JPH09300634A - Manufacture of ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the separation of dry film resist even under the state being finely patternized by a method wherein a liquid chamber part is formed on a diaphragm by electroforming over a dry film resist, which is made of photosensitive material and on which patternization is applied by photolithgraphy. SOLUTION: A dry film resist made of photosensitive material is laminated onto a thin Cu plate serving as a diaphragm and patternized by photolithography. Next, after a liquid chamber part is formed by electroforming under the condition that the diaphragm is used as an electrode, the dry film resist is dissolved with solvent. Concretely, after the liquid chamber part 2 is formed by electroforming under the condition that the diaphragm 3 is used as an electrode, the dry film resist 7 is removed with 3% sodium hydroxide aqueous solution so as to integrally form the liquid chamber part 2 on 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 method for manufacturing an ink jet head used in an apparatus such as a printer for forming an ink image on a medium such as recording paper by discharging ink droplets.

[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. At that time, the adhesive should not protrude from the liquid chamber as much as possible.

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. The most common method of forming the diaphragm is to use an electroforming method. 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.

In addition, when the liquid chamber component and the diaphragm are joined, the liquid chamber and the island must be aligned, but the higher the density, the more difficult this alignment becomes. If this alignment is not successful and a displacement occurs, the driving force for ejecting ink is not well transmitted to the liquid chamber, and in the worst case, ejection is impossible.

[0013]

In the present invention, in order to solve the above-mentioned problems, a dry film resist made of a photosensitive material is laminated on a Cu thin plate to be a diaphragm, and is patterned by using a photolithography technique. . After that, electroforming is performed using a diaphragm made of Cu as an electrode to form a liquid chamber component. Finally, the dry film resist is dissolved with a solvent to form a liquid chamber.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a method for manufacturing a liquid chamber portion of an ink jet head of the present invention. The manufacturing method of the present invention will be described with reference to FIG. First, a dry film resist 7 made of a photosensitive material was thermocompression bonded onto a diaphragm 3 made of Cu formed by an electroforming method. Liston FX-150 made by DuPont is used for the dry film resist 7.
(Thickness 50 μm), and thermocompression-bonded under the conditions of a roll temperature of 100 ° C., a roll speed of 2 to 3 m / min, and a roll pressure of 10 N / cm ² . In this example, Liston FX-150 was used in two layers. Therefore, dry film resist 7
Has a thickness of about 100 μm. A method of laminating two or more layers of dry film resist 7 is a commonly used method.

Next, the dry film resist 7 thermocompression-bonded on the diaphragm 3 is patterned into a desired shape by the photolithography technique. The desired shape here is a shape that becomes a mold of the liquid chamber. First, as shown in (1) of FIG. 1, the dry film 7 is exposed through an exposure mask 6 that has been subjected to desired patterning. Since the dry film resist 7 used is a negative resist, the unexposed portion remains after development.
The mask 6 used has a structure which is patterned in a Cr film on glass and is generally used in the LSI field. Therefore, the pattern of the mask 6 is guaranteed to have a submicron level accuracy. In this embodiment, the liquid chamber width of the inkjet head is 70 μm, and the liquid chamber interval is 14 μm.
The patterning is performed with a design of 0 μm corresponding to 180 dpi, and the mask precision is sufficient to be used for patterning a liquid chamber of this size.

In this embodiment, a double-sided aligner manufactured by Union Optical Co., Ltd. is used as an exposure device, and the mask 6 is aligned with the island of the diaphragm 3. Therefore, the alignment accuracy of the island of the diaphragm 3 and the liquid chamber was patterned with an accuracy of 2 μm or less.

Next, as shown in FIG. 1B, the dry film resist 7 exposed in a desired shape is developed using a predetermined developing solution. In this example, 1% sodium carbonate aqueous solution was used as a developing solution, and development was carried out at a temperature of 35 ° C. for 2 to 3 minutes. Generally, dry film resist is glass,
It is said that the adhesion is extremely poor with metals such as Si, Au, and SUS. To check the adhesion of dry film resist, glass, Si, Au, SUS, Cu
An attempt was made to pattern a dry film resist on the substrate using the mask of 180 dpi used in this example. As a result, excluding Cu, peeling occurred between the dry film and the substrate during development, and patterning at 180 dpi could not be performed. As you can see from this result, C
u has much higher adhesion to the dry film resist than other materials. By laminating the dry film 7 on the diaphragm 3 made of Cu as in this example, the peeling problem at the time of development was solved, and the dry film resist 7 could be patterned on the diaphragm 3.

Next, using the diaphragm 3 made of Cu as an electrode, the liquid chamber component 2 is formed by electroforming as shown in FIG. 1 (3). Cu is a highly conductive material and is very suitable as an electrode for electroforming. In this embodiment, the liquid chamber component 2 is formed by Ni electroforming, but it is not necessary to pay particular attention to Ni.

Finally, the dry film resist 7 is removed, and the liquid chamber component 2 is integrally formed on the diaphragm 3 as shown in (4) of FIG. The dry film resist 7 was removed by dissolving with a 3% sodium hydroxide aqueous solution.

By the method as described above, it was possible to integrally form the diaphragm and the liquid chamber component having the liquid chamber of 180 dpi without using the adhesive.

[0021]

According to the present invention, Cu, which has a very high adhesiveness with the dry film resist, is used as the material of the diaphragm, and the dry film resist is laminated directly on the diaphragm. The dry film resist does not peel off.

Further, according to the present invention, since the liquid chamber shape is patterned by the dry film resist by photolithography generally used in the LSI field, the alignment accuracy is very high. If the photolithography technique is used, the alignment accuracy of about several μm is very easy. Therefore, it can be manufactured with a sufficient margin for increasing the density to 180 dpi or more.

Further, according to the present invention, since the liquid chamber component is directly formed on the Cu thin plate to be the diaphragm by the electroforming method, the liquid chamber component and the diaphragm are bonded to each other in spite of the liquid chamber structure equivalent to 180 dpi. The strength is very high.

Further, according to the present invention, the adhesive is not used at all, and the problems such as the adhesive squeezing out and the adhesive shortage, which have been a problem in the adhesion of the fine liquid chamber structure portion of 180 dpi or more, have been solved. There is no need to think at all.

[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 Dry Film Resist

Claims (5)

[Claims] 1. A piezoelectric ink jet head having a liquid chamber part having a liquid chamber for storing ink and a diaphragm acting as a vibrating plate for pressurizing the ink in the liquid chamber, wherein the liquid chamber part is photosensitive. A method for manufacturing an inkjet head, comprising: a step of patterning a dry film resist made of a material by a photolithography technique; and a step of forming it on the diaphragm by an electroforming method. 2. A step of using a photolithography technique in which an exposure mask having a liquid chamber pattern is used, and the liquid chamber pattern is aligned with the pattern provided on the diaphragm. The method for manufacturing an inkjet head according to claim 1. 3. The method of manufacturing an ink jet head according to claim 1, further comprising a step of performing electroforming using the diaphragm as an electrode. 4. The dry film resist has a thickness of 50 μm.
The inkjet head manufacturing method according to claim 1, wherein the inkjet head is m or more. 5. The method for manufacturing an ink jet head according to claim 1, wherein the diaphragm is made of Cu.