JP2645083B2 - Thermal recording head and method of manufacturing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal recording head used for a video printer, a facsimile, and the like.

[Conventional technology]

FIG. 4 is a sectional view showing a part of a conventional thermal recording head. In the figure, 1 is an alumina ceramic substrate, 2 is a partial glaze provided on the alumina ceramic substrate 1, 3 is a resistor film provided on the partial glaze 2, 4 is a thickness provided on the resistor film 3 The electrode film is about 1 μm, and the electrode film 4 is not provided at the center of the partial glaze 2 of the electrode film 4, and a heating resistor 5 having a length 1 is formed by the resistor film 3 in this portion. 6 is an electrode film 4, a heating resistor 5
The electrode portion 4a is formed by the electrode film 4 and the protective film 6 on the electrode film 4 with the protective film provided thereon, and the heat generating portion 5a is formed by the heat generating resistor 5 and the protective film 6 on the heat generating resistor 5. Make up.

In this thermal recording head, since the surface of the heat generating portion 5a has an arc shape, the contact pressure with the recording paper 8 conveyed in contact with the drum 7 can be increased.

[Problems to be solved by the invention]

However, in such a thermal recording head, since a step corresponding to the thickness of the electrode film 4 exists at the end of the heat generating portion 5a, a gap 9 is formed between the recording paper 8 and the heat generating portion 5a. As shown by the broken line in FIG. 5, the contact pressure of the end of the heat generating portion 5a with the recording paper 8 is reduced, so that stable coloring cannot be obtained at the end of the heat generating portion 5a, so that the roughness is reduced. And the contact width W with the recording paper 8 is equal to the length l of the heat generating portion 5a.
50% to 70%, white streaks occur between dots, and a high-quality image print cannot be obtained. In particular, when the recording paper 8 has high rigidity and is not easily deformed, the contact width W becomes extremely small, white stripes between dots are conspicuous, and the image quality of the image print is considerably deteriorated. In addition, since the gap 9 is generated, the heat generated at the end of the heating resistor 5 does not contribute to color development, so that the color development efficiency is low and the power applied to the head is increased. Further, since the contact pressure of the end portion of the electrode film 4 with the recording paper 8 becomes locally excessive, the electrode portion 4a and the heat generating portion 5a are mechanically
May be thermally damaged. Further, since the electrode portion 4a provided with the electrode film 4 is also in contact with the recording paper 8, the heating resistor 5
Since the heat generated in step (1) dissipates to the recording paper 8 via the electrode film 4, the heat generated in the heating resistor 5 cannot be effectively contributed to the color development, and the generation efficiency is reduced. growing.

Further, for the purpose of improving the unevenness of the contact pressure distribution with the recording paper, as shown in JP-A-59-19178, a convex portion having a height corresponding to the thickness of the electrode film in the glaze. A thermal recording head has been considered in which the surface of the electrode and the upper surface of the projection are provided on the same plane.

However, in such a thermal recording head, not only the heat-generating part but also the electrode part comes into contact with the recording paper, and the contact area with the recording paper becomes large, so that the contact pressure of the heat-generating part becomes small. Cannot be obtained, so that roughness occurs and a high-quality image print cannot be obtained. In addition, since the electrode portion also comes into contact with the recording paper, the heat generated by the heating resistor dissipates to the recording paper via the electrode film, so that the heat generated by the heating resistor cannot effectively contribute to color development. Since the generation efficiency is reduced, the power applied to the head is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a high-quality image print can be obtained, the power applied to the head can be reduced, and there is no risk of damaging the electrode portion and the heating portion. It is intended to provide a manufacturing method.

[Means for solving the problem]

In order to achieve this object, according to the present invention, in a thermal recording head provided with an electrode portion and a heating portion on a partial glaze, the height on the partial glaze is sufficiently larger than the thickness of the electrode film of the electrode portion. And a flat convex portion having an upper surface extending over a predetermined length in the recording paper transport direction, and the flat heat generating portion having a predetermined length is provided on the convex portion.

