JPS631555A - Heat-sensitive recording thermal head - Google Patents

Abstract

PURPOSE:To enable clear recording and to improve the durability, by providing an electrode on a head base and a heat-resistant non-conductive material layer at a heating portion between the electrodes then applying a heating element layer and a protection film layer sequentially thereon, thereby eliminating a recess at the heating portion contacting with a heat-sensitive medium. CONSTITUTION:Electrodes 2 composed of Cr-Cu material are arranged in grid on a head base 1 where the surface of alumina is covered with glass. Said electrodes 2 have the thickness of 0.5mum and the width of 60mum and the heating portions are formed in a gap of 200mum between the electrodes 2 at the opposite sides. Then a heat-resistant non-conductive material layer 3 composed of SiO2 is formed in stripe with the width of 200mum and the thickness of 0.6mum to be higher slightly than the electrode 2 in the heating portion or the gap while penetrating through the gap between the electrodes 2 at the opposite sides. Then a heating element layer 4 of Si-Ta is formed with the thickness of 0.1mum and the width of 80mum above the electrode 2 and the non-conductive material layer 3. A protection film layer 5 composed of SiC and Si3N4 is provided with the thickness of about 3mum through spattering above the heating element layer 4 while covering the exposed portion of the heating element layer 4 and the head base 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermal head for heat-sensitive recording, which performs heat-sensitive recording by applying heat to a heat-sensitive medium.

Conventional technology Thermal recording heads used in thermal transfer printers and the like print on thermal media such as thermal transfer ink ribbons, which thermally transfer the information to general paper according to the information to be recorded, and thermal coloring paper, which colors the paper itself with heat. It is now possible to add This conventional thermal head for heat-sensitive recording will be explained with reference to FIGS. 3 to 5.

In Figures 3 and 4, 1o1 is a thermal head;
102 is a heat-sensitive medium, and 103 is a roller. The thermal head 101 has a heating element layer 105 made of a thin film of a material with high electrical resistance and an electrode 106 provided on the front surface of a head base 104. A protective film layer 107 is provided on the upper surface of the heating element layer 105 and the electrode 106. 106 is connected to the terminal 108. 109 is a contact portion between the protective film layer 107 of the thermal head 101 and the heat-sensitive medium 102.

As is clear from FIG. 5, the details of the thermal head 101 are such that a thin heat generating layer 105 is provided on a head base 104, electrodes 106 are provided in a grid pattern on this heat generating layer 105, and these electrodes 106 and heat generating A protective film layer 107 that also serves as wear resistance is provided on the body layer 105.

Next, the operation of the above conventional example will be explained. For example, the heat-sensitive medium 102, which is heat-sensitive coloring paper, is sent upward by the roller 103, and the thermal head controller 1 is moved left and right. During this time, the heating element layer 1
05 between the electrodes 106 to generate heat, and the contact portion 1 with the heat-sensitive medium 102 through the protective film layer 107.
09 to perform recording on the heat-sensitive medium 102.

In the illustrated example, one heating element layer 105 is shown, but it is common to configure a plurality of heating element layers, and the principle is the same.

Problems to be Solved by the Invention The thin film head structure shown in FIG. 5 has the advantage of being able to improve printing resolution because it allows fine pattern processing, but it has the following problems. There is.

In order to sufficiently transfer the heat of the thermal head 101 to the heat-sensitive medium 102, it is necessary to press the thermal head 101 against the heat-sensitive medium 102 with a considerably strong force.

That is, if the density of recording is increased by increasing the amount of heat generated by the thermal head 101, the heat generating portion of the thermal head 101 will become high in temperature and the life of the thermal head 101 will be shortened, so the pressing force cannot be reduced. . If the pressing force is insufficient, the heat will be transferred to the heat-sensitive medium 1.
02 is not sufficiently transmitted, the density of the recording becomes insufficient or a part of the recording becomes unclear C2. On the other hand, if the pressing force is large, the protective film layer 10 on the surface of the thermal head 101
7 violently rubs against the heat-sensitive medium 102, causing wear and significantly reducing the durability life of the thermal head 101. As described above, a decrease in the pressing force causes the recording to become unclear, and an increase in the pressing force causes a problem in that the durable life of the thermal head 101 is shortened. In the configuration of the conventional example described above, the heat-generating portion in contact with the heat-sensitive medium 102 in the protective film layer 107 is the concave portion 107a, so that heat transfer is poor, clear recording is achieved, and the durability of the thermal head 101 is improved. It was difficult.

In addition, the protective film layer 10 covering the end of the electrode 106
The film thickness No. 7 requires a sufficient thickness (generally 5 to 10 μm) to completely block the end of the electrode 106 from the outside air, and also has the problem of requiring a long time for the film forming process in terms of production.

Therefore, the present invention solves the above-mentioned problems of the conventional method, and makes it possible to record clearly, improve durability, and improve reliability and obtain high resolution. Furthermore, the present invention aims to provide a thermal head for heat-sensitive recording that can improve productivity.

゛ Means for solving the problems and the technical means of the present invention for solving the above problems are: an electrode provided on a head base; and a heat generating point between the electrodes on the head base. A heat-resistant, non-conductive material layer provided on the electrode, a heating element layer provided on the heat-resistant, non-conductive material layer, and a protective film layer provided on the heating element layer. be.

For production The effects of the above technical means are as follows.

