JPH05124238A - Preparation of end face type thermal head - Google Patents

Abstract

PURPOSE:To provide a method for preparing an end face type thermal head wherein fluctuation of film thickness of an overcoat glass can be decreased and an arbitrary film thickness can be obtd. and in addition, even a fine wiring pattern can be masked with good accuracy. CONSTITUTION:A heat generating resistor 2 is provided on the top part of an end face substrate 1 and a masking 3 is applied on the part where an overcoat glass film is not formed by means of screen printing using a resin and then, this substrate 1 is immersed in a paste 11 of the overcoat glass and after it is taken up, the substrate 1 is rotated. By rotating the base sheet 1, the paste film 11' adhered on the substrate 1 becomes uniform in thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an end face type thermal head, and more particularly to a method for manufacturing a thick film end face type thermal head characterized by the step of forming an overcoat glass film.

[0002]

2. Description of the Related Art In a thick film end face type thermal head, a heating resistor 31 is provided on the top of an end face substrate 30 as shown in FIGS. The overcoat glass film provided on the top side of the substrate 30 cannot be formed by screen printing due to the shape of the substrate 30, and thus is formed by the dip method.

The dip method is performed by the procedure shown in FIGS. First, in FIG. 8 and FIG. 9, the top side of the substrate 30 is immersed in the paste 40 of the overcoat glass. After the immersion, the substrate 30 is pulled up from the paste 40 as shown in FIG. As a result, the overcoat glass 41 ′ is attached to the top side of the substrate 30. Further, by drying the overcoat glass 41 ′ in FIG. 11, the overcoat glass film 41 is formed on the substrate 30, and the heating resistor 31 is covered with the film 41.

[0004]

However, in the dipping method, a considerable unevenness occurs in the film thickness of the overcoat glass in the longitudinal direction of the heating resistor 31. This film thickness unevenness is shown in Table 1. However, Table 1 shows the film thickness unevenness of the overcoated glass after drying, and the overcoated glass was C. G. It is abbreviated and is described about three kinds of paste viscosities. Further, the right end, center, and left end of the substrate represent respective positions of the heating resistor 31 shown in FIG.

[0005]

[Table 1]

The uneven film thickness of the overcoat glass as shown in Table 1 causes the following problems. : Since the permeation amount of the overcoat glass varies greatly depending on the heating resistor part, the resistance value of the heating resistor after the overcoat glass film is formed varies greatly, and the resistance value is sufficient even if pulse trimming is performed. Dot dots will appear and it will be defective. : When printing is performed with uneven film thickness, the thick portion of the overcoat glass film is thinly printed, and the thin portion of the overcoat glass film is darkly printed, which causes a print density difference and deteriorates the print quality.

Further, in the above-mentioned dipping method, the viscosity of the applicable paste is about 4000 cps at the finest, and at such paste viscosity, since the viscosity is low, it is difficult to arbitrarily set the film thickness. is there. Further, when the dipping method is performed, it is necessary to mask the substrate portion on which the overcoat glass film is not formed, and a heat resistant tape is used for this masking. The heat-resistant tape having a size corresponding to the pattern is attached to a predetermined portion of the substrate by alignment. However, in this case, the tape sticking accuracy is low with respect to the wiring pattern on the substrate, so it is difficult to cover or expose the fine pattern with the overcoat glass film.

In addition to this, as can be seen from FIG.
When the heat resistant tape 50 is attached to a predetermined portion of the substrate 30 to form the overcoat glass film 41, the film thickness at the boundary 42 between the substrate 30 and the heat resistant tape 50 becomes thick. When the heat-resistant tape 50 is peeled off in this state, the film 41 at the boundary 42 is shown in FIG.
It becomes a thick film shape as shown in. Incidentally, the film thickness dimension b of the boundary 42 is about 90 μm. Such a thick film becomes a problem when a hard coat that protects the IC and the wire is applied in a subsequent process.

