JPH04244861A - Thermal head - Google Patents

Abstract

PURPOSE:To realize a thermal head improved in the concn. of pressure to a heating part and showing good printing efficiency in low cost as compared with a conventional one. CONSTITUTION:In a thermal head wherein a glaze layer 2 is formed on an insulating substrate 1 and a resistance film layer 3 is formed on the glaze layer 2 and a common electrode 5 and individual electrodes 6 are formed on the resistance film layer so as to provide the interval for forming a heating part 4 and a protective film 7 is formed so as to cover the heating part 4, the common electrode 5 and the individual electrodes 6, the heating part 4 is formed to the corner part 23 being the crossing of the upper surface part 21 and side surface part 22 of the glaze layer 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal print head with improved printing efficiency.

0002

2. Description of the Related Art Conventional thermal heads include partial glaze type, double partial glaze type, and true edge type. As shown in FIG. 11, the partial glaze type thermal head has a resistive film layer 3 formed on the upper surface of the edge of a substrate 1 on a partial glaze layer 2 with a width of about 300 to 1200 μm and a curvature. In order to form a heat generating part 4 on the top of the glaze layer 2 of the film layer 3, a common electrode 5 and an individual electrode 6 are formed on both sides with the top of the glaze layer 2 placed, and the upper surface is further covered with a protective film 7. It is something that Further, in the double partial glaze type thermal head, as shown in FIG. 12, only the lower glaze layer 2a of the partial glaze type heat generating part 4 is raised into a convex shape by glaze etching or the like.

[0003] A true edge type thermal head is shown in Fig. 13.
As shown in the figure, a glaze layer 2 and a heat generating part 4 are provided on the end surface of a substrate 1. In addition, as a modification, as shown in FIG. 14, a part of the edge of the substrate 1 is cut diagonally, and glaze layers 2A, 2B, and 2C are formed not only on the upper surface 1A of the substrate 1 but also on the slope 1B and the end surface 1C. , there is one in which a heat generating portion 4 is formed on the slope 1B.

0004

[Problem to be solved by the invention] In the thermal head,
In order to print on rough paper and improve printing efficiency, it is necessary to concentrate the pressure of the heating resistor on the ribbon, transfer paper, and platen. As shown in FIG. 15, in the partial glaze type, the glaze layer 2 having the heat generating part 4 comes into contact with the platen rubber 10 over a wide range via the ink ribbon 8 and the transfer paper 9, and the pressure on the heat generating part 4 is concentrated. The problem is that it is not possible to obtain enough. This problem can be solved to some extent by using the true edge type. However, in the true-edge type shown in FIG. 13, the current substrate thickness is about 2 mm, which is rather thick, and the original characteristics of the true-edge type cannot be fully exhibited. In addition, a point common to the thermal heads shown in Figures 13 and 14 is that the side edges of the substrate are processed and printing is performed on the edges, so it is not possible to take out many pieces from a large substrate at once. As a result, there was a problem in that the cost per piece increased.

[0005] The present invention has been made in view of the above problems, and it is possible to realize a product with good pressure concentration on the heat-generating part, and therefore with good printing efficiency, and at a lower cost than the conventional one. The purpose is to provide a thermal head that can

[0006]

[Means and effects for solving the problems] The thermal head of the present invention includes forming a glaze layer on an insulating substrate, forming a resistive film layer on the glaze layer, and forming a heat generating portion on the resistive film layer. A common electrode and individual electrodes are formed at intervals, and a protective film layer is formed covering the heat generating part, the common electrode, and the individual electrodes, wherein the heat generating part is formed at a corner part of the glaze layer. ing.

[0007] According to this thermal head, the heat generating portion is provided at the corner portion of the glaze layer where the glaze top surface portion and the glaze side surface portion or the glaze top surface portion and the glaze slope portion intersect. Wasteful pressure distribution to the substrate part is eliminated, and pressure is sufficiently concentrated to the heat generating part. In addition, by half-cutting the glaze substrate,
Since the multi-chip substrate can be transferred to the next process of film formation and patterning without being divided, mass production is possible and the cost per piece is low.

[0008]

[Examples] The present invention will be explained in more detail with reference to Examples below. FIG. 1 is a sectional view of a main part of a thermal head showing an embodiment of the present invention. The thermal head of this embodiment has a substrate 1 on which an underglaze layer 2 is formed.
The basic structure in which the resistive film layer 3, common electrode 5, and individual electrodes 6 are formed and further covered with a protective film 7 is not particularly different from the conventional one.

