JPH0872251A - Inkjet head manufacturing method - Google Patents

Abstract

(57) [Summary] [Objective] To provide a method for manufacturing an inkjet head, which has excellent printing quality and mass productivity. [Structure] A plate in which a tapered portion is formed and an orifice portion is not penetrated is formed by injection molding using polysulfone which is a resin material. The peak portion 103 corresponds to the taper portion and is formed on the die core 110 made of cemented carbide. Since the die core 110 made of cemented carbide has a low surface roughness, the release resistance of the injection-molded product at the time of release is small, and the plate can be released without deforming. Next, a nozzle plate is produced by irradiating an excimer laser beam on the bottom of the tapered portion of the plate to make a hole in the orifice portion. Since this nozzle plate is not deformed, it can be bonded well.

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 having a nozzle plate having an ink ejection port.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a nozzle plate on which nozzles for ejecting ink of an ink jet head are formed, a sheet-shaped plate is punched by pressing or drilling, There has been proposed a method of forming nozzles on a film-shaped plate as disclosed in Japanese Patent Laid-Open No. 61-32761 by using a high energy beam (for example, an excimer laser beam). FIG. 10 shows a schematic cross-sectional view of the nozzle plate of the inkjet head manufactured by this method.
The ink flow path 12 is formed by bonding the cover plate 3 and the piezoelectric ceramics plate 2, and the nozzle plate 31 is bonded so that the nozzle 32 corresponds to the position of the ink flow path 12 to form an inkjet head. .

Further, in Japanese Patent Laid-Open No. 1-108056, a method of forming a tapered nozzle by using an excimer laser and oscillating the excimer laser beam and a plate which is a material of a nozzle plate relative to each other. Is disclosed.

Further, Japanese Patent Laid-Open No. 3-297651 discloses a method for forming a nozzle plate by nickel electroforming or injection molding.

[0005]

However, in the method for making a hole in a film-shaped plate by an excimer laser beam as disclosed in the above-mentioned Japanese Patent Laid-Open No. 61-32761, as shown in FIG. In addition, since the volume inside the nozzle 32 is small, there is a problem that air intrudes into the nozzle 32, good ink ejection cannot be performed, and print quality deteriorates.

Further, in the method of using the excimer laser disclosed in Japanese Patent Application Laid-Open No. 1-108056 to relatively oscillate the excimer laser beam and the plate which is the material of the nozzle plate, a tapered nozzle is used. However, there is a problem that the laser beam irradiation time is long, the cost is high, and the mass productivity is poor.

Further, the nickel electroforming method disclosed in Japanese Patent Laid-Open No. 3-297651 has a problem that the manufacturing cost is high and the mass productivity is poor.

On the other hand, in the method of forming the nozzle plate by the injection molding method, since the degree of freedom of the nozzle shape is large, the volume inside the nozzle can be increased, but if the surface roughness of the die member forming the nozzle is poor. Since the nozzles of this type of inkjet head have a high degree of integration, there is a problem that the mold release resistance when the molded product is released from the mold after injection molding becomes large, and the product deforms or in some cases breaks. was there.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method of manufacturing an ink jet head having excellent printing quality and mass productivity.

[0010]

In order to achieve this object, according to a first aspect of the present invention, there is provided a method of manufacturing an ink jet head having a nozzle plate having an ink ejection port, wherein the ink ejection port is formed. It is characterized in that the nozzle plate is molded by an injection molding method using a cemented carbide on a mold member having a convex portion.

According to a second aspect of the present invention, the ink ejection port includes an orifice portion for ejecting ink, and a taper portion that connects the orifice portion and the ink flow path.

According to a third aspect of the present invention, the projections of the mold member have a grain size of greater than about 10/20 μm and about 41/75 μm.
It is characterized in that it is formed by cutting means of diamond abrasive grains smaller than m.

According to a fourth aspect of the present invention, the cutting means uses a metal-based bonding agent.

