JPH0667630B2 - Thermal head - Google Patents

Description

The present invention relates to a thermal head used for recording an image or the like on plain paper or the like via a photosensitive paper or an ink ribbon.

[Background of the Invention]

Conventionally, a thermal head as shown in the sectional view of the main part of FIG. 3 is known. In this thermal head, a heat storage layer 2 such as a glaze layer is provided on a substrate 1 made of ceramic such as alumina, then a resistor 3 such as tantalum nitride is provided from the heat storage layer 2 to the substrate 1, And resistor 3
In order to supply electric power to the resistor 3, a lead signal electrode 4 and a common electrode 5 made of a metal such as aluminum are provided on the resistor 3, and finally, oxidation and friction of the resistor 3, the signal electrode 4 and the common electrode 5 are performed. It is formed by providing a protective layer 6 made of silicon dioxide, tantalum pentoxide or the like on the resistor 3, the signal electrode 4 and the common electrode 5 for preventing the above. In this thermal head, the end faces of the signal electrode 4 and the common electrode 5 face each other on the surface of the resistor 3 on the heat storage layer 2,
The surface of the protective layer 6 between the facing portions, that is, the print dot portion P
Becomes depressed by the thickness of the signal electrode 4 and the common electrode 5,
Therefore, the contact of the photosensitive paper 10 (or the plain paper via the ink ribbon) with the print dot portion P becomes insufficient,
Since the thermal efficiency is deteriorated, the quality of the print is deteriorated, and the photosensitive paper 10 and the like are strongly contacted with the portions of the left and right ends of the print dot portion P where the surface of the protective layer 6 is high. It has the drawback that parts will wear out faster.
In order to prevent the print quality from deteriorating, the heat generation of the resistor 3 may be increased, but this does not solve the problem that the life of the resistor 3 or the like is shortened and the protective layer 6 is easily worn. .

As a means for solving such a problem of the conventional thermal head, the thermal head shown in the cross-sectional view of the principal part of FIG. 4 is known from Japanese Patent Application Laid-Open No. 60-112459, and
The thermal head shown in the perspective views of the essential parts of FIGS. 5 and 6 is known from Japanese Patent Application Laid-Open No. 60-137670.

The thermal head of FIG. 4 is different from the thermal head of FIG. 3 in that the surface of the resistor 3 on the heat storage layer 2 while the signal electrode 4 and the common electrode 5 face each other is the same as the surface of both electrodes. A trapezoidal metal layer 7 made of aluminum, copper or the like is provided so as to be lifted up to a certain height, and an insulating layer 8 made of silicon dioxide or the like is provided so as to cover the surfaces of the metal layer 7 and the heat storage layer 2.
And the resistor 3, the signal electrode 4, and the common electrode 5 are provided on the insulating layer 6 as in the thermal head shown in FIG. 3, and the insulating layer 6 is an antioxidant layer such as silicon dioxide. This is a two-layer structure of 6a and a wear resistant layer 6b such as tantalum pentoxide. That is, the thermal head of FIG.
The trapezoidal metal layer 7 provided on the heat storage layer 2 brings the surface of the resistor 3 between the signal electrode 4 and the common electrode 5 to the same height as the surfaces of both electrodes, and the print dot portion P is not dented. Thus, the drawbacks of the thermal head shown in FIG. 3 are eliminated. However, in the thermal head, the number of steps is increased compared to the step of manufacturing the thermal head shown in FIG. 3 only by the step of providing the metal layer 7 and the insulating layer 8. Moreover, in the step of providing the metal layer 7, since the metal layer 7 has thermal conductivity unlike the heat storage layer 2 and the insulating layer 8, it is necessary to be independent for each resistor 3, and therefore, by the vapor deposition or the sputtering. This is a troublesome process that requires patterning by photoetching after forming a thin film.