Further, in a method of manufacturing a thermal recording head having an electrode portion and a heating portion provided on a partial glaze, a part of the partial glaze having an arc-shaped surface is polished to provide a flat surface, and the flat surface paper is conveyed. By etching a portion other than the fixed length in the direction, after providing a convex portion having a flat upper surface having a height sufficiently larger than the thickness of the electrode film of the electrode portion,
A resistor film and the above-mentioned electrode film are formed, and the above-mentioned electrode film on the above-mentioned convex part is removed by etching to form the above-mentioned flat heating part having a certain length.

[Action]

In this thermal recording head, since the upper surface of the heat generating portion is flat and the upper surface of the heat generating portion is located above the upper surface of the electrode portion, the heat generating portion is uniformly formed on the recording paper over the entire length of the heat generating portion. The contact can be made with a sufficiently large contact pressure, and the electrode portion does not come into contact with the recording paper.

Further, in a method of manufacturing a thermal recording head having an electrode portion and a heating portion provided on a partial glaze, a part of the partial glaze having an arc-shaped surface is polished to provide a flat surface, and a paper transport direction of the flat surface is provided. By etching a portion other than the fixed length, after providing a convex portion having a flat upper surface having a height sufficiently larger than the thickness of the electrode film of the electrode portion, forming a resistor film, the electrode film, If the electrode film on the convex part is removed by etching to form a flat heating part with a certain length,
A thermal recording head can be easily manufactured.

〔Example〕

FIG. 1 is a sectional view showing a part of a thermal recording head according to the present invention. In the figure, 10 is an alumina ceramic substrate, 11 is a partial glaze provided on the alumina ceramic substrate 10, 13 is a convex portion provided on the partial glaze 11, the upper surface of the convex portion 13 extends over a certain length in the recording paper transport direction. The protrusions 13 are flat and parallel to the surface of the alumina ceramic substrate 10, and the corners 15, 16 of the protrusion 13 are rounded. Reference numeral 17 denotes a resistor film having a thickness of about 200 to 2000 mm provided on the partial glaze 11, reference numeral 18 denotes an electrode portion having a thickness of about 1 μm provided on the resistor film 17, and an electrode film 18 on the projection 13. Is not provided, and a heating resistor 19 having a length 1 is formed by the resistor film 17 in this portion. Reference numeral 20 denotes a protection film provided on the electrode film 18 and the heating resistor 19, and the protection film 20 oxidizes the electrode film 18 and the heating resistor 19,
Prevents corrosion and wear. The electrode portion 51 is constituted by the electrode film 18 and the protection film 20 on the electrode film 18, and the heating portion 21 is constituted by the heating resistor 19 and the protection film 20 on the heating resistor 19.

In this thermal recording head, the upper surface of the heat generating portion 21 is flat, and as shown in FIG. 2, the diameter of the drum 22 around which the recording paper 26 composed of the photographic paper 23 and the ink paper 24 is wound has a length l. The heat generating part 21 and the recording paper 26
Contact with the recording paper
Even when the stiffness of 26 is high and it is difficult to deform, a substantially uniform contact pressure can be obtained over the entire length of the heat generating portion 21 as shown by the solid line in FIG. For this reason, stable coloring is obtained even at the end of the heat generating portion 21, so that no roughness occurs and the ink 25 corresponding to the length 1 of the heat generating portion 21 can be transferred to the photographic paper 23. Therefore, high-quality image prints can be obtained without the occurrence of white stripes between dots, and the heat generated at the end of the heating resistor 19 also contributes to color development. Therefore, since the contact pressure with the recording paper 26 does not locally become excessive, there is no possibility that the electrode portion 51 and the heat generating portion 21 are mechanically and thermally damaged. Further, since the upper surface of the heat generating portion 21 is located above the upper surface of the electrode portion 51, only the heat generating portion 21 contacts the recording paper 26, and the electrode portion 51 does not contact the recording paper 26. For this reason, the heat generated by the heating resistor 19 does not radiate to the recording paper 26 via the electrode film 18, so that the heating resistor 19
The heat generated in 19 can be effectively contributed to color development,
Since the generation efficiency does not decrease, the power applied to the head does not increase, and since the contact area with the recording paper 26 decreases, the contact pressure of the heat generating portion 21 increases, so that stable coloring can be obtained. Therefore, high quality image prints can be obtained without roughness.

