JPH04173352A - Thermal head - Google Patents

Abstract

PURPOSE:To eliminate an area in which coloring does not take place between heating parts, prevent the density of a heating dot which is adjacent to a non-heating dot from decreasing, and improve the coloring efficiency by providing a thermal conductor through an insulation film in such a manner that the thermal conductor covers a part or the whole area between heating resistors which are adjacent in the main scanning direction. CONSTITUTION:A thermal head is equipped with a heat storage layer 2, a plurality of heating resistors 3 which are arranged in the main scanning direction, and an individual electrode 4 and a common electrode 5 which are connected to the heating resistors 3, on an insulation substrate 1. A thermal conductor 10 is provided through an insulation film 11 in such 1 a manner that the thermal conductor 10 covers a part or the whole area 1 between the heating resistors 3 which are adjacent in the main scanning direction. By providing the thermal conductor 10 between the adjacent heating resistors 3 in the main scanning direction of a heating resistor row which is formed on the insulation substrate 1, through the insulation film 11, a part of heat which is generated by the heating resistors 3 is dispersed between the heating resistors 3 also by the thermal conductor 10, and a coloring area is extended. Therefore, an area in which coloring does not take place between heating dots is eliminated, and in addition, the density of a heating dot which is adjacent to a non-heating dot is prevented from decreasing, and the coloring efficiency of heating dots is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a thermal head installed in a facsimile, a printer, etc.

<Prior Art> FIG. 6 shows the structure of the heating resistor section of a conventional thermal head. 3(a) is a plan view of the heating resistor, and FIG. 2(b) is a sectional view taken along line BB in FIG. 1(a).

As shown in the figure, in the conventional thermal head, polyimide resin or the like is laminated as a heat storage layer 2 on an insulating substrate l using a technique such as a roll coating method or a spin code method. 3 (e.g., Ta 5iO1, etc.), individual electrodes 4, and common electrodes 5 (e.g., AQ, etc.) are sequentially laminated and etched using techniques such as photolithography to form a predetermined pattern. It has a structure in which a wear protection film 6 (for example, 5iAQoN, etc.) is laminated by a sputtering method or the like.

<Problem to be solved by the invention> However, according to the configuration of the conventional thermal head,
When energized, current flows concentratedly in the center of the heat generating resistor 3, and heat is concentrated in the center of the heat generating resistor 3. As a result, it cannot be said that the temperature at the center of the heating resistor becomes sufficiently high, or that the temperature between the heating resistors does not become sufficiently high.

For this reason, when coloring thermal paper, only a small area can be colored, and as shown in Figure 7, printed dots 7
The spaces between the two do not connect, leaving a portion X that does not develop color, resulting in a lower overall color density and lower color development efficiency.

Therefore, as a means to solve the above problem, there is a method of forming an AQ layer on the heating resistor so as to have a band shape in the main scanning direction. However, in this case, if there is a non-heat generating dot,
Heat from the heat generating dots diffuses toward the non-heat generating dots through the band-shaped Aa layer, and in particular the concentration of the heat generating dots adjacent to the non-heat generating dots decreases.

In view of the above, the present invention provides a thermal head having a heat generating part that eliminates areas where no color develops between heat generating parts (dots), prevents a decrease in density of heat generating dots adjacent to non-heat generating dots, and improves coloring efficiency. With the goal.

<Means for Solving the Problems> The means for solving the problems of the present invention, as shown in FIG. and an individual electrode 4 connected to the heating resistor 3
and a common electrode 5,
A good thermal conductor IO is provided via an insulating film 11 so as to cover part or all of the space between the heating resistors 3 adjacent to each other in the main scanning direction.

<Function> In the above-mentioned means for solving the problem, the heat-generating resistor IQ is provided between the heat-generating resistors 3 adjacent in the main scanning direction of the heat-generating resistor row formed on the insulating substrate l via the insulating layer 11. A part of the heat generated by the resistor 3 is also dispersed between the heat generating resistors 3 by the heat conductor 10, and the coloring area is expanded.

Therefore, it is possible to eliminate one region where no color is developed between the heat generating dots and to prevent the density of the heat generating dots adjacent to the non-heat generating dots from decreasing, thereby improving the coloring efficiency of the heat generating dots.

<Example> An example of the present invention will be described below with reference to FIGS. 1 to 4.

