JPH09314851A - Formation of microactuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain miniaturized microactuators for an ink jet recording apparatus in high density by forming an org. film on a substrate having electrode films formed thereon and forming recessed parts on the org. film to cast a piezoelectric material into the recessed parts and baking the piezoelectric material to form piezoelectric elements having a predetermined shape. SOLUTION: Electrode films 12 are formed on a substrate 11 by sputtering and a positive dry film 13 is bonded thereon and, after a metal mask 14 is arranged on the film 13, the film 13 is exposed through the mask 14. Whereupon, a polymeric main chain at the exposed parts is cut because the film 13 is a positive type and the exposed parts are eliminated by developing treatment. A piezoelectric material 16 composed of metal alkoxide is cast into the formed recessed parts 5 and baked at about 700 deg.C to evaporate the org. film to form sintered PZTs 17. After electrodes 18 are formed on the PZTs 17 by sputtering, polarizing treatment is applied across the electrodes 18 and the electrode film 12 to form miniaturized microactuators for an ink jet recording apparatus in high density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an actuator of a recording head in an ink jet recording apparatus.

[0002]

2. Description of the Related Art An ink jet recording apparatus is an apparatus for recording image information by discharging ink from a nozzle onto a recording sheet by displacing a piezoelectric element based on an electric signal.

A method for forming a piezoelectric element of a conventional ink jet recording apparatus will be described in detail. First, a ceramic plate forming method will be described. Here, PZT that is generally popular as a piezoelectric material will be referred to. PZT is usually
Mix powders of PbO, ZrO ₂ and TiO _{2 at} a predetermined ratio,
After adding the resin, it is adjusted to a predetermined thickness with a doctor blade or the like, and after firing, it becomes a ceramic plate. Next, a method for forming the piezoelectric element will be described with reference to FIG. After bonding the ceramic plate 41 to the substrate 42, a metal film 43 is attached to the upper part of the ceramic plate and the upper part of the substrate by sputtering or the like, the upper part of the ceramic plate is ground, and the metal film is divided into front and back to form an electrode film A44 and an electrode film B45. To do. After that, it is cut into a predetermined shape by dicing or the like, and a polarization process is performed by applying a voltage between the electrodes A and B to form a piezoelectric element. Further, a manufacturing process of the ink jet head will be described with reference to FIG. (A) is a side view of the inkjet head, and (b) is a perspective view of the inkjet head.
An ink jet head is manufactured by joining a vibration plate 52, a liquid chamber 54 in which a pressure chamber 53 is formed, and a nozzle plate 55 on the piezoelectric element 51, and finally wiring an FPC 56 to the electrode film.

[0004]

Generally, machining by dicing or the like is not suitable for precision machining. In the mechanical processing, when the piezoelectric element is cut, it is easy to form a work-affected layer such as a microcrack on the piezoelectric element due to the working stress. When there is a microcrack, moisture at high humidity is trapped in the crack, the insulation resistance value decreases, and the displacement amount decreases. Further, processing errors such as chipping are likely to occur. When chipping occurs, the area for applying pressure is reduced, and the displacement force is reduced. Further, the variation between the piezoelectric elements also increases.

An object of the present invention is to provide a microactuator for an ink jet recording apparatus which can easily achieve high density and miniaturization.

[0006]

In order to solve the above problems, the present invention forms an organic film on a substrate on which an electrode film is formed, forms a recess in the organic film, and forms a piezoelectric film in the recess. It is characterized in that a piezoelectric element having a predetermined shape is formed by pouring a material and firing it.

The firing temperature of the piezoelectric element is 500 to 700 ° C. when the piezoelectric material is composed of a metal alkoxide.
1000 to 1500 if composed of metal oxide
Degrees. Therefore, in either case, the organic substance evaporates in the firing process, and disappears after the firing, and a predetermined piezoelectric element can be formed. In addition, since the organic film can be patterned by exposure and development by imparting excimer laser or photosensitivity, it is possible to form a microactuator for an inkjet recording device which has a much higher density and a smaller size than ever before.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. 1 is a perspective view showing a process of forming a microactuator, FIG. 2 is a perspective view showing a process of manufacturing an inkjet head, and FIG. 3 is a sectional view of a pressure chamber showing an operating state of the inkjet head. First, the process of forming the microactuator will be described with reference to FIG. The electrode 12 is formed on the substrate 11 by sputtering or the like. A positive type dry film 13 is bonded thereon. A metal mask 14 is arranged on the surface and exposure is performed. Since it is a positive type, the polymer main chain in the exposed portion is broken and the average molecular weight is reduced, and the exposed portion disappears by developing. A piezoelectric material 16 composed of a metal alkoxide is poured into the recess 15. In the case of PZT, this piezoelectric material used a PZT sol solution by dissolving acetate, zirconium alkoxide, and titanium alkoxide in 2-methoxyethanol and hydrolyzing them. After that, by firing at about 700 ° C., the organic film evaporates and the sintered PZT1
7 is completed. An electrode 18 is formed on the PZT 17 by sputtering or the like, and a polarization treatment is performed with the electrode film 12 to form a microactuator.

