JP2766564B2 - Thermal head and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head having high printing efficiency, an electronic apparatus such as a printer, a word processor, a facsimile, a plotter, and the like, and a method of manufacturing the thermal head.

[0002]

2. Description of the Related Art Conventional thermal heads of a partial glaze type, a double partial glaze type, and a true edge type are known. As shown in FIG. 4, the partial glaze type thermal head forms a partial glaze layer 2 having a width of about 300 to 1200 μm and a curvature on an upper surface end of an insulating substrate 1, and a resistive film layer 3 thereon. In order to form a heat generating portion 4 on the top of the glaze layer 2 of the resistive film layer 3, a common electrode 5 and an individual electrode 6 are formed on both sides of the top of the glaze layer 2, and the upper surface thereof is further covered with a protective film 7 It is covered with. As shown in FIG. 5, the double partial glaze type thermal head is one in which only the glaze layer 2a below the partial glaze type heat generating portion 4 is raised in a convex shape by glaze etching or the like.

[0006] The true edge type thermal head has a glaze layer 2 and a heat generating portion 4 provided on an end surface of an insulating substrate 1 as shown in FIG. Further, as a modification, as shown in FIG. 7, the edge of the insulating substrate 1 is partially cut obliquely, and the glaze layers 2a, 2b, 2c are formed not only on the upper surface 1a of the insulating substrate 1 but also on the inclined surface 1b and the end surface 1c. There is one in which the heat generating portion 4 is formed on the slope 1b.

[0004]

In the thermal head, it is necessary to concentrate pressure on the ribbon of the heating resistor portion, the paper to be transferred, and the platen in order to print on rough paper and to increase the printing efficiency. Among the above-described conventional thermal heads, those of the partial glaze type and the double partial glaze type are, as shown in FIG. 8, an ink ribbon 8 of a glaze layer 2 having a heating portion 4 and a platen rubber 10 via a transfer paper 9. However, there is a problem that the contact of the heat generating portion 4 cannot be sufficiently obtained. Further, as shown in FIG. 6, the true edge type for solving this problem has not yet achieved a sufficient effect because the current substrate thickness is as large as about 2 mm. Further, a problem common to the thermal heads shown in FIGS. 6 and 7 is that, in a method in which a side end surface of a substrate is processed and printing is performed on the end surface, a large number of individual substrates can be formed at a time. However, as a result, there is a disadvantage that the cost per unit becomes high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a low-cost thermal head in which pressure is concentrated on a heat generating portion, printing efficiency is high, and a method for manufacturing the same. Aim.

[0006]

In order to achieve the above object, a thermal head according to a first aspect of the present invention has a partial glaze layer formed on an insulating substrate and a resistive film formed on the partial glaze layer. A common electrode and an individual electrode are formed on both sides of the crest on the resistive film layer, and a top portion of the resistive film layer is used as a heat generating portion, and a protective film layer covering the heat generating portion, the common electrode, and the individual electrode is formed. A groove extending in the extension direction of the partial glaze layer is formed in each of the insulating substrate portions near both skirts of the partial glaze layer, and a partial glaze layer having a trapezoidal cross section is arranged between the grooves. And

In this thermal head, grooves extending in the direction of extension of the partial glaze layer are formed in the insulating substrate near both skirts of the partial glaze layer, and a partial glaze layer having a trapezoidal cross section is arranged between the grooves. A common electrode and an individual electrode are formed on both sides of the top of the partial glaze layer having a trapezoidal cross section, and the top serves as a heat generating portion. Therefore, the heat-generating portion protrudes greatly upward from its periphery, and unnecessary pressure dispersion to the periphery other than the heat-generating portion is eliminated, and pressure is applied only to the heat-generating portion. As a result, printing efficiency is improved, wasteful heat storage can be eliminated, and high-speed printing can be achieved.

According to a third aspect of the present invention, there is provided a method of manufacturing a thermal head, comprising: forming a partial glaze layer having a curved cross section on an insulating substrate; Removing the insulating substrate portion near the mountain skirt to form a trapezoidal cross-sectional shape of the partial glaze layer, and forming a groove extending in the extending direction of the partial glaze layer in the insulating substrate portion near the mountain skirt of the partial glaze layer And a step of processing the corners of the glaze layer having a trapezoidal cross section into a smooth curved surface, and forming a resistive film and an electrode portion on the glaze layer having the rounded trapezoidal cross section, and then forming a heating section. And forming a protective film layer covering the electrode portion.

