JPS6253850A - Manufacture of thermal head for thermal recording - Google Patents

Abstract

PURPOSE:To reduce the cost of a thermal head as well as raise its characteristic by a method in which a wear-resistant protective film is formed by applying a solution composed primarily of a metal alkoxide on the surfaces of heating elements and electrodes and then baking it by heating. CONSTITUTION:A solution of a metal alkoxide, e.g., silicon tetraethoxide, as a main component is applied to pattern on heating resistors 3 and electrodes 4 by dipping, etc., and baked at 150 deg.C for one hour, for example, in the air to form an oxide film composed primarily of SiO2. The wear-resistant protective film 5 is very dense film of a hardness (Vickers) of 500Hv, which can play sufficiently role as the protective film 5 since the thickness of the film can be freely regulated, although the hardness of the film is slightly lower than that of a thin film.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a thermal head for heat-sensitive recording, which is applied to various fields such as facsimiles, printers, recorders, etc., and particularly relates to a method of forming a wear-resistant protective film. be.

2. Description of the Related Art A conventional thermal head generally includes a heating resistor 7, an electrode 8 electrically connected to the heating resistor 7, and a heating resistor 7 and an electrode on an insulating substrate 6, as shown in FIG. The structure is formed by a wear-resistant protective film 9 that prevents wear of the parts 8 and 8. Furthermore, two types of thermal heads have been developed based on the method of forming the heating resistor material: (1) thin film type and (2) thick film type.

The abrasion-resistant protective film 9 of these two types of thermal heads is: (1) Thin film type: A hard abrasion-resistant protective film formation technology using a thin film formation technique, such as a sputtering method, 6:I
) Thick film type: Formed using a glass layer formation technology using a thick film formation technology.

Problems to be Solved by the Invention The above-mentioned thin-film type wear-resistant protective film can be made of a variety of hard materials.For example, SiC, which has the second highest hardness after diamond, can be used as the wear-resistant protective film. On the other hand, a common drawback of thin film forming technology is that it takes a long time to form a thin film, making it difficult to mass-produce long heads for facsimile machines and the like. Furthermore, since the equipment required to form the thin film is expensive, the step of forming the wear-resistant protective film becomes a major obstacle to reducing the price of the head. In this situation, there is no big difference even if a vacuum evaporation method, a reactive snow/vine method, or a gas phase reaction method is used instead of the snow/vine method. In particular, compared to other thin film formation techniques, the gas phase reaction method should originally be able to minimize the time required to form a wear-resistant protective film, but it is important to avoid affecting the heating element of the thin film. In order to achieve this, the reaction temperature must be kept low, so it is rarely used in practice.

On the other hand, the method of using a glass layer as an abrasion-resistant protective film using thick film formation technology has no problems technically or in terms of mass production. This is determined by the softening point of the glass, which is selected so as not to impair its properties, making it difficult to increase the speed of the head.

(2) In order to raise the operating temperature of the heating element, glass with a high softening point must be used, and there are disadvantages such as the need to form the heating element and electrodes that can withstand temperatures higher than the softening point of the glass.

The method of manufacturing a thermal head for heat-sensitive recording according to the present invention eliminates the above-mentioned conventional drawbacks.

Means for Solving the Problems In order to solve the above problems, the present invention provides a wear-resistant protective film that is formed by applying a solution containing metal alkoxide as a main component onto the heating element and the electrodes, and then heating and baking the solution. It is characterized by

Function The present invention solves the conventional problems by using the method described above, and the formation of a wear-resistant protective film is accomplished by simply applying a solution containing a metal alkoxide as a main component and then heating and baking it at a low temperature. That's fine.

The solution containing a metal alkoxide as a main component used in the present invention usually has heat resistance of 1000° C. or more when fired at 1006° C. to 200° C.

Therefore, if the wear-resistant protection forming technique according to the present invention is applied to a thin film type thermal head, the film forming process will be greatly simplified and it will be very effective in reducing the head price.

