JPH05270034A - Thermal head - Google Patents

Abstract

PURPOSE:To perform high-grade printing by shortening the peeling distance of an ink ribbon up to a heating resistor and a substrate edge by shifting the heating peak part of the heating resistor toward the substrate edge. CONSTITUTION:A glaze layer is formed to the end part of the surface of a substrate 1 and a plurality of heating resistors 2 are arranged on the upper surface of the glaze layer and the common electrode connected to the respective heating resistors is provided on the side of a substrate edge 1a and individual electrodes 4 are provided on the other side and the heating resistors 2 are formed so that the width dimension of each of them on the side of the common electrode 3 is smaller than that of each of them on the side of the individual electrodes 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head,
In particular, the present invention relates to a thermal head capable of increasing the temperature distribution on the common electrode side when the heating resistor generates heat.

[0002]

2. Description of the Related Art Generally, a thermal head mounted on a thermal transfer printer has, for example, a plurality of heating resistors linearly arranged on the same substrate and is energized and heated according to desired printing information. It is used for transfer recording on plain paper through an ink ribbon.

FIG. 3 shows a conventional thermal head. The upper surface of a glaze layer (not shown) made of glass or the like and having an arc-shaped cross section is formed on the upper surface of an insulating substrate 1 made of ceramics such as alumina. Are formed by depositing heat-generating resistors 2, 2 ... Made of Ta2N or the like by vapor deposition, sputtering, etc., and then etching them to form a plurality of linearly aligned parts. The common electrode 3 connected to each heating resistor 2 is connected to the substrate edge side, and the individual electrode 4 for independently energizing each heating resistor 2 is connected to the other side. The common electrode 3 and the individual electrode 4 are made of, for example, aluminum, copper, gold, or the like, and are deposited by vapor deposition, sputtering or the like, and then formed into a pattern of a desired shape by etching.

In a thermal transfer printer, a heat resistance selected based on a predetermined print signal is applied in a state where such a thermal head is pressed against a predetermined sheet conveyed to the platen portion via an ink ribbon. By energizing the individual electrodes 4 of the body 2, the ink of the ink ribbon is melted and transferred to perform desired printing on the paper.

In recent years, even in such a thermal transfer printer, there is a demand for higher quality printing, and in order to realize this, a substrate for peeling the ribbon from the center of the heating resistor 2 of the thermal head is used. The size up to the edge 1a is reduced, the glaze layer 2 is projected, and the heating resistor 2 is formed on this projected portion.

With such a structure, the ink ribbon is peeled off from the recording paper before the ink is cooled and solidified, and the pressure contact load to the platen is concentrated on the heat generating portion of the thermal head. Good printing can be performed on plain paper using a ribbon, and the substrate edge 1a for peeling the ink ribbon from the heating resistor 2 is used.
The shorter the dimension, the higher the print quality.

[0007]

However, in the above-mentioned conventional thermal head, the dimension from the heating resistor 2 to the substrate edge 1a from which the ink ribbon is peeled off is large enough to form a large number of dots unless the common electrode 3 is formed. Since a common drop occurs at the time of energizing the device and a predetermined amount of heat generation cannot be obtained, approximately 200 μm is required, and it is difficult to further reduce this dimension.

[0008]

According to the present invention, in the above-mentioned conventional thermal head, the width dimension of the heating resistor 2 between the common electrode 3 and the individual electrode 4 is formed uniformly. Paying attention to the fact that the temperature peak at the time of heat generation in the heat generating resistor 2 is located substantially at the center of the heat generating resistor 2, and by shifting the heat generating center of the heat generating resistor 2 to the common electrode 3 side,
The purpose of the present invention is to provide a thermal transfer printer of high print quality by reducing the dimensions from the center of heat generation to the substrate edge 1a. A glaze layer is formed on the surface of the substrate 1 and a plurality of glaze layers are formed on the upper surface of the glaze layer. The heating resistors 2 are arranged, and the common electrode 3 and the individual electrode 4 connected to each of the heating resistors 2 are arranged.
In the thermal head formed by connecting and, the heating resistors 2 are shaped such that the common electrode 3 side is narrower in width than the individual electrode 4 side.

