JPH09300628A - Manufacture of ink-jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the bond strength between a liquid chamber part and a diaphragm in spite of a liquid chamber structure corresponding to 180dpi by a method wherein electroforming is applied to a liquid chamber mold, which is produced by excimer laser abrasion working, so as to form the liquid chamber member in order to obtain the liquid chamber member by vanishing the liquid chamber mold through heat decomposition. SOLUTION: After a thin polypropylene plate 8 having the thickness of about 200μm is bonded onto a diaphragm, which is made of Ni by electroforming, excimer laser abration working is applied through a patternized mask 6 to the thin plate 8 so as to form a liquid chamber mold 7. Next, through a liquid chamber member 2 is formed by Ni electroforming under the condition that the diaphragm 3 is used as an electrode, the diaphragm 3 and the liquid chamber member 2 are very strongly bonded together due to the fact that both the diaphragm and the liquid chamber member are made of one and the same material. Finally, the liquid chamber mold 7 is removed through heat decomposition so as to integrally form the liquid chamber member 2 and the diaphragm 3 in order to obtain an integrally molded body of the liquid chamber member 2 equipped with liquid chambers corresponding to 180dpi and the diaphragm 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method for forming a complicated and fine shape by an electroforming method, and more particularly to a printer for forming ink images on a medium such as recording paper by ejecting ink droplets. The present invention relates to a method for manufacturing an inkjet head used in an apparatus.

[0002]

2. Description of the Related Art A conventional piezoelectric ink jet head includes a piezoelectric element for generating a driving force for discharging ink,
A liquid chamber component having a liquid chamber that doubles as an ink flow path and a pressure chamber for ejecting ink, a diaphragm that transmits the driving force generated by the piezoelectric element to the liquid chamber, and the ink that is pressurized in the liquid chamber is ejected. Nozzle plate having ink ejection holes (hereinafter referred to as nozzles).

FIG. 1 shows an example of a conventional piezoelectric ink jet head. The liquid chamber component 2 has a large number of deep groove-shaped liquid chambers 2a which also serve as ink flow paths and ink pressurizing chambers. Each liquid chamber 2a corresponds to the nozzle 1a provided in the nozzle plate 1, and one nozzle 1a is arranged in one liquid chamber 2a. Therefore, in order to make the inkjet head have high resolution, it is necessary to narrow the intervals between the liquid chambers 2a formed in the liquid chamber component 2. The nozzle plate 1 and the liquid chamber component 2 are usually bonded with an adhesive.

The diaphragm 3 is usually a thin plate having a thickness of about 3 to 5 μm, and is provided with a convex groove called an island 3a, which protrudes by about 20 μm. When the piezoelectric element 4 expands and contracts due to the electrostrictive effect, this island causes the distortion to occur in the liquid chamber 2a.
It is for surely communicating to. Therefore, the island 3a has a liquid chamber 2a and a piezoelectric element 4 corresponding to the island 3a.
It is arranged so as to overlap with. The liquid chamber component 2 and the diaphragm 3 are bonded with an adhesive.

The piezoelectric element 4 corresponds to each liquid chamber 2a of the liquid chamber component 2 and is in a separated state so as not to affect the other liquid chambers 2a. These separated piezoelectric elements 4 are fixed on a base 5. Generally, for manufacturing reasons, a step is taken in which the piezoelectric element 4 which is not separated at first is bonded to the base 5 with an adhesive and then only the piezoelectric element 4 is separated by cutting. These piezoelectric element 4 and base 5
In a state in which is bonded, the piezoelectric element 4 and the corresponding island 3a formed on the diaphragm 3 are bonded with an adhesive.

As a liquid chamber component of a conventional piezoelectric ink jet head, it is general that an organic material such as epox is molded by an injection molding method. However, the organic material has drawbacks such as low rigidity and difficulty in applying sufficient pressure to the ink when pressed. So instead of organic materials, Zr
There is also one molded by using a processing method called a powder injection molding method in which an oxide such as O ₂ is molded by injection molding. These molding methods always require a mold. However, since a very large pressure is applied when a material is injected into a mold, it is difficult to make the mold into a fine shape, and these methods are not suitable for those having a fine shape.