The thermal head of this embodiment is characterized by a corner portion 23 where the top surface 21 and side surface 22 of the glaze layer 2 intersect.
The heat generating part 4 is formed in the. That is, the resistive film layer 3
is formed from the top surface 21 of the glaze layer 2 to the side surface 22, a common electrode 5 is formed on the side surface 22 of the glaze layer 2, an individual electrode 6 is formed on the top surface 21 of the glaze layer 2, and a heat generating portion 4 is formed on the corner portion 23. It is configured to be located.

FIG. 2 is a sectional view of a main part of a thermal head according to another embodiment of the present invention. This thermal head has a partial glaze 2, whereas the one shown in FIG. This thermal head has a shape obtained by cutting vertically from the top of the partial glaze 2 including the substrate 1 of the conventional thermal head shown in FIG. Therefore, the thickness of the partial glaze 2 of the thermal head of this embodiment is thinner at the center and thickest at the edges. This thermal head, like the one in FIG.
A common electrode 5 is formed on the side surface 22 and individual electrodes 6 are formed on the top surface 21.

[0011] The thermal head shown in Figs. 1 and 2 has a heat-generating portion formed at the corner of the glaze layer at a right angle or a substantially right angle on the main body of the thermal head. In this case, pressure can be concentrated and applied to the heat generating part. FIG. 3 is a sectional view of a main part of a thermal head according to still another embodiment of the present invention. This thermal head cuts the end of the underglaze layer 2 diagonally to provide an inclined surface 24, and the upper surface 21 of the underglaze layer 2
The common electrode 5 is formed on the inclined surface 24 and the individual electrodes 6 are formed on the upper surface 21 so that the heat generating section 4 is located at the corner portion 23 where the inclined surface 24 intersects with the slanted surface 24 . While the angle α of the corner portion 23 of the glaze layer 2 of the thermal head in FIG. 1 is a right angle,
The angle α of the corner portion 23 of the thermal head of this embodiment is an obtuse angle, and since the inclined surface 24 of this thermal head can be made wider than the side surface 22 of FIG. 1, the width of the common electrode pattern can be made larger. Easy to form.

FIG. 4 is a sectional view of a main part of a thermal head according to still another embodiment of the present invention. In this thermal head, the edge side of the partial glaze layer 2 of the thermal head shown in FIG.
The heat generating portion 4 is formed at the corner portion 23 where the upper surface 21 and the inclined surface 24 intersect, and the effect obtained is the same as that in FIG. 3.

FIGS. 5 and 6 are sectional views of main parts of a thermal head according to still another embodiment of the present invention. The thermal head in FIG. 5 has almost the same structure as the thermal head in FIG. 1, and the thermal head in FIG. 6 has almost the same structure as the thermal head in FIG. In contrast, the corner portion 23 of the thermal head shown in FIGS. 5 and 6 has a curvature (R). At the corner part 23 of the thermal head shown in Figs. 1 and 3, chips or chips may occur during cutting.
Since burrs remain and the surface smoothness is low, pattern formation is somewhat difficult, but since the corner portions 23 of the thermal heads in these examples have a curvature and are rounded, chips and burrs are also avoided. The surface smoothness is high and pattern formation is easy.

Next, a method of manufacturing the thermal head of the above embodiment will be explained. First, as shown in FIG. 7, a ceramic substrate 1 on which a glaze layer 2 is formed is half-cut to a depth d exceeding the thickness of the glaze layer 2 to form a groove 11. This groove 11 has an inverted trapezoidal shape so that the angle α of the corner portion 23 of the glaze layer 2 is an obtuse angle. As a result, an inclined surface 22 is formed at the end of the glaze layer 2. However, in this embodiment, the depth exceeding the thickness of the glaze layer 2 is d, but depending on the case, the depth may not exceed the thickness of the glaze layer 2. For example, this is the case when the glaze layer is thick or the inclination angle is large (obtuse angle). Although not shown, the substrate 1 is a large substrate that can accommodate a large number of thermal heads, and a plurality of grooves 11 are formed in the substrate.

[0015] At the time of the above half-cut, the glaze layer 2
There are chips and burrs left on the corner part 23 of the board 1, and the smoothness of the surface is low.
Currently, the glaze normally used is 800 to 100.
Approximately 0°C is suitable, but if high melting point glasses are developed in the future, the temperature may be set to 1000°C or higher. ). As a result, the corner portion 23 of the glaze layer 2 has a curvature and is rounded, as shown in FIG.
The smoothness of the surface also improves, making subsequent pattern formation easier.

