JP3094738B2 - Manufacturing method of end face type thermal head - Google Patents

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 end face type thermal head in which a heating element is provided on an end face of a substrate.

[0002]

2. Description of the Related Art Conventionally, as one of the thermal heads often used, there is an end face type thermal head in which a heating element is provided on an end face of a substrate. When printing with the thermal head sliding on the thermal paper,
An abrasion-resistant protective film that functions to prevent the heating element and the electrodes from abrading the paper surface is provided around the heating element. For example, a thermal head of this type is disclosed in
What was shown in Unexamined-Japanese-Patent No. 558 was common.
In recent years, in the manufacturing process of this end face type thermal head,
There is a strong demand for preventing the glaze layer from being etched in the surface treatment of the heating element and the electrode when forming the wear-resistant protective film.

Hereinafter, a method of manufacturing a conventional end face type thermal head will be described with reference to the drawings. FIG. 3 is a perspective view showing a conventional end face type thermal head. As shown in FIG. 3, the end-face type thermal head comprises a plate-like glazed alumina substrate 11 having one end face 11a and main planes 11b and 11c, a glaze 11d made of glass or the like, and a heating element 1
2, a common electrode 13b provided with an image signal electrode 13a provided with an image signal electrode lead-out part 17 as the electrode 13, a common lead lead-out part 18, a wear-resistant protective film 14, an electrode coat 15, and a semiconductor A connection layer 16 for connecting terminals is formed. First, from one end face 11a of a plate-shaped glazed alumina substrate 11 made of alumina or the like, a main plane 11 on one side is formed.
b, a glaze layer 11d made of glass or the like is formed, and then a plurality of heating elements 2 are formed in a row while forming a glaze etch prevention film on a part of the glaze layer 11d on one end face 11a of the glazed alumina substrate 11. The image signal electrode 13a extends from one end face 11a of the glazed alumina substrate 11 to one main plane 11b.
To the main plane 11c on the other side, and then the surface treatment (oxide film treatment) of the heating element 12 and the electrode 13 is performed in order to form the abrasion-resistant protective film 14 in close contact.
This is performed using a processing solution containing F (hydrogen fluoride), and an abrasion-resistant protective film 14 is formed from one end face 11a to both main planes 11b and 11c. Electrode coat 1 to prevent short circuit
5 and a connection layer 1 for connecting a semiconductor terminal that drives the heating element 12 so as to cover the image signal electrode lead-out portion 17.
6 is formed.

[0004]

However, in the conventional method of manufacturing an end face type thermal head, the wear-resistant protective film 14 is not used.
In the surface treatment (oxide film treatment) of the heating element 12 and the electrode 13 before the formation, the glaze layer 1 sandwiched between the main plane 11b of the glazed alumina substrate 11 and the image signal electrode 13a is formed.
1d is about 4 by treatment solution containing HF (hydrogen fluoride).
The glaze layer 11d on the lower surface of the connection layer 16 that connects the image signal electrode 13a and the semiconductor terminal that drives the heating element 12 is also etched, and the image signal of the image signal electrode 13a is etched. Since the connection layer 16 in the connection between the electrode extraction portion 17 and the semiconductor terminal becomes unstable with respect to the surface of the glaze layer 11d and weakens the connection force, there is a problem that the reliability of the connection of the connection layer 16 is reduced. Was.

The present invention solves the above problems and provides a method of manufacturing an end face type thermal head which prevents etching of a glaze layer by surface treatment before forming a wear-resistant protective film.

[0006]

According to the present invention, a plurality of heating elements are formed in a row on one end face of a plate-like insulating substrate having two end faces and two main planes. A first step, and a second step of forming an image signal electrode along one main plane from the one end face and a common electrode along the other main plane from the one end face; A third step of surface-treating a part of the heating element and the image signal electrode formed on the end face, and a surface part for the wear-resistant protective film which is a part of the common electrode; A fourth step of forming a protective film by coating; a fifth step of forming a connection layer on the image signal electrode; and a sixth step of forming a common lead extraction layer on the common electrode. Heat is generated between two end faces and two main planes of the insulating substrate during the third step. A surface protection film forming step of forming a surface protection film so as to cover at least the main plane on the image signal electrode side except for the one end face on the side, and between the third step and the fourth step. And a surface protective film removing step of removing the surface protective film.

