JP2001301217A - Thermal print head and method of manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal head suitable for high speed printing in which print quality is enhanced, and a method of manufacture. SOLUTION: A heat insulation layer made of a heat insulation material having a chevronwise cross-section is protruded from one major surface of a heat resistant substrate, a heater layer is laminated on the surface part of the heat resistant substrate including the heat insulation layer, a common electrode and an individual electrode are applied to the surface of the heater layer such that the forward end parts have a specified interval at the head part of the heat insulation layer, and a heat resistant wear resistant protective film layer is formed on the surface part including the part between the forward end parts of the common electrode and individual electrode wherein the protective film layer at a part corresponding to the head part of the heat insulation layer serves as a recording part. In such a thermal print head, the recording part has a continuous convex surface on the top and the protective film layer is made thicker by an amount corresponding at least to the thickness of the common electrode and individual electrode in a region other than that where the heat insulation layer protrudes as compared with the protective film layer between the forward end parts of the common electrode and individual electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a thermal print head used in a thermal printer and a method of manufacturing the same.

[0002]

2. Description of the Related Art Heretofore, there has been a dot impact printer equipped with an impact dot head which can simultaneously print on a plurality of recording media. This dot impact printer is for printing by pressing a copy-type recording medium made of pressure-sensitive paper (registered trademark) using an impact dot head. However, this dot impact printer has problems such as loud printing noise, slow printing speed, poor image quality, and necessity of regular maintenance and inspection.

On the other hand, a thermal printer using a thermal print head (hereinafter simply abbreviated as a thermal head) does not produce a printing noise, has a high printing speed, is easy to maintain and inspect, and so on. Because of the low running cost, they are frequently used in printers for distribution terminals, facsimiles, digital plate making machines, and the like. Hereinafter, a schematic configuration of the thermal head will be described with reference to FIG. In FIG. 3, a ceramic substrate 2 is fixed on an aluminum substrate 1 as a support substrate. On the surface of the ceramic substrate 2, a glaze layer 3 as a heat insulating layer having a mountain-shaped cross section is formed in a row in a direction perpendicular to the paper surface.
The heating resistor layer 4 is laminated on the surface of the ceramic substrate 2 including A common electrode 5 is provided on the surface of the heating resistor layer 4.
The common electrode 5 is formed on one side of the glaze layer 3 and the individual electrode 6 is formed on the other side. These common electrode 5 and individual electrode 6
Are opposed to each other with a predetermined gap at the apex of the chevron of the glaze layer 3. Further, a heat-resistant and abrasion-resistant protective film layer 7 is formed on the surface of the common electrode 5 and the individual electrodes 6, and the top of the protective film layer 7 is a recording portion 10a.

[0004]

In the above-mentioned thermal head, the ends of the common electrode 5 and the individual electrodes 6 are provided on both sides of the top of the heating resistor layer 4 having a continuous convex curved surface. The protective film layer 7 is formed with a step on the surface, and the protective film layer 7 having a predetermined thickness is laminated on the surface having the step, thereby forming a step on the top itself of the protective film layer 7 which becomes the recording portion 10a. Although this step is suppressed to about 0.5 to 1.5 μm, if the recording medium is relatively thick or hard, a space is formed between the bottom near the step and the recording medium (not shown). However, there has been a problem that it is difficult for sufficient heat to be transmitted to the recording medium, and the printing quality is reduced accordingly. In addition, the step difference increases the contact resistance of the recording medium to the recording unit 10a, increases the torque loss of the recording medium feeding mechanism, and is one factor that makes high-speed printing difficult.

The present invention has been made to solve the above problems, and has as its object to provide a thermal head suitable for high-speed printing while improving printing quality.

[0006]

The invention according to claim 1 is
A heat-insulating layer made of a heat-insulating material is provided on one main surface of the heat-resistant substrate so as to have a chevron-shaped cross section, and a heat-generating resistor layer is laminated on the surface of the heat-resistant substrate including the heat-insulating layer. Having a common electrode and an individual electrode respectively attached to the surface of the heating resistor layer so as to have a predetermined interval at the top of the head,
Heat resistant to the surface including the common electrode and the tip of the individual electrode,
In a thermal print head in which a wear-resistant protective film layer is formed and the protective film layer at a portion corresponding to the top of the heat insulating layer is a recording portion, the recording portion has a continuous convex curved surface, a common electrode and a common electrode. Compared with the protective film layer between the tip portions of the individual electrodes, the thickness of the protective film layer in the region other than the area where the heat insulating layer is protruded is increased by at least the thickness of the common electrode and the individual electrode. Things.