The thermal head shown in FIG. 5 is different from the thermal head shown in FIG. 3 in that after the signal electrode 4 and the common electrode 5 are provided, it is necessary to eliminate the depression of the print dot portion P on the resistor 3 between the electrodes. The point is that an electrically insulating heat conducting member 9 made of silicon carbide, aluminum oxide or the like is provided, and the last insulating layer 6 is provided with a layer thickness whose surface matches the surface of the heat conducting member. In this thermal head, the depression of the print dot portion P is eliminated, but the distance between the surface of the resistor 3 and the surface of the print dot portion P between both electrodes is the same as the surface of both electrodes and the print dot portion P.
The thickness of both electrodes is larger than the distance of the surface of the electrode, and therefore, when compared with the case where the same material as the heat conducting member 9 is used for the insulating layer 6 of the thermal head of FIG.
As the distance becomes larger, the heat transfer coefficient becomes smaller and the thermal efficiency becomes worse. Therefore, it becomes necessary to increase the heat generation amount of the resistor. In addition, the manufacturing process of the thermal head is apparently one more process than the manufacturing process of the thermal head shown in FIG. Although it seems that the process is simplified, in practice, providing the heat conducting member 9 such as silicon carbide or aluminum carbide on the resistor 3 in a fine pattern is to provide the metal layer 7 of the thermal head shown in FIG. It is much more troublesome than that, and it is also extremely difficult to provide the protective layer 6 so as not to adhere to the surface of the heat conducting member 9. Therefore, after the protective layer 6 is provided, it adheres to the surface of the heat conducting member 9. On the contrary, it requires a surface polishing step for removing the protective layer 6, which is more troublesome than the manufacturing step of the thermal head shown in FIG.

The thermal head shown in FIG. 6 is provided with the signal electrode 4 and the common electrode 5 after the signal electrode 4 and the common electrode 5 are provided so that the thermal conductive member 9 of the thermal head shown in FIG. An insulating layer 8 made of silicon dioxide or the like for covering the surfaces of the electrodes and the resistor 3 is provided, on which a metal heat conducting member 9'is further protected, like the heat conducting member 9 of the thermal head shown in FIG. The layer 6 is provided. As with the thermal head shown in FIG. 5, this thermal head has a large gap between the surface of the resistor 3 and the surface of the print dot portion P between both electrodes by the thickness of both electrodes, which deteriorates the thermal efficiency and protects it. Layer 6
After the provision of the protective layer 6 attached to the surface of the heat conducting member 9 '
However, the manufacturing process is more complicated than that of the thermal head manufacturing process shown in FIG.

Further, it is difficult to form the thermal heads shown in FIGS. 3 to 6 into an edge type which can easily and clearly print on rough paper. That is, the thermal head shown in FIGS. 3 to 6 is such that a portion connecting all of the common electrodes 5 is provided on the further left side of the drawing. Therefore, the position of the print dot portion P, that is, both electrodes 4 are provided. The distance between the resistor 5 and the resistor 3 is inward from the edge of the substrate 1. With such a thermal head, if you try to record on rough paper, which is said to have rough surface roughness and smoothness of 5 to 10 seconds, which is said to be preferable for recording paper in Europe and America, the printing is extremely unclear under normal conditions. Therefore, it is necessary to press the recording paper against the print dot portion P more strongly than under normal conditions. On the other hand, in the case of the edge type thermal head in which the position of the print dot portion P is provided close to the edge of the substrate 1, the recording paper is contacted obliquely with respect to the thermal head. The pressure contact between the portion P and the recording paper is good, and clear printing can be performed even on rough paper under normal conditions.

[Object of the Invention]

The present invention has been made based on the background described above, the distance between the surface of the printing dot portion and the surface of the resistor is shortened, and the printing dot portion is not dented, and the thermal process is simple. The first purpose is to provide the head, and the second purpose is to provide the edge type thermal head.

[Structure of Invention]

The present invention provides an auxiliary electrode layer provided on a supporting member, an insulating layer provided on the auxiliary electrode layer leaving at least a part of the auxiliary electrode layer at an end portion of the supporting member, and the insulating layer. A resistor layer provided on the support member, which is also provided on a part of the auxiliary electrode layer on which the insulating layer is not provided at the end of the support member, and at the end of the support member, It is provided on the resistor layer so as not to overlap with the insulating layer and so that the end portion faces the end portion of the insulating layer through the resistor layer, and is also provided on the auxiliary electrode layer. A second electrode, and a first electrode provided on the resistor layer so as not to be in direct contact with the second electrode,
The thermal head is characterized by having:

〔Example〕

The present invention will be described below with reference to the embodiments shown in FIGS. 1 and 2.

FIG. 1 is a sectional view of an essential part showing an example of the thermal head of the present invention, and FIG. 2 is a partial plan view of the thermal head of FIG. 1 excluding a protective layer.