Next, a method of manufacturing the thermal recording head shown in FIG. 1 will be described with reference to FIG. First, as shown in FIG. 3 (a), a partial glaze 11 having an arcuate surface is provided on the alumina ceramic substrate 10 by printing and firing a glass paste on the alumina ceramic substrate 10. Next, as shown in FIG.
By polishing the top of 11 the width l ₁ is for example 400
A flat surface 12 of μm is provided. Next, as shown in FIG. 3 (c), a photoresist is applied on the partial glaze 11,
By a normal photolithography process, the width l is, for example,
Protrusions 13 having a thickness of 300 μm and a height h of 5 μm are provided. Next, as shown in FIG. 3D, a resistor film 17 is provided on the partial glaze 11 by vapor deposition, sputtering, or the like. Next, as shown in FIG. 3E, an electrode film 18 whose thickness is sufficiently smaller than the height h is provided on the resistor film 17 by vapor deposition, sputtering, or the like. Next, FIG. 3 (f)
As shown in FIG. 5, the heat generating resistor 19 is formed by removing the electrode film 18 on the projection 13 by physical or chemical etching. Next, as shown in FIG.
A protective film 20 is provided on the electrode film 18 and the heating resistor 19 by sputtering, CVD, or the like.

Note that the process of forming the heat generating portion is not limited to the above-described embodiment, and other thin film process technology or thick film process technology may be used.

〔The invention's effect〕

As described above, in the heat-sensitive recording head according to the present invention, the heat-generating portion can be uniformly contacted with the recording paper with a sufficiently large contact pressure over the entire length of the heat-generating portion. Since the print can be obtained and the contact pressure with the recording paper does not locally become excessive, there is no possibility that the electrode portion and the heat generating portion are damaged, and the electrode portion does not contact the recording paper. Therefore, the coloring efficiency is high and the power applied to the head is small.

Further, in the method for manufacturing a thermal recording head according to the present invention, the thermal recording head can be easily manufactured, so that the manufacturing cost of the thermal recording head is reduced.

 Thus, the effect of the present invention is remarkable.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a part of a thermal recording head according to the present invention, FIG. 2 is an explanatory view of the operation of the thermal recording head shown in FIG. 1, and FIG. 3 is a thermal recording head shown in FIG. FIG. 4 is a sectional view showing a part of a conventional thermal recording head, and FIG. 5 is a graph showing the relationship between the position of the thermal recording head and the contact pressure. 10 ... Alumina ceramic substrate 11 ... Partial glaze, 13 ... Protrusion 21 ... Heat generation part, 51 ... Electrode part

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Kazuhiko Ato 1410 Inada, Katsuta-shi, Ibaraki Prefecture Tokai Plant, Hitachi, Ltd. (56) References JP-A-63-3971 (JP, A) JP-A-62 JP-A-187050 (JP, A) JP-A-58-63477 (JP, A) JP-A-56-42667 (JP, A) JP-A-62-73963 (JP, A) JP-A-62-280051 (JP, A) JP-A-63-51155 (JP, A) JP-A-60-208263 (JP, A) JP-A-63-191655 (JP, A) Fully open Showa 60-5842 (JP, U) Really open Showa 63- 25545 (JP, U) Japanese Utility Model 63-124137 (JP, U) Japanese Utility Model 63-179132 (JP, U)

Claims (2)

(57) [Claims] 1. A thermal recording head having an electrode portion and a heating portion provided on a partial glaze, wherein the recording head has a height sufficiently larger than the thickness of the electrode film of the electrode portion on the partial glaze and the upper surface has a recording surface. A thermal recording head comprising: a flat convex portion provided over a predetermined length in a paper transport direction; and the flat heating portion having a predetermined length provided on the convex portion. 2. A method of manufacturing a thermal recording head having an electrode portion and a heating portion provided on a partial glaze, wherein a portion of the partial glaze having an arc-shaped surface is polished to provide a flat surface, After etching a portion other than the fixed length in the paper transport direction, a convex portion having a flat upper surface having a height sufficiently larger than the thickness of the electrode film of the electrode portion is provided, and then the resistor film and the electrode A method for manufacturing a thermal recording head, comprising: forming a film; and removing the electrode film on the convex portion by etching to form the flat heating portion having a predetermined length.