JPH058416A - Edge surface type thermal head - Google Patents

Abstract

PURPOSE:To make manufacture of an edge surface type thermal head simple and to make manufacturing cost low. CONSTITUTION:An edge surface type thermal head is obtained as follows,: it is composed of a substrate 6, an underglaze 5 two dimensionall successively laminated on a plane 6b of a substrate 6 crossing an edge surface 6a along the edge surface 6a of the substrate 6, a common electrode 4 and an individual electrode 3, a heating element 7, an overglaze 1 covering the heating element 7 and respective electrodes 4, 3, and the overglaze covering the edge surface thereof: the common electrode 4 and the individual electrode 3 and, in a comb teeth manner, alternately arranged and heating elements 7 fill between them: a section 8 of the heating element and respective electrodes 4, 3 is taken as a printing surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head. More specifically, the present invention relates to an end surface type thermal head in which a heating resistor is arranged on the end surface of a substrate.

[0002]

2. Description of the Related Art In a conventional end surface type thermal head, as shown in FIG. 7, a heating resistor 103 is arranged on an end surface of a substrate and a driving integrated circuit 105 and the like are mounted on a different plane 104 orthogonal to the end surface 102. It is mounted so that only the heating resistor 103 faces the printing medium 106. At this time, the heating resistor 103 and the flat surface 104 on the end face 102
Two planes orthogonal to the driving integrated circuit 105 above,
An electrode 107 is formed over 104 and is connected.

Therefore, conventionally, the end surface 10 of the substrate 101 is
Corner portion 1 between the front surface 2 and the back surface 104 of the substrate 101
08 is processed into a curved surface and the end surface 102,
The electrode 107 was formed by depositing a metal thin film on the curved corner portion 108 and both surfaces and simultaneously etching the thin metal film by a photolithography technique.

Further, the substrate 101 is formed by utilizing the thick film printing technique.
End face 102, another plane 1 of the substrate 101 orthogonal to this
There is also a method in which a metal film is formed on 04 (so-called front surface and back surface) and the curved corner portion 108, and this is also etched by photolithography or the like to form an electrode.

[0005]

However, when the electrode 107 is formed by vapor deposition, the end face 10 of the substrate 101 is formed.
2. In order to etch the metal thin films deposited on the front and back surfaces 104 of the substrate which are orthogonal to the corner portion 108 and the end surface 102, accurate masking and exposure control over the surfaces having different angles are required. This complicates the manufacturing of the head and reduces the yield. That is, the formation of the electrodes by patterning becomes three-dimensional, the process is complicated and the cost is high, and the patterning is difficult, and the yield due to the defective connection is deteriorated.

Also, when the thick film printing technique is used, like the thin film forming technique by vapor deposition, the end surface 102, the curved corner portion 108, and the front and back surfaces 104 of the substrate 101 orthogonal to the end surface 102 are formed within a range of only a few mm. It is difficult to print a uniform film thickness on the substrate and requires high technology. In either case, a special mask and exposure technique are required for patterning the end surface by photolithography.

An object of the present invention is to provide an end face type thermal head which is easy to form and inexpensive.

[0008]

In order to achieve the above object, an end surface type thermal head according to the present invention comprises a substrate and an underglaze laminated on a plane of the substrate which intersects the end surface along the end surface of the substrate. , A common electrode and an individual electrode, a heating resistor, an overglaze that covers the heating resistor and each electrode, and an overglaze that covers these end faces. The common electrode and the individual electrode are alternately arranged in a comb shape. The heat generating resistors are arranged and filled between them, and the cut surfaces of the heat generating resistors and each electrode are used as the printing surface.

[0009]

Therefore, according to this thermal head structure, it is possible to obtain an electrode by two-dimensional patterning, which has conventionally required three-dimensional patterning. That is, an under-glaze, an electrode, a heating resistor, and an over-glaze are two-dimensionally sequentially laminated on a plane orthogonal to the end face of the substrate, and the end face type thermal head is obtained by cutting them along the end face of the substrate. To be

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows an example of the end face type thermal head of the present invention. This end surface type thermal head includes a substrate 6 and an underglaze 5 formed on a flat surface 6b of the substrate 6 which intersects the end surface 6a along the end surface 6a of the substrate 6.
From the common electrode 4 and the individual electrodes 3, the heating resistor 7, the overglaze 1 covering the heating resistor 7 and the electrodes 4 and 3, and the overglaze covering the cut end faces 8 (not shown). The common electrodes 4 and the individual electrodes 3 are alternately arranged in a comb shape, and the heating resistors 7 are filled between them. 8 is provided so as to form a printing surface.

The substrate 6 is usually made of ceramics such as alumina ceramics to obtain a heat radiation function and mechanical strength. The underglaze 5 constitutes a heat retaining layer with a material having a lower thermal conductivity than the substrate 6, for example, glass. The overglaze 1 has a function of preventing the heating resistor 7 from deteriorating and protecting it from damage or abrasion due to a mechanical external force, and is usually made of glass. In the case of this embodiment, the heating resistor 7 is made of a thick film resistor. As the thick film resistor, for example, R
uO ₂ is often used and is formed into a desired shape by thick film printing. Although not shown, a PCB board (printed wiring board) is provided on the board 6 or another board and receives a driving integrated circuit for selectively heating the heating resistor 7 and an external signal. A connector, an element for distributing the connector to a corresponding driving integrated circuit, and the like are mounted as necessary. The driving integrated circuit is connected to the corresponding electrodes 3 and 4 on the substrate 6 by wire bonding or the like.