In the thermal head of the present invention shown in FIGS. 1 and 2, the heat storage layer 2 of the glaze layer is provided on the substrate 1 along the edge of the substrate 1, and then the heat storage layer 2 and the surface of the substrate 1 are provided. An auxiliary electrode layer 5'made of the same metal layer as the signal electrode and the common electrode is formed so as to cover the insulating electrode 8 and the insulating layer 8 is left at a part of the auxiliary electrode layer 5'at the end of the substrate 1 to leave the auxiliary electrode layer 5 '. ′ On top. Next, the resistor layer 3 is formed on the insulating layer 8 and also on a part of the auxiliary electrode layer 5 ′ where the insulating layer is not provided at the end portion of the substrate 1. Then, the signal electrode 4 as the first electrode is provided on the resistor layer 3 so that the end portion of the substrate 1 does not overlap with the insulating layer 8 and the end portion of the insulating layer 8 is interposed via the resistor layer 3. Resistor layer 3 facing the end
The common electrode 5, which is the second electrode, is provided on the top. Part of this common electrode 5 is partially directly connected to the auxiliary electrode layer 5 ′ as shown in FIG. 2 and is provided at the end of the substrate 1 which is lower than the surface of the resistor layer to form the resistor layer 3. They are formed almost continuously at the same height. In this way, the signal electrode 4 and the common electrode 5 face each other via the resistor layer 3. And finally, it is manufactured by providing a protective layer 6 covering the entire upper surface.

This thermal head eliminates at least the drawbacks of the thermal head shown in FIG. 3, and since the auxiliary electrode 5'is provided, the width of the common electrode 5 on the edge side can be made extremely narrow. As an edge type thermal head, clear printing can be easily performed even on rough paper. In the manufacturing process of this thermal head, the process of providing the auxiliary electrode 5'of the metal layer is increased by one process, and the number of processes is apparently the same as that of the thermal head of FIG. It is much simpler than the manufacturing process of FIG. 4 in which the metal layer 7 having an independent fine pattern is provided for each resistor 3 of the thermal head. Therefore, it is significantly simpler than the manufacturing process of the thermal head shown in FIGS.

In the thermal head of the present invention shown in FIG. 1, the resistor 3 has the signal electrode 4 and the common electrode 5 as shown in FIG.
In the middle of, a plane shape having a length 1 linder circuit portion whose circuit width is narrower than the uniform width of the portion connected to both electrodes is used.
10 and the position of the print dot portion P which is in close contact with the ink ribbon. By doing so, it is possible to perform clear dot printing even on the contour.

The present invention is not limited to the examples described above, and the positions of the signal electrode and the common electrode may be interchanged, and the resistor may not have the Myanmar circuit part.

〔The invention's effect〕

As described above, the edge-type thermal head having the print dot portion at the end of the present invention can make the width of the common electrode on the edge side extremely narrow by providing the auxiliary electrode, Since it is provided close to the edge portion, clear printing can be easily performed even on rough paper. Further, since the resistor layer and the second electrode are formed so as to be substantially flush with each other, no recess is formed in the print dot portion, and the surface distance between the print dot portion and the resistor layer can be reduced, resulting in excellent thermal efficiency. It also has features. Further, the manufacturing process has many effects that it can be manufactured by a much simpler manufacturing process as compared with the conventional thermal head which does not cause a depression in the printed dot portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part showing an example of a thermal head of the present invention, FIG. 2 is a partial plan view of the thermal head of FIG. 1 excluding a protective layer, FIGS. 3, 4, and 5, FIG. 6 is a cross-sectional view and a perspective view of a main part of a conventional thermal head. 1 ... Substrate, 2 ... Heat storage layer, 3 ... Resistor (layer), 4 ... Signal electrode (layer), 5 ... Common electrode (layer), 5 '... Auxiliary electrode (layer), 6 ... ... Protective layer, 8 ... Insulating layer, P ... Print dot part.

Claims (1)

[Claims] 1. An auxiliary electrode layer provided on a support member; an insulating layer provided on the auxiliary electrode layer, leaving at least a part of the auxiliary electrode layer at an end portion of the support member; A resistor layer that is provided on a layer and that is also provided on a part of the auxiliary electrode layer where the leading edge layer is not provided at the end of the support member, and the end side of the support member. In, without overlapping with the insulating layer, and so that the end portion thereof faces the end portion of the insulating layer via the resistor layer, it is provided on the resistor layer,
The thermal head further comprises a second electrode also provided on the auxiliary electrode layer, and a first electrode provided on the resistor layer so as not to be in direct contact with the second electrode.