JPH10166635A - Thermal head and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermal head, and a production method thereof, in which contact with a recording material is improved while transmitting heat finely thereto and to enhance image quality. SOLUTION: A grease layer 25 is formed on an insulating substrate 23 and then a heating element layer 27 and an electrode layer 29 are formed sequentially thereon. Subsequently, the electrode layer 29 is etched to expose a part of the heating element layer 27 and a protective layer 31 is formed on the surface thereof followed by formation of a recessed heating part 33 in the surface of the protective layer 31. In such a thermal head 21, a protrusion 37 having forward end higher than the surface of the protective layer 31 formed on the electrode layer 29 is provided in the center of the recessed heating part 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used for thermal recording of a facsimile or a printer and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a thermal head used for thermal recording, as shown in FIG. 3, a glaze layer 3 is formed on an insulating substrate 1, and a heating resistor layer 5 and an electrode layer 7 are formed thereon. It is generally known that the resistor layer 5 is exposed by exposing the resistor layer 5 by sequentially stacking and etching the electrode layer 7, and then a protective layer 9 for preventing abrasion is formed on the surface thereof. In this thermal head, a portion where the electrode layer 7 is missing becomes the heat generating portion 11, and a large number of the heat generating portions 11 are arranged to form a heat generating pattern. Then, a voltage is applied to the predetermined electrode layer 7 in accordance with the image to be printed, whereby
Is selectively heated, and the generated heat forms an image on the image receiving surface of the recording material by coloring the thermal paper or transferring the ink ribbon.

[0003]

However, the heating section 11 of the conventional thermal head described above removes the electrode layer 7 by etching to expose the resistor layer 5, so that the resistor layer 5 is exposed.
Even if the protective layer 9 is laminated, the shape of the recess remains on the surface. For this reason, the heat generating portion 11 comes into contact with the recording material at the concave portion, and the state of contact with the recording material or the ink ribbon is poor, and the heat of the heat generating portion 11 is not sufficiently transmitted, so that an appropriate color density can be obtained. However, there is a problem that printing unevenness occurs. In order to solve such a problem, for example, in the case of a partial glaze in which a glaze layer is formed in a convex shape (not shown), the leading end portion of the protective layer is removed by polishing, and the heat generating portion 11 is formed as a flat surface to form a recording material. However, in such a shape, since the heat generating portion 11 has a flat surface, fine heat cannot be transmitted to the recording material, and the density distribution of the details in the highlight portion is reduced. A new problem arises in that the texture is not uniform and the roughness is increased.

The present invention has been made in view of the above circumstances, and provides a thermal head capable of improving the contact property with a recording material and transmitting fine heat to the recording material, and a method of manufacturing the same. The purpose is to improve the quality.

[0005]

To achieve the above object, a thermal head according to the present invention comprises a glaze layer formed on an insulating substrate, and a heating resistor layer and an electrode layer formed on the glaze layer. Are sequentially laminated, the electrode layer is etched to expose a part of the resistor layer, and a protective layer is formed on the surface to form a concave heat generating portion on the surface of the protective layer. A convex portion having a tip higher than the surface of the protective layer laminated on the electrode layer is formed at the center of the concave heat generating portion.

A method of manufacturing a thermal head according to the present invention is a method of manufacturing a thermal head having a concave heat-generating portion on the surface of a protective layer, wherein a projecting portion forming layer is formed on the protective layer, Forming a mask on the surface of the protruding portion forming layer corresponding to the heat generating portion with a width smaller than that of the heat generating portion, etching the protruding portion forming layer using the mask as an etching mask, and removing the mask to form a center. In this case, a concave heat generating portion having a convex portion is obtained.

In the thermal head configured as described above,
Since the convex portion higher than the surface of the protective layer protrudes from the concave heat generating portion, the recording material comes into close contact with the front end surface of the convex portion, heat is sufficiently transmitted, and an appropriate color density can be obtained. In addition, since the protruding portions protrude with a narrow width, fine heat can be transmitted.

In the method for manufacturing a thermal head, a protruding portion forming layer is formed on a protective layer, a mask is formed on the surface of the protruding portion forming layer, and the protruding portion forming layer is etched.
A convex portion having an arbitrary height can be formed at the center of the concave heat generating portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a thermal head and a method for manufacturing the same according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view of a thermal head according to the present invention. The thermal head 21 includes an insulating substrate 23
A glaze layer 25 is formed thereon, and a heating resistor layer 27 and an electrode layer 29 are sequentially laminated thereon, and the electrode layer 29 is etched to expose the resistor layer 27, and the surface thereof is worn. A protective layer 31 for prevention is formed. Therefore, in the thermal head 21, by etching the electrode layer 29, the heat generating portion 33 appears as a concave portion 35 on the surface of the protective layer 31.

