JPS6316273B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to thermal type printing heads.

In a thermal type printing head used for printing on thermal paper, the character shape of the type is heated by a heating element, and when it comes into contact with the thermal paper, it develops color according to the shape of the character. For this type of printing, there are two methods: one in which the heating element is constantly heated, and the other in which the heating element is instantaneously energized to generate heat only during printing. However, the former method poses a risk of fire or burns, and requires preheating at the beginning of use. There are drawbacks such as the need to keep In this respect, the latter method only instantaneously supplies a large amount of power, and the heat is generated in an extremely short period of time, so it does not have the drawbacks of the former method.

By the way, a configuration as shown in FIG. 4 has been considered as a conventional print head of this type for use in the latter method. In the figure, 1 is an insulating head board;
Reference numerals 2 and 3 denote electrodes for conducting electricity, 4 a resistance heating element, 5 an electric insulator, and 6 a metal type plate, on the surface of which a letter-shaped portion 7 is formed in a convex manner. The type plate 6 was then bonded to the surface of the insulator 4 with an adhesive.

However, when using a print head with such a configuration, although it is only necessary to heat the glyph portion 7, the heat generated in the heating element 4 is transferred to the electrical insulator 5,
Since the heat is conducted to the glyph 7 via the adhesive and the type plate 6, it takes time for the heat to be conducted.Also, considering the heat loss in the process of heat conduction, the electric power for the heat generation of the heating element 4 is reduced. We need to increase the supply of
Furthermore, due to heat accumulation in the type plate 6 combined with the supply of large electric power, the print density changes greatly when printing is repeated, and in order to make this density uniform, it is necessary to
There is the inconvenience of having to control the amount of power supplied.

The purpose of this invention is to increase the thermal efficiency of the print head.

The present invention is characterized in that metal shaped portions are formed on the surface of the heating element with an electrically insulating layer interposed therebetween.

Embodiments of this invention will be explained with reference to the drawings: 1
1 is a head substrate made of ceramic or the like; 12;
Reference numeral 13 represents an electrode for conducting electricity, and reference numeral 14 represents a resistance heating element.
These configurations are not much different from those shown in FIG. However, in this invention, an insulating layer 15 made of glass or the like with good thermal conductivity is formed on the surface of the heating element 14 by firing, and a convex shape portion 16 made of metal with good thermal conductivity is formed directly on the surface. do. To form the font portions 16, for example, silver paste may be printed in the shape of the font and fired, or silver paste may be applied to the entire surface of the insulating layer 15 and fired, and then the font portions may be left and other portions may be etched. Just remove it. These are carried out by methods well known in thick film and semiconductor technology. When the shape portion 16 is formed of silver paste, if it cannot be sufficiently thick, the surface of the shape portion 16 may be plated with another metal with good thermal conductivity, such as nickel, to form a double layer. . FIG. 3 shows an example of the structure, and 17 indicates a nickel layer. Incidentally, the entire surface of the insulating layer 15 may be plated with silver paste and further plated with nickel, and then etched according to the shape. Here, the word-shaped portion refers only to a convex portion that is directly formed in a convex shape on the surface of the insulating layer 15 and has a desired shape such as a character when viewed from above.

In the above configuration, when the electrodes 12 and 13 are connected to a power source for heat generation, a current flows through the heat generating element 14, which generates heat. The generated heat is conducted to the glyph portion 16 via the insulating layer 15 and heated. Therefore, when the character part 16 is in contact with the thermal paper, there is an instantaneous moment (several milliseconds to several hundred milliseconds) between the electrodes 12 and 13.
When a large current is applied to the font, the heated font portion 16 colors the thermal paper according to the shape of the font, allowing the desired printing to be performed.

In the configuration shown in the figure, if a thermal insulating layer (for example, glass) having poorer thermal conductivity than the head substrate 11 is formed on the surface of the head substrate 11, the heating element 14
Since the heat from the head board 11 is prevented from being conducted to the head board 11 as much as possible, and therefore the heat loss can be reduced accordingly, the power supply can be reduced compared to the case where no thermal insulating layer is provided. It is convenient to be able to do this.

As detailed above, according to the present invention, the shape portion and the thermally conductive electrical insulating layer are integrally formed, and the electrical insulating layer is formed on the surface of the resistance heating element. The heat from the heating element is now directly conducted to the glyphs through the electrical insulation layer, so there is no need to heat the entire metal type plate in order to heat the glyphs, as was the case in the past. Since there is no heat, the thermal efficiency when heating the character part is higher than that of conventional ones, and along with this, the required printing can be done with low power, and the amount of heat stored is also reduced due to the low power supply. , even when printing repeatedly, there is no unevenness in print density, and no current flows on the surface, so
This has the effect that even if someone were to touch this part, there would be no risk of electric shock.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of the invention, Fig. 2 is a perspective view showing an embodiment of the invention;
3 is a sectional view of another embodiment, and FIG. 4 is an exploded perspective view of the conventional example. 11... Head substrate, 12, 13... Electrode, 1
4... Heating element, 15... Electrical insulating layer, 16... Character shaped portion.

Claims (1)

[Scope of Claims] 1. A resistance heating element that generates heat when energized is formed on the surface of the head board, a thermally conductive electrical insulating layer is formed on the surface, and a metal A thermal type printing head with a convex shape. 2. A thermal type printing head according to claim 1, wherein the glyph portion is a double layer of metal.