JPS5839675B2 - net twin head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal print head, and more particularly to a method for manufacturing a thermal print head in which a heating element is formed by printing a resistive paste.

In the conventional method of manufacturing this type of thermal print head, as shown in FIGS. 1 to 3, a common terminal 2 is provided on the surface of an insulating base 1.
A plurality of individual terminals 3 are formed, and a resistive paste is printed so as to extend over each individual terminal 3 and the common terminal 2, thereby forming a plurality of dot-shaped heating elements 4 in a line.

According to the thermal printing head manufactured in this manner, by appropriately selecting individual terminals 3 and applying a voltage between them and the common terminal 2, a heating element straddling the selected individual terminals 3 can be generated. 4 begins to generate heat, and by sequentially selecting individual terminals 3 and energizing them while moving one of the head or the thermal paper relative to the other, arbitrary characters, symbols, and figures can be printed on the thermal paper. You will be able to do this.

However, in the illustrated conventional thermal print head, if the pitch of the heating elements 4 is made narrow enough to improve print quality,
Due to the fluidity of the applied resistance paste, adjacent heating elements may come into contact with each other during printing, making it difficult to form each heating element independently.

In particular, a resistive paste with a high resistance value has a large amount of glass, so it becomes more fluid, and therefore it becomes increasingly difficult to form each heating element separately and independently.

Also, the cross section of the heating element 4 printed with resistance paste becomes semicircular as shown in FIG. It is small compared to the width of the bottom surface of the body 4.

In other words, even if the pitch of the heating elements 4 is sufficiently narrowed, the interval between the printed images becomes wide, and the void ratio of the printed images becomes large.

Needless to say, this causes poor print quality.

In order to solve these problems, instead of manufacturing the heating elements 4 individually, it is possible to print resistance paste across all the individual terminals 3 and the common terminal 2 to form a band-shaped heating element. This is conceivable, but according to this, only the area between the selected individual terminal and the common terminal needs to generate heat, but the area around it also generates heat due to leakage current, and as a result, the amount of heat is greater than expected. This may cause the thermal paper to develop color, making printed characters etc. unclear and reducing print quality.

An object of the present invention is to provide a method for manufacturing a thermal print head that can improve print quality.

This invention forms a heating element by forming an insulating layer with a plurality of protrusions on the surface of an insulating base by printing an insulating paste, and then printing a resistive paste so as to completely fill the space between each insulating layer. It is characterized by

An embodiment of this invention will be explained based on FIG. 4 and subsequent figures.

A common terminal 12 and a plurality of individual terminals 13 are formed on the surface of an insulating substrate 11 made of ceramic or the like.

These configurations are not particularly different from the conventional example.

However, according to the present invention, an insulating paste is printed between each individual terminal 13 to form a protruding insulating layer 14.

In this case, the insulating layer 14 is formed so as to extend over the surface of the common terminal 12.

Next, a resistance paste for a heating element is printed between each insulating layer 14 to form a heating element 15.

The heating element 15 is printed so as to completely fill the space between adjacent insulating layers 14.

In order to supply electricity to the heating element 15, the heating element 15 is formed so as to straddle between the common terminal 12 and each individual terminal 13.

During this printing, the insulating layer 14 acts as a partition wall, so the fluidity of the resistance paste ensures that it fills the spaces between the insulating layers 14, and the paste is printed in the same shape as the space partitioned by the insulating layer 14. Become so.

Therefore, unlike the conventional example shown in FIG. 2, the heating element does not have a semicircular cross section, and the surface can be made almost flat. There is no contact with each other.

In the example actually manufactured by the present inventor, the width of the individual terminals 13 is 130μ, the gap between the individual terminals 13 is 70μ, the width of the insulating layer 14 is 50μ, the height is 20 to 30μ, and the terminal 13.1
The length between the heating elements 15 and 15 was 200μ, and the width of the heating element 15 was 500μ.

In the thermal printing head manufactured as described above, when electricity is applied between the common terminal 12 and the individual terminals 13, the heating element portion existing between the terminals 12 and 13 generates heat.

Therefore, the parts involved in coloring the thermal paper are both terminals 1
It can be considered that the area is approximately equal to the portion located between 2.13 and partitioned by adjacent insulating layers 14.

Therefore, the interval between adjacent colored parts can be considered to be approximately the width of the insulating layer 14, so even if this width is made equal to the interval between the bottoms of the adjacent heating elements 4 in FIG. Considering that in the configuration, only the area near the top surface of the heating element 4 is colored by +4, the interval between the colored parts can be made much narrower than in the case of Fig. 2. .

In the example shown in FIG. 5, the thickness of the heating element 15 is made to be the same as the height of the insulating layer 14, but as shown in FIG. It may become like this.

However, if it becomes too thick, heat will be generated over a wide area due to leakage current, so it is preferable to make it within about 10 μm from the top surface of the insulating layer, for example.

At this level, even if the leakage current flows, it will not cause the thermal paper to develop a wide range of color.
Rather, it is convenient that the color development interval becomes narrower by developing a slight color.

As detailed above, according to the present invention, an insulating layer of a plurality of protrusions is formed by printing an insulating paste,
Since the heating element is formed by printing a resistive paste between each insulating layer, the insulating layer not only provides insulation between the heating elements, but also serves as a partition wall to print the resistive paste. Therefore, no matter how fluid a heating element made of paste is used, the interval between color development can be made sufficiently small, and therefore, high-quality printing is possible.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional thermal printing head, FIG. 2 is a sectional view taken along the line AA in FIG. 1, FIG. 3 is a sectional view taken along the line BB in FIG. 5 is a sectional view taken along the line C-C of FIG. 4, FIG. 6 is a sectional view taken along the line D-D of FIG. 7, and FIG. FIG. 3 is a cross-sectional view of the manufactured thermal print head. 12.13...Terminal, 14...Insulating layer, 15...Heating element.

Claims (1)

[Claims] 1. On the surface of an insulating base, an insulating layer with a plurality of protrusions is formed in parallel by printing an insulating paste, and then a resistance paste for a heating element is applied across the terminals for conducting electricity on the surface of the base. A method for manufacturing a thermal print head, comprising: printing the above-mentioned insulating layers so as to fill the space between them to form a heating element between each insulating layer.