is adhesively fixed (see FIG. 4D). The pressure chamber forming part 55 has a shape in which four pressure chamber parts 5 of one ink jet head are combined, and the positioning pin 51c of the substrate positioning jig 51 is located at a position corresponding to each positioning pin 51c. The positioning pin 51c is fitted into the fitting hole 55b of the pressure chamber forming part 55 at the time of fixing.
As a result, all the individual electrodes 24 on the four substrates 41
The entire pressure chamber opening 55a of the pressure chamber forming part 55 accurately corresponds to each other.

Next, the four substrates 41 are removed from each substrate setting portion 51a of the substrate positioning jig 51, and the four substrates 41 are melted and removed with hot phosphoric acid, KOH or the like (FIG. 4 (e)).
reference). Thereafter, the pressure chamber forming part 55 is divided into four parts and finished into a predetermined shape to form the pressure chamber part 5, and the ink passage part 6 and the nozzle plate previously integrated with the pressure chamber part 5 are formed. By fixing 13, four ink jet heads are completed (see FIG. 4F).

Therefore, in the above embodiment, the patterning of the Pt films 42 on the four substrates 41 is performed simultaneously, so that the piezoelectric actuators 21 for four ink jet heads can be formed efficiently. Moreover, P
When the t film 42 is patterned, the four substrates 41 are positioned with respect to each other, and when the common electrode 22 and the pressure chamber forming component 55 are fixed, the four substrates 41 remain in the same state as the patterning.
1 are positioned with respect to each other, all the individual electrodes 24 on the four substrates 41 and all the pressure chamber openings 5 of the pressure chamber forming parts 55
5a correspond accurately, and the individual electrode 24 is not displaced from the portion corresponding to the pressure chamber 3. As a result, it is possible to easily manufacture many ink jet heads at a time while preventing deterioration in the quality of printing or printing. Therefore, the productivity of the piezoelectric actuator and the inkjet head can be improved as much as possible.

In the above embodiment, the piezoelectric elements 23 are not individualized, but the piezoelectric elements 23 may be individualized similarly to the individual electrodes 24. In this case, PZT
After the film is formed, it may be patterned into the same shape as the Pt film 42. In this patterning, the four substrates 41 may be positioned on each substrate setting portion 51a of the substrate positioning jig 51 so as to be positioned with respect to each other. Good. Also, the common electrode 2
2 can also be patterned, but it is necessary to electrically connect the divided parts.

Further, in the above embodiment, the common electrode 22
Is also used as the diaphragm, but the diaphragm may be provided separately.
In this case, after forming the common electrode 22, a diaphragm film may be formed on the entire common electrode 22, and the common electrode 22 and the pressure chamber forming component 55 may be fixed through the diaphragm film.

[0026]

As described above, in the method of forming a piezoelectric actuator according to the present invention, at least one of the two electrode films is patterned on a plurality of substrates with the plurality of substrates positioned with respect to each other. I made it. Also,
In the method of manufacturing an inkjet head of the present invention, at least one of the two electrode films on a plurality of substrates is patterned in a state where the plurality of substrates are positioned with respect to each other,
On the plurality of substrates, the electrode film formed on the side opposite to the substrate of the piezoelectric element film and one pressure chamber forming part for forming a pressure chamber are fixed with the plurality of substrates positioned with respect to each other. . Therefore, according to these inventions,
A large number of piezoelectric actuators and ink jet heads can be manufactured at one time, and the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing an inkjet head to which a method for forming a piezoelectric actuator and a method for manufacturing an inkjet head according to an embodiment of the present invention are applied.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a schematic explanatory view showing a method for manufacturing an ink jet head.

FIG. 5 is a plan view showing a substrate positioning jig.

[Explanation of symbols]

 Reference Signs List 3 pressure chamber 21 piezoelectric actuator 22 common electrode 23 piezoelectric element 24 individual electrode 41 substrate 51 substrate positioning jig 55 pressure chamber forming part

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroyuki Matsuo 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 2C057 AF93 AG45 AP02 AP24 AP32 AP52 AP77 BA03 BA14

Claims (2)

[Claims] 1. A method for forming a piezoelectric actuator, wherein electrodes are provided on both sides in the thickness direction of a piezoelectric element, comprising: preparing a plurality of substrates;
Forming and laminating two electrode films; and patterning at least one of the two electrode films on the plurality of substrates, with the plurality of substrates positioned relative to each other. A method for forming a piezoelectric actuator. 2. A pressure chamber filled with ink, and a piezoelectric actuator having electrodes disposed on both sides in the thickness direction of the piezoelectric element, and the piezoelectric actuator is turned on by applying a voltage between the two electrodes. What is claimed is: 1. A method for manufacturing an ink jet head in which a pressure chamber is deformed so as to reduce the volume thereof and discharges ink in the pressure chamber, comprising: preparing a plurality of substrates;
Forming and laminating two electrode films, and patterning at least one of the two electrode films on the plurality of substrates in a state where the plurality of substrates are positioned relative to each other; Fixing an electrode film formed on the opposite side of the piezoelectric element film and the one pressure chamber forming part for forming a pressure chamber on the plurality of substrates while the plurality of substrates are positioned with respect to each other. And a step of removing the plurality of substrates after the fixing step.