JPH0667627B2 - Thermal head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head, and more particularly to a thermal head configured to transmit a predetermined energization signal to a heating resistance element via a flexible wiring sheet.

[Conventional technology]

Generally, a transfer type thermal recording type printer uses an ink donor sheet coated with a heat-meltable ink as an ink ribbon. This type of printer has a configuration in which the ink of an ink donor sheet is transferred to a recording sheet and recorded by Joule heat generated by passing a pulsed current through a heating resistance element of a thermal head.

This transfer type thermal recording type printer has many advantages such as a simple mechanism and less noise. Therefore, it has a wide range of application fields from large line printers to ultra-compact and lightweight printers. Particularly in recent years, printers have become indispensable for information devices such as Japanese word processors and personal computers.

On the other hand, the transfer-type thermal recording method has a drawback that rough paper having poor surface smoothness cannot be printed clearly due to the unevenness of the contact surface. On the other hand, these days,
As shown in FIGS. 3 to 5, a technique has been disclosed in which the above-mentioned drawback is improved by setting a predetermined elevation angle α with respect to the recording surface.

To further explain this, in FIG. 3 to FIG.
The thermal head 20 has a structure in which the heating resistance element 10 is formed near the edge of the head chip 21 by a photoetching technique, and the head chip 21 is attached to the heat sink 22 at an angle. For this reason, when the thermal head 20 shown in FIGS. 3 to 5 is used, the head chip surface of the thermal head 20 is diagonally opposed to the platen, so that the contact point to the recording paper is made. The contact pressure (contact pressure) of the heating resistance element 10 portion provided increases. Therefore, even if the recording paper is rough paper, ink can be relatively easily transferred to all the recording positions under the same conditions.

In the conventional example shown in FIGS. 3 to 5, a plurality of lead wires from the heating resistance element 10 of the head chip 21 are guided to the outside through the flexible wiring sheet 25. The flexible wiring sheet 25 is mounted on the heat sink 22 while being supported by the reinforcing plate 26. In this case, the wiring sheet 25 and the lead portion 21A of the head chip 21 are electrically connected by soldering. Further, in FIG. 3, h indicates the receding dimension of the edge from the reference surface S due to the inclination of the surface of the head chip 21.

[Problems to be solved by the invention]

In such a conventional example, since the surface of the head chip 21 described above has a constant elevation angle α, the wiring sheet 25 is mounted in a twisted state by the elevation angle α.

Therefore, due to the twist of the wiring sheet 25, there is a disadvantage that a mounting portion such as solder is peeled off due to a slight external vibration, a change in wind pressure, or the like.

In addition, when assembling or maintaining, the wiring sheet 25 must be twisted once to be aligned with the surface of the head chip 21. Therefore, the twisting and mounting work of the wiring sheet 25 requires many steps. Yes, it was one of the causes of the high cost.

[Object of the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the disadvantages of the conventional example, and particularly to provide a thermal head which is easy to assemble and durable.

[Means for solving problems]

In the present invention, the thermal resistance element is provided at the end of the head chip surface having a constant elevation angle α with respect to the reference surface,
A wiring sheet is connected to the lead portion on the head chip surface. The sheet surface of this wiring sheet is fixed to the reference surface or a surface substantially parallel to the reference surface. Then, a configuration is adopted in which about 1/2 of the head chip surface is projected outward from the reference surface while maintaining the same elevation angle α with respect to the reference surface of the thermal head.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Here, the same reference numerals are used for the same constituent members as those in the conventional example described above.

In the embodiment shown in FIGS. 1 and 2, the thermal head 1 supports a head chip 21 having a heating resistance element 10 arranged near the edge and the head chip 21 at a predetermined elevation angle α with respect to a reference plane S. And a heat sink 2. The heating resistor element 10 is formed by the photoetching technique as in the conventional example described above.

The head chip 21 includes a lead portion 21 from the heating resistance element 10.
A is provided. Further, the reference plane S is the reinforcing plate 26.
It is flush with the outer surface of.

The wiring sheet 5 is screwed to the outer surface of the reinforcing plate 26. The wiring sheet 5 has a convex shape in this embodiment, and the protruding portion is soldered to the lead portion 21A of the head chip 21 for each lead wire.

Here, the head chip 21 is provided so as to project toward the outside (the platen side) from the above-described reference surface S while the elevation angle α is maintained at about 1/2 of the print surface side. For this reason,
The wiring sheet 5 is twisted as a whole by the angle α with the one edge as a reference, whereas in the present embodiment, the wiring sheet 5 is twisted as a whole by the angle α with the central portion as a reference. ing.

Therefore, in the above-described conventional example, the other end of the wiring sheet 5 is stretched and twisted by the dimension h, whereas in the present embodiment, the extension of each of the one end and the other end is h / 2, thus In general, the rate of elongation of each part due to the twist is halved. For this reason, in the present embodiment, the inconvenience that the soldering is peeled off due to the rigidity of the wiring sheet 5 is significantly reduced, and when the wiring sheet 5 is mounted, the pattern is adjusted according to the pattern of the lead portion 21A of the head chip 21. It is easy, and there is an advantage that the assembly work can be remarkably facilitated and the process can be shortened.

〔The invention's effect〕

According to the invention, about 1 of the head chip surface having an elevation angle α
/ 2 is projected from the reference plane to the outside, the elongation of each part due to the twisting of the wiring sheet is halved compared to the conventional example, so that not only the assembly work is extremely easy but also the wiring It is possible to provide an excellent and durable thermal head capable of significantly reducing sheet peeling accidents.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, and FIG.
3 is a plan view showing a conventional example, FIG. 4 is a front view of FIG. 3, and FIG. 5 is a perspective view showing a conventional example. 5 ... Wiring sheet, 10 ... Heating resistance element, 21 ... Head chip, 21A ... Lead part, S ... Reference plane.

Claims (1)

[Claims] 1. A thermal resistance element is provided at an end of a head chip surface having a constant elevation angle α with respect to a reference surface, and
In a thermal head formed by connecting a wiring sheet to the lead portion on the head chip surface and fixing the sheet surface of the wiring sheet to the reference surface or a surface substantially parallel to the reference surface, with respect to the reference surface of the thermal head A thermal head characterized in that about half of the head chip surface is projected outward from the reference surface while maintaining the same elevation angle α.