JP3123823B2 - Method for manufacturing substrate for thermal head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a substrate for a thermal head of a thermal transfer printer in which a glaze layer is formed on one or both surfaces of a ceramic substrate. More specifically, the present invention relates to a method for manufacturing a thermal head substrate when a ridge having a W / H of 10 to 40 is formed on a glaze layer.

[0002]

2. Description of the Related Art In recent years, there has been a growing demand for improving the printing quality and increasing the printing speed of a thermal transfer printer. In order to meet this demand, it is essential for the thermal head substrate used in the thermal transfer printer that the surface of the glaze layer formed on the substrate surface should be smooth and free of undulations and defects, and it should be used together with the heating resistor. It is necessary to increase the contact with the thermal paper. For this reason, the formation part of the heating resistor of the glaze layer is formed as a convex ridge having a curved surface. As a method of forming such a ridged glaze layer, a glass paste is printed and baked on the entire surface of the ceramic substrate, and then a similar glass paste is printed and baked on a portion where the ridges are required. There is an indirect method of forming a ridge on the entire glaze layer. As another method, two types of glass pastes having different softening points are used. First, a glass paste having a high softening point is printed and baked on portions other than the ridge forming portions of the ceramic substrate, and then the ridge forming portions are formed. There is a direct method in which a glass paste having a low softening point is printed so as to have a desired height and then fired to form a ridge on the entire glaze layer.

[0003]

However, in the above-mentioned indirect method, the curvature of the ridge can be made relatively small because the flow of the glass on the ceramic substrate is small, but the undulation near the top of the ridge is large or the ceramic substrate has a large curvature. On the other hand, the direct method has a problem that fine wiring of the conductor must be performed.On the other hand, the direct method has very few defects such as disconnection because the conductive wiring can be formed on the surface of the smooth glaze layer. At the glaze baking temperature for obtaining the surface of the glaze layer, the glass viscosity is low at less than 10 ⁴ poise, so that the convex glass on the flat glass easily flows and has a radius of curvature of 15 convex.
There was a disadvantage that it was difficult to reduce the size to less than mm. In addition, there is an increasing demand for high-definition printing and color printing, but in order to realize this demand, a convex with a small radius of curvature of preferably 5 mm or less is formed on the surface of a smooth glaze layer. In addition, it is necessary that the undulation near the top of the ridge is 1 μm or less. However, at present, the above-described method of manufacturing a substrate for a thermal head cannot be used. An object of the present invention is to provide a method for manufacturing a thermal head substrate in which a ridge having a W / H of 10 to 40 has a curvature radius of 1 mm or more and 15 mm or less. Another object of the present invention is to provide a method of manufacturing a thermal head substrate in which the undulation near the top of the ridge is 1 μm or less and fine wiring of a conductor on a ceramic substrate is unnecessary.

[0004]

As shown in FIG. 1, according to the present invention, a glass glaze layer 12 having a smooth surface is formed on a whole or a part of one or both sides of a ceramic substrate 11, and a part of the glass glaze layer 12 is formed. The remaining part is removed by removing the glass glaze layer of the other part, and the part left
3 is a method for manufacturing a thermal head substrate in which the glass glaze layer 12 is heat-treated at a temperature equal to or higher than the softening point of the glass to process the vicinity of the top of the ridge 13 into a curved surface. The characteristic configuration is that the ridge has a width of W and a height of H, and is formed such that 10 ≦ W / H ≦ 40, and the viscosity of the glass softened by the heat treatment is 10 ⁴ to 10 ^5.
It is to be performed at a temperature that becomes poise.

The glass powder used as the raw material of the glass glaze layer formed on one or both sides of the ceramic substrate of the present invention is one that satisfies both the insulation and heat resistance required for a thermal head used in a thermal transfer printer. It is. For example, as main components of this glass powder, Si, C
a, Ba, Al and B, and Al ₂ O ₃ —BaO—B
₂ O ₃ to form a glass glaze layer of -CaO-SiO ₂ system. As shown in FIG. 1 (a), a glass paste composed of a glass powder and a binder is adhered onto a ceramic substrate 11 by screen printing or spraying and fired to obtain a glass glaze layer 12 having a smooth surface. Subsequently, as shown in FIG. 1 (b), ridges 13 are partially formed on the smooth glass glaze layer 12 by dry or wet etching, polishing such as surface grinding, or the like. The glass glaze layer 1 which is removed by etching, polishing, etc. when forming the ridge 13 partially
2 must be smaller than the thickness of the glass glaze layer 12 formed first on the ceramic substrate 11. In particular, the present invention is a manufacturing method in the case where the width / height of the ridge 13 is H and the W / H of the ridge 13 is 10 to 40.

Further, as shown in FIG. 1 (c), the partially formed ridge 13 is subjected to a heat treatment at a temperature higher than the softening point of the glass and at a viscosity of the glass of 10 ⁴ to 10 ⁵ poise. Then, the rectangular ridges 13 shown in FIG. 1B are rounded. The feature of the present invention lies in this heat treatment. Specifically, it is performed under the following conditions. The heat treatment is performed at a temperature at which the viscosity of the softened glass becomes 10 ⁴ to 10 ⁵ poise. At a temperature at which the viscosity of the glass is less than 10 ⁴ poise, the radius of curvature of the ridge after heat treatment exceeds 15 mm, while at a temperature over 10 ⁵ poise, the top of the ridge after heat treatment is not completely curved. A flat portion remains, and the radius of curvature is less than 1 mm.

