JPH0536692Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermal head used in a thermal printer device.

[Prior Art] FIG. 5 is a longitudinal sectional view of a conventional double-sided simultaneous printing type thermal head.

In FIG. 5, a glass layer 3 having a glaze 3a whose vertical cross-sectional shape has a substantially normal distribution shape is formed on a substrate 2 made of ceramic, and a resistor made of tantalum nitride is formed on the upper surface of the glass layer 3. body membrane 4
is formed. Next, electrode films 5a and 5b made of Al, for example, are formed on the resistor film 4 at the apex of the glaze 3a, spaced apart from each other by a predetermined distance. Further, on the resistor film 4 on which the electrode films 5a and 5b are not formed, and on the electrode films 5a and 5
A wear-resistant protective film 6 made of, for example, SiC is formed on b. Here, the resistor film 4 at the apex of the glaze 3a with the electrode films 5a and 5b separated by a predetermined distance constitutes the upper thermal head portion 1a of the heating resistor.

Further, a lower thermal head section 1b having the same structure as the upper thermal head section 1a is formed, and each thermal head section 1a and 1b is provided so that the apex of each glaze 3a of each thermal head section 1a and 1b is opposed to each other. . The thermal paper 7 is sandwiched between the upper and lower thermal heads 1a and 1b from above and below, respectively, and a predetermined driving voltage is applied between the electrode films 5a and 5b of each of the thermal heads 1a and 1b. The resistor films 4 of the heads 1a and 1b generate heat, thereby heating the thermal paper 7 in a predetermined shape and printing. Further, the thermal paper 7 is sandwiched between rollers 8a and 8b, and as the rollers 8a and 8b rotate, the thermal paper 7 is discharged to the left in the drawing.

[Problems to be solved by the invention] In the above-mentioned double-sided simultaneous printing thermal head, if the upper and lower thermal head sections 1a and 1b press against the thermal paper 7 uniformly with a predetermined pressure, good printing can be achieved. However, for example, if the height of the glaze 3a on either one of the thermal heads is not uniform, and there are warps or undulations, the thermal head will not be evenly pressed against the thermal paper, resulting in blurred printing. The point was hot.

According to the inventor's experiments, the thermal head section 1
The deviation of the height h of glaze 3a in a and 1b is 10 μm
When the deviation is within the above deviation, good printing can be obtained, but when the deviation is greater than the above deviation, the printing becomes blurred, and good printing cannot be achieved.

The object of the present invention is to solve the above problems and provide a thermal head that can perform double-sided printing simultaneously even when the height deviation of the glaze 3a exceeds 10 μm.

[Means for Solving the Problems] The present invention provides a thermal head that prints by applying a predetermined voltage to a heating resistor formed at the apex of the glaze. 2 glazes are formed respectively
Thermal head parts are arranged to face each other, and the glaze having the heating resistor of at least one of the thermal head parts is formed so as to face the valley between the adjacent glazes of the other thermal head part. It is characterized by

[Function] With the above configuration, the glaze having the heating resistor is formed to face the valley between adjacent glazes of another thermal head, so that the printed portion of the thermal paper is Since the thermal paper is sandwiched between the glazes forming the troughs, the thermal paper is pressed against the heating resistor that performs printing, so even if the height deviation of the glaze exceeds a predetermined value,
Printing can be performed well.

[Embodiment] First Embodiment FIG. 2 is a perspective view of the appearance of the lower thermal head portion 10a of the thermal head according to the first embodiment of the present invention. FIG. 2 is a longitudinal sectional view taken along line A-A' of a thermal head for double-sided simultaneous printing, which includes an upper thermal head section 10b and a lower thermal head section 10a having the same structure as section 10a. In FIG. 1 and FIG. 2, the same parts as in the above-mentioned drawings are designated by the same reference numerals.

The thermal head of this first embodiment differs from the conventional thermal head described above in that each of the upper and lower thermal heads 10a and 10b is provided with three glazes 3a to 3c, respectively. The heating resistor portions 10a and 10b are formed in each glaze 3a. below,
The above differences will be explained in detail.

In FIG. 1, on both sides of a glaze 3a having a heating resistor portion 50 in which electrode films 5a and 5b are formed at a predetermined distance apart, glazes 3b and 3c, which are approximately the same height as the glaze 3a, are placed at a distance l _{1 .} They are provided so as to extend in parallel to each other and in the width direction of the thermal head. Both glazes 3
A resistor film 4, electrode films 5a and 5b, and a protective film 6 are formed on layers b and 3c as in the conventional case.

Here, the heating resistor 50 at the top of the glaze 3a is formed in 24 dots in the width direction of the thermal head, and the above three glazes 3a, 3b, 3
C is provided in each of the upper and lower thermal heads 10a and 10b, respectively.

