JP3125458B2 - Ink jet head and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to an ink jet head for performing printing on paper or the like.

[0002]

2. Description of the Related Art FIG. 4 is a sectional perspective view showing an example of the prior art. In FIG. 4, the nozzle forming member 10 has a plurality of nozzle openings 11 formed therein. Nozzle forming member 1
0 is connected to the pressure chamber forming member 20. The Ni film 301 is connected to the pressure chamber forming member 20. The Ni film 301 has a thick portion, which is the Ni pressure plate 31.
It is one. The Ni pressure plate 311 includes a pressure generator 40,
They are joined by an adhesive 70. Nozzle forming member 10
The area surrounded by the pressure chamber forming member 20 and the Ni film 301 is the ink chamber 21 and is filled with ink.

The Ni film 301 is a foil manufactured by electroforming Ni. The Ni pressure plate 311 is made of Ni
It is manufactured by patterning on the film 301 and repeating the electroforming process. That is, the Ni film 301
And the Ni pressure plate 311 are manufactured in an integrated configuration by Ni electroforming.

The thickness of a Ni film 301 manufactured by electroforming Ni is 3 μm. This is the minimum thickness that can be formed without defects in the electroforming method.

FIG. 5 shows another conventional technique. In FIG. 5, other members except for the PI film 302 and the SUS pressure plate 312 are exactly the same as those in FIG.

The PI film 302 is a 5 μm thick polyimide resin. The material of the SUS pressure plate 312 is stainless steel. The SUS pressure plate 312, after laminating a stainless steel foil on the PI film 302,
It is manufactured by patterning with a photosensitive resist and performing etching.

[0007]

However, of the above-mentioned prior arts, when manufacturing by Ni electroforming, there is a problem that the reaction force of the Ni film 301 applied to the pressure generator 40 becomes large.

In the case of the prior art described above, the pressure generator 40 uses a vertical piezoelectric element. When the voltage is released to the pressure generator 40 by a signal from the drive circuit, the pressure generator 4
0 displaces the Ni pressure plate 311 and the Ni film 301.

The high rigidity of the Ni film 301 means that the reaction force obstructing the displacement of the pressure generator 40 is high. Therefore, the ink chamber 2 generated by the pressure generator 40
1 is small. Therefore, the ink ejection efficiency is poor. Ni film 301 as rigid as metal foil
In this case, the power generated by the pressure generator 40 is absorbed and the efficiency deteriorates.

Next, another conventional technique, in which the stainless steel foil SUS pressure plate 312 is laminated on the PI film 302, can solve the above-mentioned problem of the reaction force.

However, the PI film 302 and SU
It is difficult to join the S pressure plate 312. Known joining techniques, such as lamination and adhesion, have a problem that sufficient joining reliability cannot be obtained, and peeling occurs during use, so that the force of the pressure generator 40 cannot be transmitted and ink cannot be ejected.

[0012]

According to the present invention, there is provided an ink jet head comprising a plurality of nozzle openings, an ink chamber corresponding to the nozzle openings, and a pressure generating device capable of expanding and contracting in a pressurizing direction for pressurizing ink in the ink chamber. And a film that separates the ink chamber from the pressure generating device, and a pressure plate disposed on the film corresponding to the pressure generating device, wherein the pressure plate has a surface joined to the pressure generating device. It has an R portion at an end and is formed integrally with the same resin material as the film. In addition, the method for manufacturing an ink jet head according to the present invention includes a plurality of nozzle openings, an ink chamber corresponding to the nozzle opening, a pressure generating device that can expand and contract in a pressing direction for pressing the ink in the ink chamber, In a method of manufacturing an ink jet head including a film for separating a device and an ink chamber, and a pressure plate disposed on the film corresponding to the pressure generating device, the heat-melted resin is placed at a position corresponding to the pressure plate. An ink jet method comprising: a step of supplying the resin on a grooved master; and a step of pressing the resin with a plate at an interval of a film thickness from the side on which the resin of the master is arranged. Head manufacturing method.

[0013]

【Example】

(Embodiment 1) FIG. 1 shows a main sectional view of an embodiment of the present invention.

In FIG. 1, the nozzle forming member 10 includes:
A plurality of nozzle openings 11 are formed. The pressure chamber forming member 20 is connected to the nozzle forming member 10. The PI film 30 is connected to the pressure chamber forming member 20. PI
The film 30 has a thick portion, which is the PI pressure plate 3
It is one. The pressure generator 40 is joined to the PI pressure plate 31 with an adhesive 70.