[0014]

In the method of manufacturing an ink jet head of the present invention having the above structure, the surface roughness of the mold member is reduced by using cemented carbide for the mold member having the convex portion forming the ink ejection port. Therefore, the mold release resistance when the molded product is released from the mold after injection molding is reduced, and the molded product is released from the mold without being deformed.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. For the sake of convenience, the same parts and equivalent parts as in the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

The ink jet head 1 of the first embodiment is
As shown in FIG. 1, it is composed of a piezoelectric ceramic plate 2, a cover plate 3 and a nozzle plate 61. The piezoelectric ceramic plate 2 is made of a polarized piezoelectric ceramic material, has a plurality of grooves (not shown), and a side wall (not shown) separating the grooves. A metal electrode (not shown) is formed on the upper half. The cover plate 3 is made of ceramics and has the ink inlet 21 and a manifold (not shown). The nozzle plate 61 is made of resin and has nozzles 64 as ink ejection ports.

The piezoelectric ceramics plate 2 and the cover plate 3 are adhered to each other with an epoxy adhesive so that the upper surfaces of the grooves are covered with the cover plate 3 and a plurality of ink flow paths 12 are formed in the lateral direction 65 (see FIG. 2). Is configured.

Then, by adhering a nozzle plate 61 provided with a nozzle 64 as an ink ejection port to the end faces of the piezoelectric ceramic plate 2 and the cover plate 3 at a position corresponding to the position of each ink flow path 12, the ink jet is carried out. The head 1 is formed.

FIG. 2 shows a sectional view of the ink jet head 1 of the first embodiment. The nozzle 64 formed on the nozzle plate 61 includes a taper portion 63 and an orifice portion 6.
It consists of two.

Here, a method for manufacturing the nozzle plate 61 will be described. First, the plate 71 in which the tapered portion 63 is formed and the orifice portion 62 does not penetrate (FIG. 3)
Is formed by injection molding using polysulfone which is a resin material.

FIG. 4 shows a schematic view of a mold structure used in this injection molding. In FIG. 4, the mountain portion 103 corresponds to the taper portion 63 of the nozzle plate 61 (or the plate 71) and is formed on the die core 110 made of cemented carbide.

The mold core 110 shown in FIG. 5A is manufactured as follows. As shown in FIG. 5B, a die core material 10 having a continuous mountain portion 13 having a shape in which mountain portions 103 (FIG. 5A) are continuous is manufactured by cutting, grinding, wire cutting, or the like. To do. Since the surface of the continuous mountain portion 13 thus manufactured is a cemented carbide, the surface roughness is small. Then, with a metal bond diamond blade using a diamond abrasive grain having a grain size of 30/40 μm, a groove is formed in the continuous mountain portion 13 to divide it. As a result, FIG.
Mold core 1 in which each mountain portion 103 is independent as shown in FIG.
10 is obtained. Then, each mountain portion 10 of the mold core 110
The shape of the groove bottom between the three is a flat shape 102, as shown in FIG. Further, when the cemented carbide is grooved with a diamond blade, the surface roughness of the grooved surface becomes small. Therefore, it is possible to reduce the mold release resistance at the time of mold release of the injection molded product without polishing the grooved surface of the fine mountain portion 103.

For the ink jet head 1 of this type, a groove width of about 50 to 300 μm is usually formed in the mold core 110. A diamond blade having a width corresponding to the groove width is selected.

As shown in FIG. 4, the die core 110 made of cemented carbide formed by the above-described method is mounted on the movable side mold plate 101 side, and the fixed side mold plate 104 and the movable side mold plate 10 are mounted.
Clamp 1 and 1. Next, the mold core 110 on which the ridges 103 are formed, the fixed side mold plate 104, and the movable side mold plate 10
In the cavity 120 surrounded by 1, the molten polysulfone is introduced through the gate 100 through the sprue 106, filled in the cavity 120 of the mold, and the tapered portion 63 is formed, as shown in FIG. The plate 71 is injection molded. Next, after leaving for a predetermined cooling time, the fixed side mold plate 104 and the movable side mold plate 101 are opened. Then, the plate 71 is taken out from the cavity 120 by moving the eject pin 105. At this time,
Since the surface roughness of the mountain portion 103 of the mold core 110 is small, the mold release resistance when the plate 71 is released from the mold is small,
The plate 71 can be released from the mold without being deformed, which is excellent in mass productivity.

On the other hand, in the case of using the mold core of the conventional alloy tool steel for molds, since the surface roughness is large, the mold release resistance of the crest portion is large, and when the mold is released, as shown in FIG. As shown, the force of the eject pin 105 is applied in the direction of the arrow 20, the plate 21 is deformed, and the nozzle plate is not bonded to the piezoelectric ceramic plate 2 and the cover plate 3 well.

