JPH04347663A - Manufacturing method of thermal print head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal print head used in a thermal printer.

0002

[Prior Art] Conventional thermal printers have problems when printing at high speed, especially when printing on paper with a rough surface.
There was a problem in that printing quality was poor due to poor transfer and other factors.

To solve this problem, conventionally, as shown in FIG. 5, the width (W) of the glaze 2 formed on the substrate 1 has been changed.
This was achieved by making the glaze narrower and increasing the height (H) of the glaze. Further, by making the thermal print head have an end-face type structure, the heating resistor portion 5 could be formed in a portion of the glaze where the radius of curvature is small. As shown in FIG. 6, a manufacturing method for protruding the heating resistor forming portion of the glaze is as shown in FIG. A method of reducing the radius of curvature by printing and baking the second glaze 3 has been proposed. Furthermore,
As shown in FIG. 7, after forming a glaze on the substrate 1 by printing and baking, the heating element forming part is covered with a resist or the like in order to make the heating element forming part protrude, and the non-covered part is removed by etching. A method was proposed to make it convex.

0004

[Problems to be Solved by the Invention] When manufacturing a thermal print head using each of the conventional structures, in the forming method shown in FIG. It is a value. Any wider than this (W
) becomes smaller, the height (H) becomes smaller, and the height (H) becomes smaller.
When the width (W) is increased, the width (W) increases, and as a result, the radius of curvature r of the glaze does not change. Further, in the case of the forming method shown in FIG. 6, the second glaze forming the heating element part has a width of 10
A thickness of 0μ to 200μ and a height of about 40μ are required. This glaze is formed by a general screen printing method, but the printing pattern accuracy is about ±100μ, and the width (W) of the glaze formed after baking increases, resulting in stable printing quality. I couldn't. Furthermore,
In the case of the formation method shown in Fig. 7, the shape precision variation of the glaze formed on the substrate is approximately ±10%, and due to the synergistic effect with the variation in the amount of etching in the non-coated area, the variation in the radius of curvature r after the glaze is finished is also large. Become. For this reason, as in the case of the forming method shown in FIG. 6, variations in printing quality were likely to occur depending on the head.

An object of the present invention is to accurately produce a glaze with a small radius of curvature r in order to obtain good printing on rough paper and high print quality.

[0006]

[Means for Solving the Problems] In order to obtain a glaze with a small radius of curvature, the present invention provides a substrate 1 or a first glaze 2 with a contact angle of 4 with a second glaze 3 during melting.
The main feature is that this is a manufacturing method in which the second glaze 3 is formed after coating the substance 4 with an angle of 5° or more.

[0007]

Embodiments Below, embodiments of the present invention will be explained based on the drawings.

FIG. 1 shows a side cross-sectional view showing a method of manufacturing a thermal print head according to the present invention, and a pattern diagram of a coating material.

FIGS. 2, 3, and 4 are explanatory diagrams of a method for manufacturing a thermal print head according to the present invention. In the figure, 1 is a substrate, 2 is a first heat-resistant glazed glass, 3 is a second heat-resistant glazed glass, 4 is a coating material, 5 is a heating resistor part, 6 is a common electrode part, and 7 is an insulating layer ,
8 is a heating resistor layer, 9 is an electrode layer, and 10 is a protective film layer.

[0010] On the substrate 1 or on the first glaze 2 on the substrate 1, the contact angle with the second glaze 3 during melting is 45.
A method for manufacturing a thermal print head that obtains a glaze with a small radius of curvature by forming a second glaze after coating the material 4 with a radius of curvature greater than or equal to 50° is as follows. Although Pt will be described as an example of the material 4 that satisfies the contact angle of 45°, the material used for coating is not limited to this.

First, Pt is deposited on a heat-resistant insulating substrate 1 made of alumina or the like using a vacuum thin film device such as sputtering or a general screen printing method to form the first layer of Pt on the substrate surface as shown in FIG.
The film is formed on areas other than the glaze forming area. Next, on the alumina surface 11 other than this Pt pattern part, a high melting point type glass frit is applied to a height of 6 by a general screen printing method.
It is printed to a thickness of about 0μ and fired at a firing temperature of about 980°C to 1000°C. At this time, the firing temperature of the first glaze 2 is preferably a temperature below the melting point of the coating material.

