JPH04107153A - Thick film type thermal head and manufacture therefor - Google Patents

Abstract

PURPOSE:To obtain printing with excellent picture without allowing the quality deterioration because of unevenness over the surface of photographic printing paper by manufacturing a thermal head in a structure wherein the height of an overglaze layer is made same on positions over heating resistance bodies and over places between the heating resistance bodies. CONSTITUTION:Parts positioned over patterns of thick film resistance bodies 4 and photosensitive resists 5 are removed and, at the same time, the thick film resistance bodies embedded in openings 5' of the photosensitive resists 5 are removed so that the thick film resistance bodies become same in the height with the thick films of the photosensitive resists 5. After this, the thick film resistance bodies are sintered and, at the same time, the photosensitive resists 5 are burnt and removed after gasification. An overglaze layer 6 is then formed by means of screen printing and an anti-wear layer is formed after burning is applied thereon. In forming of the overglaze layer, the height of the overglaze is made higher on positions over the heating resistance bodies 4 than on positions over places between the heating resistance bodies 4. After this, grinding is applied over the surface of the overglaze layer 6, and thereby the height of the overglage layer 6 is made same either on the heating resistance bodies and on the positions over the places between the heating resistance bodies.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an individually facing thick film thermal head,
In particular, to improve the print quality of dye-sublimation printers,
The present invention relates to the structure of an overglaze and its manufacturing method.

(Prior art) Individually facing thick film type thermal heads using the conventional lift-off method are manufactured by forming a heating resistor, then coating the head with an overglaze paste, which will become an overglaze layer, by screen printing, and then baking the head. There is.

FIG. 2 shows the structure around a part of the resistor of the conventional thick-film thermal head described above.

The same figure (A) is the top view, the same figure (B) is the b of the same figure (A)
-A cross-sectional view taken along the line b, the same figure (C) is the C- of the same figure (A)
It is a sectional view along the C line. In the figure, 1 is a ceramic substrate, 2 is a common electrode, 3 is an individual electrode, 4 is a heating resistor, and 6 is an overglaze layer.

Since the heating resistor 4 is formed by the lift-off method and there are gaps between the heating resistors, when an overglaze layer is formed, the cross-sectional shape of the overglaze on the heating resistor in the main scanning direction is as shown in the same figure (C ), a convex shape 7 is formed along the convex shape on the heat generating resistor, and a recess 8 is formed in the overglaze layer between the heat generating resistors.

When this thick-film thermal head is installed in a sublimation printer and prints, the convex portion of the overglaze on the heating resistor presses the surface of the photographic paper along with the heat generated by the heating resistor. FIG. 3 is for explaining the printing situation. The surface of photographic paper 9 for a sublimation printer has a property of being easily deformed by heat. Therefore, when printing with a thick-film thermal head in which the cross-sectional shape near the surface shows a recess between the heating resistors as shown in Figure (A), the top view in Figure (B) and the top view in Figure (C) As shown in the cross-sectional view, the surface of the photographic paper 9 has concave portions 1 for each dot in the area corresponding to the convex portion 7 of the overglaze on the heating resistor.
0, more dye is attached on top of it, and a convex shape 11 is generated. The portion corresponding to the recess 8 between the heating resistors becomes a convex portion 12 . For this reason, the surface of the photographic paper becomes extremely uneven on a dot-by-dot basis, resulting in deterioration of the quality of the printed image.

This depression cannot be overcome by improving the firing conditions as described in Japanese Patent Publication No. 63-9728.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances, and is designed to provide an individually facing thick film thermal head using the lift-off method in the unlikely event that burglaze on the heating resistor is removed. By creating a structure in which the height of the overglaze between the heating resistors is equal, the dot reproducibility is not compromised.
The purpose of the present invention is to provide a thick-film thermal head that can improve image quality by eliminating unevenness on the surface of photographic paper printed by a dye-sublimation printer, etc., and to provide a method for manufacturing the thick-film thermal head for this purpose. .

(Means for Solving the Problems) In the first aspect of the present invention, in the individually facing thick film type thermal head, the height of the overglaze on the heating resistor is equal to the height of the overglaze between the heating resistors. In the second invention, in the method for manufacturing a thick-film thermal head, after forming individual heating resistors facing each other on a substrate by a lift-off method, an overglaze layer is placed between the heating resistors. formed so that the height of the overglaze is higher than the height of the heating resistor,
This method is characterized in that the overglaze layer is then polished to flatten the surface.

(Function) The present invention has a structure in which the height of the overglaze on the heating resistor is equal to the height of the overglaze between the heating resistors, so that the surface of the photographic paper for a sublimation printer can be Even if heat is applied, since the surface of the overglaze on the heating resistor is flat, the surface of the photographic paper will not be deformed, and unevenness on the surface of the photographic paper can be eliminated.