The nozzle forming member 10 and the pressure chamber forming member 2
The area surrounded by 0, the PI film 30, and the PI pressure plate 31 is the ink chamber 21 and is filled with ink.
The ink is supplied from the common flow channel 22 to the ink chamber 21 through the supply port 23.

In this embodiment, a vertical laminated piezoelectric element is used as the pressure generator 40. Pressure generator 40
Are divided into an active part 41 which is displaced by the drive voltage and an inactive part 42 which is not displaced. The inactive portion 42 of the pressure generator 40 is joined to the electrode 51 on the fixed substrate 50.

A common electrode 52 is soldered to the surface of the pressure generator 40 that is not joined to the fixed substrate. The electrode 51 and the common electrode 52 are
0 connects to the drive circuit.

The operation will be described. The voltage is applied to the pressure generator 40 in the standby state by the drive circuit. As a result, the active portion 41 is smaller than the natural length. By the ejection command, that is, the voltage release, the pressure generator 40 returns to the natural length. This displacement pushes the PI pressure plate 31 toward the nozzle forming member 10. Ink chamber 21
The pressure of the ink inside is increased by the displacement of the PI pressure plate 31 and is ejected from the nozzle opening 11 as ink droplets.

After the ejection of the ink droplets, a voltage is applied to the pressure generator 40, and the operation returns to the standby state again. Then, the ink corresponding to the ejected ink droplet amount is replenished from the supply port 23.

In this embodiment, the PI film 30 and P
The I pressure plate 31 is integrally formed of a polyimide resin. Since the rigidity is lower than that of the Ni film 301 described in the conventional example, the generated reaction force is low.

However, the PI film 3 of this embodiment
It was difficult to manufacture the 0 and PI pressure plates 31 by conventional resin molding methods, that is, mechanical processing, injection molding, etching, and the like. This is because the target value of the thickness of the PI film 30 is 5 μm or less.

Therefore, in this embodiment, the manufacturing method adopted is casting. FIG. 2 shows a conceptual diagram thereof.

In FIG. 2, the master 130 is a stainless steel plate. On the master 130, the PI pressure plate 31
The groove 131 is laid at a position corresponding to. This groove 13
1 was formed by a normal half etching technique.

After the heated and melted resin is supplied onto the master 130, the resin is pressed by a hot press 132. At this time, the interval between the hot press 132 and the master 130 becomes the PI film 30. After cooling, it is separated from the master 130 and fired.

By such a process, the target thickness of the PI film 30 was 5 μm or less. An inkjet head using this is a conventional Ni film 301.
The amount of ejected ink droplets was increased by 30% as compared with the ink jet head configured using. This is PI film 30
This is because the reaction force that hinders the displacement of the pressure generator 40 has decreased due to the low rigidity of the pressure generator 40.

(Embodiment 2) Another embodiment using the present invention will be described with reference to FIG. The configuration of the ink jet head is the same as that of the first embodiment, but aims to increase the printing density.

In order to increase the printing density, the PI pressure plate 3
It is necessary to reduce the pitch of 1. In the manufacturing method described in the first embodiment, the master 130 is manufactured by etching a stainless steel plate. Master 23 of this embodiment
0 is shown in FIG. The master 230 shown in FIG. 3 is manufactured by subjecting a stainless steel plate to electrical discharge machining.

The etching process for the stainless steel plate is as follows.
The ratio of the groove depth to the groove width is 1: 1, and in order to arrange the PI pressure plates 31 with high density, that is, with a narrow pitch, the groove depth must be reduced.

As already described in the first embodiment, the PI pressure plate 3
1 and the pressure generator 40 are joined by an adhesive 70.
At this time, if the thickness of the PI pressure plate 31 is small, the adhesive 70
Protrudes into the area of the PI film 30 and the pressure generator 40
To increase the reaction force.

In the master 230, a groove 231 is formed on a stainless steel plate by electric discharge machining. According to the electric discharge machining, the ratio of the groove depth to the groove width can be freely set. Therefore,
High-density P with a thickness that can cope with the exudation of the adhesive
The arrangement of the I pressure plate 31 becomes possible.

In this embodiment, the pitch of the PI pressure plate 31 could be reduced to 180 dots / inch. This is a conventional technique in which a stainless steel plate is laminated on a PI film 302, and the stainless steel plate is etched to form a SU.
The method of obtaining the S pressure plate 312 cannot be realized. In the prior art, the SUS pressure plate 312
This is because the bonding area between the Pl and the PI film 302 decreased, and sufficient bonding strength could not be obtained.