[0012] Generally, on a surface with a dense surface, the surface tension is small, and this surface is most likely to grow as an interface. Conversely, the sparser the surface, the more foreign particles will be attracted to the surface, making the arrangement denser. Therefore, when using conventional manufacturing methods,
Because the partially glazed glass is directly printed and fired on the heat-resistant insulating substrate 1 such as alumina, it may appear rough if the contact angle is <45° due to the effects of unevenness and pores on the substrate surface. The contact angle of the substrate decreased, and the formed glaze spread and wetted easily over the substrate surface. When firing the glaze, the interfacial tension between the first glaze 2 and the coated substance 4 is greater than the surface tension of the substance 4 coated on the substrate 1. Glaze 2 results in growth with a small radius of curvature r.

Next, on the substrate 1 having this partial glaze, an insulating material layer 7 such as SiN is formed by sputtering or a vacuum thin film apparatus such as CVD. After this, SiN
The portion a shown in FIG. 2 of the common electrode pattern forming portion of the insulator layer 7 is removed by etching or the like so that it can be electrically connected to the thin film electrode pattern to be formed in the subsequent steps.

On the heat-resistant insulating substrate 1 formed as described above, a heating resistor layer 8 and an electrode layer 9 are formed into a laminated film using a vacuum thin film apparatus such as sputtering. Next, a photoresist is applied to the entire surface of this laminated film using a general spin coater, roll coater, etc., and after prebaking, it is exposed to light using a photomask, developed, and etched to form a heating resistor and an electrode pattern. Thereafter, an insulating heat-resistant protective layer 10 having wear-resistant and oxidation-resistant functions is formed on this thin film pattern using a vacuum thin film apparatus such as sputtering.

FIG. 3 shows another embodiment 2 of the method for manufacturing a thermal print head according to the present invention. In this embodiment, Pt will be described as an example of a material that satisfies the contact angle of 45°. First, a high-melting point type glass frit is printed on a heat-resistant insulating substrate 1 such as alumina to a height of about 40 μm using a general screen printing method, and fired at a temperature of about 980°C.
The first glaze 2 is formed by firing at 1000°C. It is desirable that the height of the first glaze 2 be as thin as possible, and the firing temperature of the glaze must be kept below the melting point of the substance to be coated. The radius of curvature r of this first glaze 2 is preferably as large as possible, and as a measure of wetting with the substrate surface, a contact angle of 10° or less is desirable. Next, Pt is printed and fired by a screen printing method on areas other than the second glaze portion 3 where the heating element portion 6 is formed to form a pattern. Furthermore, the heating element formation position 2 on the first glaze (P
A second glaze 3 is printed and fired by a screen printing method between the t-patterns. At this time, since the surface on which the second glaze 3 is formed on the first glaze 2 is smooth, the influence on the contact angle is small, and furthermore, the surface energy of the second glaze during melting is P
The contact angle is 45° because it is larger than the surface energy of t.
The second glaze 3 formed under the above tension grows with a small radius of curvature r. After this, the coated P
t is removed by etching.

Heat-resistant insulating substrate 1 formed as described above
A laminated film is formed on top of the heating resistor layer 8 and electrode layer 9 using a vacuum thin film apparatus such as sputtering. Next, apply photoresist to the entire surface of this laminated film using a general spin coater.
It is coated using a roll coater or the like, and after prebaking, it is exposed to light using a photomask, developed, and etched to form a heating resistor and an electrode pattern. Thereafter, an insulating heat-resistant protective layer 10 having wear-resistant and oxidation-resistant functions is formed on this thin film pattern using a vacuum thin film apparatus such as sputtering.

FIG. 4 shows another embodiment 3 of the method for manufacturing a thermal print head according to the present invention. In this example, the purpose of obtaining a glaze with a small radius of curvature is to leave a part of the coating material as a common electrode (thick film pattern) 6.
It is intended to be used in electrical continuity with the thin film electrode layer 9. A as a substance that satisfies the contact angle of 45°
Although the description will be made using u as an example, the material used for coating is not limited to this.