The thermal head having the above structure is manufactured as follows.

First, an underglaze 5 made of glass or the like is formed on the entire surface 6b of the substrate 6 by the thick film printing technique. An electrode material such as Au paste is printed on the entire surface of the underglaze 5 by a thick film printing technique, and then baked to form a first metal layer. Then, the first metal layer is patterned by a known photolithography technique to obtain the individual electrode 3 having a desired shape. For example, as shown in FIG. 3, a plurality of parallel linear individual electrodes 3, ..., 3 are obtained. Incidentally, a few electrodes are shown in the drawings for the sake of simplicity. This individual electrode 3,
The insulating film 2 is overlaid and printed on the terminal side of the ... Next, a paste-like electrode material to be the common electrode 4 is overlaid on the individual electrodes 3, ..., 3 and printed, and this is fired to form a second metal layer. Similar to the first metal layer, the second metal layer is patterned by a known photolithography technique to form the common electrode 4 between the individual electrodes 3, ..., 3 (see FIG. 4). Each end of the common electrode 4 is connected across the insulating film 2 to form one electrode. A heating resistor 7 is overlaid and printed in a paste state on the tip side of the common electrode 4 and the individual electrodes 3, ..., 3 and baked at a predetermined temperature (see FIG. 5). Further, the overglaze 1 made of glass or the like is printed on the heating resistor 7 and fired (see FIG. 6). Then, the heating resistor 7 is cut together with the substrate 6 and the overglaze 1, and an overglaze (not shown) is formed on the cut surface 8 as a protective film for abrasion resistance by a printing technique or the like. The cut heating resistor and the electrode end surface 8 become a printing surface, and the printing medium is parallel to this surface,
For example, the thermal head of the present invention is used by sliding a prepaid card or the like.

At the time of cutting the end face, as shown in FIG. 2, it is possible to increase the cross-sectional area of the heating resistor 7 and increase the size of the printing dot by cutting the substrate 6 obliquely. Become. That is, it is possible to adjust the print dot size of the thermal head by changing the inclination of the cut.

The above-described embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the common electrode 4 is superimposed and printed on the individual electrodes 3, ..., 3 formed, but the invention is not particularly limited to this, and the individual electrodes 3, 3 are formed on the common electrode 4. ..., 3 may be overlapped and printed. Further, the cut shape of the end face is not particularly limited to the direction as shown in FIG. 2, and may be cut in the direction opposite to the illustrated direction.

[0017]

As is apparent from the above description, according to the present invention, the electrodes and the heating resistors are alternately formed in a comb shape on the plane of the substrate along the end face of the substrate and the heating resistors are filled between them. Since the printed surface is composed of the heating resistor and the lateral cut surface of the electrode, not only the patterning of the electrode but also the heating resistor and all other layers are formed on the substrate surface. It can be formed two-dimensionally and can be formed easily and accurately using thick film printing technology,
The photolithography process can be easily performed using a normal mask. Therefore, the end surface type thermal head of the present invention,
The manufacturing process can be simplified and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention in which overglazing of a printing surface is omitted in the drawing.

FIG. 2 is a perspective view showing another embodiment of the present invention, in which overglazing of the printing surface is omitted in the drawing.

FIG. 3 is a perspective view showing one of manufacturing steps of the end surface type thermal head of the present invention, showing a state in which individual electrodes are formed.

FIG. 4 is a perspective view showing one of the manufacturing steps of the end surface type thermal head of the present invention, showing a state in which a common electrode is formed.

FIG. 5 is a perspective view showing one of the manufacturing steps of the end surface type thermal head of the present invention, showing a state in which a heating resistor is formed.

FIG. 6 is a perspective view showing one of the manufacturing steps of the end surface type thermal head of the present invention, showing a state in which an overglaze is formed and the end surface is cut.

FIG. 7 is an explanatory diagram showing a schematic structure of a conventional end surface type thermal head.

[Explanation of symbols]

1 Overglaze 3 individual electrodes 4 common electrode 5 Underglades 6 substrate 7 Heating resistor 8 Horizontal cut surface (end surface)

Claims (2)

[Claims] 1. A substrate, an underglaze laminated on a plane of the substrate which extends along the end face of the substrate and intersects the end face, a common electrode and individual electrodes, a heating resistor, and the heating resistor and each electrode are covered. The above-mentioned common electrodes and individual electrodes are alternately arranged in a comb shape and filled with a heating resistor between them, and the heating resistor and the above-mentioned heating resistor and An end face type thermal head characterized in that the cut surface of each electrode is a printed surface. 2. The end surface type thermal head according to claim 1, wherein the end surface is cut obliquely with respect to the plane of the substrate.