JPS631552A - Ink jet drop generator - Google Patents

Abstract

PURPOSE:To improve the long term reliability of jointing strength, by jointing a head body and an orifice plate through a sheet adhesive punched in the vicinity of a thin hole, and providing a cap covering the vicinity of a joint section between the orifice plate and a head body, thereby bearing the jointing load the sheet adhesive and the reinforcement (shearing strength of the adhesive) of the cap. CONSTITUTION:An orifice plate 3 is arranged on a head body 1 through a sheet adhesive 6, then a cap 7 is fitted in the head body 1 thereafter an adhesive 5 is filled in a gap between the cap 7 and the head body 1 and hardened with the orifice plate 3 being pressurized. The cap 7 is arranged to enclose the orifice plate 3 except the region of 0.1mm radius from a thin hole 4. The sheet adhesive 6 is placed between the head body 1 and the orifice plate 3 then heated (for 30min under the temperature of 170 deg.C) under pressurized condition (50-200psi). Consequently, they are fonded. When the adhesive 5 is filled into the gap between the cap 7 and the head body 1, it is pressurized continuously from the direction of an arrow 9 during the interval between filling and hardening.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet drop generator, and more particularly to a technique for joining a heel body and an orifice plate of an inkjet drop generator.

Fig. 4 is a cross-sectional configuration diagram of main parts for explaining an example of a conventional inkjet trotub generator.
is the head body, 2 is the liquid chamber, 3 is the orifice plate,
4 is a fine hole, 5 is an adhesive, and as shown in the figure, the orifice plate is bonded to the head body with an adhesive such as epoxy. However, in the above-mentioned drop generator, (1) it is difficult to suppress variations in the application (or injection) of the adhesive (liquid), and the liquid chamber or the microholes are often clogged with the adhesive.

(2) Since it is a detailed work, it is difficult to mechanize the application (or injection) of adhesive, and it is highly dependent on human manual labor, resulting in poor productivity.

(3) Placing the burden of bonding solely on the adhesive is harsh and poses a problem in long-term reliability.

(4) Variations in the application (or injection) of the adhesive cause non-uniformity of the adhesive layer, making the vibration characteristics of the drop generator unstable.

There were other advantages.

Purpose The present invention was made in view of the above-mentioned circumstances.
In particular, this was developed with the aim of providing a new joint structure between the head body and orifice plate in an inkjet drop generator. Structure 1 In order to achieve the above object, the present invention comprises a head body having a liquid chamber for guiding ink to an orifice portion, and an orifice plate having at least one fine hole, the head body and the orifice plate having a fine hole. a cap that is joined by a sheet-like adhesive hollowed out in the vicinity and that covers the vicinity of the joint between the orifice plate and the head body; in other words, a belly body that has a liquid chamber that guides ink to the orifice; consisting of an orifice plate having at least one microhole;
The head body and the orifice plate are joined by a sheet of adhesive that is hollowed out near the microhole, and a cap that encloses the orifice plate is attached to an area within a radius of 0.1 m around the microhole. The cap presses the orifice plate in a direction perpendicular to its joint surface.

Hereinafter, the present invention will be explained based on examples.

1 to 3 are sectional views of essential parts for explaining embodiments of the present invention, in which 6 is a sheet adhesive;
4 is a cap, and other parts having the same function as the prior art shown in FIG. 4 are given the same reference numerals as in the case of FIG. 4.

In the embodiment shown in FIG. 1, an orifice plate 3 is placed on a head body 1 via a sheet adhesive 6, a cap 7 is placed on top of the orifice plate 3, and the cap 7 is fitted into the head body 1. The adhesive 5 is filled into the gap between the cap 7 and the hemlock body 1 and cured while the orifice plate 6 is kept under pressure. Note that the cap 7 is disposed so as to surround the orifice plate 3 while avoiding an area within a radius of 0.1++n+ around the microhole 4. As the sheet adhesive 6, for example, S H EL
There is something like Tl401 from DAHL (USA), which is placed between the adherend (here, the head body 1 and the orifice plate 3) and pressurized fi (50 ~
Bonding is achieved by heating at 200 psi (170° C. for 30 minutes).

The role of the cap 7 in the present invention is to
to create a pressurized state when bonding the orifice plate 3 and the head body 1 together (in this case, pressure is applied to the cap part by a jig, etc. not shown), and the orifice plate 3 is bonded by the sheet adhesive 6. The purpose is to maintain the orifice plate 3 in a pressurized state at all times even after it is bonded. Therefore, when filling the gap between the cap 7 and the head body 1 with the adhesive 5, pressure must be continued from the direction of the arrow 9 using a jig or the like (not shown) during the period from filling to hardening.