[0007]

With the above structure, in the surface treatment before the formation of the wear-resistant protective film, the image signal electrode take-out portion on the main plane on which the connection layer is formed is covered with the surface protective film. The glaze layer on the lower surface can be protected from the processing solution for surface treatment, preventing glaze etching of the glaze layer due to surface treatment before the formation of the wear-resistant protective film, and improving the reliability of connection of the connection layer. Is what you can do.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a state in which a surface protective film is formed in the present embodiment. The outline of the end-face type thermal head is the same as that of the conventional example, so that the description is omitted. As shown in FIG. 1, a method of manufacturing an end face type thermal head is as follows. Second, a plurality of heating elements 2 are formed in a row while forming a glaze-etch prevention film on a part of the glaze layer 1d on one end face 1a of the glazed alumina substrate 1. One end face 1a
And the common electrode 4 is formed from the one end face 1a to the other main plane 1c. Fourth, a resist or the like is formed on the main plane 1b on the image signal electrode 3 side. To form a surface protection film 5, and then immerse the entire substrate in a surface treatment solution and treat the surface of the unprotected portion with HF (hydrogen fluoride) and an acid.
In addition, a wear-resistant protective film 6 is formed on the upper surface of the image signal electrode 3 and the common electrode 4, the surface protective film 5 is removed sixth, and a connection layer and an electrode coat are formed seventh.

The characteristics of the method of manufacturing the end face type thermal head of the present invention having the above-described structure will be described below. At the time of surface treatment at the time of forming the wear-resistant protective film 6,
Since the surface protection film 5 is formed in advance on the main plane 1b on the image signal electrode 3 side by a resist or the like, the main plane 1b
The upper glaze layer 1d is not etched by the surface treatment liquid.

As described above, according to this embodiment, the surface protection film is formed on the main surface 1b on the image signal electrode 3 side during the surface treatment at the time of forming the wear-resistant protection film. The glaze layer on the lower surface is not etched by the surface treatment liquid, and the reliability of connection of the connection layer can be improved.

The surface protection film may be formed by a printing method in which the surface protection film is directly formed on the main surface on the image signal electrode side, or by a method similar to the two main surfaces excluding the end surface on the heating element side. A dip method in which a surface protective film is formed on three surfaces of a substrate by immersing the end surfaces in a protective film solution, or a surface protective film is formed on four surfaces of a substrate by immersing four surfaces of the substrate in a protective film solution. The same effect can be obtained by using a three-sided dip coating spinner method or the like in which a layer of the surface protective film is made uniform and the surface protective film on the end face on the side of the heating element is exposed and developed and removed.

Further, depending on the method of forming the surface protective film, the surface protective film is not only formed on the main plane on the image signal electrode side, but also in FIG.
As shown in (1), the same effect can be obtained by simultaneously forming on the main plane on the common electrode side or on the end face of the other end of the substrate with the heating element side.

[0013]

As described above, according to the manufacturing method of the present invention, before the formation of the wear-resistant protective film, the surface protective film is formed on at least the main plane on the image signal electrode side. By the surface treatment at the time, the occurrence of glaze etching of the glaze layer on the lower surface of the connection layer can be prevented,
An object of the present invention is to provide a method of manufacturing an end face type thermal head capable of enhancing the connection between the image signal electrode extraction portion and the semiconductor for driving the heating element and improving the reliability of connection of the connection layer.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a surface protective film is formed in a method of manufacturing an end surface type thermal head according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state where a surface protective film is formed in the embodiment.

FIG. 3 is a perspective view showing a conventional end face type thermal head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Alumina substrate 1a End surface 1b, 1c Main plane 2 Heating element 3 Image signal electrode 4 Common electrode 5 Surface protective film 6 Wear resistant protective film

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yoshito Takenouchi 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Tsutomu Nakanishi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-2-111566 (JP, A) JP-A-62-149461 (JP, A) JP-A-62-259873 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/335

Claims (2)

(57) [Claims] 1. A first step of forming a plurality of heating elements in a row on one end surface of a plate-shaped insulating substrate having two end surfaces and two main planes, and one main plane from the one end surface A second step of forming an image signal electrode along the top, a common electrode from the one end face to the other main plane, and a part of the heating element and the image signal electrode formed on the one end face Third, a surface treatment for a wear-resistant protective film surface part which is a part of the common electrode.
A fourth step of forming a wear-resistant protective film on the surface-treated surface, a fifth step of forming a connection layer on the image signal electrode, and a common lead extraction layer on the common electrode. In the sixth step of forming the image signal, between the second step and the third step, at least the image signal except for the one end face on the heating element side of the two end faces and the two main planes of the insulating substrate. A surface protection film forming step of forming a surface protection film so as to cover the main surface on the side of the electrode for use, and a surface protection film removing step of removing the surface protection film between the third step and the fourth step. A method for manufacturing an end face type thermal head having: 2. A surface protection film is formed so as to cover at least the main surface on the image signal electrode side and the end face on the heating element side instead of the step of forming the surface protection film, and thereafter the surface protection film on the end face on the heating element side is formed. 2. The method according to claim 1, further comprising the step of removing the film between the second step and the third step.