A convex portion 37 is formed at the center of the concave portion 35, and the convex portion 37 is formed on the protective layer 31 laminated on the electrode layer 29.
It protrudes higher than the surface. Therefore, the heat in the heat generating portion 33 is transmitted from the bottom of the concave portion 35 to the tip of the convex portion 37. The convex portion 37 has a width w of 40 μm,
The height h from the surface of the protective layer 31 is about 4 μm. By projecting the projections 37 from the surface of the protective layer 31, the contact with the recording material is improved, and fine heat can be transmitted to the recording material. However, if the projection amount is excessive, While the heat transfer from the heat generating part 33 decreases,
Dust (scrap of a recording material or the like) may be caught, thereby deteriorating the recording quality. Therefore, the height h from the surface of the protective layer 31 is preferably about 4 μm as described above.

Next, a procedure for manufacturing the thermal head 21 thus configured will be described with reference to FIG. FIG. 2 shows FIG.
FIG. 7 is a cross-sectional view showing a procedure for manufacturing the thermal head shown in FIG. First, as shown in FIG. 2A, a glaze layer 25 made of glass or the like is formed on an insulating substrate 23 made of a material such as alumina. Next, a resistor layer 27 is formed on the glaze layer 25 with a predetermined thickness by an RF sputtering method. Further, on the resistor layer 27, an electrode layer 29 made of an alloy of aluminum and silicon or the like is formed with a predetermined thickness by a DC sputtering method.

The electrode layer 29 is formed by photoetching.
It is formed in a predetermined shape so that the resistor layer 27 is exposed. The portion from which the electrode layer 29 has been removed becomes a concave heat generating portion 33. Resistor layer 27 exposed by removing electrode layer 29
Then, a protective layer 31 made of silicon dioxide or the like is formed on the electrode layer 29 by RF sputtering. Next, the protrusion forming layer 41 is formed on the protective layer 31 with silicon tetranitride or the like.
To form Thereafter, a mask 43 having a width smaller than that of the concave portion 35 is formed in a portion corresponding to the heat generating portion 33 of the projecting portion forming layer 41, and as shown in FIG. Etch. afterwards,
By removing the mask 43, the heat generating portion 33 shown in FIG. 1 having the convex portion 37 formed at the center is obtained.

In the thermal head 21 configured as described above, a predetermined voltage is applied to the heating section 3 in accordance with an image to be printed.
3, the heat generating portion 33 generates heat, and the heat is transmitted to the tip of the convex portion 37. As a result, an image is formed on the image receiving surface of the recording material by coloring of the thermal paper in contact with the tip of the convex portion 37 or transfer of the ink ribbon. In such an operation, the thermal head 21 is provided with the concave heating section 33.
From the surface of the protective layer 31 laminated on the electrode layer 29, the recording material pressed by the platen comes into close contact with the distal end surface of the convex portion 37, and the conventional concave portion The heat generating portion 33 comes into better contact with the recording material as compared with the heat generating portion that has remained in the shape. Also,
Convex part 3 with narrower width than conventional heat generating part with polished flat surface
Since the protrusions 7 protrude, fine heat can be transmitted, and the density distribution of the highlight portion becomes uniform.

In the above-described example, the case where the convex portion 37 is provided on the entire glaze type thermal head has been described. However, the thermal head according to the present invention has the convex shape provided on the partial glaze type thermal head. You may.

[0015]

As described above in detail, according to the thermal head of the present invention, the convex portion is formed to project from the concave heat-generating portion, and its tip is made higher than the surface of the protective layer. By making close contact with the front end surface of the projection, heat can be sufficiently transmitted, an appropriate color density can be obtained, and image quality can be improved. In addition, since the convex portion projects with a narrow width, fine heat can be transmitted, the density distribution of details can be made uniform, and the roughness of the highlight portion can be eliminated.

According to the method of manufacturing a thermal head according to the present invention, a projecting portion forming layer is formed on a protective layer, and a mask is formed on the surface of the projecting portion forming layer to etch the projecting portion forming layer. Thus, a concave heat generating portion having a convex portion at the center can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a thermal head according to the present invention.

FIG. 2 is a sectional view showing a procedure for manufacturing the thermal head shown in FIG.

FIG. 3 is a sectional view of a conventional thermal head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Thermal head 23 Insulating substrate 25 Glaze layer 27 Heating resistor layer 29 Electrode layer 31 Protective layer 33 Heating part 37 Convex part

Claims (2)

[Claims] 1. A glaze layer is formed on an insulating substrate, a heating resistor layer and an electrode layer are sequentially laminated on the glaze layer, and the electrode layer is etched to expose a part of the resistor layer. And forming a protective layer on the surface of the protective layer to form a concave heat generating portion on the surface of the protective layer. A thermal head characterized by forming a convex portion having a high tip. 2. A method for manufacturing a thermal head having a concave heat generating portion on a surface of a protective layer, the method comprising forming a projecting portion forming layer on the protective layer, the projecting portion corresponding to the concave heat generating portion. A mask is formed on the surface of the formation layer with a width smaller than that of the heat-generating portion, and the mask is used as an etching mask to etch the protruding portion-forming layer. A method for manufacturing a thermal head.