In other words, since a heat-resistant, non-conductive material layer is provided at the heat-generating portion between the electrodes, there are few steps, and even if the heat-generating layer is extremely thin ((0.1 to 0.2 μm)), it can be uniform. It can be formed thickly, and the head surface becomes almost flat after the protective film layer is formed.Therefore, it improves the heat transfer efficiency when recording by transferring heat from the thermal head to the heat-sensitive medium. Clear recording can be made, and the pressing force during recording can be reduced, reducing wear and improving durability.Also, as mentioned above, the protective film layer can be formed thin and uniformly. High reliability can be ensured, resolution is improved, and productivity is also improved.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show a first embodiment of the present invention, with FIG. 1 being a sectional view and FIG. 2 being a plan view with the protective film layer removed.

As shown in FIGS. 1 and 2, an electrode 2 made of Cr-Cu material is placed on a head base 1 whose alumina surface is covered with glass.
were arranged in a grid pattern. These electrodes 2 have a film thickness of 0.5μ
The m1 width was 60 μm, and it was formed by Hol-IJ lithographic technology, and the heating area between the electrodes 2 on both sides was formed with a gap of 200 μm. Next, SiO is added to the gap where the heat is generated.
A heat-resistant, non-conductive material layer 3 made of Z material is sputtered through a mask to a width of 200 μm and a film thickness of 0.6 μm.
That is, it was formed to be slightly higher than electrode 2. This heat-resistant, non-conductive material layer 3 is formed so as to penetrate through the gap between the electrodes 2 on both sides.
It was formed into two stripes. Next, a heating element layer 4 made of 8i-Ta material is placed on the electrode 2 and the heat-resistant, non-conductive material layer 3.
was formed to have a thickness of 0.1 μm by sputtering and a width of 80 μm by photolithography. At this time, since the difference in level between the end of the electrode 2 and the end of the heat-resistant, non-conductive material layer 3 is as small as about 0.1 μm, there is no risk of defects such as disconnection. SIC and Si3N4 are applied from above this heating element layer 4 to cover the exposed parts of the heating element layer 4 and the head base 1.
A retention film layer 5 of approximately 3 μm is formed by sputtering.
The thickness was set at .

According to the above embodiment, 8i0z is placed at the heat generating part between the electrodes 2.
Since the heat-resistant, non-conductive material layer 3 is provided, when the heat generating layer 4 and the protective film layer 5 are sequentially provided on the layer 3, there is no recess on the surface of the head heat generating part, but rather, there is no recess as shown in 5a. The head was able to protrude, making good contact with the heat-sensitive medium, and enabling clear recording without pressing the head against the heat-sensitive medium with strong force. Furthermore, since there is almost no step difference at the end of the electrode 2, a sufficient hermetic protection effect for the electrode 2 and the heating element layer 4 can be obtained even if the thickness of the protective film layer 5 is half that of the conventional one. Furthermore, since the protective film layer 5 could be made thinner, the heat conduction response to the heat-sensitive medium was improved, and the resolution could be improved. Further, since the heating element layer 4 was provided on the electrode 2, the electrode 2, which is easily oxidized, was protected, and the occurrence of electrical contact and oxidative corrosion during use due to high temperatures could be reduced.

Note that in the above embodiment, the heat-resistant, non-conductive material layer 3 was provided after the electrode 2 was provided, but the heat-resistant, non-conductive material layer 3 was provided first,
Thereafter, electrodes 2 may be provided on both sides. In addition, the thickness of the heat-resistant, non-conductive material layer 3 is set according to the thickness of the electrode 2.
It is fine as long as the difference in height is small, whether it is higher or lower than the height of
As mentioned above, it is desirable to form the heat-resistant, non-conductive material layer 3 slightly higher than the electrode 2 in terms of heat transfer.

Effects of the Invention As described above, according to the present invention, electrodes are provided on the head base, a heat-resistant, non-conductive material layer is provided at the heat-generating portion between the electrodes, and a heat-generating layer and a protective film layer are sequentially formed from above. This eliminates the need for recesses in heat-generating areas that come into contact with the heat-sensitive medium.
Clear recording can be performed without requiring strong pressing force, and durability can be improved. Furthermore, since high reliability can be ensured even if the protective film layer is thinner than before, the recording resolution can be improved and the weather resistance of the electrodes can also be improved. Furthermore, since the step difference at the end of the electrode is reduced, the protective film layer can be formed to have a substantially uniform thickness, and productivity can be improved.

[Brief explanation of drawings]

1 and 2 show a thermal head for heat-sensitive recording according to an embodiment of the present invention, in which FIG. 1 is a sectional view, FIG. 2 is a plan view with the retention film layer removed, and FIGS. The figures show a conventional thermal head for heat-sensitive recording, with Figure 3 being a perspective view and Figure 4 being a perspective view.
The figure is a plan view, and FIG. 5 is an enlarged sectional view. DESCRIPTION OF SYMBOLS 1... Head base body, 2... Electrode, 3... Heat-resistant, non-conductive material layer, 4... Heat generating layer, 5... Protective film layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3

Claims (4)

[Claims] (1) An electrode provided on the head base; a heat-resistant, non-conductive material layer provided on the head base at the heat-generating portion between the electrodes; 1. A thermal head for heat-sensitive recording, comprising: a heat generating layer; and a protective film layer provided above the heat generating layer. (2) The thermal head for heat-sensitive recording according to claim 1, wherein the heat-resistant, non-conductive material layer is provided in a striped pattern. (3) The thermal head for heat-sensitive recording according to claim 1 or 2, wherein the heat-resistant, non-conductive material layer is made of glassy ceramic. (4) The thermal head for heat-sensitive recording according to any one of claims 1 to 3, wherein the heat-resistant, non-conductive material layer is formed slightly higher than the electrodes.