Subsequently, after heat treatment, a resistive film layer 3, a common electrode 5, and an individual electrode 6 are formed, a well-known pattern is formed in a photolithography process, and a protective film 7 is formed. Then, as shown in FIG. 9, a substrate before division is obtained. Finally, it is cut and divided along line AA in FIG. 9 to obtain individual thermal heads 12 shown in FIG. 10. Through the above steps, the thermal head shown in FIG. 6 is completed.

In this manufacturing method, the glaze layer 2 is half-cut and the corner portions 23 are formed at an obtuse angle, so the process is no different from that of a normal flat head, and a large number of thermal heads can be processed at the same time. Further, if chips and burrs are removed in the process shown in FIG. 7, and film formation and pattern formation are performed without heat treatment, the thermal head shown in FIG. 3 can be obtained. Further, in the step of FIG. 7, if the shape of the half-cut groove 11 is made into a rectangular groove instead of an inverted trapezoid, and the film formation process and pattern formation are performed without performing heat treatment, the thermal head of FIG. 1 is obtained, Further, by making the shape of the groove 11 rectangular and performing heat treatment, film formation processing, and pattern formation, the thermal head shown in FIG. 5 is obtained.

Although the above manufacturing method has been described with respect to a thermal head in which an underglaze layer 2 is formed on the upper surface of a substrate 1, it is also possible to manufacture a thermal head having a partial glaze layer as shown in FIGS. 2 and 4. It can be manufactured in a similar manner.

[0019]

[Effects of the Invention] According to the present invention, since the heat-generating portion is formed at the corner of the glaze layer, the thermal head can concentrate sufficient pressure on the heat-generating portion, and good thermal transfer printing can be performed on rough paper. It becomes possible. In addition, due to pressure concentration,
Printing efficiency is also improved, making it possible to print with low energy, eliminating wasteful heat storage, and enabling faster printing. Furthermore, the ribbon peeling distance is also reduced, which also improves printing efficiency.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a thermal head according to an embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a thermal head according to another embodiment of the invention.

FIG. 3 is a sectional view of a main part of a thermal head according to another embodiment of the invention.

FIG. 4 is a sectional view of a main part of a thermal head according to another embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a thermal head according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view of a main part of a thermal head according to another embodiment of the present invention.

FIG. 7 is a sectional view of an intermediate product for explaining a method of manufacturing a thermal head according to an embodiment of the present invention.

FIG. 8 is a sectional view of an intermediate product for explaining a method of manufacturing a thermal head according to an embodiment of the present invention.

FIG. 9 is a sectional view of an intermediate product after forming a protective film and before being divided into individual parts, for explaining the method of manufacturing a thermal head according to an embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a thermal head after being divided into individual parts for explaining a method of manufacturing a thermal head according to an embodiment of the present invention.

FIG. 11 is a partial cross-sectional view showing an example of a conventional thermal head.

FIG. 12 is a partial sectional view showing another example of a conventional thermal head.

FIG. 13 is a partial cross-sectional view showing another example of a conventional thermal head.

FIG. 14 is a partial cross-sectional view showing another example of a conventional thermal head.

FIG. 15 is an explanatory diagram for explaining a problem with a conventional thermal head.

[Explanation of symbols]

1 Board 2 Glaze layer 3 Resistive film layer 4 Heat generating part 5 Common electrode 6 Individual electrodes 7 Protective film 23 Corner section

Claims (3)

[Claims] Claim 1: A glaze layer is formed on an insulating substrate, a resistive film layer is formed on the glaze layer, and a common electrode and individual electrodes are formed at intervals such that a heat generating portion is formed on the resistive film layer. , in a thermal head in which a protective film layer is formed covering the heat generating part, the common electrode, and the individual electrodes, the glaze layer is an intersection between a glaze top surface portion and a glaze side surface portion, or a glaze top surface portion and a glaze slope portion. A thermal head characterized in that the heat generating portion is formed at a corner portion. Claim 2: The glaze layer is provided with a sloped portion whose thickness gradually becomes thinner toward the edge, and a heat generating portion is formed at a corner portion starting from the sloped portion toward the edge. Item 1
Thermal head listed. 3. The thermal head according to claim 1, wherein the corner portion of the glaze layer has a curvature, and a heat generating portion is formed at the corner portion.