JPS6322665A - Manufacture of thermal head - Google Patents

Abstract

PURPOSE:To improve a print quality and reduce power consumption by forming a recessed part in the glass of a thermal resistor electrode using a photoetching method and thereby forming a projected thermal resistor. CONSTITUTION:A printed and baked glass having a thickness of 30-80mum is formed on the entire upper surface of a ceramic substrate 1, and a tantalum 3 having a film thickness of 500-1,200Angstrom is formed by a sputtering method. After the formation of a regist 4 at a position which becomes the bottom of a thermal resistor using a photolithograph technique, the tantalum 3 and glass 2 are etched simultaneously with fluoric acid and the regist 4 is stripped off. Then they are heated to 480-550 deg.C in an oxygen atmosphere and consequently the tantalum 3 is oxidized to tantalum pentaoxide 5. A thermal resistor 6 of chromium silicon having a film thickness of 500-1,200Angstrom is formed, and then an electrode 7 of thin aluminium film having a thickness of 0.5-2mum is formed using a sputtering technique.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present FJA relates to a method of manufacturing a thermal head used in printers, facsimile recording units, etc.

[In conventional thermal heads, in order to improve printing quality and reduce power consumption, the heating resistor part is formed more convexly than the four electrode parts to improve the adhesion between the thermal head and the thermal recording paper. It is effective to do the same as above.

Therefore, in conventional thermal heads, as described in Japanese Patent Application Laid-Open No. 59-11407d, a convex portion mainly composed of a fired body of metal oxide is provided on a ceramic substrate, and the convex portion One in which a heating element is formed on the top has been proposed.

[Problem to be solved by the invention J] However, in the proposed configuration, it is difficult to control the position of the convex part, so when creating a large number of thermal heads on the same substrate, the center of the convex part and the heating resistor are difficult to control. The center of the image may not match.

For example, Figure 2 (,) shows a state in which the center of the protrusion and the center of the heating resistor are aligned, and Figure 2 (b) shows that the center of the heating resistor is aligned with the center of the protrusion in the direction of movement of the thermal recording paper. As shown in the deviated state, the surface of the ceramic substrate 1 is coated with a thickness of 60 μm.
A glass 2 having a spherical shape is printed and fired, a chemical-resistant layer of tantalum dioxide 5 is formed on its outer peripheral surface, and a heat-generating resistor 6 made of tantalum pentoxide 5 is formed together with an electrode portion 7.

In a thermal recording system having such a configuration.

When the thermal recording paper 8 pressed by the platen row F (not shown) moves on the heating resistor 6 in the direction of the arrow A, by passing a pulse current I/c through the heating resistor 6 in synchronization with this, Form a recording surface.

However, the relationship between the power consumption when printing all dots of the respective thermal heads in FIGS. 2(a) and 2(b) and the degree of blackening of the thermal recording paper is as shown in FIGS. 3(a) and 2(b). Figure 3 (b) As shown in K, jfr2 as shown in Figure (b) (
If the center of the heating resistor deviates from the center of the convex portion (h), there is a problem that the adhesion between the thermal head and the thermal recording paper deteriorates and power consumption increases.

Therefore, in order to solve the above-mentioned problems, a method has conventionally been implemented in which the width of the convex portion is widened to increase the area of the upper surface of the convex portion.

However, in the above method, there is a problem that the adhesion between the thermal head and the thermal recording paper, which is the original purpose of forming the heating resistor into a convex portion, deteriorates.

An object of the present invention is to solve the above-mentioned conventional problems, and to manufacture a thermal head that improves the positional accuracy even if the width of the convex part is narrowed, thereby making it possible to improve printing quality and reduce power consumption. The purpose is to provide a method.

[Means for Solving the Problems] The above purpose is to form a concave portion in the furnace wall by photo-etching the glass of the electrode portion of the heating resistor, thereby substantially forming the heating resistor portion in a convex shape. It will be resolved more easily.

[Function] Using photo-etching technology, which has higher positional accuracy than conventional thick-film printing technology, allows the convex shape of the heating resistor to be made to a height of 0n! It can be formed at one time.

[Example J Hereinafter, wc1 diagrams (a) to (f) showing an example of the present invention
I will explain it in detail. FIGS. 1(a) to 1(f) are views showing a pair of sandals in which a heating resistor portion is formed in a convex shape.

