JP2915443B2 - Manufacturing method of thermal head - Google Patents

Description

The present invention relates to a method for manufacturing a thermal head, and more particularly, to a method for forming a wear-resistant film thereon.

(B) Conventional technology A conventional method of manufacturing a thermal head will be described by taking a thick film type thermal head as an example. Reference numeral 12 denotes an insulating substrate made of ceramic or the like, on which a glass glaze layer 13, an electrode 14, and a heating resistor 16 are sequentially formed (see FIG. 3A). A paste 18 is printed on the insulating substrate 12 to form a wear-resistant film 17. This paste 18 is what is called a glass frit type, and is composed of glass fine powder and an organic binder.

The insulating substrate 12 on which the paste 18 is printed is heated (fired) at a high temperature, and the organic binder component in the paste 18 is burned off.
Only the glass component remains as the wear-resistant film 17 [FIG. 3 (b)
reference〕. If the paste 18 is printed to a thickness of 18 μm, the thickness of the wear-resistant film 17 is about 6 μm.

(C) Problems to be Solved by the Invention In the thermal head, the thinner the abrasion-resistant film is, the better, in order to improve the contact state between the thermal recording paper and the heating resistor and reduce the power consumption. However, when a wear-resistant film is formed using the above-mentioned glass frit type paste, the film thickness is usually 6 to 12 μm, and a film thickness of, for example, 1 μm cannot be obtained very much.

In order to reduce the film thickness, it is conceivable to lower the viscosity of the paste. However, when the viscosity of the paste is reduced, the paste easily flows, and the risk of bleeding or the like is increased (printability is reduced). In this bleeding, the paste flows to a portion where an abrasion-resistant film should not be formed, for example, to a portion of an electrode bonding pad (connected to a driving IC chip mounted on an insulating substrate by a wire). There are cases.

In addition, the above-mentioned abrasion-resistant film is glassy, and there is a problem that pinholes are easily generated and it is difficult to make the film quality dense. One way to solve this problem is to print the paste twice, but the film thickness becomes very large, which further exacerbates the above problem.

The present invention has been made in view of the above, and has as its object to provide a method of manufacturing a thermal head capable of forming a wear-resistant film having a small film thickness and a dense film quality.

(D) Means and Action for Solving the Problems To solve the above problems, the method for manufacturing a thermal head according to the present invention prints a paste on an insulating substrate on which electrodes and heating resistors are formed, and fires the paste. And forming the wear-resistant film by firing a metal organic paste.

This metal organic paste is obtained by mixing a metal organic compound or a complex of an organic substance and a metal with a resin and a solvent. The metal organic compound is a compound directly bonded between carbon and metal, such as a compound bonded to a hydrocarbon group such as an alkyl group and an aryl group. Also,
The complex of an organic substance and a metal is a complex with an organic substance such as a carboxylic acid, and is represented by the following chemical formula, for example.

Here, Me represents a metal element such as lead (Pb), and R represents, for example, C _n H _{2n + 1} .

In the metal organic paste, an organic component is burned off by firing, and a metal oxide remains as a thin film. Assuming that the printed thickness of the metal organic paste is 18 μm, the thin film remaining after firing becomes, for example, about 0.3 μm. Accordingly, the thickness of the wear-resistant film can be reduced without impairing the printability of the paste. On the other hand, since the wear-resistant film formed by the metal organic paste is a thin film of metal oxide, the film quality can be made dense.

(E) Embodiment One embodiment of the present invention will be described below with reference to FIGS.

In this embodiment, the present invention is applied to the production of a thick film type thermal head, and FIGS. 1 (a) and 1 (b)
FIG. 2 is a sectional view of an essential part for explaining a manufacturing process of the thermal head, and FIG. 2 is a view for explaining a forming pattern of an electrode and a heating resistor.

In FIG. 1A, reference numeral 2 denotes an insulating substrate, which is made of a material such as alumina ceramic. On this insulating substrate 2, a glass glaze layer 3 as a heat storage layer is first formed. This glass glaze layer 3 prints a glass frit type paste on the insulating substrate 2,
This is formed by firing.

On the glass glaze layer 3, a common electrode 4 and an individual electrode 5 are formed. The common electrode 4 and the individual electrodes 5 are formed in a comb shape as shown in FIG. 2 and are arranged so as to mesh with each other. The common electrode 4 and the individual electrode 5 also have the glass glaze layer 3
It is formed by printing a gold paste on it and baking it.

Further, a heating resistor 6 is formed on the glass glaze layer 3 so as to straddle the common electrode 4 and the individual electrode 5.
The heating resistor 6 is also formed by printing and firing a ruthenium (Ru) -based paste.

So as to cover the electrodes 4, 5 and the heating resistor 6,
The metal organic paste 8 is printed. The metal organic paste is obtained by mixing one or more kinds of metal organic compounds or a complex of an organic substance and a metal with a solvent and a resin. Metal-organic compounds, complexes of organic substances and metals include, for example, lead (Pb) complexes, Is used. The optimum composition of the metal organic paste is determined by an experiment. At this time, it is not necessary to pulverize and pulverize the glass as in the related art, so that the experiment can be easily performed.

FIG. 1B shows a state in which the metal organic paste is baked to form a wear-resistant film 7. When the metal organic paste is fired, organic components (C, H, etc.) are burned off, and vitrified metal oxide such as lead oxide remains as the wear-resistant film 7. Assuming that the printing thickness of the metal organic paste is 18 μm, the thickness of the wear-resistant film 7 is
It can be reduced to about 0.3 μm, so that the contact between the heating resistor 6 and a thermosensitive recording paper (not shown) can be improved, and the power consumption of the thermal head can be reduced.

Also, since the film thickness can be reduced in this way, it is possible to print the metal organic paste twice,
It is also easy to suppress the occurrence of pinholes in the wear-resistant layer 7 and obtain a dense film quality.

In the above embodiment, a thick film type thermal head is described, but the present invention is also applicable to a thin film type thermal head.

(F) Effects of the Invention As described above, the method for manufacturing a thermal head according to the present invention is characterized in that the paste for forming the wear-resistant film is a metal organic paste. The film thickness can be reduced. Also,
Since the film thickness is small, it is possible to print the paste twice, and it is easy to suppress the occurrence of pinholes and to make the film quality dense. Further, since it is not necessary to lower the viscosity of the paste and reduce the thickness of the wear-resistant film, the printability of the paste is not impaired. In addition, there is an advantage that an experiment for determining the composition of the paste can be easily performed.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are longitudinal sectional views of a main part for explaining a manufacturing process of a thermal head according to an embodiment of the present invention, and FIG. 2 is an electrode and a heating resistor of the thermal head. FIGS. 3 (a) and 3 (b) are diagrams for explaining the pattern of the body, and are each a longitudinal sectional view for explaining a manufacturing process of a conventional thermal head. 2: Insulating substrate, 4: Common electrode, 5: Individual electrode, 6: Heating resistor, 7: Abrasion resistant film, 8: Metal organic paste.

Claims (1)

(57) [Claims] 1. A method for manufacturing a thermal head in which a paste is printed on an insulating substrate on which electrodes and heating resistors are formed, and the paste is baked to form a wear-resistant film, wherein the wear-resistant film is made of a metal organic paste. A method for manufacturing a thermal head, characterized by firing.