JPH04107154A - Formation of over-glaze for heating resistance body - Google Patents

Abstract

PURPOSE:To form over-glaze in a shape corresponding to the inner shape of a metal mold by a method wherein the over-glaze is formed by means of screen printing and burning and after this, lapping is made with lapping agent that is applied to the inside of the metal mold which is made in a shape in accordance with the shape and film thickness to which the over-glaze is desirably formed. CONSTITUTION:After burning is applied to an over-glaze 5 which is formed by moans of screen printing, lapping agent 7 is pasted to the inside of a metal mold 6, and lapping is made to the surface of the over-glaze in the main scanning direction. The metal mold 6 is made in such shape that inner corners thereof are rounded. In application of the lapping, a number of metal molds, each of which is different in shapes and sizes, are prepared. These molds are used in dimensional order, starting with the biggest one, and thereby over-glazes in desired shapes in desired thickness are formed. With the metal mold, with its inner corners rounded, used for the lapping work, the over-glaze is formed, after the lapping, in a shape having a flat top on the upper surface and curved surfaces on both of the side parts 8, 9. Thereby fitting of the surface of the over-glaze to the thermosensitive paper is made smooth when thermosensitive recording is executed.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to the formation of an overglaze, which is a wear-resistant layer of a heating resistor in a thermal head used in a recording section of a thermal recording type facsimile machine or printer. It is about the method.

(Prior Art) An overglaze, which is a wear-resistant layer of a conventional thick-film heating resistor, is usually formed by screen printing after the heating resistor is formed on a substrate.

FIG. 3 shows an example of a conventional thermal head in which an overglaze is formed in this manner, and is a sectional view of a thick film type thermal head. In the figure, 1 is a ceramic substrate, 2 is a common electrode, 3 is an individual electrode, 4 is a heating resistor, and 5
is an overglaze. The shape of the overglaze 5 is reproduced as it was formed by screen printing. This shape is influenced by the viscosity of the overglaze paste used, its wettability with the base, etc., and differences occur in the height and width of the shape, but the essence of the chevron shape remains the same. However, in the thermal recording method, variations in the shape and thickness of the overglaze have a large effect on heat distribution, printing characteristics, paper contact, and the like.

For this reason, in order to control the shape and film thickness of the overglaze, conventional methods include changing the properties of the overglaze paste in the overglaze printing process before baking the overglaze, or changing the film thickness of the screen and the screen openings. Although we have made some changes, we are unable to obtain the desired shape.

In addition, the thick film type overglaze paste is made by blending glass component particles and a vehicle, and even if the overglaze is leveled after screen printing, the shape of the overglaze paste will depend on the paste characteristics of the overglaze. There is a problem in that the glass component particles are melted during overglaze firing and the shape after screen printing is distorted. Due to these factors, it has been difficult to obtain a desired shape and film thickness.

Although the method described in Japanese Patent Publication No. 63-9728 improves the firing conditions, this alone is not sufficient to form an overglaze of a desired shape.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned circumstances. The object of the invention is to provide an overglaze forming method that can realize a predetermined shape and film thickness. In a method for forming an overglaze in a thermal head in which a plurality of resistors are individually arranged in parallel, after forming an overglaze on the heating resistor, the overglaze is removed using a mold having a predetermined internal shape and a lapping agent. It is characterized by wrapping.

It is possible to use two or more molds of different sizes as molds having a predetermined inner shape, and perform wrapping in multiple steps. At that time, the wrapping agent may be changed.

(Function) The present invention involves forming an overglaze, which is a wear-resistant layer of a heating resistor, by screen printing and baking, and then lapping it with a lapping agent in a mold that matches the desired shape and thickness of the overglaze. By doing so, an overglaze having a shape based on the inner shape of the mold can be formed. For the desired shape, use several types of molds, attach a wrapping agent to the inside of the mold, and apply the overglaze by changing from a larger mold to a smaller mold in order to match the shape after overglaze firing. You may wrap it. By achieving the desired shape and overglaze film thickness, variations in heat distribution and printing characteristics are reduced, and the contact between the heating resistor and thermal paper is improved, allowing for thermal transfer type, thermal type, or thermal sublimation type. The printing characteristics of the mold recording method can be improved.

