JPH06320770A - Thermal head - Google Patents

Abstract

PURPOSE:To realize the cost reduction due to the abolishment of a ceramic substrate becoming a base and the simplification of a head construction method in a thermal head used as a recording element and to achieve the enhancement of image quality and the extension of life by enhancing the contact state of a heater with image receiving paper and a transfer medium. CONSTITUTION:A thermal head consists of a substrate 101, the heater parts 102 provided on the substrate 101 side by side and the protruding parts 101a provided directly under the heater parts 102 and a heat-resistant ultraviolet curable or thermosetting resin is applied to the whole area containing the protruding parts 101a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a coloring type thermal system,
The present invention relates to a thermal head used for a recording portion of a printer or a facsimile of a thermal sublimation or thermal fusion printer system.

[0002]

2. Description of the Related Art FIG. 4 is an explanatory diagram showing the structure of a conventional thermal head. In the figure, 401 is an alumina substrate, 402 is a glass layer, 403 is a heating element, 404 is a conductive layer, 405 is a common ground portion, 406 is a heating portion, and 40 is a heating element.
Reference numeral 7 is a protective film, and 408 is an IC (integrated circuit). A metal (aluminum) support (alumina substrate 401) is coated with a heat-resistant resin layer (glass layer 402), and a heating element 403 and a conductive conductor are formed thereon. (Conductive layer 404, common ground portion 405) is formed, and the abrasion resistant layer is formed on the uppermost layer.

As a recent general method, there is known a thermal head in which a wear resistant layer is formed after a heating element and a conductor are formed on a ceramic substrate. On the other hand, the method of constructing the thermal head as shown in FIG. 4 has an economical advantage that the ceramic substrate having high component cost can be eliminated.

Further, as reference technical documents related to the present invention, Japanese Patent Laid-Open Nos. Sho 63-189254 and Sho 63-1 are available.
89255, JP-A-63-302068,
JP-A-63-302069, JP-A-64-519
No. 55, and Japanese Patent Application Laid-Open No. 1-222159 are disclosed.

[0005]

However, in the conventional thermal head (FIG. 4) as shown above, there is an economical advantage by eliminating the ceramic substrate, but the thermal storage and heat dissipation properties are reduced. It is difficult to control and control the temperature stably to maintain a uniform concentration. Also, by improving the contact between the heater and the image receiving paper, or between the heater and the transfer medium, heat transfer is improved, and good color development (transfer)
There was a technical problem such as the need to create a structure for obtaining

Further, when a thermal head is used for thermal transfer printing or the like, in order to obtain a good transferred image without white spots and roughness during recording, in order to efficiently perform heat transfer of the heater, a convex shape is formed directly below the heater. Therefore, the heater, the ink sheet, and the image receiving paper must be in close contact with each other with a high contact pressure.
Therefore, as the shape of the convex portion, which is expected to have a contact pressure effect, the width direction is 100 to 200 μm and the height direction is 50 to 10 μm.
0 μm is necessary. However, in the conventional thermal head, when the heater is placed on the resin coating,
Since a high contact pressure cannot be applied to the heater, the ink sheet, and the image receiving paper, there are problems such as white spots and the like on the image and shortening of the life such as cracking of the head itself.

The present invention has been made in view of the above, and in a thermal head used as a recording element, a ceramic substrate serving as a base is eliminated and a cost reduction is realized by simplifying a head construction method, and a heater is used. The purpose is to improve the contact state with the image receiving paper and the transfer medium to improve the image quality and extend the service life.

[0008]

In order to achieve the above object, the present invention has heaters arranged in parallel on a head substrate, and the heater and the head substrate are coated with a heat-resistant ultraviolet-curable or thermosetting resin. In the thermal head having the above configuration, the head substrate is provided with a convex portion provided directly below the position where the heater is arranged, and the entire area including the convex portion is coated with a heat-resistant ultraviolet curable or thermosetting resin. A thermal head is provided.

The convex portion is formed by performing a coating process a number of times by screen printing.
Further, the convex portion is formed in a substantially trapezoidal shape by printing with a narrower printing width toward the uppermost layer.

[0010]

In the thermal head according to the present invention, a convex portion is provided immediately below the heater, and the entire area including the convex portion is coated with a heat-resistant ultraviolet-curable or thermosetting resin to provide insulation and heat storage. , And obtain surface smoothness.

