JPH06183000A - INKJET HEAD AND METHOD OF MANUFACTURING THE SAME - Google Patents

Abstract

(57) [Summary] [Object] To provide an ink jet head having high precision and high reliability, and a manufacturing method thereof. A nozzle plate 2 having one or a plurality of nozzles 3 arranged so as to face a recording medium, one or a plurality of flow paths for forming an ink cavity 8, and ink droplets are ejected. The nozzle plate 2 and the ink flow path are joined so that the nozzle 3 and the ink cavity 8 correspond to each other to form an ink droplet ejection port. A corner filling member 7 is filled in the corner portion of the joint between the ink flow path and the nozzle plate in order to eliminate the corner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head in an ink jet recording apparatus, and more particularly to an ink jet head excellent in high frequency response and a method for manufacturing the same.

[0002]

2. Description of the Related Art In an inkjet head having a high frequency response, in order to ensure stable printing quality, ink is completely filled in an ink cavity and energy for ejecting ink droplets is applied at every operation. In this case, the energy must be applied to the ink droplet ejection without loss of energy. However, there is a possibility that bubbles will be drawn from the nozzle when a reaction negative pressure occurs immediately after the ink droplets are ejected, and as a measure to prevent the bubbles from being drawn in, the following methods have conventionally been typically used. It has been commercialized.

A member such as a flow path plate forming an ink cavity is gradually narrowed toward the nozzle portion and processed by injection molding or the like so as to be tapered toward the nozzle. When forming the nozzle on the nozzle plate, the nozzle itself is tapered by processing with a high energy beam such as an excimer laser. The wettability of the nozzle plate forming the nozzle is improved by gold plating or the like, and an ink thin film is formed around the nozzle portion of the nozzle plate. A nozzle hole is formed by a punch and a die (for example, Japanese Patent Laid-Open No. 4-39053).

[0004]

However, each of the above methods has the following drawbacks. In order to attach a narrowed portion to a member such as a flow path plate, it is necessary to process the narrowed portion on the order of several μm, which requires extremely high-tech molding. Further, in order to further increase the degree of integration of the nozzles in the future, it is extremely difficult to perform narrowing molding. When the plate is perforated with an excimer laser, which is a high-energy beam, ordinarily, the hole diameter of the surface on which the laser hits becomes larger than the hole diameter of the back surface through which the laser hits. Therefore, after attaching the nozzle plate to the head main body, the method of processing the holes corresponding to the ink cavities formed by the flow paths forms an inverse taper shape in the ink ejection direction, With this, stable ink droplet ejection cannot be performed. Further, when the nozzle plate is bored by the above method, after the hole is formed, the nozzle plate must be aligned so as to correspond to the ink cavity and the nozzle plate must be joined, which is a difficult process. When an ink thin film is formed on the nozzle plate, it becomes difficult to control the amount of ink forming the thin film.
Since the ink is always exposed in a place very close to the printing medium, inconvenience is likely to occur in print quality control. It requires a burr removal process after drilling and is difficult to manage along with the inspection.

The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide an ink jet head which is precise and has high reliability, and a manufacturing method thereof. is there.

[0006]

In order to achieve the above object, the present invention provides (1) a nozzle plate having one or a plurality of nozzles arranged to face a recording medium, and an ink cavity. One or a plurality of flow paths and a pressure generating means for generating a pressure for ejecting ink droplets, and the nozzle plate and the ink flow path are joined so that the nozzle and the ink cavity correspond to each other. In the ink jet head that forms the ink droplet discharge port, a corner filling member for eliminating the corner is formed at a corner formed in the cavity of the joint portion of the ink flow path and the nozzle plate. Further, in (1), (2) the corner filling member has a streamlined shape of the ink cavity from the wall surface of the ink flow path to the nozzle. It is a UNA shape, or,
(3) The corner filling member is an epoxy resin, or (4) the epoxy resin is a two-liquid room temperature (or medium temperature) curable resin, or (5) the epoxy resin is The present invention is characterized in that a reactive diluent is added, and further, (6) a nozzle plate having one or a plurality of nozzles arranged so as to face the recording medium, and an ink cavity are formed. One or a plurality of flow paths and a pressure generating means for generating a pressure for ejecting ink droplets, and the nozzle plate and the ink flow path are joined so that the nozzle and the ink cavity correspond to each other. In the method of manufacturing an ink jet head in which the ink droplet discharge ports are formed, the fluid resin is filled in the ink cavity, and then gas is passed through the nozzle from the ink cavity side. While flowing out to the outside air, the fluid resin is formed at a corner portion in the cavity of the joint portion of the ink flow path and the nozzle plate. Further, in (6), 7) The gas flowing at the time of forming the fluid resin is a heated gas.

[0007]

1 is an enlarged cross-sectional view of an essential part for explaining an embodiment of an inkjet according to the present invention, and FIG. 2 is an overall perspective view showing an example of an inkjet head to which the present invention is applied. In FIGS. 1 and 2, 1 is an ink flow path plate, 2 is a nozzle plate, 3 is a nozzle, 4 is a pressure generating member, 5 is a substrate, 6 is a cover plate member, and 7 is corner filling added by the present invention. It is a member.

