JPH0639172B2 - Thermal head and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a thermal head improved so that a heat generating area of a heat generating layer can easily come into contact with the printing paper regardless of the smoothness of the printing paper and a thermal head thereof. It relates to a manufacturing method.

<Prior Art> A conventional general thermal head is shown in FIGS. 5 and 6 and will be described with reference to these.

In these drawings, reference numeral 1 is an insulating substrate made of, for example, ceramic. On one surface of the insulating substrate 1, a glaze layer 2 having a substantially semi-arcuate shape in a vertical cross section and a substantially band shape in a plan view is formed. In the direction orthogonal to the longitudinal direction of the glaze layer 2, strip-shaped heat generating layers 3 are formed in parallel at a constant interval so as to straddle the glaze layer 2 in correspondence with the number of print dots. On the surface of the heat generating layer 3, the conductor layer 4 is deposited so that the heat generating region 3a is formed on the top of the glaze layer 2. Due to the conductor layer 4, the heat generating region 3a is in a depressed state. In addition, each of the above layers is a protective layer 5 except a part.
And the protective layer 5 above the heat generating area 3a is also depressed (see FIG. 6).

<Problems to be Solved by the Invention> At the time of printing, it is general to perform an operation of pressing a thermal paper, which is a printing paper, against the heat generating area 3a in the recessed state by a platen roller having a circular or flat cross section. .

However, in the thermal head having the recessed heating area 3a, if a printing paper having a low smoothness, that is, a relatively rough surface is used, the contact state of the printing paper with the heating area 3a is likely to be incomplete, and the printing paper is used. The heat conduction to the thermal paper is impaired, and the print density is inevitably reduced. For this reason, it has been necessary to use printing paper with high smoothness in the conventional thermal head.

The present invention has been devised in view of the above circumstances. Even when a printing paper having a low smoothness is used, the contact state of the heating area of the heating layer with the printing paper is good, and a thermal head capable of realizing high-quality printing, and It is intended to provide a manufacturing method thereof.

<Means for Solving the Problem> A thermal head according to a first aspect of the present invention includes a plurality of glaze layers each having a substantially semi-arcuate longitudinal section and a substantially band shape in plan view, and a glaze formed on the glaze layer. And a plurality of heat generating layers that are independent of each other and that are formed over the glaze layer so as to cover the top surface of the convex region and that correspond to the convex region. The heat generating layer on the top surface of the convex area is higher than the other areas.

A method of manufacturing a thermal head according to a second aspect of the present invention includes a step of forming a glaze layer having a substantially semi-arcuate vertical cross section and a substantially band shape in a plan view on an insulating substrate, and a glaze raised from other portions. A step of forming a plurality of convex regions independent of each other on the glaze layer, and a step of forming a plurality of heat generating layers that straddle the glaze layer and cover the top surfaces of the convex regions. Therefore, the transition point of the convex region is set lower than the transition point of the glaze layer.

<Operation> Since the convex region on the glaze layer is in a raised state, the printing paper easily comes into contact with the heat generating layer (heat generating region) on the convex region. Further, since the convex regions are independent of each other, the heat generation energy is concentrated on the heat generation region.

<Example> Hereinafter, an example according to the present invention will be described with reference to the drawings.

In FIGS. 1 and 2, reference numeral 10 indicates an insulating substrate made of ceramic or the like, and a glaze layer 11 having a substantially semi-arcuate longitudinal section and a substantially band shape in a plan view is formed on one surface thereof. .

A plurality of substantially hemispherical convex regions 12 independent of each other are formed on the glaze layer 11. The number of the convex regions 12 is formed corresponding to the number of print dots of the thermal head itself, for example, having a diameter of about 0.3 mmφ and formed at intervals of about 0.15 mm.

Then, in the direction orthogonal to the longitudinal direction of the glaze layer 11, heat generation layers 13 each having a substantially band shape in a plan view are formed in parallel with each other at regular intervals in a direction corresponding to the number of the convex regions 12 so as to straddle the glaze layer 11. ing. The heat generating layer 13 has a convex region 12
The heat generating layer 13 on the convex region 12 is covered with the heat generating region 13a.

The surface of the heat generating layer 13 excluding the heat generating area 13 a is covered with a conductor layer 14 made of, for example, gold or aluminum, and the heat generating area 13 a is exposed from the conductor layer 14.

Furthermore, the surface of each layer as described above is covered with the protective layer 15, and this protective layer 15 also rises above the convex region 12 (see FIG. 2).

Even with the thermal head configured as described above, during printing, as is well known, an operation of pressing a printing sheet (not shown) against a heat generating area using a platen roller (not shown) having a circular or flat cross section is performed. Since the heat generating area 13a is raised above the other portions, the printing paper is likely to come into contact with the heat generating area 13a through the protective layer 15.

