JP2002205407A - Ink-jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable ink-jet head capable of electrically contacting with a printer main body stably. SOLUTION: In an ink-jet head with the configuration of fixing a head frame body structure member (structure member) 101 and a flexible substrate 205, a buffer layer 30 is provided between the head frame body structure member 101 and the flexible substrate 205.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink jet head used for a copying machine, a facsimile, a word processor, a printer as an output device of a host computer, a video printer, and the like.

[0002]

2. Description of the Related Art In an ink jet head, a circuit for driving an ink droplet ejection energy generating element is formed on a substrate on which the element is formed. The circuit includes a tape automated bonding (TAB) or a flexible print. A circuit (FPC) or the like is used.

The above circuit is fixed to a print head structural member and connected to a printer main body. Conventionally, for fixing electric circuit components to a structural member, ethyl vinyl acetate (EVA) or ethyl acrylic acid (EAA) is used. Adhesion using a hot melt sheet as a base polymer or a method of forming a caulking pin on a structural member and fixing the FPC by caulking have been used.

[0004]

However, since the structural member is generally a plastic molded product, it has been difficult to control the flatness of the surface on which the flexible substrate is fixed. When ribs or dug-outs having different resin thicknesses are formed on the back side of the fixing surface, it is more difficult to manage the flatness.
As a result, there is a problem that even if the flexible substrate is fixed on a surface where the flatness is not controlled, the electrical contact with the printer main body is not stabilized.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly reliable ink jet head capable of stably making electrical contact with a printer main body.

[0006]

According to a first aspect of the present invention, there is provided an ink jet head adopting a structure in which a structural member and a flexible substrate are fixed. Is provided with a buffer layer.

According to a second aspect of the present invention, in the first aspect, the buffer layer is made of silicone rubber.

According to a third aspect of the present invention, in the first aspect of the present invention, the buffer layer is made of ethylene-propylene rubber.

According to a fourth aspect of the present invention, in the first aspect, the buffer layer is formed of a rubber member having a rubber hardness of 25 to 70 degrees.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the thickness of the buffer layer is set to 0.05 to 1 mm.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In the present invention, the specific structure of the ink jet head is not important, and the present invention is applicable to various types of ink jet heads in which a flexible circuit board such as TAB or FPC is fixed to a structural member. Also, the specific structure of the electrical connector of the printer body is not important, and the present invention provides a dimple-shaped F connector.
It can correspond to various types such as a PC and a spring-type connector pin.

According to the present invention, a buffer layer is provided between the structural member and the flexible substrate.

Here, the buffer layer is preferably an elastic body, and rubber, sheet, sponge, gel, etc. can be used as long as it can correct the flatness of the structural member. Further, a thermoplastic elastomer can also be appropriately selected, and a styrene-based, olefin-based, ester-based,
Urethane type, isoprene type, 1,2-butadiene type, vinyl chloride type, amide type, ionomer type and the like can be used. Further, a preferable example is a rubber member. Specifically, silicone rubber, ethylene-propylene rubber (EPDM), butyl rubber, isobutylene rubber,
Styrene rubber, fluorine rubber, nitrile rubber and the like can be mentioned.

The most suitable examples of the rubber used for the ink jet head that can withstand the atmosphere of the alkaline ink include silicone rubber and EPDM.
In this case, the rubber hardness is preferably 20 to 70 degrees (JIS-A). If the rubber hardness is more than 70 degrees, it is too hard and cannot function as a buffer layer.

The thickness of the buffer layer can be appropriately selected in the range of 0.05 to 1 mm in consideration of the flatness of the structural member. Also, the buffer layer need not necessarily be flat,
There is no problem if a convex shape or the like is formed to assist the electrical contact.

FIG. 1 is a perspective view of an ink jet head unit, FIG. 2 is a perspective view of an ink jet according to the present invention, and FIGS. 3 to 6 are sectional views taken along line AA 'of FIG.

In FIG. 1, reference numeral 201 denotes a flow path member;
Is a base plate, 203 is a printed wiring board, 205
Is a flexible substrate, and in FIG. 2, 101 is a head frame structural member.

3 to 6, reference numeral 20 denotes an adhesive layer,
Reference numeral 30 denotes a buffer layer.

FIG. 3 shows a structure in which the buffer layer 30 is bonded to the head frame structural member 101 and the flexible substrate 205 with the adhesive layer 20, and FIG. 4 shows a structure in which the buffer layer 30 is bonded to the head frame structural member 101. 5 shows a structure in which the buffer layer 30 is bonded to the flexible substrate 205, and FIG. 6 shows a structure in which the buffer layer 30 is provided between the flexible substrate 205 and the head frame structural member 101.

