JPS5918228B2 - Thin film thermal head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a configuration of a heat generating portion of a thermal head for various heat-sensitive recordings, particularly a thin film type thermal head.

As is well known, current thermal recording methods require maintenance and
As a free recording method, it is being applied in various fields such as recorders, printers, and faxes.

Various types of thermal heads have been developed for this purpose, but these heads can be classified according to the method of forming the heating element material: a) thin film type b) thick film type c) silicon type being classified.

Among these, the thin-film thermal head is the most promising as a method that can cover everything from popular models to high-end models in the future, in that a fine heating resistor can be easily formed.

FIG. 1 shows the structure of the heating element of a conventional thin-film thermal head.

In FIG. 1, 1 is an insulating substrate made of, for example, alumina;
2 is an insulating layer such as glass, which is useful for smoothing the surface of the insulating substrate 1 and improving the thermal efficiency of the thermal head; 4 is an electrode; 5 is a protection for improving the heat resistance of the heating resistor 3; Layer 6 is an abrasion-resistant layer for protecting the heating resistor 3 from contact abrasion caused by the heat-sensitive recording paper.

0 As can be seen from the above description, if an appropriate method is used, the roles of the insulating layer 2 and the protective layer 5 can be shared by the substrate 1 and the wear-resistant layer 6, respectively.

Thermal with the heating element configured as shown in Figure 1...5
Heads or thermal heads configured by integrating the protective layer 5 and the wear-resistant layer 6 have already been developed as described above, but these heads have the following problems.

This problem is the problem i0 of paper gas generated during thermal recording.

Figure 2 schematically shows how paper gas is generated. In Figure 2, □ shows the heating element part as a whole as shown in Figure 1, 6a is the surface of the wear-resistant layer of the heating element part □, 6
b is a depression caused by the thickness of the electrode 4 in FIG. 1, 8 is a thermosensitive recording paper, Ba 5 is a base paper, 8b is a coloring layer formed on the base paper Ba, and 9 is a thermal recording paper 8 - The rollers 10 and 11 used to press the head and feed it are paper gas. In Figure 2, the heating element part 7 of the thermal head
By rotating the roller 9 in the direction of the arrow while applying an appropriate electric power to the thermosensitive recording paper 8, arbitrary recording can be performed on the thermal recording paper 8, but at the same time paper gases 10 and 11 as shown in FIG. 2 are generated. do. The generation of paper gas 10 and 11 in Fig. 2 is illustrated for various types of fax thermal heads, but two types of paper gas are also generated in thermal heads for other purposes. It will be done. and,
Naturally, the generation of paper gas reduces the quality of thermal recording, so it is desirable to develop recording paper that generates less paper gas. Paper gas 10, 11 in the situation shown in Figure 2
The occurrence of this cannot be avoided. In FIG. 2, the heating element portion 7
The amount of paper gas 10 generated on the surface 6a varies depending on the recording density, and as the thermosensitive recording paper 8 moves, it tends to be dragged and moved or fallen off. Further, the adhesion force of this paper gas 10 to the wear-resistant layer is also small. Therefore, this paper gas 1
The deterioration in recording quality due to 0 can be prevented to a considerable extent by improving the paper feeding mechanism, such as the roller material, roller diameter, and pressure force, and by periodically cleaning the thermal head. On the other hand, paper gas 1 generated in the recess 6b of the wear-resistant layer
The amount of 1 does not change much and is mostly fixed.

It can be considered that this increase is suppressed by contact abrasion with paper. Further, this paper gas 11 is strongly attached to the recess 6b of the wear-resistant layer, and if it is forcibly removed, it often causes damage to the thermal head. Since this paper gas 10 is generated by the depressions 6b in the wear-resistant layer, it can be reduced by reducing the depressions 6b to improve contact with the paper.

The present invention provides a thin film type thermal head constructed to achieve these objectives.

The present invention is a thin film type thermal head characterized in that a wear layer is formed on a wear-resistant layer, and the structure thereof will be explained below with reference to FIG. 3 showing an embodiment of the present invention.

In FIG. 3, 12 is an insulating substrate such as alumina, 13
14 is an insulating layer such as a glass layer, Ta, N, NiCr, S
A heating resistor such as i-Ta, 15 a multilayer electrode such as Cr-Au, 16 a protective layer of the heating resistor 14 such as SiO2, 17 a wear-resistant layer such as SiCl alumina, and 18 a main point of the present invention. This is a wear layer formed on the wear-resistant layer 17.

As described above, the wear-resistant layer 17 may also have the effect of the protective layer 16, and in that case, the protective layer 16 is omitted. The wear layer 18 is desirably thicker than the recess determined by the thickness of the electrode 15, and naturally the wear layer 17
It is necessary that the material be less hard and easily abraded. For example, when using SiC as the wear-resistant layer 17, SiO2, Ta2
Examples include O, TiO2, zrO2, sil glass, and the like. Further, this wear layer 18 may be made of a good electrical conductor such as metal as long as it is formed so as not to overlap with the electrode 15. now,
In the configuration of the thin film thermal head as described above,
The state of contact between the thermal head and the heat-sensitive recording paper at the beginning of printing is as shown in FIG.

In FIG. 4, reference numeral 19 indicates the heating element portion in FIG. 3, excluding the wear layer 18. 18a is the surface of the wear layer, 18b is a depression caused by the thickness of the electrode 15 shown in FIG. 3, 20 is a thermosensitive recording paper, and 21 is a paper feeding roller.

Here, when printing is performed by rotating the roller 21 in the direction of the arrow, paper gases 22 and 23 are generated in the same manner as explained in FIG. However, since the abrasion layer 18 is formed on the surface of the head, the abrasion layer 18 wears out as the printing time elapses, resulting in a state as shown in FIG.
will come into full contact with the head. In FIG. 4, reference numeral 18' indicates a portion of the worn layer that is removed due to wear.
In addition, in Fig. 5, the wear layer 1 as the printing time elapses.
8, the abrasion progresses further, but when the abrasion progresses to the position shown by the broken line 11'', the abrasion speed is drastically reduced because a wear-resistant layer is formed on the upper layer of the heating element part 19, and a stable printing condition is achieved. is obtained.

The present invention is constructed as described above, and by bringing the thin film type thermal head into close contact with the thermal recording paper, a'). The print head no longer blurs and the dots become clearer.

b) High-density printing is possible with low power consumption.

c), printing response is improved.

d) Due to the above-mentioned matters, it is possible to increase the printing speed.

The following effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional thin-film thermal head, FIG. 2 is a cross-sectional view of the same in the printing state, and FIG. 3 is a cross-sectional view of an embodiment of the thin-film thermal head according to the present invention.
FIG. 4 is a sectional view in the same initial printing state, and FIG. 5 is a sectional view in the printing state after the same period of time has elapsed. 12...Insulating substrate, 13...Insulating layer, 14...Heating resistor, 15...Electrode, 17...Wear resistance Layer, 18...wear layer.

Claims (1)

[Claims] 1. A heating resistor, an electrode, and an abrasion-resistant layer are formed on an insulating substrate or a substrate on which an insulating layer for heat insulation is formed, and a heat-generating resistor, an electrode, and an abrasion-resistant layer are formed on the abrasion-resistant layer. A thin film type thermal head characterized by forming an abrasion layer made of a material that is easy to wear.