JPH0752431A - Substrate for edge face type thermal head - Google Patents

Abstract

PURPOSE:To attain the high printing efficiency when a thermal head is completed and generate no color shading, drawing and the like at the time of printing by improving the flatness on the surface of a glazed layer. CONSTITUTION:A substrate for an edge face type thermal head comprises a ceramic substrate 15 having a couple of main faces 11 facing each other and edge faces 13 formed successively to the main faces in the protruding curved face shape and a glass glazed layer 14 formed on the edge faces, and the angle thetaformed by the tangent 21 to the edge faces at an intersection 17 of the main faces with edge faces of the ceramic substrate 15 is at least 25 deg.. Also it is desirable to make a section A including the intersection 17 curving in the range of 20-100mum with the intersection as a center and connecting smoothly the main faces with edge faces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head substrate for a thermal transfer printer. More specifically, it relates to an end face type thermal head substrate in which a glaze layer is formed on the end face of a ceramic substrate.

[0002]

2. Description of the Related Art In a thermal head using a substrate of this type, since the surface on which the heating resistor is formed is the end face of the substrate, the flatness of the heating resistor portion is improved, and the head is used for recording paper on a platen roller. Contact evenly. As a result, this type of thermal head is able to print well on rough paper such as plain paper and hard paper such as cards, with the addition of heat storage and heat dissipation of the glaze layer, and the recording unit is compact and lightweight. Can be converted. Conventionally, in order to further improve the printing quality and improve the printing efficiency, it is known that the end surface of the end face type thermal head substrate has a convex curved surface. As shown in FIG. 3, this end face type thermal head substrate has a glaze layer formed on the end face 3 by forming an end face 3 following a pair of opposing main faces 1 and 2 of a ceramic substrate 5 into a convex curved surface. Four
Has been devised to reduce the radius of curvature of.

[0003]

However, in the above conventional thermal head substrate, when the glass paste is applied to the end face 3 of the convex curved surface and the glass paste is baked to form the glaze layer 4, the end face is not formed. The glass melted on the main surface 1 or 2 from the edge 7 which is the boundary portion easily flows down partially. As a result, the thickness of the top of the glaze layer 4 corresponding to the portion 6 where the molten glass flows down on the main surface 1 or 2 becomes small, which contributes to the undulation near the top of the glaze layer where the resistor is formed. . When printing with a thermal head in which a heating resistor is formed on the swelled glaze layer, the heat generated by the resistor cannot be stored uniformly in the glaze layer, and the heat dissipation during printing becomes uneven, resulting in uneven colors. Problems such as line sticking occur. Therefore, the waviness at the top of the glaze layer is required to be 1 μm or less. An object of the present invention is to provide a substrate for an end face type thermal head, which has a higher flatness on the surface of the glaze layer, has high printing efficiency, and does not cause color unevenness or line spread during printing.

[0004]

In order to achieve the above object, the structure of the present invention will be described with reference to FIGS. 1 and 2.
The present invention relates to a ceramic substrate 15 having a pair of main surfaces 11 and 12 facing each other and an end surface 13 formed on the convex surface following the main surfaces, and a glass glaze layer 14 formed on the end surface. This is an improvement of a substrate for an end face type thermal head provided with. The characteristic structure is that the angle θ formed by the tangent line 21 to the end face and the main face at the intersection line 17 between the main face and the end face of the ceramic substrate is at least 25 degrees. Further, in the present invention, a line 17 of intersection between the main surfaces 11 and 12 and the end surface 13 of the ceramic substrate 15
It is desirable to make the portion A including a curved surface in the range of 20 to 100 μm around the intersection line 17 to smooth the connection between the main surface and the end surface.

[0005]