[0007]

The W (width) and H (width) of the glass glaze layer 12 are used to make the convex stripes 13 of the glass glaze layer 12 round.
After forming a ridge so that the ratio (W / H) of (height) is in the range of 10 to 40, and performing a heat treatment in the range of 10 ⁴ to 10 ⁵ poise, the radius of curvature of the ridge is reduced. 1 to 15 mm
Can be processed in the range of

[0008]

The present invention will be described below in detail with reference to examples.
You. The present invention is not limited by this embodiment.
No. Aluminum 270mm long, 50mm wide, 1mm thick
A ceramic substrate 11 having a content of 96% was prepared. this
A glass powder having a softening point of 855 ° C. (trade name:
ASF1760, manufactured by Asahi Glass Co., Ltd.) and ethylcellulose
Glass paste obtained by mixing with terpineol
The glass glaze layer 12 is formed by screen printing.
After drying the glass glaze layer 12 at 150 ° C.,
Baking was performed at 50 ° C. for 30 minutes. The thickness of the glass paste is
The thickness was adjusted to 60 μm after firing (FIG. 1 (a)).
W (width) is 0.3 m for each of the glass glaze layers 12
m, 0.5mm, 0.8mm and 1.1mm, length is
270mm, H (height) is 0.03mm, 4 kinds of width
Are formed. These ridges 13 are ridges
The other parts were formed by surface grinding (FIG. 1 (b)). Change
Then, heat treatment was performed under the conditions 12 shown in Table 1
It was rounded (FIG. 1 (c)). W / H of four kinds of convex parts
Are 6.7, 16.7, 26.7 and 36.7, respectively.
Met. There is a rectangular convex part formed by grinding.
Temperature of the glaze substrate at 1020 ° C. and 1050 ° C.
℃, 1100 ℃, and the holding time at the maximum temperature
And heat treated for 15 minutes. Here, the heat treatment is performed at a heating rate, firing
Time, holding time at maximum temperature, cooling rate and cooling time, etc.
The firing conditions are determined in advance by a preliminary test and stored in a storage device.
60 minutes profile of firing furnace
Based on the file. This glass at the highest temperature after heat treatment
From the conversion table, the viscosity of ^{Four .9}Poise,
1050 ° C at 10^4.5Poise and 1 at 1100 ° C
0^4.1Poise. Glass glaze layer 1 after heat treatment
When the surface of No. 2 was observed, it was very smooth and defect-free.
Further, the ridge 13 was curved and rounded. Furthermore,
The radius of curvature of the roundness and the undulation in the longitudinal direction were measured. The result
The results are shown in Table 1. (Hereafter, this page margin)

[0009]

[Table 1]

From the results shown in Table 1, the W / H before the heat treatment was 1
When the heat treatment temperature is set to 0.0 to 36.7 and the heat treatment temperature is set so that the glass viscosity falls within a specific range, the radius of curvature of the ridge after the heat treatment is 1.1 to 14.5, and the top of the ridge is formed. It can be seen that all the undulations are 0.2 μm or less.

[0011]

As described above, according to the present invention, the heat treatment after forming the ridge having a W / H of 10 to 40 in the glass glaze layer is performed under a specific temperature condition. Since the waviness of the glass glaze layer at the top is 1 μm or less, a glass glaze layer having a smooth surface without irregularities is obtained, and a glass glaze layer having a curved portion having a radius of curvature of 1 to 15 mm is obtained. A thermal head substrate provided with a glass glaze layer having excellent insulation and heat insulation properties and a large heat storage effect can be manufactured. In addition, when the heating resistor layer is formed on the ridge, a thermal head that does not require fine wiring of a conductive wire and has a small variation in resistance value can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a thermal head substrate showing the production of the thermal head substrate of the present invention in the order of steps.

[Explanation of symbols]

 Reference Signs List 11 ceramic substrate 12 glass glaze layer 13 ridge

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mitsuru Suda 2270 Yokoze, Yokoze-cho, Chichibu-gun, Saitama Prefecture Mitsubishi Materials Corporation Ceramics Research Laboratory (72) Inventor Tadashi Besso 2270 Yokoze, Yuji-Yokoze-cho, Chichibu-gun, Saitama Mitsubishi (56) References JP-A-3-175057 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/335 G04B 41/86

Claims (1)

(57) [Claims] 1. A glass glaze layer (12) having a smooth surface is formed on one or both surfaces of a ceramic substrate (11), or on the entire surface or on a part thereof, and a glass glaze layer (12) is left on a part of the glass glaze layer (12). By removing the glaze layer, the remaining portion is formed into a ridge (13), and the glass glaze layer (1
2) a method of manufacturing a substrate for a thermal head in which the vicinity of the top of the ridge (13) is heat-treated at a temperature equal to or higher than the softening point of the glass into a curved surface, wherein the ridge has a width W, When the height is H, the film is formed so as to satisfy 10 ≦ W / H ≦ 40, and the heat treatment is performed at a temperature at which the viscosity of the softened glass becomes 10 ⁴ to 10 ⁵ poise. Substrate manufacturing method.