Then, the heating resistor part 50 at the top of the glaze 3a of the lower thermal head part 10a enters the valley part 3c of the upper thermal head part 10b, and the heating resistor part 50 at the top of the glaze 3a of the upper thermal head part 10 Two thermal head portions 10a and 10b are provided facing each other so as to fit into the valley portion 3d of the lower thermal head portion 10a. here,
The glaze 3a of the upper and lower thermal head sections 10a and 10b is different from that of the other thermal head sections 10a and 10b, respectively.
The glazes 3b and 3c of glazes b and 10a are spaced apart from each other by a predetermined distance. Thermal paper 7 is fed between these two thermal head sections 10a and 10b from the right side of the drawing in FIG.
By applying a predetermined drive voltage between the electrode films 5a and 5b of the electrode films 0a and 10b, the resistor films 4 of the upper and lower thermal head sections 10a and 10b generate heat, thereby shaping the thermal paper 7 into a predetermined shape. is heated and printed.

In FIG. 1, for convenience of illustration, the thermal paper 7 is shown to be separated from the protective film 6 of each upper and lower thermal head portion 10a and 10b by a predetermined distance, but in reality, the thermal paper 7 is separated from each glaze. It is pressed against the protective film 6 at each vertex of 3a, 3b and 3c,
(The same applies to the following drawings.) Glaze 3
Good printing can be performed by the heat generating resistor section 50 of a.

In the inventor's experiments, the length l ₁ between the vertices of each glaze was 1.5 μm, the width l ₂ of each glaze was 1.2 μm,
When the height hp of each glaze in the protective film 6 is 50 μm, the deviation of the height h of the glaze mentioned above is ±
Good printing was possible even at 25 μm.

Second Embodiment FIG. 3 is a longitudinal sectional view of a thermal head according to a second embodiment of the present invention, and the same parts in FIG. 3 as in the above-described drawings are designated by the same reference numerals.

This thermal head includes a lower thermal head portion 11a having two glazes 3a and 3c;
It consists of an upper thermal head part 11b having book glazes 3b and 3a, and the top of the glaze 3a of the lower thermal head part 11a faces the valley part 3d of the glass film 3 of the upper thermal head part 11b, and the upper thermal head part 11b The top of the glaze 3a is located at the valley 3e of the glass film 3 of the lower thermal head portion 11a.
An upper thermal head section 11b and a lower thermal head section 11a are arranged so as to face each other. Similar to the first embodiment described above, this thermal head has the following features:
Since the printed portion of the thermal paper 7 is sandwiched between the glazes, the thermal paper is pressed against the heating resistor portion 50 (vertical portion of the glaze 3a) that performs printing, so that printing can be performed satisfactorily.

Third Embodiment FIG. 4 shows a third embodiment in which the glaze 3a of the heating resistor section 50 is provided on the paper feeding side of both the upper and lower thermal heads 12a and 12b. In this third embodiment, the portion of the thermal paper 7 to be printed by the lower thermal head section 12a is sandwiched between the glazes 3a and 3c of the upper thermal head section 12b and pressed downward in the drawing, so that the lower surface can be printed well.

Other Embodiments In the above embodiments, the upper and lower thermal head sections each having two or three glazes formed on the substrate 2 are used, but the present invention is not limited to this. Four or more glazes may be formed.

In addition, in the above embodiment, 1 made of SiC
Although the protective film 6 of the layer is formed, the present invention is not limited to this.
The first layer may be formed of SiO ₂ and the second layer may be formed of TaO ₅ to form a two-layer protective film 6.

[Effects of the invention] As detailed above, according to the invention, two thermal head portions each having a glaze formed adjacent to a glaze having a heating resistor are disposed opposite to each other, and at least one of Since the glaze having the heating resistor in the thermal head section is formed so as to face the valley between adjacent glazes in the other thermal head section, the printed portion of the thermal paper will not touch the glaze forming the valley. As a result, the thermal paper is pressed against the heating resistor that performs printing, so there is an advantage that good printing can be performed even if the height deviation of the glaze exceeds a predetermined value.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of a thermal head according to a first embodiment of the present invention; FIG. 2 is a perspective view of the external appearance of one thermal head portion of the thermal head shown in FIG.
FIG. 3 is a vertical cross-sectional view of a thermal head according to a second embodiment of the present invention, FIG. 4 is a vertical cross-sectional view of a thermal head according to a third embodiment of the present invention, and FIG. 5 is a vertical cross-sectional view of a conventional thermal head.
c: glaze; 3d, 3e: valleys of glass film; 4: resistor film; 5a, 5b: electrode film; 6:
. . . protective film, 7 . . . thermal paper, 10a . . . lower thermal head portion, 10b . . . upper thermal head portion, 5
0...Heater resistor portion.

Claims (1)

[Scope of utility model registration request] In a thermal head that prints by applying a predetermined voltage to a heating resistor formed at the top of a glaze, two thermal head portions each having a glaze formed adjacent to the glaze having the heating resistor are provided. A thermal device characterized in that the glazes arranged to face each other and having the heating resistors in at least one of the thermal head portions are formed so as to face the valleys between adjacent glazes in the other thermal head portion. Head.