[Function] The main surfaces 11 and 12 and the end surface 1 of the ceramic substrate 15
If the angle θ between the tangent line 21 to the end face at the intersection line 17 with 3 and the main surface is set to 25 degrees or more, the flow of the molten glass from the end face to the main surface at the time of firing is reduced, so that the glaze layer 14 Waviness near the top is also reduced. However, when the angle θ exceeds 25 degrees and becomes too large, the vicinity of the intersection line 17 corresponding to the connecting portion between the main surface and the end surface is formed at an acute angle, and smoothness is lost, so that the wiring is glazeed later. When it is formed continuously from the layer 14 to the main surface, there is a possibility that problems such as disconnection may occur. Therefore, it is desirable that the portion A including the intersection line 17 between the main surface and the end surface be curved around the intersection line 17 in the range of 20 to 100 μm to smooth the connection between the main surface and the end surface.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. The invention is not limited by this example. <Example 1> Length 200 mm, width 10 mm, thickness 2 mm
A ceramic substrate 15 having an alumina content of 96% was prepared. As shown in FIGS. 1 and 2, the entire flat end face in the length direction of the substrate 15 is ground to form a convex curved end face 1.
Formed 3. In this example, the end surface 1 of the ceramic substrate 15
The radius of curvature of 1.2 in the range of 1.5 mm in the center of 3
It was formed on a curved surface of mm. Further, the radius of curvature was determined as follows for each of the remaining both end portions of the end surface 13 of 0.25 mm. That is, the tangent 21 to the end face at the intersection line 17 between the main surface 11 and the end face 13 of the ceramic substrate 15
The end face 1 so that the angle θ between the main surface and
The remaining 0.25 mm area of both end portions of 3 was polished. The portion A including the line 17 of intersection of the main surface 11 and the end surface 13 was not specially polished and was not curved.

A glass paste obtained by mixing glass powder [GA-1, manufactured by Nippon Electric Glass Co., Ltd.], ethyl cellulose and terepionel was applied to the end surface 13 of the ceramic substrate 15 by spraying. afterwards,
After drying the applied glass paste at 150 ° C,
It was baked at 50 ° C. for 60 minutes. Gold was adhered to the glaze layer 14 thus formed on the end face 13 by sputtering, and wiring having a line width of 60 μm and a line interval of 30 μm was formed by photoetching to prepare a thermal head substrate.

<Embodiment 2> A portion A of an intersection line 17 between the main surface 11 and the end surface 13 is curved by polishing within a range of 60 μm centering on the intersection line 17 to smooth the connection between the main surface and the end surface. A thermal head substrate was prepared by repeating the same method as in Example 1 except that the above work was performed.

<Comparative Example 1> Main surface 1 of ceramic substrate 15
The 0.25 mm range of the remaining both end portions of the end face 13 was polished so that the angle θ between the tangent line 21 to the end face and the main surface at the intersection line 17 between 1 and the end face 13 was 20 degrees. The same method as in Example 1 was repeated except that a thermal head substrate was prepared.

<Comparative Example 2> Main surface 1 of ceramic substrate 15
The range of 0.25 mm at the remaining end portions of the end face 13 is ground so that the angle θ between the tangent line 21 to the end face and the main surface at the intersection line 17 between 1 and the end face 13 is 20 degrees, and A part A including an intersection line 17 between the main surface 11 and the end surface 13 was curved by polishing around the intersection line 17 within a range of 60 μm, and a work for smoothing the connection between the main surface and the end surface was performed. A thermal head substrate was prepared by repeating the same method as in Example 1 except for the above two points.

<Embodiment 3> Main surface 1 of ceramic substrate 15
The range of 0.25 mm at the remaining both ends of the end face 13 is ground so that the angle θ between the tangent line 21 to the end face and the main surface at the intersection line 17 between 1 and the end face 13 is 30 degrees, and A part A including an intersection line 17 between the main surface 11 and the end surface 13 was curved by polishing around the intersection line 17 within a range of 60 μm, and a work for smoothing the connection between the main surface and the end surface was performed. A thermal head substrate was prepared by repeating the same method as in Example 1 except for the above two points.

<Comparative Example 3> Main surface 1 of ceramic substrate 15
The range of 0.25 mm of the remaining both end portions of the end face 13 was polished so that the angle θ between the tangent line 21 to the end face and the main surface at the intersection line 17 between 1 and the end face 13 was 30 degrees. The same method as in Example 1 was repeated except that a thermal head substrate was prepared.

<Embodiment 4> Main surface 1 of ceramic substrate 15
The 0.25 mm range of the remaining both end portions of the end face 13 is polished so that the angle θ between the tangent line 21 to the end face and the main surface at the intersection line 17 between 1 and the end face 13 is 40 degrees, and A part A including an intersection line 17 between the main surface 11 and the end surface 13 was curved by polishing around the intersection line 17 within a range of 60 μm, and a work for smoothing the connection between the main surface and the end surface was performed. A thermal head substrate was prepared by repeating the same method as in Example 1 except for the above two points.

