JPH01130958A - Thermal head - Google Patents

Abstract

PURPOSE:To improve printing quality by forming chamfered portions at upper corners of an insulating substrate, as well as forming a thermal resistance layer, a lead conductor layer and a protection film layer on the chamfered portions of this insulating substrate as well as the horizontal surface thereof. CONSTITUTION:A V-shaped groove 20 is formed by a cutting tool in the surface of a ceramic substrate 11 at a boundary portion where the substrate 11 is to be divided into individual chips prior to such division of the substrate. Afterwards, glaze layers 12 are formed on the substrate at positions away from a contact line B between the inclined surface 11a of the V-shaped groove and the horizontal surface 11b of the ceramic substrate 11 by a predetermined distance L. Then, before the ceramic substrate 11 is divided into individual chips, a thermal resistance layer 13, a lead conductor layer 14 and a protection film layer 15 are formed on the upper surface of the ceramic substrate 11. The ceramic substrate 11 is then broken at the dead bottom of the V-shaped groove 20, and individual chips 16 are thereby obtained. A notched inclined surface is thus formed at the end portion of the so obtained thermal head chip without polishing such end portion thereof, and a contact surface line A is made smooth. This eliminates any risk of damaging paper and transfer ribbons when printing is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a thermal head having a head chip with an end notch.

(B) Conventional Technology Generally, in the case of a serial thermal head, the shape of the end of the head chip has a large effect on printing quality.

That is, when the wafer breaks into individual head chips, the edges are very sharp and the edges can damage the paper or transfer ribbon. In order to avoid such problems, the conventional thermal head is provided with a notch 8 at the end 7, as shown in FIG. The thermal head shown here has a glaze layer 2, a heating resistor layer 3, a lead conductor layer 4, and a protective film layer 5 formed on a ceramic substrate 1.
After breaking into individual chips 6, the ends 7 are polished to form notches 8 and have an obtuse angle.

(c) Problems to be Solved by the Invention In the conventional thermal head described above, since the notch 8 of the end 7 is formed by polishing, the contact surface between the horizontal surface of the end 7 of the head chip 6 and the polished slope is The problem remained that A was still sharp and the paper and transfer ribbon were scratched at this point, degrading print quality.

The present invention has focused on the above-mentioned problems, and an object thereof is to provide a thermal head that can reduce the number of acute angle portions at the edges and further improve printing quality.

(d) Means and operation for solving the problems In the thermal head of the present invention, an end notch is formed at the upper corner of an insulating substrate, and a heating resistor is provided on the horizontal surface of the insulating w plate and on the end notch. The structure is formed by forming film forming parts such as a body layer, a lead conductor layer, and a protective film layer.

In this thermal head, a notch cut surface is formed in advance at the end of an insulating substrate, and a heat generating resistor layer, a lead conductor layer, a protective film, etc. are formed on the horizontal portion and end cut surface of the insulating substrate. Since a portion is formed, the contact surface between the horizontal surface of the obtained head chip and the cut end surface is smooth, and damage to the paper or transfer ribbon at this contact surface is reduced.

(e) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 1 is a partial sectional view of a thermal radar chip showing an embodiment of the present invention. The thermal head chip 16 of this embodiment is provided with a cutting notch 18 on the end 17 of the ceramic (insulating) substrate 11 in such a manner as to form a slope 11a, and furthermore, the horizontal surface 11b of the ceramic substrate 11 and the slope (the end cut surface ) A glaze layer 12 is formed on the horizontal plane 11b at a predetermined distance from the tangent line B to the ceramic substrate 11a, and a heating resistor layer 13 is formed on the ceramic substrate 11 and the glaze layer 12.
, a lead conductor layer 14, 14, and a protective film layer 15 are laminated. Of course, the slope 11a of the ceramic substrate 11
A heating resistor layer 13, a lead conductor layer 14, and a protective film layer 15 are also formed thereon. In this thermal head chip 16, the part where the lead conductor layer 14.14 is not formed becomes a printed dot part 19, and in a serial type multi-head, a plurality of these printed dot parts 19 are arranged in parallel in the front and back directions of the paper surface. .

In this thermal radar chip 16, the cutting notch 18 is not formed by polishing, but is
By cutting the end portion 17 of the ceramic substrate 1, an inclined surface 11a is formed in advance, and the horizontal surface 11b and the inclined surface 11 of the ceramic substrate 11 are
Since the heating resistor layer 13, the lead conductor layer 14, and the protective film layer 15 are formed on the surface a, the tangent line A between the slope and the horizontal surface after film formation becomes very smooth, and this tangent surface It is almost impossible for the paper or transfer ribbon to be damaged by the line.

Next, a method for manufacturing the thermal radar chip of this embodiment will be explained.

First, as shown in FIG. 2(A), a V-shaped groove 20 is made with a cutting blade at the boundary portion of the surface of the ceramic substrate 11, which is to be divided into individual chips, at the boundary where the ceramic substrate 11 is divided into individual chips. This groove may be a U-shaped groove or the like.

Next, a glaze layer 12 is formed parallel to the V-shaped groove 20 at a predetermined distance from the contact line B between the slope 11a of the V-shaped groove 20 and the horizontal surface 11b of the ceramic substrate 11.

Thereafter, without dividing the ceramic substrate 11 into individual chips, as shown in FIG.
and a protective film layer 15 is formed. After the film is formed, it breaks at the bottom apex of the V-shaped groove 20 to obtain individual thermal head chips 16, as shown in FIG. 2(C).

In this manufacturing method, a cutting blade cuts the ceramic substrate into seven parts.
Although a heating resistor layer, a lead conductor layer, and a protective film are formed on the grooves, the ends of the resulting thermal head chip are not subjected to any abrasion treatment, but are formed with notched slopes. can be formed, and the tangent line A in Figure 1 becomes smooth,
No more damage to paper or transfer ribbon during printing.

In addition, in this manufacturing method, a cutting blade is used to form the figure 7 groove, so by using a cutting blade with a sharp tip,
The angle of the slope portion of the end notch can be made large and constant.

Furthermore, since the 7-shaped groove is formed using a cutting blade, the tangential line between the horizontal and sloped parts of the ceramic substrate becomes clear, and the glaze layer can be positioned based on this tangential line.
This is convenient for keeping the distance from the end to the glaze layer as small as possible and constant with high precision.

(F) Effects of the Invention According to this invention, an end cutout is formed at the upper corner of an insulating substrate, and a heating resistor layer, a lead conductor layer, and a protective film layer are formed on the horizontal plane and the cut end of the insulating substrate. However, the contact surface between the horizontal surface and the inclined surface on the top surface is smooth, and the corners of this contact surface reduce damage to the paper surface and transfer ribbon during printing, improving print quality. improves.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the main parts of a thermal head chip showing an embodiment of the present invention, and FIGS. FIG. 3, which is a diagram for explaining the manufacturing method, is a sectional view of a main part of a conventional thermal head chip. 11: Ceramic substrate, 12: Glaze layer, 13: Heat generating resistor layer, 14: Lead conductor layer, 15; Protective film layer, 16
: thermal head chip, 17: end, 18: cutting notch. Patent Applicant ROHM Co., Ltd. Agent Patent Attorney Shigeru Nakamura] Ir) 16]1

Claims (1)

[Claims] (1) An end notch is formed at the upper corner of the insulating substrate, and film forming parts such as a heating resistor layer, a lead conductor layer, and a protective film layer are formed on the horizontal surface of the insulating substrate and the end notch. A thermal head characterized by being