In addition, in the above-mentioned embodiment, the convex region 12 is formed into a substantially hemispherical shape, but the present invention is not limited to this, and may be, for example, a substantially trapezoidal shape. Further, although the convex regions 12 are separated from each other at regular intervals, the intervals may be set arbitrarily, and in order to increase the number of print dots, the glaze layers 11 are arranged in parallel in two rows. It is conceivable to provide such an arrangement that the convex regions 12 are alternately displaced.

Next, an example of a method of manufacturing the thermal head having the above-described structure will be described with reference to FIGS. 3 and 4.

A paste having a transition degree of about 800 ° C. is applied in a band shape on the surface of the insulating substrate 10 by, for example, screen printing,
Through the firing process, a glaze layer 11 having a substantially semicircular cross section is obtained (see FIG. 3 (a)). Depending on where on the insulating substrate 10 the glaze layer 11 is formed, it is classified into, for example, an edge type or a center type thermal head.

A paste having a transition point of about 600 ° C. is applied to the upper part of the glaze layer 11 at regular intervals in the longitudinal direction, for example, by screen printing, and a plurality of substantially hemispherical independent convex regions are formed through a firing process. 12 (Fig. 3
See (b) and Figure 4 (a)). In order to form this convex region 12, it is important to make the transition point of the paste that is the material of the glaze layer 11 higher than the transition point of the paste that is the material of the convex region 12. This is because the glaze layer 11 is formed prior to the convex region 12, and therefore when the transition point of the paste used as the material of the glaze layer 11 is lower than the transition point of the paste used as the material of the convex region 12, the convex region 12 is formed. This is because the glaze layer 11 previously formed is dissolved during the firing.

The glaze layer 1 covers the top surface of the convex region 12 and
Resistor film such as tantalum nitride is formed by, for example, sputtering so as to straddle No. 1 in a direction orthogonal to the longitudinal direction thereof to obtain a heat generating layer 13 having a substantially band shape in plan view (see FIGS. 3 (c) and 4 ( See b)).

Exothermic layer 13 excluding the exothermic region 13a on the convex region 12
The conductor layer 14 is deposited on the surface of the substrate by, for example, the lithography technique and the vapor deposition method (see FIG. 3 (d)).

After this, so as to cover each of the layers except a part thereof,
A protective layer 15 such as glass is applied (see FIG. 2).

The method of manufacturing such a thermal head is not limited to the above embodiment. For example, the glaze layer 11 can also be formed by an etching process using a lithographic technique. In addition, the convex region 12 can be applied by a dispenser or the like, and its material is, for example, aluminum or the like, and an insulating film is formed thereon, and then the heating layer 13 is formed.
It is also possible to form the conductor layer 14 by a thick film printing technique.

<Effects of the Invention> According to the thermal head of the present invention, since the heat generating area of the heat generating layer is in a state of being raised above the other portion due to the convex area, the contact state of the heat generating area with the printing paper is good at the time of printing. Become. That is, even if a printing paper having a low smoothness and a relatively rough surface is used, the raised heating area follows the rough surface and efficiently comes into contact therewith, and as a result, heat conduction during printing is improved. Therefore, the thermal head of the present invention can realize high-quality printing regardless of the smoothness of the printing paper.

Furthermore, since each convex area is independent of the other convex areas, the heat generation energy in the heat generating area is concentrated during printing. From such an effect, the printing efficiency is improved,
The effect is that high quality printing can be performed regardless of the smoothness of the printing paper.

[Brief description of drawings]

FIG. 1 is a plan view of a thermal head which is an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG.
(d) is a process cross-sectional view for explaining an example of the manufacturing method of the thermal head, and FIGS. 4 (a) and 4 (b) are FIG. 3 (b) and
FIG. 5 is a side view of (c), FIG. 5 is a perspective view of a conventional thermal head, and FIG. 6 is a vertical cross-sectional view of the main part of this thermal head. 10 ... Insulating substrate 11 ... Glaze layer 12 ... Convex area 13 ... Heating layer 13a ... Heating area

Claims (2)

[Claims] Claim: What is claimed is: 1. A glaze layer having a substantially semi-arcuate longitudinal section and a substantially band shape in plan view, a plurality of mutually independent convex regions formed of glaze formed on the glaze layer, and the convex region. And a plurality of heat-generating layers formed over the glaze layer so as to cover the top surface of the convex area, and the heat-generating layer on the top surface of the convex area is A thermal head characterized by being raised from the part. 2. A plurality of protrusions independent of each other, comprising a step of forming a glaze layer having a substantially semi-circular shape in a vertical cross section and a substantially band shape in plan view on an insulating substrate, and a glaze raised from other portions. The step of forming a partial region on the glaze layer, and the step of forming a plurality of heat generating layers covering the top surface of the convex region across the glaze layer, A method of manufacturing a thermal head, characterized in that the transition point is set lower than the transition point of the glaze layer.