<Comparative Example 4> Main surface 1 of ceramic substrate 15
The range of 0.25 mm of the remaining both end portions of the end surface 13 was polished so that the angle θ between the tangent line 21 to the end surface and the main surface at the intersection line 17 between 1 and the end surface 13 was 40 degrees. The same method as in Example 1 was repeated except that a thermal head substrate was prepared.

<Measurement and Evaluation> Examples 1 to 4 and Comparative Example 1
For each of the thermal head substrates Nos. 4 to 4, the presence or absence of glass flow to the main surface during glaze layer formation, the degree of undulation at the top of the end face after glaze layer formation, and the presence or absence of defects such as wiring breakage were examined. The degree of waviness at the top of the end face was measured by a surface roughness meter, and the others were visually measured. The results are shown in Table 1.

[0016]

[Table 1]

As is clear from Table 1, Example 1 in which both end portions of the end face 13 were polished so that the angle θ was 25 degrees
In the case of the end face type thermal head substrate of No. 2 and No. 2, since the molten glass does not flow down to the main surface 11, the waviness of the top surface of the glaze layer is smaller than 1 μm. Further, regardless of whether or not the work for making the portion A including the intersecting line 17 into a curved surface by polishing is performed, a problem such as disconnection of wiring does not occur. On the other hand, the end surface 1 is adjusted so that the angle θ becomes 20 degrees.
In the case of the end face type thermal head substrates of Comparative Examples 1 and 2 in which both end portions of No. 3 are polished, there is no inconvenience such as disconnection of wiring, but the work of making the portion A including the intersecting line 17 into a curved surface by polishing Regardless of whether or not the above is performed, since the molten glass flows down to the main surface 11, the waviness of the glaze layer surface becomes larger than 2 μm.

The angle θ of Example 3 and Comparative Example 3 was 30 degrees, and the angle θ of Example 4 and Comparative Example 4 was 40 degrees, both of which exceeded 25 degrees, so that melting occurred. The glass thus formed does not flow down to the main surface 11, and the waviness on the top surface of the glaze layer is smaller than 1 μm. However, the portion A including the intersection line 17 between the main surface 11 and the end surface 13 is 6
In the case of Examples 3 and 4 in which the work of making the curved surface by polishing in the range of 0 μm and smoothing the connection between the main surface and the end surface is additionally performed, wiring problems such as disconnection do not occur. In the case of Comparative Examples 3 and 4 in which the work for smoothing the connection between the main surface and the end surface is not performed, wiring problems such as disconnection occur.

[0019]

As described above, according to the present invention, the angle θ between the main surface and the tangent to the end surface at the intersection of the main surface and the end surface of the ceramic substrate is set to 25 degrees or more. The flow of the molten glass from the end face to the main face is reduced, and the waviness of the top surface of the glaze layer is reduced. As a result, heat storage and heat dissipation of the glaze layer are performed uniformly, so that printing defects such as color unevenness and line spread during thermal transfer printing are eliminated.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of a substrate for an end surface type thermal head according to the present invention.

FIG. 2 is a perspective view of a main part thereof.

FIG. 3 is a perspective view of a main part of a substrate for an end surface type thermal head of a conventional example.

[Explanation of symbols]

 11, 12 main surface of ceramic substrate 13 end surface of ceramic substrate 14 glaze layer 15 ceramic substrate 17 intersection line between main surface and end surface of ceramic substrate 21 tangent to end surface at intersection line θ angle between tangent line and main surface A intersection line Part containing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masamune Betsumune 2270 Yokoze, Yokoze-cho, Chichibu-gun, Saitama Sanritsu Materials Co., Ltd. Ceramics Research Laboratory (72) Hiroshi Ishii 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Bamboo Sanryo Materials Co., Ltd. Ceramics Laboratory

Claims (2)

[Claims] 1. A ceramic substrate (15) having a pair of main surfaces (11, 12) facing each other and an end surface (13) formed on the main surface in a convex curved surface, and formed on the end surface. In the end face type thermal head substrate provided with the glass glaze layer (14), the line of intersection (17) between the main surface and the end face of the ceramic substrate.
An end face type thermal head substrate, wherein an angle (θ) formed by the tangent line (21) to the end face and the main surface is at least 25 degrees. 2. The portion (A) including the intersecting line (17) between the main surface (11, 12) and the end face (13) of the ceramic substrate (15) is in the range of 20 to 100 μm around the intersecting line (17). The end face type thermal head substrate according to claim 1, wherein the end face type thermal head substrate is curved to make the connection between the main surface and the end face smooth.