JP2002002006A - Thick film type thermal printing head and its forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the trouble without decreasing a durability that is caused by swelling a part of a protecting film 8 from a thick film heating resistor 7 in a thermal printing head in which the heating resistor 7, thin film electrode patterns 4 and 6 for energization to the heating resistor and the protecting film 8 for covering these heating resistor and electrode patterns are formed to a surface of a head substrate 1. SOLUTION: A film thickness of the part of the heating resistor 7 at the protecting film 8 is made smaller than that of the other part, and a protecting film 9 of a second layer is formed to a surface of the protecting film 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thick-film type thermal print head in which a heating resistor for printing is formed as a thick film, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In general,
In this type of thermal print head, a thick film, a heating resistor, an electrode pattern for the heating resistor, and a protective film made of glass or the like covering the heating resistor and each electrode pattern are formed on the surface of a head substrate. With this configuration, the heating resistor portion of the surface of the protective film is partially raised by the thickness of the heating resistor.

Accordingly, when the printing paper is fed while being moved by pressing the platen roller against the heating resistor portion of the surface of the protective film, the printing paper is moved to a raised portion on the surface of the protective film. In particular, sticking such as strong rubbing noise or heat fusion occurs, which may cause problems such as inability to feed the paper smoothly or poor printing.

[0004] In order to improve the smoothness of the paper feed, after forming a protective film, a portion of the surface of the protective film which swells at the heating resistor may be cut off by polishing. .

[0005] However, cutting off the portion of the surface of the protective film that swells at the location of the heat generating resistor by polishing as described above requires a thinner film at the portion of the protective film where the heat generating resistor is formed. The abrasion resistance in this part is reduced, and the durability of the thermal print head is reduced.

[0006] The present invention provides a thermal print head which solves the above-mentioned problems without reducing durability.
And a method for manufacturing the same.

[0007]

In order to achieve this technical object, the present invention provides a method of forming a thick-film heat-generating resistor on a surface of a head substrate, an electrode pattern for energizing the heat-generating resistor, In a thermal print head formed with a protective film covering a resistor and an electrode pattern, the thickness of the protective film at a portion of the heating resistor,
It is characterized in that a second protective film is formed on the surface of the protective film by making it thinner than other portions. Is the thing.

Further, the manufacturing method of the present invention comprises a step of forming a thick-film heating resistor on a surface of a head substrate, a step of forming a current-carrying electrode pattern for the heating resistor, and covering these. Forming a protective film, further comprising: removing a portion of the heating resistor from the surface of the protective film; and, following the removing step, a second protective film is formed on the surface of the protective film. And a forming step. "

[0009]

As described above, the second protective film is formed on the surface of the protective film after the thickness of the protective film in the heating resistor portion is made thinner than the other portions. By doing so, a part of the protective film,
Under the condition that the predetermined thickness is secured by the second protective film, the swelling in the heating resistor portion is caused by reducing the thickness of the protection film in the heating resistor portion. Can be almost eliminated, or the height of the swell can be greatly reduced.

Therefore, according to the present invention, it is possible to surely improve the non-smoothness of paper feeding and the printing failure due to the sticking without lowering the durability.

The second protective film is formed by the same method as that for forming the protective film by forming the lower protective film from the same glass as described in claim 2. Alternatively, the second protective film may be made of Sialon to improve the durability, as described in claim 3.

Further, according to the manufacturing method of the present invention, it is possible to easily reduce the thickness of the protective film at the heating resistor portion by a simple processing, so that a significant increase in cost can be avoided. is there.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 to FIG. 6 show a first embodiment.

In this figure, reference numeral 1 denotes a ceramic head substrate, and a glaze layer 2 is formed on the entire surface of the head substrate.
Are formed.

On the surface of the glaze 2, a common electrode 3 extending in the longitudinal direction, a large number of first electrode patterns 4 extending in a comb-like shape from the common electrode 3, a large number of individual electrodes 5, A second electrode pattern 6 extending thinly from each individual electrode 5 has a film thickness of 1 μm such that one of the first and second electrode patterns 4 and 6 enters between the other electrode patterns. A heating resistor 7 formed of the following gold and extending in a line parallel to the common electrode 3 across both the first electrode pattern 4 and the second electrode pattern 6 is formed by screen printing or the like. It is formed in a thickness of about 3 to 9 microns.

On the surface of the glaze layer 2, a protective film 8 of glass having a thickness of about 6 to 10 μm is formed on the common electrode 2, the first and second electrode patterns 4, 4.
6. Screen printing and subsequent baking are performed so as to cover the individual electrodes 4 and the entire heating resistor 7.

By forming the protective film 8 in this manner, the heating resistor 7 on the surface of the protective film 8 is partially covered by a maximum of about 6 as indicated by reference numeral 8a in FIG. It will rise to a height of about a micron.

Therefore, the raised portion indicated by reference numeral 8a in the protective film 8 is polished to remove the raised portion as shown in FIG. It is removed by cutting to reduce the height. By the removal by the polishing process, the thickness of the protective film 8 can be partially reduced at the heating resistor 7.

After the removal by the polishing process, a second protective film 9 made of glass and having a thickness of about 6 to 10 μm is formed on the surface of the protective film 8 as shown in FIG. , Screen printing and subsequent baking.

Thus, the portion of the heating resistor 7 is
Under the condition that a predetermined thickness is secured by a part of the protective film 8 and the second protective film 9, the swelling at the heating resistor 7 is determined by the thickness of the protective film 8. Can be almost eliminated by reducing the thickness of the heating resistor 7 or the height of the swell can be significantly reduced.