FIG. 1 is an enlarged cross-sectional view of the vicinity of the nozzle when the ink jet head shown in FIG. 2 is cut in the longitudinal direction of the flow path, and covers the ink cavity 8 formed by the flow path plate 1 and the cover plate member 6. The nozzle plate 2 is bonded so as to perform the above, and a high energy beam such as an excimer laser beam is emitted from the outside of the ink cavity so as to correspond to each ink cavity 8 to form a nozzle. The diameter of the formed nozzle is larger on the outside air side irradiated with the laser light than on the inside of the ink cavity. The nozzle 3 can be formed before the nozzle plate 2 is joined to the end of the ink cavity. In this case, the nozzle diameter can be increased inside the ink cavity. However, the nozzles formed and the ink cavities must be bonded so as to correspond to each other, and thus high-precision alignment and a technique of forming an adhesive layer so as not to fill the nozzles during bonding are required.

FIG. 4 shows an example of a conventional ink jet head in which a member 1 such as a flow path plate is gradually narrowed toward a nozzle 3 of a nozzle plate 2 and a flow path is tapered toward the nozzle. As shown in the figure, the provision of the narrowing portion 9 facilitates the discharge of bubbles, but it is very difficult to form the narrowing.

FIG. 5 shows a flow path plate member 1 with a nozzle plate 2
It is a figure which shows the prior art example when there is no narrowing toward the end (narrowing 9 in FIG. 4). In this case, as shown in the figure, a corner 10 is formed at the joint between the flow path plate 1 and the nozzle plate 2. Occurs. The corner portion 10 makes it easy to trap the air bubble drawn from the nozzle when ejecting the ink droplet, and makes it difficult to eject the air bubble once trapped, which significantly reduces the stability of the ink droplet ejection. It was a factor. On the other hand, according to the present invention, as shown in FIG. 1, since the corner filling portion 7 is provided at the corner, air bubbles are trapped in the corner like the conventional inkjet head. There is no such thing.

Next, a method of forming the corner filling member 7 will be described. FIG. 5 in which the nozzle is formed by the procedure described above.
A small amount of room temperature curable resin having low viscosity is filled in the head ink cavity from the ink supply path to the head having the shape shown in FIG. In order to remove the excess resin and adjust the shape of the corner filling member, a gas such as nitrogen or air is poured from the ink supply path. The gas flow rate and flow rate are adjusted so that the excess resin is smoothly removed from the nozzle, and the gas is continuously flowed after the removal so that the shape of the corner filling member is maintained until the resin is cured. Then, the corner filling member forms a streamlined shape that is an ideal shape for the ink to flow. The gas that is passed to accelerate the curing is passed near the curing temperature of the resin (40
If it is heated to about 80 ° C.), the formation time can be shortened significantly.

As the low-viscosity curable resin material forming the corner filling member, a two-component room temperature curable epoxy resin is suitable. Considering durability against ink, epoxy resin is more excellent as an epoxyphenol-based or nitrilephenol-based adhesive, a curing agent is an acid anhydride-based, and an aromatic polyamine-based, but the curing temperature is 150 ° C.
The above is necessary. When the head constituent material is formed of a plurality of materials in terms of ink droplet ejection characteristics (for example, the ink flow path plate is a resin such as polyphenylene sulfide (PPS) or polycarbonate (PC), the pressure generating member is a ceramic such as PZT or silicon). It is desirable to adopt a construction method that does not apply high temperature to the head because of the difference in the substrate) and the coefficient of linear thermal expansion. Therefore, room temperature or medium temperature (about 80 ℃)
An epoxy adhesive that uses a chain-like aliphatic polyamine, a cycloaliphatic polyamine, or a fatty aromatic polyamine, which is a curing agent that cures at, is adopted. These curing agents have a relatively high amine value and a small amount of curing agent is used to cure the epoxy resin, resulting in low viscosity when uncured.Epoxy resin cured with another ordinary temperature curing type polyamidoamine curing agent. Compared with, the ink tends to swell less easily.

The diameter of the nozzles 3 on the nozzle plate 2 may be 30 μm or less in order to highly integrate the ink jet head and improve the ejection characteristics of ink droplets.
As described above, when a finer structure is required, it is preferable to form the corner filling member 7 into an ideal shape in the viscosity range (1000 to tens of thousands of cps) of the normal two-component room temperature curable resin described above. Have difficulty. Therefore, for example, butyl glycidyl ether (BGE) (viscosity 1.5 cps / 25 ° C.), styrene oxide (SO) (viscosity 2 cps / 25 ° C.),
Phenyl glycidyl ether (PGE) (viscosity 7 cps
/ 20 ° C) and cresyl glycidyl ether (CGE)
About 10 reactive diluents (viscosity 6 cps / 25 ° C)
From 30 to 30%, the viscosity is dramatically reduced (Fig. 3
), The excess resin remaining in the ink cavity described above can be smoothly removed from the nozzle.