Fig. 1 is a plan view of the heating resistor portion of a thermal head according to an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the line A-A in Fig. 1, and Fig. 3 is a plan view of the heating resistor portion of a thermal head according to an embodiment of the present invention. FIG. 4, which is a diagram comparing the surface temperatures of the heating resistor portions, is also a diagram showing the printed dots. Note that the same reference numerals are given to the same functional parts as those of the prior art shown in FIG. 6.7.

As shown in FIG. 1.2, the thermal head of this embodiment includes, on a heat-resistant insulating resin substrate l, a heat storage layer 2, a plurality of heat generating resistors 3 arranged in the main scanning direction, and the heat generating resistors 3. A good thermal conductor IO is provided via an insulating film II so as to cover a part between the heating resistors 3 adjacent to each other in the main scanning direction. There is.

The method for manufacturing the above thermal head will be described in detail.

First, a polyimide layer is formed on the surface of a heat-resistant insulating resin substrate 1 as a heat storage layer 2 using a technique such as a roll coating method or a spin cord method.

Then, on the surface of the heat storage layer 2, a common electrode 5,
The individual electrodes 4 and the heat generating resistors 3 are laminated, and these are etched by photolithography or the like to form a predetermined pattern. After that, between the heat generating resistors 3, a good thermal conductor 10 (for example, 1 etc.) or a heat generating resistor is placed between the heat generating resistors 3. Insulating layer I so that a part of body 3 overlaps
Formed via I.

Finally, a protective film 6 (for example, S1AffO
N, etc.) is formed by a sputtering method or the like.

The thickness of the heat conductor 10 is set to 4,000 to prevent a large step from occurring near the heating resistor 3.

In this way, by providing the thermal conductor 10 between the heating resistors 3 adjacent to each other in the main scanning direction of the row of heating resistors with the insulating film 11 interposed therebetween, a part of the heat generated by the heating resistors 3 is transferred to The good conductor 10 diffuses the light between the heat generating resistors 3, expanding the coloring area.

Here, FIG. 4 shows a comparison of the surface temperature on the heating resistor with and without the thermal conductor jO.

In the figure, ■ indicates a case where there is no good thermal conductor jO, and D indicates a case where there is a good thermal conductor 10.
If yes, Y indicates the color development limit temperature.

As shown in the figure, in the case of Y-T with a good thermal conductor lO, the temperature between the heating resistors 3 becomes higher than in the case with or without a good thermal conductor jO, and becomes higher than the coloring limit temperature Y. Therefore, as shown in FIG. 4, the blank spaces between the printed dots 7 are filled, the printing density becomes high, and the coloring efficiency is improved.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

For example, as shown in FIG. 5, the same effect can be obtained even if the thermal conductor IO is made oval rather than square, and the thermal conductor IO is provided so as to cover between the heating resistors 3.

Furthermore, similar effects can be obtained even when ceramic is used for the insulating substrate.

<Effects of the Invention> As is clear from the above description, according to the present invention, by forming a good thermal conductor between adjacent heating resistors in the main scanning direction with an insulating layer interposed therebetween, the heat generated by the heating resistors can be reduced. The heat also spreads between the heating resistors, expanding the printing area.

Therefore, it is possible to improve the color development efficiency of heat-generating dots by eliminating the area between heat-generating dots and preventing the concentration of heat-generating dots adjacent to non-heat-generating dots from becoming low. It has an excellent effect.

[Brief explanation of drawings]

Fig. 1 is a plan view of the heating resistor portion of a thermal head according to an embodiment of the present invention, Fig. 1.2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is a plan view of the heating resistor portion of a thermal head according to an embodiment of the present invention. Figure 4 is a diagram comparing the surface temperature of the heat generating resistor section in the case of the case, Figure 4 is a diagram showing the printed dots, Figure 5 is a diagram showing another embodiment, Figure 6 is
a) is a plan view of the heating resistor part of a conventional thermal head;
FIG. 6(b) is a sectional view taken along the line BB in FIG. 6(a), and FIG. 7 is a diagram showing printed dots thereof. 1 insulating substrate, 2 heat storage layer, 3 heating resistor, 4 individual electrodes,
5 common electrode, lO conductor, 11 insulating film. Applicant Noyab Co., Ltd.

Claims (1)

[Claims] A thermal head including, on an insulating substrate, a heat storage layer, a plurality of heat generating resistors arranged in the main scanning direction, and individual electrodes and a common electrode connected to the heat generating resistors, adjacent to the main scanning direction. A thermal head characterized in that a good thermal conductor is provided through an insulating film so as to cover part or all of the space between the heating resistors.