As shown in FIG. 6, the raised portion 8a of the protective film 8 is polished by bringing the rotating grinding wheel A into contact and moving relatively in the longitudinal direction of the heating resistor 7 in this state. Or, as shown in FIG. 7, a belt C having abrasive particles coated on its surface is wound around a plurality of rollers B, and the belt C is brought into pressure contact with the belt C while rotating. This is performed by relatively moving the resistor 7 in the longitudinal direction. As another polishing method, there is a method in which abrasive particles are sprayed on the raised portion 8a of the protective film 8. As a method other than the polishing process, there is a method of removing the raised portion 8a of the protective film 8 by etching with a chemical.

Next, FIGS. 8 to 11 show a second embodiment.

In the second embodiment, the head substrate 1 '
When the glaze layer 2 'is formed on the surface of the glaze layer 2', the heat generation resistor 7 'and the heat generation resistor 7' This is a case where first and second electrode patterns (not shown) for energizing the body 7 'are formed.

Also in this case, a protective film 8 'made of glass is formed on the surfaces of the head substrate 1' and the glaze layer 2 ', so that the heating resistor 7' on the surface of the protective film 8 ' As shown by the reference numeral 8a 'in FIG. 9, the raised portion 8a' is removed by polishing or the like in the same manner as described above so that the raised portion 8a 'is removed as shown in FIG. Or,
Alternatively, the thickness of the protective film 8 'is partially reduced at the portion of the heating resistor 7' by reducing the height.

Next, on the surface of the protective film 8 ', FIG.
As shown in FIG. 7, a second protective film 9 'also made of glass.
Is formed to have substantially the same film thickness by screen printing and subsequent baking, whereby a part of the protective film 8 'and a second protective film are formed on the heating resistor 7'. Under the condition that a predetermined film thickness is secured by 9 ', the swelling at the heating resistor 7' is reduced by reducing the thickness of the protective film 8 'at the heating resistor 7'. Thus, it can be almost eliminated, or the height of the swell can be greatly reduced.

Further, in the third embodiment of the present invention, the second protective film 9 ″ is replaced by a protective film 8,
Instead of glass as in the case of 8 ', it is made of sialon mainly composed of a Si-Al-N-based compound having a smaller thickness than the protective films 8 and 8'.

That is, as shown in FIGS. 4 and 10, after the removal by polishing or the like is completed, the head substrate 1,
1 ′ is placed in a sputtering vessel maintaining a high degree of vacuum, and a sialon target is disposed at a position facing the surface of the head substrate 1, 1 ′. ′ By applying a target voltage to the second protective film 9 ″.
8 ′.

As described above, this second protective film 9 ″ is
By using sialon instead of glass, it is possible to improve the wear resistance and, consequently, the durability, and also to reduce the weight.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a main part of a thermal print head according to a first embodiment.

FIG. 2 is a plan view of FIG.

FIG. 3 is an enlarged cross-sectional view showing a state where a protective film is formed in the first embodiment.

FIG. 4 is an enlarged cross-sectional view of the first embodiment with a raised portion of the protective film removed.

FIG. 5 is an enlarged sectional view showing a state in which a second protective film is formed on the surface of the protective film in the first embodiment.

FIG. 6 is a perspective view showing a state in which the protective film is being polished.

FIG. 7 is a perspective view showing another polishing process.

FIG. 8 is an enlarged sectional view of a main part according to the second embodiment.

FIG. 9 is an enlarged sectional view showing a state where a protective film is formed in the second embodiment.

FIG. 10 is an enlarged cross-sectional view of a second embodiment in which a protruding portion of the protective film is removed.

FIG. 11 is an enlarged cross-sectional view showing a state where a second protective film is formed on the surface of the protective film in the second embodiment.

FIG. 12 is an enlarged sectional view of a main part showing a third embodiment.

[Explanation of symbols]

 Reference Signs List 1, 1 'head substrate 2, 2' glaze layer 3 common electrode 4 first electrode pattern 5 individual electrode 6 second electrode pattern 7, 7 'heating resistor 8, 8' protective film 8a, 8a 'raised portion of protective film 9, 9 ', 9 "Second protective film

Claims (5)

[Claims] 1. A heating resistor having a thick film, an electrode pattern for energizing the heating resistor, on a surface of a head substrate.
In a thermal print head comprising a heating film and a protective film covering the electrode pattern, a thickness of the protective film at a portion of the heating resistor is made thinner than at other portions to protect the protective film. A thick film type thermal print head, wherein a second protective film is formed on the surface of the film. 2. A thick film type thermal print head according to claim 1, wherein said protective film is made of glass, and said second protective film is made of the same glass as said protective film. 3. The protective film according to claim 1, wherein said protective film is made of glass, and said second protective film is made of Sialon containing a Si-Al-N-based compound as a main component. Thick film type thermal print head. 4. A step of forming a thick-film heating resistor on the surface of a head substrate, forming an energizing electrode pattern for the heating resistor, and forming a protective film covering these. And a step of removing a portion of the heating resistor from the surface of the protective film, and a step of forming a second protective film on the surface of the protective film following the removing step. A method for manufacturing a thick film type thermal print head. 5. The method according to claim 1, wherein the step of forming the second protective film comprises:
A method for manufacturing a thick-film type thermal print head, wherein sputtering is performed using a sialon having an i-Al-N compound as a main component as a target.