(Example) Hereinafter, a method for forming an overglaze, which is a wear-resistant layer of a heat generating resistor according to the present invention, will be described with reference to Examples shown in the accompanying drawings.

FIG. 1 is a cross-sectional view for explaining how lapping is performed using a lapping mold used in an embodiment of the overglaze forming method of the present invention. In the figure, 1 is a ceramic substrate, 2 is a common electrode, 3 is an individual electrode, 4 is a heating resistor, 5 is an overglaze, 6 is a mold, and 7 is a wrapping agent applied to the inside of the mold.

After baking the overglaze printed by screen printing, a wrapping agent 7 is kneaded inside the mold 6,
Lap the overglaze surface in the main scanning direction.

As the mold 6, a mold having a shape in which the inner corner was removed was used.

At this time, several types of molds with different shapes and sizes are prepared, and the lapping is performed using the larger molds in order to form an overglaze having a desired shape and film thickness. In order to prevent this mold from coming into contact with the substrate and causing overglaze other than the top of the heating resistor, or scraping the electrode or ceramic substrate, the length of the mold's legs should be shorter than the top surface of the ceramic substrate and overglaze. .

The lapping agent attached to the inside of the mold is made of a material harder than that of the overglaze, such as diamond or silicon carbide, so that a predetermined surface quality can be obtained. When using the particle size of the lapping agent in this case, if a particle size of submicron to several microns is used, the surface property will be smooth, the distance from the top surface of the heating resistor to the top surface of the overglaze will be equal, and the heat distribution of the printed dots will be uniform, resulting in a high Image quality thermal recording can be achieved.

If the heating resistor at this time is formed with high precision, the surface of the overglaze will be smoother and the precision of the film thickness will be increased.

When the inner corner of the mold is removed and a curved surface (R) is attached, the shape of the overglaze after wrapping will be as shown in Figure 2, with R on both sides 8 and 9 of the top surface, and the top surface It has a flat, semi-cylindrical shape, allowing smooth contact between the thermal paper and the surface of the overglaze during thermal recording. The top surface is flat and the edges on both sides of the top surface prevent stinging and damage to the thermal paper.

In addition to the shape in which the top surface of these overglazes is flat and rounded on both sides of the top surface, any desired shape can be obtained by changing the shape of the inside of the mold. Furthermore, these overglaze forming methods are not limited to heat-sensitive recording type heating resistors, but are also effective for forming overglazes on intuitive thermal recording type heating resistors.

(Effects of the Invention) As is clear from the above explanation, according to the method for forming an overglaze which is a wear-resistant layer of a heating resistor according to the present invention, the heat distribution of the heating resistor becomes uniform and the print image quality is improved. Moreover, the contact between the overcraze surface and the paper is the same as above, and stella kink and damage to the paper can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view for explaining how wrapping is performed using a wrapping mold used in an embodiment of the overglaze forming method of the present invention, and FIG. 2 is a cross-sectional view of the overglaze that has been wrapped. A sectional view for explaining the shape, FIG. 3 is a sectional view of a conventional thermal head. 1... Ceramic substrate, 2... Common electrode, 3...
Individual electrode, 4... Heating resistor, 5... Overglaze, 6... Mold, 7... Wrapping agent. Patent applicant Fuji Xerox Co., Ltd.

Claims (1)

[Claims] In a method for forming an overglaze in a thermal head in which a plurality of heating resistors are individually arranged in parallel on a substrate, after forming an overglaze on the heating resistor, a mold having a predetermined internal shape and a lapping agent are used. , a method for forming an overglaze on a heating resistor, the method comprising wrapping an overglaze.