Next, the plate 71 molded by the above method
The nozzle plate 61 is manufactured by irradiating the thin portion 72 with an excimer laser beam to punch the orifice portion 62.

Then, as described above, the piezoelectric ceramic plate 2 and the cover plate 3 are bonded together as in the ink jet head, and then the nozzle plate 61 is bonded. Inkjet head 1 manufactured in this way
The nozzle plate 61 of FIG.
Since the adhesive portion has a flat shape as shown in (a), good adhesion can be achieved.

Further, in the case of the nozzle plate 31 in which the nozzles 32 are formed by the excimer laser beam on the film-shaped sheet as shown in FIG. 10, the volume of the nozzles 32 is small, so that air often enters the nozzles. However, when the nozzle plate 61 having the shape shown in FIG. 2 is used, since the volume of the nozzle 64 is large, there is no invasion of air and good ink ejection can be performed, resulting in poor ink ejection. The quality is good.

Here, the diamond blade used when manufacturing the above-mentioned mold core will be described. Bonding agents for diamond blades include resin-based, metal-based, and vitrified-based ones. When a metal bond is used for the diamond blade, the angle of the edge of the tip of the blade can be formed well, and since the hardness is high, the edge hardly wears during processing. On the other hand, when a resin bond is used for the diamond blade, the angle of the edge at the tip of the blade can be formed favorably, but since the hardness is weak, the edge is worn during processing, as shown in FIG. 6 (b). Shape of the groove bottom is R shape 12
It becomes 2. Further, when a vitrified bond is used for the diamond blade, it is difficult to form a good angle at the tip of the blade, and the groove bottom does not have a flat shape.

Further, when an experiment was conducted on diamond abrasive grains, the grain size was 325/400 (approximately 41/75 μm).
When a larger abrasive grain is used, the tip of the diamond blade does not have a flat shape because the grain is large, and therefore the groove bottom does not have a flat shape. Further, when the abrasive grains having a grain size smaller than 10/20 μm are used, the diamond blade is worn during the machining, and the tip shape is immediately rounded, as shown in FIG. 6 (b). The groove bottom has an R shape 122.

As described above, the metal bond is used as the bonding material, and the grain size is larger than 10/20 μm.
If a diamond blade with abrasive grains smaller than / 75 μm is used, the groove bottom can be formed into a flat shape,
The nozzle plate 61 can be bonded well. Here, for example, the shape of the groove bottom as shown in FIG.
When injection molding is performed using the die core 130 having the shape 122, as shown in FIG. 7B, the bonding portion with the piezoelectric ceramic plate 2 becomes the R-shaped nozzle plate 51, and the bonding cannot be performed well. Or, the adhesive may stick out into the nozzle and adversely affect the ejection.

Next, a second embodiment according to the present invention is shown in FIG. In FIG. 8, a nozzle 94 of a nozzle plate 91 is provided with an orifice portion 92 which is penetrated by an excimer laser beam.
And a parabolic taper portion 93 formed during injection molding. This parabolic taper portion 93 makes the ink flow better than that of the linear taper portion 63 of the above embodiment. The nozzle plate 91 having such a shape cannot be manufactured by a method of forming a tapered nozzle by relatively oscillating the excimer laser beam and a plate which is a material of the nozzle plate as in the related art. Although difficult, according to the second embodiment, mass production can be easily performed.

Next, a third embodiment according to the present invention is shown in FIG. In FIG. 9, the nozzle 84 of the nozzle plate 81 is composed of a taper portion 83 and an orifice portion 82, which are simultaneously formed during injection molding. In this way, it is not necessary to make a hole by laser processing.

As the material of the nozzle plate according to the first, second and third embodiments described above, in addition to polysulfone, liquid crystal polymer, polyacetal, polyphenylsulfone, polyphthalamide, polyphenylene oxide, polyphenylene sulfide, Resin materials such as polyether imide, polyether sulfone, and polycarbonate can be used.