In this embodiment, it has been confirmed by a durability test that the PI film 30 and the PI pressure plate 31 are integral with each other and have no problem in the bonding strength.

[0033]

According to the ink jet head of the present invention, a plurality of nozzle openings, ink chambers corresponding to the nozzle openings, a pressure generating device that can expand and contract in a pressurizing direction for pressurizing ink in the ink chamber, In an ink jet head having a film for isolating the apparatus and the ink chamber and a pressure plate provided on the film corresponding to the pressure generating device, the pressure plate has an R at an end of a surface joined to the pressure generating device. The pressure generating device has no problem that the joint portion between the pressure plate and the film is peeled off by being formed integrally with the same resin material as the film, and the film has high elasticity. And the vibration generated by the pressure generating device can be efficiently transmitted to the ink in the ink chamber, so that a sufficient amount of ink is ejected with good responsiveness. It has the effect that the door can be. Further, there is an effect that the adhesive bonding the pressure plate and the pressure generating device can be held without protruding onto the film by the R portion of the pressure plate. Also,
A method for manufacturing an ink jet head according to the present invention includes a plurality of nozzle openings, an ink chamber corresponding to the nozzle opening, a pressure generating device that can expand and contract in a pressing direction that pressurizes ink in the ink chamber, a pressure generating device, In a method of manufacturing an ink jet head having a film for isolating an ink chamber and a pressure plate disposed on the film corresponding to a pressure generating device, a groove formed by heating and melting the resin at a position corresponding to the pressure plate. A conventional resin molding method comprising: a step of supplying the resin onto a master on which the resin is applied, and a step of pressing the resin with a plate at an interval corresponding to the thickness of the film from the side on which the resin of the master is disposed. Difficult to perform by machining, injection molding, etching, etc.
This has an effect that projections serving as pressure plates can be easily and accurately formed on a thin resin film having a thickness of μm or less.

[0034]

[Brief description of the drawings]

FIG. 1 is a main cross-sectional view of an inkjet head according to an embodiment of the present invention.

FIG. 2 shows a PI film 3 shown in FIG. 1 according to an embodiment of the present invention.
FIG. 7 is an explanatory diagram of a method for manufacturing the 0 and PI pressure plates 31.

FIG. 3 shows a PI film 30 and a PI film according to another embodiment of the present invention.
Explanatory drawing of the manufacturing method of the pressure plate 31.

FIG. 4 is a main cross-sectional view of a conventional inkjet head.

FIG. 5 is a main cross-sectional view of another conventional inkjet head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Nozzle forming member 11 Nozzle opening part 20 Flow path forming member 21 Ink chamber 22 Common flow path 23 Supply port which guides ink from a supply flow path to an ink chamber 30 PI film in the present invention 31 PI pressure plate in the present invention 40 Vertical lamination Pressure generator 41 composed of piezoelectric element 41 Active part of piezoelectric element 42 Inactive part of piezoelectric element 50 Fixed substrate 51 Electrode on fixed substrate 52 Common electrode 60 Flexible printed board 70 Adhesive 80 Case 130 Half-etched on stainless steel plate 131 A groove formed by half-etching on a stainless steel plate 132 Hot press 230 A master formed by electric discharge machining on a stainless steel plate 231 A groove formed by electric discharge machining on a stainless steel plate 301 Ni electroformed film 302 Polyimide resin film 311 N i Electroformed pressure plate 312 Stainless steel foil pressure plate

Claims (2)

(57) [Claims] An ink chamber corresponding to the plurality of nozzle openings, an ink chamber corresponding to the nozzle opening, a pressure generating device that can expand and contract in a pressurizing direction for pressurizing ink in the ink chamber, and the pressure generating device and the ink chamber. In an inkjet head including a film to be separated and a pressure plate disposed on the film corresponding to the pressure generation device, the pressure plate has an R portion at an end of a surface to be joined to the pressure generation device. And an ink-jet head formed integrally with the same resin material as the film. 2. An ink chamber corresponding to a plurality of nozzle openings, an ink chamber corresponding to the nozzle opening, a pressure generating device that can expand and contract in a pressurizing direction for pressurizing ink in the ink chamber, and the pressure generating device and the ink chamber. In a method for manufacturing an ink jet head including a film to be separated and a pressure plate disposed on the film corresponding to the pressure generating device, a groove processing is performed on a resin melted by heating at a position corresponding to the pressure plate. An ink jet head comprising: a step of supplying the applied resin onto a master; and a step of pressing the resin with a plate at intervals from the side on which the resin of the master is arranged by the thickness of the film. Manufacturing method.