As described above, the present invention is very useful in terms of productivity, cost, and characteristics of thermal heads.

Example An example of the manufacturing method of the present invention will be described below.

FIG. 1 is an enlarged view of the heating element portion of a thermal head for heat-sensitive recording obtained by the method of manufacturing a thermal head for heat-sensitive recording of the present invention. In the figure, 1 is an insulating substrate such as alumina, 2 is a glass glaze layer, 3 is a heating resistor film, 4 is an electrode, and 5 is a wear-resistant protective film according to the present invention.

The method for forming the wear-resistant protective film 6 according to the present invention uses silicon tetraethoxide as the main component, for example.

1 of metal alkoxides such as silicon tetramethoxide, titanium tetra-n-butoxide, aluminum triisopropoxide and zirconium tetraisopropoxide
A mixture of one or more seeds is dissolved in an alcoholic solvent and water, and a solution containing a small amount of an acid such as hydrochloric acid or an alkali such as ammonia as a catalyst is applied in a pattern.
Furthermore, the SiO□
, TiO2°At203. This is a method for obtaining an oxide film consisting of a main component such as ZrO□.

Hereinafter, explanation will be given using specific examples.

<Example 1> A metal alkoxide solution containing silicon tetraethoxide as the main component was applied in a pattern onto the heating resistor 3 and the electrode 4 by dipping or the like, and then baked in air at 150'C for 1 hour to form a 5in2 solution. The oxide film as a component is 4 to 6μ
n was formed.

The abrasion-resistant protective film 5 according to this embodiment forms a very dense film, and the Picchus hardness of this film is 500 Hv.
It was about. Although the hardness of the film is somewhat lower than that of a film formed by forming a thin film, since the film thickness can be freely adjusted, it can sufficiently fulfill its role as the wear-resistant protective film 5.

<Example 2> A metal alkoxide solution containing silicon tetramethoxide and zirconium tetraisopropoxide as main components was applied in a pattern onto the heating resistor 3 and the electrode 4 by spraying or the like, and then baked in air at 250°C for 30 minutes. Then, SiO
□, an oxide film mainly composed of ZrO□ was formed to a thickness of 4 to 6 μm.

The wear-resistant protective film 5 according to this example also forms a very dense film as in Example 1, and the Picchus hardness of this film is about aoogv, forming a film with higher hardness than Example 1. Ta.

<Example 3> A metal alkoxide solution containing aluminum triisopropoxide as the main component was applied in a pattern onto the heating resistor 3 and the electrode 4 using a spinner, and then heated in air at 200°C for 1 hour.
Baking for a while, mul! An oxide film containing 203 as a main component was formed to a thickness of 4 to 6 μm.

The abrasion-resistant protective film according to this example also forms a dense film as in Example 1, and the hardness of the film is 1000H or more, but the adhesion strength is as high as that of Example 1. It has some disadvantages compared to .

Since the wear-resistant protective film 5 formed according to the embodiment of the present invention can be formed very easily, an inexpensive thermal head can be obtained.

Effects of the Invention As described above, the formation of the wear-resistant protective film according to the present invention requires only applying a solution containing a metal alkoxide as the main component and firing at a low temperature. It is of great industrial value that a thermal head for heat-sensitive recording with improved head characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a heating element part of a heat-sensitive recording head obtained by a method of manufacturing a thermal head for heat-sensitive recording in an embodiment of the present invention, and FIG. 2 is a perspective view showing a heating element part of a conventional heat-sensitive recording head. FIG. DESCRIPTION OF SYMBOLS 1...Insulating substrate, 3...Heating resistor film, 4...Electrode, 6...Wear-resistant protective film.

Claims (1)

[Claims] It consists of a resistor film formed on an insulating substrate, a power supply electrode, and an abrasion-resistant protective film, and is characterized in that the abrasion-resistant protective film is formed by applying and baking a solution containing a metal alkoxide as a main component. A method for manufacturing a thermal head for heat-sensitive recording.