As a processing method suitable for forming a fine shape, there is an etching method. By using etching, it is possible to easily pattern a metal plate having a thickness of about several hundred μm into a groove shape. However, even in this method, the groove width equivalent to the film thickness is the limit in terms of increasing the density, and is not so effective. Further, in the case of etching, since the groove penetrates, a plate-shaped member must be bonded to one of the surfaces of the metal plate to be used as a liquid chamber component, which complicates the process.

On the other hand, the diaphragm for transmitting the driving force generated by the piezoelectric element to the liquid chamber component is generally formed separately from the liquid chamber component. As a method of forming the diaphragm,
The most common method is to use electroforming. This is because if the electroforming method is used, it is possible to integrally form fine and precise islands on a thin plate.

The liquid chamber component and the diaphragm, which are separately formed, are joined by an adhesive or the like. The point required in this joining process is to make the adhesive layer as thin as possible so that the adhesive layer does not protrude into the liquid chamber that serves as the ink channel of the liquid chamber component, and
That is, the ink in each ink channel is firmly adhered so as not to be conducted. These requirements become more difficult as the inkjet head advances in the direction of higher density.

[0010]

In recent years, there has been a demand for a higher density of 180 dots per inch (hereinafter referred to as 180 dpi) or more. Naturally, the distance between the liquid chambers and the distance between the nozzles are also required to be equivalent to 180 dpi. 180
The interval corresponding to dpi means that the liquid chamber and the nozzle are formed at an interval of 141 μm. In the liquid chamber, it means that a wall partitioning between the liquid chambers is formed between 141 μm. When the width of the liquid chamber and the thickness of the wall are in a ratio of 1: 1, the width of the liquid chamber is 70.5 μm and the thickness of the wall is 70.5 μm.
m.

As described above, in the conventional ink jet head, the liquid chamber component and the diaphragm are molded separately, and an adhesive is applied to the upper surface of the wall that divides the liquid chamber of the liquid chamber component to bond it to the diaphragm. However, as the density of the ink jet head increases, it becomes more difficult to bond the adhesive, and if it exceeds 180 dpi, it is almost impossible to apply the adhesive stably. Even if it can be applied, it will be very weak in terms of bonding strength.

[0012]

In the present invention, in order to solve the above problems, an organic material which is coated or bonded on a diaphragm and which is easily decomposed by heat and which is easily ablated by excimer laser is used. By processing, patterning processing that is the reverse of the liquid chamber is performed. Then, electroforming is performed using the patterned organic material as a mold, and finally the organic material is extinguished by thermal decomposition.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a decomposition temperature of 46 is formed on a Ni diaphragm formed by electroforming.
A 200 μm thin plate made of polypropylene at 0 ° C. is bonded. Next, the adhered polypropylene is excimer laser ablated to form a liquid chamber mold. Then, the liquid chamber member is formed by Ni electroforming using the liquid chamber mold as the original mold.
Finally, the liquid chamber type is thermally decomposed at 480 ° C.

The embodiments of the present invention will be described in more detail below. FIG. 1 is a diagram showing a method for manufacturing a liquid chamber portion of an inkjet head according to the present invention. The manufacturing method of the present invention will be described with reference to FIG. First, 200 μm made of polypropylene on the diaphragm 3 made of Ni formed by electroforming.
A thin plate 8 having a thickness of 5 (this thin plate will later become the liquid chamber mold 7) was adhered with an adhesive. At this time, the thickness of the adhesive was 3 μm.

Next, the thin plate 8 made of polypropylene adhered on the diaphragm 3 is patterned into a desired shape by using an excimer laser ablation process. The desired shape here is a shape that becomes a mold of the liquid chamber.
First, as shown in (1) of FIG. 1, a mask 6 for excimer laser ablation processing having desired patterning.
The polypropylene thin plate 8 is laser-ablated through the. In this example, a KrF laser having a wavelength of 248 nm was used as the excimer laser, and the irradiation energy was set to 1 J / cm ² . Since polypropylene is an organic material and is easily ablated by laser, it is 1 J / cm.
^It can be easily processed with irradiation energy of ² . Therefore, the part irradiated by the excimer laser disappears in a short time. On the other hand, since the diaphragm 3 made of Ni and arranged in the lower layer of polypropylene is a metal, it is hard to be ablated by laser. Therefore, exposure to excimer laser irradiation for some time after the disappearance of polypropylene has little effect.