According to this manufacturing method, a partial glaze layer having a curved cross section (bowl shape) similar to the conventional one is formed on an insulating substrate, and both skirt sides of the bowl-like partial glaze layer and ridges of the partial glaze layer are formed. A portion of the insulating substrate in the vicinity is removed by, for example, laser cutting, and a groove extending in the extending direction of the partial glaze layer is formed in the insulating substrate near the skirt of the partial glaze layer, and the partial glaze layer itself is formed in a trapezoidal cross section. I do.
Then, the corners of the trapezoidal glaze layer are refired (heated), for example, so that the corners are rounded (curved). Thereby, the smoothness is increased, the pattern formation is further facilitated, and the shape of the heating element is stabilized. Furthermore,
A resistive film layer, a common electrode, and an individual electrode are formed on the upper surface of the trapezoidal glaze layer. Thereafter, a protective film layer is formed to cover the heat generating portion (the top of the trapezoidal glaze layer), the common electrode, and the individual electrodes. Therefore, it is possible to realize a thermal head in which the heat-generating portion protrudes upward more than the periphery and a sufficient pressure concentration is obtained in the heat-generating portion. Also, a half-cut (non-penetrating cut) method and a glaze corner curved surface method by reheating (re-firing) can simultaneously process a large number of heads and provide an inexpensive thermal head.

[0010]

FIG. 1 is a sectional view of a principal part showing a specific embodiment of a thermal head according to the first aspect of the present invention.

In the thermal head of this embodiment, a partial glaze layer 2 is formed at an end on an insulating substrate 1, a resistive film layer 3 is formed on the partial glaze layer 2, A common electrode 5 and an individual electrode 6 are formed on the foot of the mountain, and the top of the resistive film layer 3 is used as a heating section 4.
And a protective film layer 7 that covers the individual electrodes 6.

A feature of this thermal head is that a groove 11 extending in the extending direction of the partial glaze layer 2 is formed in the portion of the insulating substrate 1 near both skirts of the partial glaze layer 2, and a trapezoidal cross section is formed between the grooves 11. The point is that the glaze layer 2 is arranged.
That is, after the partial glaze layer 2 is formed in a curved cross section (bowl shape) similar to the conventional one, the insulating substrate 1 on both sides of the bowl-shaped glaze layer 2 and near the both mountains is removed by cutting. Thereby, the groove 11 is formed in the insulating substrate 1 and the trapezoidal glaze layer 2 is positioned between the grooves 11. As a result, the heat generating portion 4 protrudes largely upward with respect to the periphery. Therefore, unnecessary pressure dispersion to the periphery other than the heat generating portion 4 is eliminated, and pressure is concentrated only on the heat generating portion 4, so that printing efficiency is improved, unnecessary heat storage can be eliminated, and high-speed printing can be achieved. . Note that the resistive film layer 3 corresponding to the crest of the partial glaze layer 2, the common electrode 5, and a part of the individual electrode 6 are also provided in the groove 11.

FIG. 2 shows a specific manufacturing process of the method for manufacturing the thermal head shown in FIG. However, FIG. 2 shows up to the step of forming the rounded partial glaze layer 2 and the groove 11. First, in FIG. 2A, a partial glaze layer 2 having a curved cross section (bowl shape) is formed on an upper surface end of an insulating substrate 1.
Form A. Thereafter, as shown in FIG. 2B, for example, a blade 30 having a sectional shape as shown in the figure is used to remove (half-cut) the portion of the insulating substrate 1 on the skirt side and near the skirt of the bowl-shaped partial glaze layer 2. As a result, a groove 11 extending in the direction in which the partial glaze layer 2 extends in the insulating substrate 1 [(c) of FIG.
Reference], and a partial glaze layer 2 </ b> B having a trapezoidal cross section is arranged between the grooves 11. That is, the partial glaze layer 2B whose top portion protrudes greatly from the periphery is obtained.

Further, as shown in FIG. 2C, the corner 21 of the trapezoidal glaze layer 2B is formed into a smooth curved surface by a reheating (refiring) treatment or a chemical treatment with hydrofluoric acid, and the groove is formed. 11 also has a gentle curved surface. As a result, a partial glaze layer 2C having a smooth cut surface is obtained, and the subsequent patterning process is facilitated. Then, the resistive film layer 3, the common electrode 5, and the individual electrode 6 are formed on the trapezoidal glaze layer 2C whose corners 21 have been subjected to the curved surface processing. After this series of film forming processes, a protective film layer 7 covering the heat generating portion (top portion of the glaze layer 2) 4, the common electrode 5, and the individual electrode 6 is formed.
A thermal head as shown in FIG. 1 is manufactured.

