JPH0280263A - Thermal head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a thin-film thermal head used in thermal printers, facsimile machines, etc., and particularly relates to the construction of a thermal head.

[Conventional technology]

In recent years, the width of the insulating substrate, which is the main component of the thermal head, has become extremely narrow due to the design of the thermal head device and further to reduce the price of the thermal head.

Furthermore, it is necessary for the functionality of the device to position the heating resistor as close to the edge of the substrate as possible. Therefore, especially when the electrode on one side of the heating resistor is a common electrode, it is necessary to narrow the width of the common electrode itself, but if it is narrowed, the wiring resistance increases and power consumption increases. However, there was a problem in that the influence of wiring resistance on each resistor was different, resulting in a decrease in printing quality. To solve this problem, there is a conventional example, as in Japanese Utility Model Application Laid-Open No. 62-19252, in which a common electrode is provided over almost the entire surface of the substrate, and a heating resistor is provided thereon with an insulating layer interposed therebetween.

[Problem to be solved by the invention]

The above-mentioned conventional technology has cost problems because it does not take into account the cost of forming a conductive layer on the entire surface of the substrate, and also the problem of interlayer stains (in case there are defects in the insulating layer).
SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a thermal head for a shed at low cost.

[A precautionary measure to solve the problem]

The above object is achieved by limiting the width of the common electrode layer formed under the insulating layer to the necessary minimum.

[Effect]

Since the common electrode portion is provided below the heating resistor, the common electrode can be reduced in size.1 The heating resistor approaches the edge of the substrate, allowing the thermal head to be made into a shed. By the way, since there is a common electrode only in the necessary areas, the amount of material required for the conductive layer is reduced, and the overlap of wiring above and below the insulating layer is significantly reduced.9th, interlayer sheet defects can be reduced. .

Further, by arranging the step at the end of the common electrode directly under the center of the heat generating resistor, the center of the heat generating region becomes convex. Therefore, it becomes easy to bring the recording paper, etc. into close contact with this heat generating area. This means that even if the power applied to the resistor itself is reduced, a specific print density can be obtained, and the power required for recording can be reduced, which in turn can save power in printers and facsimile machines.

〔Example〕

Embodiments of the present invention will be described below with reference to FIG.

Example 1 A common electrode layer is formed on an insulating substrate and subjected to predetermined patterning using a method such as photoetching. This common electrode layer may be formed using a thick film technique. ,
An insulating layer is formed, a predetermined patterning is performed, a heating resistor layer and wiring are formed, and the pattern is completed in sequence. When etching the common electrode layer, by intentionally over-etching, it is possible to smooth out the step difference at the end of the pattern of the common electrode layer. As a result, it is possible to obtain a compact thermal head that has good paper adhesion to thermal paper without a partial glaze layer.

Example 2 In patterning the resistor of Example 1, the central part of the resistor was patterned to be located above the end of the common electrode, thereby making the central part of the resistor convex as shown in FIG. It can be made into a shape.

〔Effect of the invention〕

According to the present invention, the resistor of the thermal head can be brought closer to the edge of the substrate, which makes it possible to downsize the thermal head and improve the manufacturing process.

Since it can be produced at low cost and high yield, it can be provided at low cost. l Also, since the central part of the heating resistor can be structured to have a convex shape, the contact between the recording paper and the heating part is improved.
It becomes possible to obtain a shed thermal head with good heat transfer efficiency.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of the first embodiment of the present invention, and the second FIA is a sectional view of the second embodiment. Explanation of symbols 1...Common electrode layer, 2...Insulating substrate, 5...Insulating layer, 4...Heating resistor layer, 5... ...Wiring layer. No. IL￥1 No. 20

Claims (1)

[Claims] 1. In a thermal head having a glaze layer and a heat generating area including a power supply on an insulating substrate, a common electrode is formed at the edge of the substrate, and the glaze layer partially covers the common electrode. A thermal head characterized by having a heat generating area formed on the top.