The mask 6 used in this embodiment is a metal mask formed by etching a metal plate made of BeCu into a desired shape by etching. When a finer shape is required, there is also a mask called a dielectric mask in which a multilayer optical film is patterned on quartz glass. When a dielectric mask is used, it can be processed with micron-level accuracy. These masks are commonly used in the field of excimer laser ablation processing. In this embodiment, the liquid chamber width of the inkjet head is 70 μm.
m, the space between the liquid chambers is 140 μm, and the patterning is performed with a design equivalent to 180 dpi. The accuracy of the metal mask is sufficient for use as patterning for the liquid chambers of this size.
Masks are also cheap.

By the excimer laser ablation process, the thin plate 8 is processed into a liquid chamber mold 7 which is an electroforming mold to be performed in the subsequent steps as shown in (2) of FIG.

Next, using the diaphragm 3 made of Ni as an electrode, the liquid chamber component 2 is formed by electroforming as shown in FIG. 1 (3). Ni is a conductive material and can be used as an electrode for electroforming. In this embodiment, the liquid chamber member 2 is formed by Ni electroforming. In this embodiment, the diaphragm 3 is also formed by Ni electroforming, and the diaphragm 3 and the liquid chamber member 2 are made of the same material. Therefore, the diaphragm 3 and the liquid chamber member 2 are joined very firmly.

Finally, the liquid chamber mold 7 is removed by thermal decomposition,
An integrally formed product of the liquid chamber member 2 and the diaphragm 3 is completed as shown in (4) of FIG. As another method of removing the liquid chamber mold 7, a method of dissolving polypropylene, which is an organic material, using a solvent was tried, but the solvent did not permeate into the liquid chamber and sufficient dissolution was not possible. Therefore, an attempt was made to remove the liquid chamber mold 7 by thermal decomposition. The polypropylene used in this example has a melting point of 166 ° C. and a decomposition temperature of 46.
It has a specification of 0 ° C, and complete decomposition at 480 ° C. Therefore, in this embodiment, the temperature is 480 ° C. in a nitrogen atmosphere.
Was decomposed by heating for 1 hour. 10 ° C up to 480 degrees
The temperature was raised at a heating rate of / min. During this process of thermal decomposition,
There was no change in the liquid chamber member 2 made of Ni and the diaphragm 3.

By the method as described above, the liquid chamber type can be removed cleanly, and the liquid chamber component having the liquid chamber equivalent to 180 dpi and the diaphragm can be integrally formed without using the bonding by the adhesive. I was able to.

[0021]

According to the present invention, since the liquid chamber component is formed on the diaphragm made of Ni by the direct electroforming method and using the same material as that of the diaphragm, 180d
Despite the liquid chamber structure equivalent to pi, the adhesive strength between the liquid chamber component and the diaphragm is very high.

Further, according to the present invention, no adhesive is used at all, and problems such as adhesive squeezing out and adhesive shortage, which have been a problem in the past of adhering a fine liquid chamber structure portion of 180 dpi or more, have been solved. There is no need to think at all.

Further, according to the present invention, the liquid chamber mold can be formed by a material having a low thermal decomposition temperature, and finally decomposed by heating to be removed cleanly.

[Brief description of drawings]

FIG. 1 is a diagram showing a method for manufacturing a liquid chamber portion of an inkjet head of the present invention.

FIG. 2 is a diagram showing a component configuration of a conventional inkjet head.

[Explanation of symbols]

 1 Nozzle Plate 1a Nozzle 2 Liquid Chamber Parts 2a Liquid Chamber 3 Diaphragm 3a Island 4 Piezoelectric Element 5 Base 6 Mask 7 Liquid Chamber Type 8 Thin Plate

Claims (3)

[Claims] 1. A liquid chamber member that forms a liquid chamber that functions as a pressure chamber for ejecting ink and an ink flow path, and a diaphragm that functions as a vibrating plate for applying pressure to the liquid chamber. In the method for manufacturing an inkjet head, a step of forming a liquid chamber type by excimer laser ablation processing of an organic material on the diaphragm, a step of forming a liquid chamber member by electroforming the liquid chamber type, and the liquid A method for manufacturing an ink jet head, which has a step of eliminating the chamber type by thermal decomposition. 2. The method of manufacturing an ink jet head according to claim 1, wherein a material that is easily ablated by laser and has a low thermal decomposition temperature is used for the liquid chamber type organic material. 3. The method for manufacturing an ink jet head according to claim 1, wherein the diaphragm and the liquid chamber member are made of a material having a temperature higher than the thermal decomposition temperature of the liquid chamber type.