(Example) FIG. 1 is a process diagram for explaining an example of a thick film type thermal head of the present invention. Components similar to those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 2A, a conductive film made of Au with a thickness of 0.3 to 3.0 μm, for example, is formed on a ceramic substrate 1, and a common electrode 2 is formed by a photolithography process.
, patterning the individual electrodes 3. The heating resistor 4 is provided between the opposing electrodes 2 and 3, and since one of the printed dots corresponds to this heating resistor, the resolution of the printed dots and the wiring density of the electrodes are the same.

Next, a photosensitive resist 5 having a film thickness of, for example, about 5 to 30 μm is uniformly applied using a well-known roll coater method, spin coater method, dip method, etc., and is exposed and developed using a photomask, and the heat-generating resistor 5 is A plurality of openings 5' are formed at the locations where the bodies are provided. As the photosensitive resist 5, a resist used in the production of ordinary hybrid ICs may be used. As an example, in this example, a negative photoresist PMERN-HC600 (trade name) manufactured by Tokyo Ohka Kogyo Co., Ltd. was used. (Figure (B)).

A thick film resistor paste 4' made of, for example, RuO2 (ruthenium oxide) and glass frit is applied to the opening 5' of the photosensitive resist 5 by a screen, which is wider than the area of the opening and thicker than the film thickness of the photosensitive resist 5. It is formed by printing and dried at about 130'C ((C) in the same figure). The same figure (D) shows the ci-d cross section of the same figure (C), and the thick film resistor paste 4' is deposited above the photosensitive resist 5, and part of it is attached to the common electrode. 2. It comes into contact with the individual electrode 3.

In the next step, as shown in the same figure (E), the thick film resistor 4
', the portion of the photosensitive resist 5 on the pattern is removed. At the same time, the thick film resistor embedded in the opening 5' of the photosensitive resist 5 is removed so that it becomes equal to the thick film of the photosensitive resist 5. At this time, the thick film resistor is still dry and therefore very soft. Therefore, 2000-6
Wrapping can be easily removed using a No. 000 wrapping sheet, and the photosensitive resist 5 can be removed with high accuracy without damaging it.

The thick film resistor from which unnecessary portions have been removed in this way is fired at, for example, about 800 to 900°C to sinter the thick film resistor, and at the same time, the photosensitive resist 5 is also fired.
Remove by vaporization. In this way, as shown in FIG. 2F, a heat generating resistor 4 made of this thick film resistor is formed between the common electrode 2 and the individual electrodes 3 which face each other.

Thereafter, as shown in FIG. 6G, an overglaze layer 6 is formed as an abrasion resistant layer by screen printing, and is fired at, for example, 800 to 900°C.

Regarding the overglaze layer 6, after firing, the height of the overglaze between the heat generating resistors 4 is made to be higher than the height of the heat generating resistors 4, as shown in FIG. For this purpose, select an overglaze paste with appropriate viscosity and wettability, or perform multilayer printing.

Thereafter, by polishing the surface of the overglaze layer 6 with a lapping sheet of No. 2000 to 5000, the height of the overglaze on the heating resistor and between the heating resistors is equalized, as shown in FIG. In this way, the main scanning direction can be flattened.

In this example, LS201 was used as the overglaze material and two-layer printing was performed.

FIG. 4 shows the printing results using the thick film type thermal head produced as described above. The cross-sectional shape near the surface of the heating resistor is flat as shown in Figure (A), so when printing with this thick film type thermal head, the top view and Figure 2 (B) are the same. As shown in the cross-sectional view in (C), there are only protrusions 11 on the surface of the printed photographic paper 9 due to the sublimation dye transferred to the photographic paper, and there are no protrusions 11 on the resistor as explained in FIG. There were no impressions caused by overglaze, and it was possible to print with good image quality.

(Effects of the Invention) As is clear from the above description, according to the present invention, the overglaze on the resistor is flattened in the main scanning direction, and the overglaze caused by the unevenness on the surface of the photographic paper is This has the effect of making it possible to print with good image quality without deterioration of image quality.

[Brief explanation of the drawing]

FIG. 1 is a process diagram for explaining an embodiment of the thick film type thermal head of the present invention, FIG. 2 is an explanatory diagram of a conventional thick film type thermal head, and FIGS. 3 and 4 are FIG. 3 is an explanatory diagram of printing results by a conventional thick film thermal head and a thick film thermal head according to the present invention. 1... Ceramic substrate, 2... Common electrode, 3...
Individual electrode, 4... heating resistor, 6... overglaze layer. Patent applicant: Fuji Xerox Co., Ltd.

Claims (2)

[Claims] (1) A thick-film thermal head in which the overglaze on the heat-generating resistors and the overglaze between the heat-generating resistors are equal in height in the individually facing thick-film thermal head. (2) After forming individual heating resistors facing each other on the substrate by a lift-off method, an overglaze layer is formed so that the height of the overglaze between the heating resistors is higher than the height of the heating resistors, and then A method for manufacturing a thick-film thermal head, comprising polishing an overglaze layer to flatten the surface.