As shown in FIG. 1(a) IC, printed and fired glass 2 is formed on the entire upper surface of a ceramic substrate 1 to a uniform thickness of 30 to 80 μm.

Next, as shown in FIG. 1(b), tantalum 3 having a thickness of 500 to 1200× is formed on the glass 2 by sputtering.

Next, as shown in Fig. 1 (0), cysts 4 are formed at the lower part of the heating resistor using the photo-phosphorographic method, and after winter, hydrofluoric acid is applied as shown in Fig. 1 (d). The used tantalum 3 and the glass 2 are etched at the same time.

Next, as shown in FIG. 1(e), the resist 4 is peeled off and then heated to 480 to 550'C in an oxygen atmosphere, whereby the tantalum 3 is oxidized and transformed into tantalum pentoxide 5.

Next, as shown in FIG. 1(f'), a film made of Sifrom silicon with a thickness of 500 to 1200× is formed by sputtering.
After forming the heating resistor 6 of
The heating resistor section is completed by forming the electrode section 7 of m.

In general, in a thin-layer thermal head, tantalum pentoxide 5 is formed below the heating resistor 6 to prevent contamination from the glass 2. Therefore, in this embodiment, only the photo-etching step requires an additional work.

As a method of etching the glass 2 to form the recessed portions, a method other than the above-mentioned embodiment may be considered, in which a resist is directly formed on the glass 2.

However, the above method is not practical because the ultraviolet rays are scattered by the ceramic surface during exposure of the resist, and the resist is exposed to light due to this scattering.

Further, in this embodiment, as shown in FIG. 1(d) K, the etching of the glass 2 is stopped at about half the film thickness of the glass 2.

The reason for this is that if the film is etched to the thickness of the glass 2, wiring will be formed on a ceramic surface with a rough surface, resulting in an increase in wiring defects.

Even with conventional thick film printing technology, the glass 2 shown in Fig. 1(d)
Although it is possible to explode something similar to the zero layer, thick film printing techniques require two or more printing bakes, which increases the working time.

[Effects of the Invention j As described above, according to the present invention, the position of the convex portion of the heating resistor portion can be formed with high precision, so that the convex portion can be formed with a narrow width. This has the effect of improving printing quality and making it possible to form a thermal head with low power consumption.

[Brief explanation of the drawing]

Figures 1 (Jk) to (f) are diagrams showing the manufacturing procedure of a convex heating resistor of a thermal head showing an embodiment of the present invention;
Figure 2 <a> is a cross-sectional view showing the state in which the center of the convex part in a conventional thermal head and the center of the heating resistor coincide with h, and Figure 2 (b) is a cross-sectional view of the convex part in a conventional thermal head. FIG. 5 is a cross-sectional view showing a state in which the center of the heat generating resistor is shifted from the center (at is shown in FIG. It is a diagram showing the relationship with the degree of blackening of paper. 1... Ceramic substrate, 2... Glass, 3... Tantalum, 4... Resist, 5... Tantalum pentoxide,
6... Heating resistor, 7... Electrode section, Window heat recording section for 8. fi:j! Buried in I8F 41-11 Katsuo 1
Mouth A 2 figure (α) 1 t lami 1. Futsutan (b) 2 n” Uiri 3
〲〉〉〇〲〇〉〉〉〉〉〉〉〉〇〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉〉 Title of invention〉Relationship with fin of thermal head manufacturing method〉Name of patent applicant ＊ (51G) Manufactured by Hitachi, Ltd. Agent Contents of amendment in the brief explanation of drawings in the specification subject to personal amendment

Claims (1)

[Claims] 1. A large number of heating resistors are formed on a ceramic substrate on which a glass layer is formed, and recesses are formed by etching the glass layer in the portions that will become electrodes of these heating resistors. A method of manufacturing a thermal head characterized by the following. 2. The method of manufacturing a thermal head according to claim 1, wherein the recess is formed by the following manufacturing procedure. B. Form a tankle layer on the glass. B. Attach resist to the lower part of the heating resistor,
Do not apply resist to the part that will become the electrode. C. After etching the tantalum layer, the glass layer is etched using the same etching solution. D. Peel off the resist. E. Oxidize the tantalum layer to form a tantalum pentoxide layer.