Next, the manufacturing process of the ink jet head will be described with reference to FIG. FIG. 2 is a perspective view illustrating a manufacturing process of the inkjet head. A pressure chamber 22 and an ink supply port 23 are provided below the microactuator 21.
The liquid chamber 24 in which a so-called ink flow path is formed is joined,
A nozzle plate 26 having an ink ejection port 25 is joined underneath thereof, and finally an F
The PC 27 enables connection with an external power source and an inkjet head is manufactured. Further, the operating state of the inkjet head will be described with reference to FIG. FIG. 3 is a sectional view of a pressure chamber showing an operating state of the inkjet head.
When a voltage is applied between the electric signal lines a31 and b32 in the same direction as the polarization direction 33, the piezoelectric element extends in the electric field direction,
A pressure is applied to the ink filled in the pressure chamber 35 via the substrate 34, and the ink 37 is ejected from the ejection port 36, so that a desired character or image can be formed on a sheet (not shown).

Example 2 A PSF is used as an organic film, and a concave portion is formed in the organic film by ablation with an excimer laser. In the second embodiment, the material of the organic film and the processing method are the same as the first embodiment.
The drawings are omitted because they are the same except for the above. (Example 3) By adding water and an acid (for example, hydrochloric acid) to the piezoelectric material composed of the metal alkoxide and appropriately stirring and refluxing, the sol-gel reaction is promoted and the viscosity of the solution is increased. , Makes it easy to pour into the concave portion of the organic film. Example 3 is the same as Example 1 except that the viscosity of the piezoelectric material is different, and the drawings are omitted. (Example 4) A binder (for example, ethyl cellulose) is added to the piezoelectric material to increase the viscosity and facilitate the pouring into the concave portion of the organic film. Example 4 is the same as Example 1 except that the viscosity of the piezoelectric material is different, and the drawings are omitted.

The organic film is generally classified into three types of polymers, that is, an addition polymer, a condensation polymer and a ring-opening polymer. Condensation polymers typified by polyimide are flame-retardant.
It is known that addition polymers and ring-opening polymers other than condensation polymers evaporate sufficiently at about 0 ° C, but they do not evaporate sufficiently.

In Example 1, a positive type dry film resist was used as the organic film, but there is no problem even if it is a negative type.
Even if it is not a dry film resist, the same effect can be obtained if it is a photosensitive organic material.

Although a solution composed of a metal alkoxide is used as the piezoelectric material, the same effect can be obtained even if the resin is mixed with the metal oxide, although the firing temperature is high.

In Example 2, PSF was used as the organic film and the recess was formed by the excimer laser.
The same effect can be obtained with an organic film such as PC, PET, PEI, PAR, PEEK. Further, since the processing by the excimer laser is instantaneously decomposed and scattered, the processing is completed in a very short time, and burrs do not occur around the processing portion, which is suitable for precision processing of organic materials.

Further, if the viscosity of the piezoelectric material is increased,
The water content in the solution is relatively reduced, and the number of cracks caused by evaporation of the water during the firing process is reduced. In addition, the adhesion to the substrate is also improved as compared with when the viscosity is low.

[0016]

As described above, by patterning the piezoelectric element using the organic film of the present invention, the organic film is evaporated during the firing process, and as a result, the formation of the microactuator can be realized.

[Brief description of drawings]

FIG. 1 is a micro-actuator forming process according to a first embodiment of the present invention.

FIG. 2 shows a process of manufacturing an ink jet head according to a first embodiment of the present invention.

FIG. 3 is an operating state of a sectional view of the pressure chamber showing the first embodiment of the present invention.

FIG. 4 shows a piezoelectric element forming method showing a conventional example.

FIG. 5 shows a process of manufacturing an ink jet head showing a conventional example. (A) is a side view of an inkjet head. (B) is a perspective view of an inkjet head.

[Explanation of symbols]

 11, 34, 42 Substrate 12, 18 Electrode 13 Positive Dry Film Resist 14 Metal Mask 15 Recess 16 Piezoelectric Material 17 PZT 21 Micro Actuator 22, 35, 53 Pressure Chamber 23 Ink Supply Port 24, 54 Liquid Chamber 25, 36 Discharge Port 26, 55 Nozzle plate 27, 56 FPC 31 Electric signal line a 32 Electric signal line b 33 Polarization direction 37 Ink 41 Ceramic plate 43 Metal film 44 Electrode A 45 Electrode B 46, 51 Piezoelectric element 52 Vibration plate

Claims (6)

[Claims] 1. A piezoelectric element having a predetermined shape is formed by forming an organic film on a substrate on which an electrode film is formed, forming a concave portion in the organic film, pouring a piezoelectric material into the concave portion, and baking the piezoelectric material. A method for forming a microactuator, comprising: 2. The method of forming a microactuator according to claim 1, wherein the organic film is an organic material excluding a condensation polymer. 3. The method for forming a microactuator according to claim 2, wherein the organic film is a photosensitive organic material. 4. The method of forming a microactuator according to claim 2, wherein the recess is formed by an excimer laser. 5. The method of forming a microactuator according to claim 1, wherein a solution in which the piezoelectric material is synthesized from a metal alkoxide is used. 6. The method for forming a microactuator according to claim 5, wherein a binder is added to the piezoelectric material.