That is, when the film thickness of the overcoat glass at the boundary 42 is large, I provided on the substrate 30 as shown in FIG.
In some cases, the hard coat 70 that protects the wire 61 that connects the C60 and the IC 60 to the wiring pattern on the substrate does not cover the overcoat glass film 41. In this case, corrosion easily occurs from the portion of the film 41 (boundary 42) not covered with the hard coat 70. Also, as shown in FIG.
In some cases, the hard coat 70 largely flows over the boundary 42 toward the top side of the substrate 30, and the portion covering the boundary 42 has a projection shape. In this case, the protrusions of the hard coat 70 tend to scratch the printing paper.

The ideal shape of the hard coat 70 is shown in FIG.
6 shows. According to this, the overcoat glass film 41
There is no thick film portion when the heat resistant tape is peeled off, and the hard coat 70 covers the end portion of the film 41. In view of the above problems, an object of the present invention is to 1) reduce unevenness in film thickness of overcoat glass on a heating resistor, 2) film of an end of the overcoat glass film (a boundary with a heat-resistant tape). It is to provide a manufacturing method of an end face type thermal head that reduces unevenness in thickness, 3) obtain an arbitrary overcoat glass film thickness, 4) easily perform masking even with a fine wiring pattern. ..

[0011]

The method for manufacturing an end surface type thermal head of the present invention which achieves the above-mentioned object, comprises immersing the heating resistor side of a substrate provided with a heating resistor in a paste of overcoat glass, The method is characterized by including the step of pulling up the substrate from the paste and rotating the substrate.

In the manufacturing method of the present invention, the substrate is rotated after being immersed in the paste of the overcoat glass, so that the film thickness of the overcoat glass becomes uniform and thin, and the unevenness of the film thickness hardly occurs. The difference in the film thickness depending on the body part is minimized. Further, since the substrate is rotated to make the film thickness of the overcoat glass uniform, a highly viscous paste can be used and an overcoat glass film having an arbitrary film thickness can be formed.

Further, before the substrate is dipped, if the masking is applied to the substrate portion where the overcoat glass film is not formed by screen printing using a resin, the masking accuracy is improved, and the overcoat glass film allows fine wiring. You will be able to cover and expose the pattern. In the manufacturing method of the present invention, the rotation speed of the substrate is 200 to 8
About 000 rpm is appropriate for uniformizing the overcoat glass film. The resin used as the masking material is not specified as long as it has excellent heat resistance and chemical resistance, and examples thereof include polyimide and vinyl resin derivatives.

Incidentally, steps other than the step of forming the overcoat glass film (providing a heating resistor on the substrate, I on the substrate)
C mounting etc.) may be performed in the conventional manner.

[0015]

EXAMPLES A method for manufacturing an end face type thermal head of the present invention will be described below based on examples. First, in FIG. 1, a heating resistor 2 is provided on the top of an end face substrate 1, and a strip-shaped masking 3 is formed on the portion of the substrate 1 not covered with an overcoat glass film by screen printing using an arbitrary resin paste of the previous example. Apply. The side surface of the substrate 1 has a shape as shown in FIG.

Next, referring to FIG. 2, the substrate 1 is placed in the paste 11 of the overcoat glass placed in a suitable container 10.
Dip from the top. The paste used has an appropriately adjusted viscosity in order to obtain a desired film thickness. After the immersion, as shown in FIG. 3, the substrate 1 is pulled up from the paste 11. At this point, the paste 11 ′ is attached to the portion of the substrate 1 dipped in the paste 11. The film thickness of the attached paste 11 'varies depending on the portion of the heating resistor 2 as described above. Here, for example, the substrate 1 is rotated at a speed of about 2000 rpm in the arrow direction. As a result, the film thickness of the overcoat glass on the top of the substrate becomes thin and uniform.

After the substrate 1 is dried, the masking 3 is peeled off and fired to form the overcoat glass film 12 on the dipping portion provided on the top of the substrate 1 and containing the heating resistor 2. 4). Of course, the film 12 is not formed on the portion 3 ′ where the masking 3 is removed. Table 2 shows that the overcoat glass film is made uniform by rotating the substrate as described above. Here, 2
As with Table 1, the thickness of the overcoat glass at three locations of the heating resistor provided on the top of the substrate is shown, using various types of high-viscosity paste.

