JPH08244264A - Thermal head - Google Patents

Abstract

PURPOSE: To prevent density unevenness from being produced in print images and separation in the surface of a thermosensitive recording paper, and further keep images from being lowered in their qualities by having curvatures in substrate edges adjacent to each other with a plurality of substrates in a continuous thermal head. CONSTITUTION: A plurality of ceramics substrates 1 having heat resistance arrays 2 are arranged side by side zigzag or in a row on the radiative substrate 3, and the edge surface of the ceramics substrate 1 adjacent to the other substrate 1 is rounded to have a curvature. Ceramics substrates such as alumina with a heat resistance element array of Ta-SiO or the like, electrode, protection layer formed through a sputtering method previously are adhered in a plural manner and in parallel on a radiation substrate such as metal and SiO2 as materials to manufacture a continuous thermal heads.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used for printing a heat-sensitive color developing sheet, and more particularly to a long thermal head.

[0002]

2. Description of the Related Art As a type of thermal head, a long heat dissipation plate is further provided with a plurality of ceramic substrates having fine heating elements formed on the surface thereof by applying a semiconductor circuit forming technique. A length type thermal head is known, and in recent years, such a thermal head has been used as a small printing mechanism for a facsimile using a thermal recording paper as a recording paper.
It is commonly used. When recording is performed using this type of thermal head, the connecting portion of each ceramic substrate including the heating element is always included in the area of the printed image. Therefore, it is obvious that the printed image is affected unless the mechanical accuracy of the connecting portion is high. Here, even if the mechanical accuracy of the joint portion is sufficiently enhanced, there is a limit as the joint portion, and a slight gap or step is generated between the adjacent ceramic substrates on which the heating elements are formed. It is the current situation.
If the thermal head in such a situation is pressed against the thermal recording paper for printing, uneven density may occur in the printed image,
At times, various problems have occurred, such as peeling the surface of the thermal recording paper and degrading the image quality.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, such that density unevenness occurs in a printed image during printing and recording, and sometimes the surface of a thermosensitive recording paper is peeled off. And a thermal head that does not deteriorate the image quality.

[0004]

The present invention provides a long type thermal head in which a plurality of unit heating elements are arranged in a row or in a staggered pattern on each of a plurality of ceramic substrates provided on a heat dissipation plate. In the thermal head, the substrate edges adjacent to each other in the plurality of substrates have a curvature. A thermal head, especially a long thermal head, is generally manufactured by the following steps and manufacturing methods.

First, a heat-generating resistor element array such as Ta-SiO ₂ , an electrode, a protective layer, etc. are previously formed on a heat-dissipating substrate having high heat conductivity such as metal or SiO ₂ by sputtering, photolithography, or the like. A plurality of ceramic substrates made of alumina or the like can be bonded in parallel and in parallel to form a continuous long thermal head. In particular, in order to give a curvature to adjacent substrate edges of a plurality of substrates, which is a feature of the present invention, a substrate on which a heating resistance element is formed by precision polishing means before being mounted on the heat dissipation substrate. The rounded end face of the substrate adjacent to the other substrate is provided. Explaining the above-mentioned example of the precision polishing means, first, a cylindrical plate made of a material such as iron, which is the object to be polished, is orthogonal to the cylindrical polishing blade attached to the rotary polishing device. Press against. At this time, polishing is performed so that the corners of the edge of the object to be polished are polished first. The polishing is once stopped once the center of the side surface of the cylindrical body of the object to be polished has been polished. Then, the object to be polished is turned upside down and the polishing operation is started from the corner of the remaining edge. The degree of polishing also ends when the center of the side surface of the cylindrical body of the object to be polished is polished. By this operation, the base body of the cutting tool having the inverse R is created. Then, a desired cutting blade is completed by adhering and fixing industrial diamond particles together with an adhesive on the surface of the reverse R portion of the above cutting tool. Attach the prepared cylindrical cutting blade to the axis of the rotary drill, and with the cylindrical cutting blade vertical, gradually press the cutting blade to the boundary between adjacent substrates of the multiple substrates that form the heating resistance element. To do. By this work, the angular end faces of the adjacent substrates could be made into the end faces having the R portion. FIG. 1 shows an example of a thermal head of the present invention, in which a plurality of ceramic substrates 1 each having a heat-generating resistor element array 2 on a heat-radiating substrate 3 and arranged in parallel are discharged, and another ceramic substrate 1 is disposed. The end surface adjacent to the ceramic substrate 1 is processed so as to have a roundness so as to have a curvature.

[0006]

According to the present invention, since the plurality of substrates are thermal heads in which the substrate edges adjacent to each other have a curvature, there is a slight step between the substrates to prevent image loss. Even if the thermal recording head is pressed against the thermal recording paper, it is not necessary to damage the thermal recording paper, and a printed image with good quality can be obtained.

[0007]

[Brief description of drawings]

FIG. 1 shows an example of a thermal head of the present invention.

[Explanation of symbols]

1 ceramics substrate, 2 heating resistor element array, 3
Heat dissipation board

Claims (1)

[Claims] 1. A long thermal head in which a plurality of unit heating elements are arranged in a row or in a staggered pattern on each of a plurality of ceramic substrates provided on a heat dissipation plate. A thermal head characterized in that the substrate edge adjacent to has a curvature.