JPS60147355A - Thermal printing head - Google Patents

Abstract

PURPOSE:To improve the contact pressure of a heat generating layer to printing paper, by forming a resistance layer having a resistance value different from that of the heat generating layer between a glaze layer and said heat generating layer. CONSTITUTION:A partial glaze layer 2 for obtaining heat accumulation effect, a heat generating layer 3, a conductive layer 4 for guiding a current to the heat generating layer 3 and a resistant layer 5 are provided on a substrate 1 constituted of an insulating material such as alumina. The resistance layer 5 has a resistance value different from that of the heat generating layer 3 and is formed between the glaze layer 2 and the heat generating layer 3. When the resistance value of this resistance layer 5 is lower than that of the heat generating layer 3, an insulator may be interposed between the resistance layer 5 and the heat generating layer 3. Because the surface configuration of the heat generating layer 3 is made more uneven than that of the resistance layer 5, the contact pressure of printing paper can be made more sufficient. An entire surface glaze layer may be provided in place of the partial glaze layer 2. By this mechanism, printing quality can be enhanced and, by changing the surface configuration, heat distribution can be made uniform.

Description

Detailed Description of the Invention The present invention involves forming a gray X layer on an insulating substrate, forming a heat generating layer on this glaze layer, and forming a path on the heat generating layer to conduct current to the heat generating layer. The present invention relates to a thermal print head having a conductor layer of type 1#.

FIG. 1 is a schematic cross-sectional view of a conventional thermal printing head, and FIG. 2 is a plan view thereof. In these figures, reference numeral 1 indicates a base made of an insulating material such as alumina, and 2
3 is a partial glaze layer to obtain a heat storage effect, 3 is a heat generating layer,
4 is a conductor layer that provides a path for conducting current to the heat generating layer 3.

By the way, in a thermal printing head having such a □ configuration, the partial glaze layer 2 causes the surface shape of the heat generating layer 3 to be slightly bulged in a convex direction, which is convenient for increasing the contact pressure with the printing paper. However, since the conductive layer 4 is formed on the heat generating layer 3, the heat generating layer 3 becomes concave as shown in the figure due to the presence of the conductive layer 4, and as a result, contact with the printing paper The pressure decreases and print quality is adversely affected.

The present invention has been made in view of the above circumstances, and includes:
The main purpose is to improve the contact pressure of the heat generating layer against the printed paper.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 3 is a schematic cross-sectional view of a thermal print head according to an embodiment of the present invention, and FIG. 4 is a plan view thereof. In these figures, parts corresponding to those in FIGS. 1 and 2 are given the same reference numerals, and in FIGS. 3 and 4,
Reference numeral 1 indicates a base made of an insulating material such as alumina, 2 indicates a partial glaze layer for obtaining a heat storage effect, 3 indicates a heat generating layer, and 4
is a conductive layer that provides a path for conducting current to the heat generating layer 3.

5 is a resistance layer for providing unevenness to the surface shape of the heat generating layer 3. This resistance layer 5 has a high resistance value as well as the resistance value of the heat generating layer 3, and is formed between the glaze layer 2 and the heat generating layer 3. This resistance layer 5 is, for example, a heating layer 3.
A material to which impurities such as oxides are added is sputtered, and this is formed into a pattern as shown in the figure using a 7-etching technique. When the resistance value of the resistance layer 5 is lower than that of the heat generating layer 3, it is preferable to interpose an insulator between the resistance layer 5 and the heat generating layer 3. According to this embodiment, the surface of the heat generating layer 3 is made uneven by the resistance layer 5, so that the contact pressure with the printing paper can be made more sufficient. In place of the partial glaze M2 in this embodiment, a glaze layer may be used over the entire surface in the same manner. Further, in this embodiment, a plurality of resistive layers 5 are formed in a row in the left and right direction of the paper, but they may be formed in a row in a direction perpendicular to the paper. It is not limited in any way.

FIG. 5 is a schematic cross-sectional view of a thermal print head according to another embodiment, and FIG. 6 is a plan view thereof.

In these figures, parts corresponding to those in FIGS. 1 and 2 are given the same reference numerals. What should be noted in this embodiment is that the resistive layer 5 is formed on the entire surface of the partial glaze layer 2;
Furthermore, elongated holes 6 are formed in the heat generating layer 3.

As is clear from FIG. 6, this elongated hole 6 is formed in the shape of a square frame, and as a result, the current flows well around the heat generating layer 3, so that the heat dispersion of the heat generating layer 3 is uniform and printing is possible. The concentration can be made uniform along the shape of the heat generating layer 3. In the case of the embodiment shown in FIGS. 5 and 6, the formation pattern of the elongated holes 6 in the heat generating layer 3 can be variously modified in the same way as in the embodiments described earlier. Needless to say, it is not limited in any way. In the thermal printing head of this embodiment, illustrations of protective films and the like are omitted in the drawings.

As described above, according to the present invention, a glaze layer is formed on an insulating substrate, a heat generating layer is formed on the glaze layer, and a conductor layer is provided on the heat generating layer to provide a path for conducting current to the heat generating layer. In the thermal printing head formed by forming a □, the surface shape of the heat generating layer can be made uneven, so it is possible to improve the contact pressure of the heat generating layer against the printing paper, and this makes it possible to improve printing. Is it to further improve quality?
Also, by changing the shape, it is possible to make the heat distribution uniform.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a conventional thermal printing head;
3 is a schematic cross-sectional view of a thermal print head according to an embodiment of the present invention, FIG. 4 is a plan view thereof, and FIG. 5 is a schematic cross-sectional view of a thermal print head according to another embodiment, FIG. 6 is a plan view thereof. 1 is a base, 2 is a partial glaze layer, 3 is a heat generating layer, 4 is a conductive layer, and 5 is a resistive layer. Applicant ROHM Co., Ltd. Procedural Amendment (Method) May 24, 1980 3, Relationship to the case of the person making the amendment Patent Applicant Address 21 Saiin Mizosaki-cho, Ukyo-ku, Kyoto Name Name ROHM Co., Ltd. Representative Ken Sato - Department 4, Agent 8, insert the following sentence in the statement of contents of the amendment, page 6, line 13, between ``Sectional view'' and ``Figure 3 is''. ``Figure 2 is a plan view of the conventional thermal print head shown in Figure 1.''

Claims (6)

[Claims] (1) A thermal printing head formed by forming a glaze layer on an insulating substrate, forming a heat generating layer on this glaze layer, and forming a conductor layer on this heat generating layer to provide a path for conducting current to the heat generating layer. A thermal printing head characterized in that a resistance layer having a resistance value different from that of the heat generation layer is formed between the gray X layer and the heat generation layer. (2) In the thermal printing head according to claim 1, the resistance layer located between the glaze layer and the heat generating layer has a resistance value higher than that of the heat generating layer. head. (3) In the thermal print head according to claim 1, the resistive layer between the glaze layer and the heat generating layer is
A thermal printing head having a resistance value lower than a resistance value of the heat generating layer and an insulating layer formed between the heat generating layer and the resistive layer. (4) A thermal printing head according to claim 1, 2, or 3, in which the resistive layer has an uneven shape. (5) The thermal printing head according to claim 1, wherein holes are formed in the heat generating layer. (6) The thermal print head according to claim 1, 2, 3, 4, or 5, wherein the glaze layer is a partial glaze layer.