First, a first glaze 2 is formed on a heat-resistant insulating substrate 1 made of alumina or the like by the same process as in Example 2. Next, a second glaze portion 3 forming a heating element portion is formed.
In addition, a pattern is formed by printing and firing Au using a screen printing method. Next, a second glaze 3 is printed at the heating element formation position (between the Au patterns) on this first glaze 2 by screen printing, and fired at a firing temperature of 800°C to 980°C.
It is formed by firing at ℃. At this time, the same surface energy effect as in Example 2 is obtained, and the second glaze 3 formed under tension with a contact angle of 45° or more grows with a small radius of curvature r. After this, Au is removed by etching or the like. At this time, the common electrode side pattern 6 of the Au pattern is covered with a resist or the like, and only the uncoated portion of the Au pattern on the individual electrode pattern side is removed by etching.

On the heat-resistant insulating substrate 1 formed as described above, a heating resistor layer 8 and an electrode layer 9 are laminated using a vacuum thin film device such as sputtering in the same steps as in Examples 1 and 2. form. Next, a photoresist is applied to the entire surface of this laminated film using a general spin coater, roll coater, etc., and after prebaking, it is exposed to light using a photomask, developed, and etched to form a heating resistor and an electrode pattern. This thin film electrode pattern 9 is made of the Au
Because it is electrically connected to the thick film pattern 6, it has a power capacity that is completely different from line-type thermal print heads with a large number of dots and edge-type thermal print heads where it is difficult to secure a sufficient common electrode width. It also has the effect of preventing printing density defects due to voltage drop during dot energization. Thereafter, an insulating heat-resistant protective layer 10 having wear-resistant and oxidation-resistant functions is formed on this thin film pattern using a vacuum thin film apparatus such as sputtering.

Table 1 below shows the results of a comparison of the radius of curvature, contact angle, ribbon peeling distance, and transferability of thermal print heads manufactured by the manufacturing method of this embodiment and the conventional manufacturing method.

[0021]

[Table 1]

When forming a partial glaze using the conventional manufacturing method, the limit values for the glaze width (W) were approximately 600 μm and the glaze height (H) was approximately 50 μm, but with the manufacturing method of the present invention, When forming, the width of the glaze (
A protruding glaze with a W) of 300 μm and a glaze height (H) of about 60 μm can be produced. Furthermore, since the surface of the alumina substrate or the like on which the glaze is formed is coated, it is possible to suppress the influence of surface roughness of the substrate on the surface roughness of the glaze apex.

[0023]

As explained above, by manufacturing a thermal print head using the manufacturing method according to the present invention, it is possible to supply a thermal print head having a glaze with a small radius of curvature r, thereby improving the following points.

(1) Regarding printing quality, the paper contact property has been improved, and in particular, the occurrence of transfer defects and the like during high-speed printing on rough paper, which was a major problem, has been improved.

(2) A thermal print head having a glaze with a small radius of curvature r can increase the margin of the head mounting angle, and as a result, the ribbon separation distance (separation time) can be shortened.

As explained above, the manufacturing method according to the present invention improves the quality of the material of the thermal print head and contributes to the improvement of print quality.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a thermal print head manufactured by the manufacturing method according to the present invention. and a pattern shape diagram of the coating material.

FIG. 2 is an explanatory diagram showing a method for manufacturing a thermal print head according to the present invention.

FIG. 3 is an explanatory diagram showing a method for manufacturing a thermal print head according to the present invention.

FIG. 4 is an explanatory diagram showing a method for manufacturing a thermal print head according to the present invention.

FIG. 5 is a side sectional view showing the configuration of a thermal print head according to a conventional manufacturing method.

FIG. 6 is a side sectional view showing the configuration of a thermal print head according to a conventional manufacturing method.

FIG. 7 is a side cross-sectional view showing the configuration of a thermal print head according to a conventional manufacturing method.

[Explanation of symbols]

1 Board 2 First heat-resistant glazed glass 3 Second heat-resistant glazed glass 4 Coating substance 5 Heating resistor part 6 Common electrode part 7 Insulator layer 8 Heat generating resistor layer 9 Electrode layer 10 Protective film layer 11 Alumina surface

Claims (1)

[Claims] 1. A method for manufacturing a thermal print head comprising forming glazed glass (hereinafter referred to as glaze) on a substrate, and forming a heating resistor layer and an electrode layer on the glaze, the method comprising: The first formed on
coating the glaze with a substance that has a contact angle of 45° or more with the first glaze or the second glaze when melted; and A method for manufacturing a thermal print head, comprising the steps of printing and firing a glaze.