JPH058419A - Thermal printing head - Google Patents

Abstract

PURPOSE:To reduce density in wiring of a common terminal in a thermal printing head, to reduce the number of contact positions of the common terminal to an outside-leading terminal, and to make a heating value between each individual terminal and the common terminal almost uniform. CONSTITUTION:A common terminal 3 and an individual terminal 4 are jointly provided by superimposing them on a resistant film 2. A plurality of common terminals 3 are connected to one another with a connecting part and a side fringe of the connecting part 8 which connects adjacent common terminals 3 is made to be of a semicircular arc. Further, at least, one common terminal 3 among the common terminals 3 connected with the connecting part 8 is extended with the connecting part 8 to be connected to an outside leading terminal 6.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to thermal printheads.

[0002]

2. Description of the Related Art In a thermal print head, a plurality of individual terminals and a common terminal are alternately arranged in parallel on the surface of an insulating substrate, and a strip-shaped resistance film is formed so as to overlap with each terminal. well known.

In the thermal print head having such a structure, it is sometimes required to install the resistive film as close as possible to one edge of the substrate. In that case, all of the terminals are It is necessary to pull out from the side edge of the resistive film opposite to the above edge.

FIG. 3 shows a conventional thermal print head of this type, wherein 1 is an insulating substrate made of ceramic or the like,
Reference numeral 2 is a heat-generating resistance film formed on the surface in the form of a strip of thick film, 3 is a common terminal, and 4 is an individual terminal.
The common terminals 3 and the individual terminals 4 are alternately formed on the surface of the substrate 1, and the resistance film 2 is formed so as to overlap the terminals.

When the resistance film 2 is installed close to one edge 1A of the substrate 1 as shown in the figure, the terminals 3 and 4 are arranged from the side edge of the resistance film 2 opposite to the edge 1A. Try to withdraw. In the figure, when the individual terminals 4 are formed on the surface of the substrate 1,
An insulating film 5 is formed so as to cross each individual terminal 4, an external lead terminal 6 is formed on the surface of the insulating film 5, and then the external lead terminal 6 and each common electrode 3 are connected by wire bonding. I have to. Reference numeral 7 is a wire used for the connection. Actually, a protective film, a wear resistant film and the like are formed on these surfaces, but these are omitted in the figure.

According to this structure, if a voltage is applied between the external lead-out terminal 6 and one selected individual terminal 4,
Current flows through the resistive film portions on both sides of the individual terminal 4,
The portion where this current flows generates heat. When the heat from the heat generating portion is conducted to the thermal paper, the conductive portion is colored. In this way, the required printing is performed.

By the way, as can be understood from this configuration, when the resistive film portion partitioned by the adjacent terminals 3 and 4 is used as a unit area, two units on both sides of the individual terminal 4 are sandwiched therebetween. One print dot is made with a region, but in such a configuration, one common terminal 3 is required for each print dot, and all the common terminals 3 are individually connected to the external lead terminal 6. There must be.

Therefore, not only is the wiring density of the terminals 3 and 4 increased and the patterning thereof is troublesome, but also the number of connection points between the common terminals 3 and the external lead-out terminals 6 is large, so the connection work is also troublesome. Met.

[0009]

SUMMARY OF THE INVENTION According to the present invention, the wiring density of the common terminal is reduced, the number of connection points between the common terminal and the external lead terminal is reduced, and heat generated between the individual and common terminals is reduced. The purpose is to make the amount almost uniform.

[0010]

According to the present invention, a resistance film for heat generation and a plurality of individual resistance films formed so as to overlap with the resistance film and to be alternately positioned along the width direction of the resistance film. And a plurality of common terminals, the plurality of common terminals of the common terminals are continuous by a continuous portion formed so as to overlap the resistance film, and the side of the continuous portion that connects adjacent common terminals The edge has a semi-circular shape with a radius corresponding to the distance between the individual terminal and a common terminal adjacent to the individual terminal, and at least one of the common terminals connected by the continuous portion is extended. Then
It is characterized in that the extended common terminal is connected to an external lead terminal.

[0011]

Embodiments of the present invention will be described with reference to FIGS. In addition, the parts denoted by the same reference numerals as those in FIG. 3 indicate the same or corresponding parts. In the present invention, the common terminals 3 and the individual terminals 4 are formed along the width direction of the resistance film 2 and alternately. The plurality of common terminals 3 are connected by the connecting portion 8.

A plurality of common terminals 3 connected to the connecting portion 8
Any one of them is extended, and the extended common terminal (3A in the illustrated example) is connected to the external lead terminal 6 by wire bonding.

According to the above structure, the continuous portion 8 is connected to the external lead-out terminal 6 via the common terminal 3A. Therefore, when a voltage is applied between the external lead-out terminal 6 and one selected individual terminal 4, the resistance existing between the selected individual terminal 4 and the common terminals 3 on both sides of the selected individual terminal 4 is applied. An electric current mainly flows through the membrane 2, and the portion where the electric current flows generates heat. Due to this heat generation, required printing is performed.

In this configuration, it is not necessary to connect all of the common terminals to the external lead terminals 6 as shown in FIG. 3, so it is not necessary to lead all of the common terminals close to the external lead terminals. Therefore, the wiring density for connecting the common terminal to the external lead terminal is low, and at least one of the plurality of common terminals may be connected to the external lead terminal 6, so that the number of connections is small. .

It is easily understood that the number of common terminals 3 connected to the external lead-out terminal 6 via one common terminal 3A is substantially determined by the current capacity and electric resistance of the continuous portion 8 and the common terminal 3A. It is about to be done.

In the present invention, as shown in FIG. 1, the side edge of the continuous portion 8 connecting the common terminals 3 adjacent to each other has a radius corresponding to the distance between the individual terminals 4 and the common terminal 3. It is semicircular. According to this, in the resistance film portion forming one print dot, the distance between the terminals 3 and 4 becomes equal, which is convenient because the amount of heat generation is substantially uniform.

In the illustrated embodiment, both the individual and common terminals are formed on the surface of the substrate 1, but instead of this, the resistance film 2 is formed.
It may be formed on the surface of.

[0018]

As described above in detail, according to the present invention, the wiring density of the common terminal can be reduced and the number of connection points between the common terminal and the external lead terminal can be reduced as compared with the conventional configuration. In addition, there is an effect that the heat generation amount between the individual and common terminals can be made substantially uniform.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view of FIG.

FIG. 3 is a plan view of a conventional example.

[Explanation of symbols]

 1 substrate 2 resistive film 3 common terminal 4 individual terminal 6 external lead-out terminal 8 continuous section

Claims (1)

Claim: What is claimed is: 1. A resistance film for heat generation, a plurality of individual terminals formed so as to overlap with the resistance film and to be alternately positioned along the width direction of the resistance film, A plurality of common terminals, a plurality of common terminals among the common terminals are continuous by a continuous portion formed so as to overlap the resistance film, and a side edge of the continuous portion connecting adjacent common terminals is formed. , A semi-arcuate shape having a radius corresponding to a distance between the individual terminal and a common terminal adjacent to the individual terminal, and further extending at least one common terminal of the common terminals continuous by the continuous portion, A thermal print head that connects this extended common terminal to an external lead terminal.