According to a second aspect of the present invention, a heat insulating layer made of a heat insulating material is provided on one main surface of the heat resistant substrate so as to have a cross-sectional shape of an angle, and the surface portion of the heat resistant substrate including the heat insulating layer is provided. And forming a common electrode and an individual electrode respectively attached to the surface of the heating resistor layer such that the tips have a predetermined distance from each other at the top of the heat insulating layer. Forming a heat-resistant, abrasion-resistant protective film layer on a surface portion including between the common electrode and the tip of the individual electrode, and recording the protective film layer at a portion corresponding to the top of the heat insulating layer. The method of manufacturing a thermal print head described above further comprises the step of polishing only the protruding region of the protective film layer corresponding to the heat insulating layer to form a continuous convex curved surface on the top of the recording portion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a plan view showing the entire structure of a thermal head according to the present invention, partially cut away for ease of understanding, and FIG. 2 is an enlarged cross-sectional view of the thermal head taken along line XX. is there. In each of these drawings, a plane shape is formed to be elongated, and one main surface of an aluminum substrate 1 having a thickness determined to have a predetermined rigidity,
Heat resistance and heat transfer coefficient is relatively large 0.5-1.0mm
A thick ceramic substrate 2 and a plurality of ICs 8 arranged in rows on its side are mounted. A glaze layer 3 as a heat insulating layer having a mountain-shaped cross section is formed at the center of the ceramic substrate 2 in the width direction. On the surface of the ceramic substrate 2 including the glaze layer 3, a large number of strip-shaped heating resistor layers 4 are laminated in the vertical direction corresponding to print dots.

Among these, the glaze layer 3 is formed by screen printing or the like using glass as a main component, and the heating resistor layer 4 is formed by a thin film forming method such as sputtering using an alloy such as Ta-SiO2 as a film forming source. . The common electrode 5 and the individual electrode 6 are formed on each surface of the heating resistor layer 4 by forming a conductive layer such as aluminum and then performing photoengraving. Among these, the common electrode 5 is formed in a comb-like shape on one side when viewed from the center of the glaze layer 3, and the individual electrode 6 is on the other side, that is, the side on which the IC 8 is disposed, when viewed from the center of the glaze layer 3. The heat-generating resistor layer 4 is formed in a band shape that directly overlaps the heat-generating resistor layer 4. In this case, the respective tips of the common electrode 5 and the individual electrodes 6 are opposed to each other with a predetermined gap at the peak of the chevron of the glaze layer 3. Also, an IC is provided at each other end of the individual electrode 6.
The lead wire 9 derived from 8 is connected. Then, a heat-resistant and wear-resistant protective film layer 7 is formed on the surface of the common electrode 5 and the individual electrodes 6 by, for example, sputtering. As a result, as shown by the alternate long and short dash line, the recording portion 10a having a step is formed. That is, the protective film layer 7 also has a mountain-shaped cross-section corresponding to the protruding region of the glaze layer 3, and the top of the protective film layer 7 is reduced by the thickness of the common electrode 5 and the individual electrode 6. A surface state having a step of 0.5 μm is obtained. In the present embodiment, the recording unit 10 having a step
Only the vicinity of a is, for example, mechanically polished using a lapping tape or a polishing brush, or smoothed with sand blast, and as shown by a solid line, a convex curved surface whose top is continuous in a semi-cylindrical shape. Is formed on the recording section 10b.

In this case, the thickness of the protective film layer 7 between the common electrode 5 and the individual electrode 6 is A, the thickness of the protective film layer 7 on the common electrode 5 other than the protruding region of the glaze layer 3 is B, Assuming that the thickness of the upper protective film layer 7 is C, polishing (or smoothing) is performed so that the following equation is satisfied: A ≦ B = C (1) B (= C) −A ≧ 1.5 μm (2) I do. This means that the protective film layer 7 formed on the surfaces of the common electrode 5 and the individual electrode 6
To ensure that the common electrode 5 and the individual electrode 6 are protected while keeping the thickness as large as possible, whereby the moisture resistance of the electrode can be ensured, and the electrical characteristics can be favorably maintained for a long period of time. .

When the protective film layer 7 is polished or smoothed, it is not limited to the vicinity of the recording portion 10a having a step.
Even if the other surface is polished (or smoothed), the point is that the top of the recording portion 10b forms a continuous convex curved surface and is compared with the protective film layer between the tips of the common electrode 5 and the individual electrode 6. The protective film layer 7 in a region other than the region where the glaze layer 3 is provided.
The protective film layer may be polished so that the thickness remains at least as large as the thickness of the common electrode 5 and the individual electrode 6.

The configuration of the embodiment of the present invention has been described above.
The following description focuses on the elements formed above.

First, an elongated ceramic substrate 2 having a thickness of 0.5 to 1.0 mm having heat resistance and a relatively large heat transfer coefficient is prepared. At the center in the width direction of the ceramic substrate 2, a glaze layer 3 having a cross section of a mountain shape and a height of about 10 to 150 μm is formed linearly in the longitudinal direction by printing and sintering using glass as a material. Next, on the surface of the ceramic substrate 2 including the glaze layer 3, an alloy such as Ta-SiO is used as a film forming source by a thin film forming method such as sputtering.
By laminating about 1 μm and patterning this, a number of strip-shaped heating resistor layers 4 corresponding to print dots are formed. Next, by sputtering, Al (aluminum) or Cr (chromium) is used as a film forming source to a thickness of 0.5.
After forming a conductive layer of about 1.5 μm, the common electrode 5 and the individual electrodes 6 laminated on each surface of the heating resistor layer 4 are formed by photoengraving. In this case, the respective tips of the common electrode 5 and the individual electrodes 6 are formed so as to face each other at a predetermined apex at the peak of the chevron of the glaze layer 3. Then, a protective film layer 7 having a thickness of 2 to 15 μm is laminated on the surface portions of the common electrode 5 and the individual electrodes 6 using, for example, a heat-resistant and abrasion-resistant glass material as a film formation source.