Further, a heater is provided in parallel on the head substrate. A solvent-soluble polyimide resin is coated directly under the heater by screen printing a number of times to form convex portions. Further, the convex portion is formed into a substantially trapezoidal shape by printing with a narrower printing width toward the uppermost layer.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing the structure of the thermal head of the first embodiment according to the present invention. In the figure, S
The convex portion 101 is formed on the substrate 101 made of US (stainless steel) material.
a is formed. The convex portion 101a (portion A) has a size of about 100 to 200 μm in the width direction and 50 to 100 μm in the height direction, and is provided over the entire area in the line direction in which the heaters are arranged. In addition, the convex portion 101a is temporarily
After grinding the entire region in the vicinity of 1a, it is formed by a cutting process, an etching process, or a swaging process. After that, minute burrs at the time of processing the convex portion are removed, and further cleaning is performed to coat the entire area with the heat resistant resin coating layer 102.

Further, the heat resistant resin coating layer 10
Polyimide resin is the most suitable material for the material 2 in terms of physical properties such as heat resistance, insulation, dimensional stability, heat transfer, and adhesion.
For example, as a material suitable for the heat-resistant resin coating layer 102, DuPont has announced a solvent-soluble polyimide resin by changing the bonding position of the benzene ring of the imide group. Next, when an undercoat layer (heat resistant resin coating layer 102) using a polyimide resin is formed, a heater part (heating element) is formed.
103 is formed, and a conductor (lead electrode 1
04, the common electrode 105) is joined. Then, the abrasion resistant layer 106 is formed on the outermost layer.

FIG. 2 is a sectional view showing the structure of the thermal head of the second embodiment according to the present invention. As shown in FIG. 1, the convex portion 101a is formed of the same material using a SUS material, and the heat-resistant resin layer is coded on the convex portion 101a. In this embodiment, the convex portion is made of a resin material. To form. That is, the solvent-soluble polyimide resin used in FIG.
1 is formed. In this case, a few screen prints
Since it can be applied to a thickness of m, after performing the coating treatment of the first layer (201-1) → drying, the coating treatment of the second layer (201-2) with a width corresponding to the convex portion 201 → drying in this order. Repeat printing (201-n). As a result, the convex portion 201 having a desired constant height is formed. Finally, the entire surface is screen-printed to complete the uppermost coating layer 202. Although omitted in FIG. 2, the above-mentioned FIG.
Similarly, the heater portion 103, the lead electrode 104, the common electrode 105, and the abrasion resistant layer 106 are formed.

FIG. 3 is a sectional view showing the structure of the thermal head of the third embodiment according to the present invention. In this embodiment,
It has the same configuration as the second embodiment, but is overprinted by silk screen printing so that the cross-sectional shape of the convex portion 301 becomes a substantially trapezoidal shape. That is, the printing width is narrowed toward the first layer and the second layer to form a substantially trapezoidal convex portion 301 as shown in FIG. In this way, by forming the convex portion 301 into a trapezoidal shape, the corner portions of the convex portion 301 that come into contact with the image receiving paper 302 and the platen roller 303 form a gentle R shape in the actual printing scan, so that the abutting portion The concentrated stress in the head is reduced, which is advantageous for cracking and wear of the head.

[0016]

As described above, according to the thermal head of the present invention, the convex portion is provided immediately below the heater, and the entire area including the convex portion is covered with the heat-resistant ultraviolet curable or thermosetting resin. The coating is used, or a solvent-soluble polyimide resin is coated directly under the heaters arranged side by side on the head substrate by screen printing many times to form protrusions. In the head, the base ceramic substrate is abolished and the cost is reduced by simplifying the head construction method, and the contact state of the heater with the image receiving paper and the transfer medium can be improved, thus improving the image quality and improving the image quality. Life can be extended.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a thermal head according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing the structure of a thermal head according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing the structure of a thermal head according to a third embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a configuration of a conventional thermal head.

[Explanation of symbols]

101 Substrate 101a Convex Part 103 Heater Part (Heating Element) 106 Abrasion Resistant Layer 201 Convex Part 202 Top Coating Layer 301 Convex Part

Claims (3)

[Claims] 1. A thermal head having a structure in which heaters are arranged in parallel on a head substrate, and the heater and the head substrate are coated with a heat-resistant ultraviolet-curable or thermosetting resin. The thermal head is characterized in that it has a convex portion provided immediately below, and the entire area including the convex portion is coated with the heat-resistant UV-curable or thermosetting resin. 2. The thermal head according to claim 1, wherein the convex portion is formed by performing a coating process a number of times by screen printing. 3. The thermal head according to claim 2, wherein the convex portion is formed in a substantially trapezoidal shape by printing with a narrower printing width toward the uppermost layer.