[0018]

[Table 2]

As can be seen from Table 2, there is almost no film thickness unevenness, and film thickness unevenness due to the difference in viscosity does not occur. Further, as shown in FIG. 6, the thickness a of the overcoat glass film 12 at the boundary 13 between the substrate 1 and the masking 3 has a dimension a of about 30 μm, which is the conventional value (dimension b: 90 in FIG. 13).
It is considerably thinner than (μm). Further, FIG. 5 shows that an overcoat glass film having an arbitrary film thickness can be obtained by adjusting the viscosity of the paste. According to this, it can be seen that a film thickness of about 20 μm can be obtained by using a paste of 4000 cps at a high precision, but a thick film can be obtained in the present invention almost in proportion to the viscosity of the paste.

In addition to this, since the resin paste is masked by screen printing, even a very fine wiring pattern can be easily masked. By the way, if the wiring pattern is masked with a heat-resistant tape as in the past, the accuracy of the heat-resistant tape attachment is several hundred μm to several m
Although there is a deviation of about m, the printing deviation is 100 μ in the present invention.
It is less than m and the masking accuracy is high.

[0021]

As described above, according to the method of manufacturing the end face type thermal head of the present invention, the substrate is rotated after being immersed in the paste of the overcoat glass.
It has the following effects. (1) Since the overcoat glass film having a uniform thickness is formed on the heating resistor in the longitudinal direction thereof, the printing quality is improved. (2) The film thickness at the end (boundary with the masking) of the overcoat glass film becomes thin. (3) A high-viscosity paste can be used, and an overcoated glass film having an arbitrary film thickness can be easily obtained.

Further, when masking is performed by screen printing using a resin, the following effects can be obtained. (4) High-precision masking can be performed even with a fine wiring pattern.

[Brief description of drawings]

FIG. 1 is a diagram showing a first step (step of forming a heating resistor and masking) in the manufacturing method of the present invention.

FIG. 2 is a second process (substrate dipping process) diagram in the manufacturing method of the present invention.

FIG. 3 is a diagram showing a third step (substrate lifting / rotating step) in the manufacturing method of the present invention.

FIG. 4 is a diagram illustrating a fourth step (drying / baking step of the substrate) in the manufacturing method of the present invention.

FIG. 5 is a graph showing the relationship between paste viscosity and overcoat glass film thickness in the present invention and the related art.

FIG. 6 is a partially omitted side view showing the top of the substrate obtained by the manufacturing method of the present invention.

7A and 7B are a plan view and a side view showing a general end face substrate of an end face type thermal head.

FIG. 8 is a diagram showing a first step (step before dipping the substrate) in the conventional manufacturing method.

FIG. 9 is a diagram illustrating a second step (step during immersion of the substrate) in the conventional manufacturing method.

FIG. 10 is a diagram showing a third step (step during pulling up of the substrate) in the conventional manufacturing method.

FIG. 11 is a diagram illustrating a fourth step (step during drying of the substrate) in the conventional manufacturing method.

FIG. 12 is a partially omitted side view showing a top state of a substrate obtained by a conventional manufacturing method.

FIG. 13 is a partially omitted side view showing a state in which the heat-resistant tape is peeled off from the top of the substrate obtained by the conventional manufacturing method.

FIG. 14 is a partially omitted side view showing an embodiment in which a hard coat is applied to a substrate obtained by a conventional manufacturing method.

FIG. 15 is a partially omitted side view showing another embodiment when a hard coat is applied to a substrate obtained by a conventional manufacturing method.

FIG. 16 is a partially omitted side view showing an ideal form when a hard coat is applied to a substrate obtained by a conventional manufacturing method.

[Explanation of symbols]

 1 End face substrate 2 Heating resistor 3 Masking 11 Overcoat glass paste 12 Overcoat glass film

Claims (2)

[Claims] 1. A method of manufacturing an end surface type thermal head, which comprises: immersing a heating resistor side of a substrate provided with a heating resistor in a paste of overcoat glass, then pulling up the substrate from the paste and rotating the substrate. A method for manufacturing an end-face type thermal head, comprising: 2. The method of manufacturing an end face type thermal head according to claim 1, wherein, before the dipping, masking is applied to the substrate portion where the overcoat glass film is not formed by screen printing using a resin.