[0009]

The above-mentioned means operates as follows.

Since the center of heat generation of the heat generating resistor 2 is where the width dimension of the heat generating resistor 2 is the smallest, the heat generating peak portion is shifted to the common electrode 3 side, and the common electrode 3 having the same width as the conventional thermal head is formed. Even if formed, the distance from the center of heat generation to the substrate edge 1a becomes pseudo short.

[0011]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows an embodiment of a thermal head according to the present invention. On the upper surface of a substrate 1, a glaze layer 6 made of glass or the like having an arc-shaped cross section is formed.
A heating resistor 2 made of Ta2N or the like is deposited by vapor deposition, sputtering, or the like, and then etched to form a plurality of aligned straight lines. A common electrode 3 connected to each heating resistor 2 is connected to one side of the heating resistor 2 on the substrate edge side, and an individual electrode 4 for independently energizing each heating resistor 2 is connected to the other side. Has been done. The common electrode 3
The individual electrode 4 is made of, for example, aluminum, copper, gold, or the like, and is formed into a desired pattern by etching after being deposited by vapor deposition, sputtering, or the like.

Further, the heating resistor 2 is gradually narrowed so that the shape thereof in the vertical width dimension is smaller on the common electrode 3 side than on the individual electrode 4 side (see FIG. 1).
Alternatively, the notch 5 is formed near the common electrode 3 side (see FIG. 2).

Next, the operation of this embodiment will be described.

In the present embodiment, the heating resistor 2 selected on the basis of a predetermined print signal in a state in which the thermal head is pressed against a predetermined sheet conveyed to the platen portion via an ink ribbon (not shown). By energizing the individual electrodes 4, the ink of the ink ribbon is melted and transferred, and desired printing is performed on the paper.

In this case, in this embodiment, since the width dimension of the heating resistor 2 on the common electrode 3 side is shortened, the heating peak portion of the heating resistor 2 shifts to the common electrode 3 side (FIG. 3)), so heat generation peak and substrate edge 1
The distance between a (peeling part) can be shortened.

Therefore, in this embodiment, since the heat generation peak portion of the heat generation resistor 2 can be shifted to the common electrode 3 side, the distance from the melting of the ink ribbon to the peeling portion can be shortened, and the ink of the ink ribbon can be shortened. Since it can be reliably peeled off from the paper in a melted state, high print quality can be obtained.

[0018]

As described above, in the thermal head according to the present invention, since each heating resistor has a shape in which the width of the common electrode side is narrower than that of the individual electrode side, a heating peak portion of the heating resistor is formed. Since the distance between the substrate edges can be shortened, it can be reliably peeled from the paper when the ink on the ink ribbon is melted, resulting in high-quality printing with no print unevenness. Play.

[Brief description of drawings]

FIG. 1 is a partial front view showing an embodiment of a thermal head according to the present invention.

FIG. 2 is a partial front view showing another embodiment of the thermal head according to the present invention.

FIG. 3 is a diagram showing a temperature distribution of a heating resistor according to the present invention.

FIG. 4 is a partial front view showing a conventional thermal head.

[Explanation of symbols]

 1 substrate 1a substrate edge 2 heating resistor 3 common electrode 4 individual electrode 5 notch

Claims (2)

[Claims] 1. A glaze layer is formed on an end portion of a surface of a substrate, a plurality of heating resistors are arranged on an upper surface of the glaze layer, and a common electrode connected to each of the heating resistors is provided on a substrate edge side. A thermal head having individual electrodes connected to the other side, wherein each of the heating resistors has a shape in which the width of the common electrode side is narrower than that of the individual electrode side. 2. The thermal head according to claim 1, wherein a cutout portion is formed in the vicinity of the common electrode side of each of the heating resistors so that the width dimension thereof is narrower than that of the individual electrode side. Thermal head.