Further, the nozzle plates 61, 81, 9 are formed by using an injection molding technique of ceramic powder or metal powder.
1 can also be manufactured. That is, ceramic powder or metal powder is mixed and kneaded with a binder such as a resin material, injection-molded in a mold to obtain an injection-molded body, and then degreasing treatment is performed to remove the resin material from the injection-molded body and remove the degreased body. obtain. Further, the degreased body is inserted into a sintering furnace to perform a sintering process. By this sintering treatment, the degreased body shrinks and becomes smaller than the mold size by about 10 to 30%. For this reason, it is necessary to make the nozzle size and pitch on the die side larger in consideration of shrinkage than the product. Since this type of inkjet head has a high degree of integration of the nozzles, the flow resistance during injection molding becomes large, which is not desirable for injection moldability, but by using the ceramic or metal injection molding technology, a higher degree of integration can be achieved. It can be applied to the inkjet head of the nozzle. After the sintering process, the orifice portion 72 is penetrated by an excimer laser. Ceramic powder and metal powder are, for example, alumina, zirconia, silicon nitride,
Silicon carbide, stainless steel, or the like can be used.

The present invention is not limited to the above embodiment, and modifications can be made without departing from the spirit of the invention. For example, in the above embodiment, the nozzle 64,
84 and 94 are linear tapered portions 63, 84,
Although the taper portion 93 has a parabolic shape, the angle of this taper can be arbitrarily set within the range of the angle that can prevent air from entering. Although the excimer laser beam is used as the laser processing method, another laser processing method, for example, Y
It can also be carried out by processing with a wavelength of the AG laser beam being ¼. Further, it can be applied to various inkjet methods such as a thermal jet type and a Kaiser type.

[0037]

As is apparent from the above description, according to the method for manufacturing an ink jet head of the present invention, cemented carbide is used for the die member having the convex portion forming the ink ejection port. The surface roughness of the die member becomes small. Therefore, the mold release resistance when releasing the molded product from the mold after injection molding is small, the molded product can be released from the mold without being deformed or damaged. Good adhesion and excellent mass productivity. Moreover, since the volume inside the ink ejection port can be increased by injection molding, it is possible to prevent air from entering the ink ejection port, and the printing quality is excellent.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an inkjet head according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the inkjet head of the first embodiment.

FIG. 3 is a cross-sectional view showing a plate of the first embodiment.

FIG. 4 is an explanatory diagram showing an outline of a configuration of an injection molding die for manufacturing a nozzle plate of the inkjet head of the first embodiment.

FIG. 5 is an explanatory view showing a nozzle plate injection molding die core of the ink jet head of the first embodiment.

FIG. 6 is an explanatory diagram showing a nozzle plate injection molding die core of the inkjet head of the first embodiment and the conventional example.

FIG. 7 is a cross-sectional view showing an inkjet head of a first example and a conventional example.

FIG. 8 is a sectional view showing an inkjet head of a second embodiment of the present invention.

FIG. 9 is a cross-sectional view showing an inkjet head of a third embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a conventional inkjet head.

FIG. 11 is a sectional view showing a plate of a conventional example.

[Explanation of symbols]

 2 Piezoelectric ceramic plate 3 Cover plate 61 Nozzle plate 62 Orifice part 63 Tapered part 64 Nozzle 71 Plate 72 Thin part 81 Nozzle plate 82 Orifice part 83 Tapered part 84 Nozzle part 91 Nozzle plate 92 Orifice part 93 Tapered part 94 Nozzle part 101 Movable side Template 103 Mountain part 104 Fixed side template 110 Mold core

Claims (4)

[Claims] 1. A method of manufacturing an ink jet head having a nozzle plate having an ink ejection port formed by an injection molding method using a cemented carbide for a mold member having a convex portion forming the ink ejection port. A method for manufacturing an inkjet head, characterized in that the nozzle plate is molded. 2. The method of manufacturing an ink jet head according to claim 1, wherein the ink ejection port includes an orifice portion for ejecting ink and a tapered portion communicating with the orifice portion and the ink flow path. 3. The protrusion of the mold member has a grain size of about 1
2. The method of manufacturing an inkjet head according to claim 1, wherein the inkjet head is formed by a cutting means using diamond abrasive grains larger than 0/20 μm and smaller than about 41/75 μm. 4. The method of manufacturing an inkjet head according to claim 3, wherein the cutting means uses a metal-based bonding agent.