According to such a manufacturing method, it is possible to realize a thermal head in which the heat-generating portion 4 protrudes upward more than the periphery and a sufficient pressure concentration can be obtained on the heat-generating portion 4. Also, a half-cut (non-penetrating cut) method and a glaze corner curved surface method by reheating (re-firing) can simultaneously process a large number of heads and provide an inexpensive thermal head.

In FIG. 2B, the glaze layer 2B
When the glazing layer is reheated (refired), the glaze layer generally melts, but if left untreated, the width and height dimensions of the glaze layer 2B cut by the blade 30 change (the width and the height are large). Lower). However, since the grooves 11 exist at both skirts of the glaze layer 2B, the molten glaze layer remains on the portion of the insulating substrate 1 between the grooves 11 due to its own surface tension, and does not flow toward the grooves 11 and spread. For this reason, it becomes possible to make the corner 21 of the glaze layer 2B a curved surface without changing the width dimension and the height dimension of the glaze layer 2B.

The blade 30 used in the above manufacturing method may have a sectional shape as shown in FIG. 3 in addition to the sectional shape as shown in FIG.
Further, the thermal head of the above embodiment is used for electronic equipment such as a printer, a word processor, a facsimile, and a plotter.

[0018]

According to the thermal head and the manufacturing method of the present invention, the partial glaze layer is located between the grooves.
It has the following effect (1). (1) During the curved surface processing of the glaze layer, the glaze layer can be formed into a rounded trapezoidal cross section without changing the width dimension and the height dimension of the glaze layer. Further, the thermal head of the present invention has the following effects (2) to (4). (2) the partial glaze layer protrudes upward more than the periphery,
Sufficient pressure concentration is obtained, and printing efficiency is improved. (3) Good thermal transfer printing on rough paper is possible. (4) As a result, since the heating resistor is projected in a trapezoidal shape, it can be easily replaced without any special design change to the conventional head. Further, the manufacturing method of the present invention has the following effects (5) and (6). (5) After cutting the partial glaze layer into a trapezoidal cross section,
By performing the curved surface treatment on the cut surface, pattern formation is facilitated, and the shape of the heating element is stabilized. (6) A large number of heads can be processed simultaneously by the half-cut processing and the curved surface processing, and an inexpensive thermal head can be provided.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a manufacturing process (a process of forming a rounded partial glaze layer and a groove) of the thermal head of FIG. 1;

FIG. 3 is a sectional view showing another embodiment of the blade shown in FIG. 2 (b).

FIG. 4 is a partial sectional view of a thermal head according to a conventional example.

FIG. 5 is a partial sectional view of a thermal head according to another conventional example.

FIG. 6 is a partial sectional view of a thermal head according to still another conventional example.

FIG. 7 is a partial sectional view of a thermal head according to still another conventional example.

FIG. 8 is a diagram for explaining a problem of a conventional thermal head.

[Description of Signs] 1 Insulating substrate 2 Partial glaze layer 3 Resistive film layer 4 Heating part 5 Common electrode 6 Individual electrode 7 Protective film layer 11 Groove

Claims (3)

(57) [Claims] A partial glaze layer is formed on an insulating substrate, a resistive film layer is formed on the partial glaze layer, and a common electrode and an individual electrode are formed on both sides of the ridge on the resistive film layer. the top and the heating portion of the heating unit, in the thermal head obtained by forming a protective film layer covering the common electrode and the individual electrodes, it insulating substrate portion near both foot of the mountain of the partial glaze layer
A groove extending in the direction in which the partial glaze layer extends is formed, and
A partial glaze layer having a trapezoidal cross section between the grooves . 2. An electronic apparatus comprising the thermal head according to claim 1. 3. A step of forming a partial glaze layer having a curved cross-section on an insulating substrate, and both hill sides of the partial glaze layer.
And the insulating substrate near both skirts of the partial glaze layer
To form a trapezoidal cross-sectional shape of the partial glaze layer
With the part of the insulating substrate near the skirt of the partial glaze layer.
Forming a groove extending in the direction in which the minute glaze layer extends ,
A step of processing the corners of the glaze layer having the trapezoidal cross section into a smooth curved surface, and forming a resistive film and an electrode portion on the glaze layer having the rounded trapezoidal cross section. , Heating part,
By comprising a step of forming a protective layer covering the electrode portions
A method for manufacturing a thermal head.