As shown in FIG. 3, the buffer layer 30 and the flexible substrate 205, and the buffer layer 30 and the head frame structural member 10
1 and 2 are preferably bonded together, but FIGS.
As shown in FIG. 6, the buffer layer 30 is bonded to only one of the head frame structural member 101 and the flexible substrate 205, or the buffer layer 30 is bonded to the flexible substrate 205 and the head frame structural member 101 as shown in FIG. There is no problem even if a configuration not used is adopted.

Example 1 A substrate made of a heater and a driver by a general-purpose silicone process was die-bonded to an aluminum base plate to which a printed circuit board was attached.

Next, a top plate having discharge holes formed by excimer laser on a polysulfone resin top plate having ink flow paths, liquid chambers, and nozzles formed by injection molding is adjusted so that the discharge holes and the heater are aligned with the optimum positions. The spring assembly was obtained by fixing with the attached spring while positioning. A flexible printed circuit (FP) is attached to the spring assembly.
C) was joined to obtain a head unit.

Silicone rubber # 5442 with a pressure-sensitive adhesive (manufactured by Sumitomo 3M Limited) is bonded to the EPC in advance. The rubber hardness of the silicone rubber is 38 degrees (JIS
-A) and the thickness was 0.5 mm. The head unit is incorporated into an inkjet head structural member, and F
The four sides of the PC were fixed by caulking to obtain an ink jet head (FIG. 2). Subsequently, when the electrical contact with the printer body was checked using the ink jet head, no problem occurred (n = 100).

<Example 2> A head unit was manufactured in the same manner as in Example 1. EPDM is previously adhered to the FPC with a double-sided adhesive tape # 4357 (manufactured by Sumitomo 3M Limited). The rubber hardness of the EPDM is 50 degrees (JIS-A)
And the thickness was 0.5 mm. The head unit is incorporated into an inkjet head structural member, and the structural member and the FPC with a rubber member are adhered with a double-sided adhesive tape,
An inkjet head was obtained. Subsequently, when the electrical contact with the printer body was checked using the ink jet head, no problem occurred (n = 100). <Comparative Example 1> A head unit was manufactured in the same manner as in Example 1. No rubber member was attached to the FPC of the head unit as a buffer layer. The head unit was assembled into an inkjet head structural member, and four sides of the FPC were fixed by caulking to obtain an inkjet head. Subsequently, when the electrical contact with the printer body was checked using the ink jet head, a trouble occurred in three heads (n = 100).

Comparative Example 2 A head unit was manufactured in the same manner as in Example 1. EPD is included in the FPC of the head unit.
M is adhered with a double-sided adhesive tape.
Has a rubber hardness of 90 degrees (JIS-A) and a thickness of 0.1.
5 mm. The head unit was assembled into an inkjet head structural member, and four sides of the FPC were fixed by caulking to obtain an inkjet head. Subsequently, when the electrical contact with the printer main body was checked using the inkjet head, trouble occurred in two heads (n = 100).

[0027]

As is apparent from the above description, according to the present invention, in an ink jet head employing a structure for fixing a structural member and a flexible substrate, a buffer layer is provided between the structural member and the flexible substrate. Because it was provided,
Electrical contact between the ink jet head and the printer main body can be stably performed, and an effect that high reliability of the ink jet head can be obtained is obtained.

[Brief description of the drawings]

FIG. 1 is a complex diagram showing an inkjet head unit.

FIG. 2 is a complex diagram showing a configuration in which an inkjet head is incorporated in a structural member and a flexible substrate is fixed.

FIG. 3 is a cross-sectional view taken along line AA ′ of FIG. 2 (cross-sectional view in which a buffer layer is bonded to a flexible substrate and a structural member).

FIG. 4 is a sectional view taken along line AA ′ of FIG. 2 (a sectional view in which a buffer layer is adhered to a structural member).

FIG. 5 is a cross-sectional view taken along line AA ′ of FIG. 2 (cross-sectional view in which a buffer layer is bonded to a flexible substrate).

6 is a sectional view taken along line AA ′ of FIG. 2 (a sectional view in which a buffer layer is provided between a flexible substrate and a structural member).

[Explanation of symbols]

 Reference Signs List 20 adhesive layer 30 buffer layer 101 head frame structural member 201 flow path member 202 base plate 203 printed wiring board 205 flexible board

Claims (5)

[Claims] 1. An ink jet head employing a configuration in which a structural member and a flexible substrate are fixed, wherein a buffer layer is provided between the structural member and the flexible substrate. 2. The ink jet head according to claim 1, wherein said buffer layer is made of silicone rubber. 3. The ink jet head according to claim 1, wherein said buffer layer is made of ethylene-propylene rubber. 4. The ink jet head according to claim 1, wherein said buffer layer is made of a rubber member having a rubber hardness of 25 to 70 degrees. 5. The ink jet head according to claim 1, wherein the thickness of the buffer layer is set to 0.05 to 1 mm.