As a result, as shown by the alternate long and short dash line, a recording portion 10a having a step is formed. That is, the protective film layer 7 also has a mountain-shaped cross-section corresponding to the protruding region of the glaze layer 3, and the top of the protective film layer 7 is reduced by the thickness of the common electrode 5 and the individual electrode 6. A surface state having a step of 0.5 μm is obtained. Next, only the vicinity of the recording unit 10a is polished (or smoothed) so as to have a convexly curved surface.
Thereby, the protective film layer 7 formed on the surfaces of the common electrode 5 and the individual electrode 6 is left as thick as possible,
In addition, a thermal head portion for reliably protecting the individual electrodes 6 can be obtained. Then, the back surface of the ceramic substrate 2 is, for example,
The thermal head shown in FIG. 1 or FIG. 2 is mounted on the aluminum substrate 1 with a double-sided adhesive tape.

In the above embodiment, the case where the glaze layer 3 is formed only at the center in the width direction of the ceramic substrate 2 has been described. However, the present invention is not limited to this application. The present invention is also applied to a structure in which a glaze layer is laminated to a uniform thickness on the upper surface 2 and part or all of both sides are etched so that the mountain-shaped glaze layer 3 remains at the center in the width direction. be able to.

Thus, according to the present embodiment, the printing quality can be improved by forming the recording portion 10b having no step. Further, the contact resistance between the recording medium and the recording section 10b can be reduced, and the mechanical torque loss can be reduced, so that the recording medium can be transported at a high speed. The head is obtained.

Further, the top of the recording section has a continuous convex curved surface, and the protective film layer in an area other than the area where the heat insulating layer protrudes as compared with the protective film layer between the common electrode and the tip of the individual electrode. By increasing the thickness by at least the thickness of the common electrode and the individual electrodes, an effect that the electrical characteristics can be favorably maintained for a long period of time can be obtained.

[0018]

As apparent from the above description, according to the present invention, it is possible to provide a thermal head suitable for high-speed printing while improving printing quality.

Further, it is possible to provide a thermal head capable of maintaining good electric characteristics for a long period of time.

[Brief description of the drawings]

FIG. 1 is a plan view showing an entire configuration of a thermal print head constituting an embodiment of a thermal copy printing apparatus according to the present invention, partially cut away in order.

FIG. 2 is a cross-sectional view showing an enlarged part of the thermal print head shown in FIG.

FIG. 3 is a cross-sectional view showing a configuration of a thermal print head constituting a conventional thermal printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Aluminum substrate 2 Ceramic substrate 3 Glaze layer 4 Heating resistor layer 5 Common electrode 6 Individual electrode 7 Protective film layer 8 IC 9 Lead wire 10a, 10b Recording part

Claims (2)

[Claims] 1. A heat-insulating layer made of a heat-insulating material is provided on one main surface of a heat-resistant substrate so as to project in a mountain-shaped cross-section, and a heating resistor layer is laminated on a surface portion of the heat-resistant substrate including the heat-insulating layer. And
A common electrode and an individual electrode attached to the surface of the heating resistor layer such that a tip portion has a predetermined distance from each other at a top portion of the heat insulating layer; and a tip portion of the common electrode and the individual electrode. A heat-resistant, abrasion-resistant protective film layer is formed on the surface portion including the space, and in a thermal print head in which the protective film layer in a portion corresponding to the top of the heat insulating layer is a recording portion, the top portion of the recording portion is It has a continuous convex curved surface, compared with the protective film layer between the common electrode and the tip of the individual electrode, and at least the common thickness of the protective film layer in an area other than the area where the heat insulating layer protrudes is provided. A thermal printhead characterized in that the thickness is increased by the thickness of the electrodes and the individual electrodes. 2. A step of projecting a heat-insulating layer made of a heat-insulating material on one main surface of a heat-resistant substrate so as to have a chevron-shaped cross section, and a heating resistor on a surface portion of the heat-resistant substrate including the heat-insulating layer. Laminating layers, and forming a common electrode and an individual electrode attached to the surface of the heating resistor layer, respectively, such that a tip portion has a predetermined distance from each other at the top of the heat insulating layer, Forming a heat-resistant, abrasion-resistant protective film layer on a surface portion including between the common electrode and the individual electrode, and recording the protective film layer at a portion corresponding to the top of the heat insulating layer. A method of manufacturing a thermal print head as a part, comprising a step of polishing only a protruding region of the protective film layer corresponding to the heat insulating layer, and forming a continuous convex curved surface on the top of the recording part. Characteristic thermal printhead manufacturing method .