As another method for forming the corner filling member 7, an adhesive resin having a relatively low viscosity (for example, the above-mentioned two-component room temperature curing epoxy resin) is applied thickly on the nozzle plate 2 to form the nozzle. There is a method in which the corner filling member is formed at the same time when the plates are joined and the adhesive resin is projected during the joining. However, according to this method, a streamlined shape that is an ideal shape for ejecting ink droplets (FIG. 1)
Is difficult to form, and since the nozzle processing after joining the nozzle plates is performed with excimer laser light or the like, the nozzle diameter becomes larger on the outside air side than on the ink cavity side. This is a shape that adversely affects the stability of ink droplet ejection. Further, when a multi-nozzle head is created, it is very difficult to eliminate the shape variation of the corner filling member between the nozzles. Therefore, the method of forming the corner filling member while flowing the above-mentioned gas is selected.

[0015]

As is apparent from the above description, the present invention has the following effects. According to the first aspect of the present invention, since the corner portion of the joint between the ink flow path and the nozzle plate is provided with the corner filling member for eliminating the corner, the inclusion of bubbles from the nozzle is eliminated, and the stability and reliability are high. A large inkjet head can be provided. According to the second aspect of the present invention, the shape of the corner filling member shown in the first aspect is a streamlined shape, and it is possible to provide an ink jet head that achieves the above effects more effectively. According to the third aspect of the invention, the corner filling member can be formed more easily by using the epoxy resin as the material of the corner filling member shown in the first or second aspect. According to the invention of claim 4, when the corner filling member cannot be placed in a high temperature environment when forming the corner filling member, a high temperature is obtained by using a two-liquid room temperature (or medium temperature) curing type epoxy resin shown in claim 3. It is possible to provide an inkjet head that can achieve the above effects more effectively by eliminating the need for heating. According to the invention of claim 5, a means effective for achieving a reduction in viscosity of the resin for corner-filling member when uncured, which is necessary for forming the corner-filling member according to claim 1 or 2 more finely. Become. The invention of claim 6 is a manufacturing method for easily and uniformly forming the corner filling member shown in claims 1 and 5 in an ideal shape, and it is possible to manufacture an ink jet head that achieves the above effects. . The invention of claim 7 is effective as a means for shortening the time until the member is formed and improving the quality by heating the flowing gas in the method for forming a corner filling member shown in claim 6. is there.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part (longitudinal direction of a flow path of an inkjet head) for explaining an exemplary embodiment of an inkjet head according to the present invention.

FIG. 2 is a perspective view showing an example of an inkjet head to which the present invention is applied.

FIG. 3 is a diagram showing an example of a viscosity reducing effect of a reactive diluent.

FIG. 4 is an enlarged sectional view of a nozzle portion showing an example of a conventional inkjet head.

FIG. 5 is an enlarged cross-sectional view of a nozzle portion showing another example of a conventional inkjet head.

[Explanation of symbols]

1 ... Ink flow path plate, 2 ... Nozzle plate, 3 ... Nozzle,
4 ... Pressure generating member, 5 ... Substrate, 6 ... Cover plate member, 7 ... Corner filling member, 8 ... Ink cavity, 9 ... Narrowing portion, 10
… Corner.

Claims (7)

[Claims] 1. A device arranged so as to face a recording medium.
Alternatively, it has a nozzle plate having a plurality of nozzles, one or a plurality of flow paths for forming an ink cavity, and pressure generating means for generating a pressure for ejecting ink droplets, and the nozzle plate and the ink flow In an ink jet head in which channels are joined so that nozzles and ink cavities correspond to each other to form ink droplet ejection ports, the corners formed in the cavities at the joints of the ink flow paths and the nozzle plates are An ink jet head having a corner filling member for eliminating parts. 2. The ink jet head according to claim 1, wherein the corner filling member has a shape such that the ink cavity has a streamlined shape from the wall surface of the ink flow path to the nozzle. 3. The ink jet head according to claim 1, wherein the corner filling member is an epoxy resin. 4. The ink jet head according to claim 3, wherein the epoxy resin is a two-liquid room temperature (or medium temperature) curable resin. 5. The ink jet head according to claim 3, wherein the epoxy resin contains a reactive diluent. 6. A device arranged so as to face a recording medium.
Alternatively, it has a nozzle plate having a plurality of nozzles, one or a plurality of flow paths for forming an ink cavity, and pressure generating means for generating a pressure for ejecting ink droplets, and the nozzle plate and the ink flow In a method of manufacturing an inkjet head in which a channel and an ink cavity are joined so as to correspond to each other to form an ink droplet ejection port, a fluid resin is filled in the ink cavity, and then gas is injected from the ink cavity side to the nozzle. A method of manufacturing an ink jet head, characterized in that the fluid resin is formed at a corner portion inside a cavity of a joint portion of the ink flow path and the nozzle plate while passing through and flowing to the outside air. 7. The method of manufacturing an ink jet head according to claim 6, wherein the gas flown at the time of forming the flow path resin is a heating gas.