In reality, it is sufficient to fill and harden the adhesive at the same time when the sheet adhesive 6 is pressed and applied.

The aim of the present invention is to share the bonding strength with both the bonding by the sheet adhesive 6 and the reinforcement by the holding structure of the head cap 7. The purpose of this is to take advantage of the fact that the strength of the adhesive 5 is extremely strong against shearing. In other words, the peel strength of the epoxy adhesive is generally several kg/inch
However, the shear strength is several 100 kg/
cyl, and the use utilizing shear strength is the most desirable use of the adhesive. The cap 7 has a small window 8 near the fine hole, but in order to create a uniform pressurized state to the orifice plate 3, it is desirable that the window be as large as the liquid chamber 2 and as small as possible. . The material of the cap 7 is preferably a highly rigid metal.

FIG. 2 is a diagram showing another embodiment of the present invention. This embodiment is an embodiment in which the head body 1 is larger than the orifice plate 3. In this case, the cap 7 and the head The adhesive 5 filled in the gap in the body 1 is filled up to the vicinity of the orifice plate 3 (not only the side wall surface but also the top surface of the body).

FIG. 3 is a diagram for explaining another embodiment of the present invention,
In this embodiment, the orifice plate 3 is placed on the head body 1'' via a sheet of adhesive 6, and a cap 7 is placed thereon, and the cap 7 is screwed, for example, by a holder 10 here. The orifice plate 3 is placed in a strongly pressurized state tS. This pressurized state is usually created using a jig or the like and bonded, but in this embodiment, the cap 7 and the holder 1
A pressurized state is created by tightening o, and even after the bonding is completed,
The cap 7 and the holder 10 maintain a fastened state, and the joint strength is shared by both the sheet adhesive and mechanical fastening.

The method of fastening the cap is not limited to the illustrated embodiment; other structures (for example, springs) may be used as long as the cap can apply a force to the orifice plate in a direction perpendicular to the joint surface. etc.) may also be used.

As is clear from the above explanation, according to the present invention, (A) a sheet adhesive is used in place of the conventional liquid adhesive, and (B) liquid chambers or microscopic There is no possibility of adhesive flowing into the hole and clogging it.

(Note) Sheet adhesives are suitable for mass production because they are punched out by press according to the shape of the adherend. (c) The adhesive layer of the sheet-like adhesive has a uniform thickness, and the vibration characteristics of the drop generator do not vary.

(B) Since the bonding burden is shared by both the sheet adhesive and the reinforcement of the cap (shear strength of the adhesive), the long-term reliability of the bonding strength is high.

(C) Since the bonding burden is shared by both the adhesive and mechanical fastening, the long-term reliability of the bonding strength is high.

There are advantages such as

[Brief explanation of the drawing]

1 to 3 are sectional views of main parts for explaining an embodiment of an inkjet drop generator according to the present invention, and FIG. 4 is a main part sectional view for explaining an example of a conventional inkjet drop generator. FIG. 1... Head body, 2... Liquid chamber, 3... Orifice plate, 4... Fine hole, 5... Liquid adhesive, 6
... Sheet adhesive, 7... Cap, 8... Small window, 1o... Holder. Patent applicant: Ricoh Co., Ltd. Figure I Figure 3 Figure 2 Figure 4

Claims (4)

[Claims] (1) It consists of a head body having a liquid chamber that guides ink to an orifice portion, and an orifice plate having at least one fine hole, and the head body and orifice plate are formed by a sheet-like adhesive hollowed out near the fine hole. 1. An inkjet drop generator, characterized in that the inkjet drop generator has a cap that is joined together and covers the vicinity of the joint between the orifice plate and the head body. (2) The cap has a radius of 0.0 mm around the microhole.
Wraps the orifice plate joint part while avoiding an area of 1 mm or less, and is fitted to the head body,
The bottom surface of the cap is in close contact with the orifice plate under pressure, and the gap between the inner wall of the cap and the outer wall of the head body is filled with a liquid adhesive and hardened. The inkjet drop generator according to item (1). (3) consists of a head body having a liquid chamber that guides ink to an orifice portion, and an orifice plate having at least one fine hole; The orifice plate has a cap that surrounds the orifice plate while avoiding an area within a radius of 0.1 mm around the fine hole, and the cap presses the orifice plate in a direction perpendicular to the joint. A drop generator for inkjet that is characterized by: (4) Claim (3) characterized in that the cap presses the orifice plate in a direction perpendicular to the joint surface by mechanically fastening the cap and an independent holder. Drop generator for inkjet as described in section.