JPH0557939A - Manufacture of thick film type thermal print head - Google Patents

Abstract

PURPOSE:To reduce manufacturing cost for manufacturing a thermal print head whose heat generating resistor is divided into a plurality of dot heat generating resistors, in thermal print head of thick film type. CONSTITUTION:On a top surface of a head substrate 10, a heat generating resistor 15 is formed so as to extend in the shape of a line over both a common conductor pattern 13 and individual conductor patterns 14, Next, on the top surface of the head substrate 10, a photoresist film 16 is formed so as to cover the heat generating resistor 15. Thereafter, openings 16a are formed on each part between each individual conductor pattern in the photoresist film 16. Then, fine abrasive powders are sprayed on the part of the heat generating resistor 15, so that the line-like heat generating resistor 15 is divided into a plurality of dot heat generating resistors 15a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a so-called thick film type thermal print head in which a heating resistor is formed into a thick film, of thermal print heads used in facsimiles or printers. ..

[0002]

2. Description of the Related Art Generally, thick film type thermal print heads include continuous dot type and independent dot type. The former continuous dot type is, for example,
As described in JP-A-158136 and JP-A-1-321644, and as shown in FIGS. 13 and 14, a thick film heating resistor 2a is formed on the upper surface of the head substrate 1a.
Is formed in a line shape, and the line-shaped heating resistor 2a is
The line-shaped heat generating resistor 2 is formed by connecting the common conductor pattern 3a and the individual conductor pattern 4a at an appropriate pitch.
Among a, the dot heating resistors between the common conductor pattern 3a and the individual conductor pattern 4a are individually made to generate heat.

On the other hand, the latter independent dot type is described in, for example, FIG. 1A of JP-A-54-123039, and as shown in FIGS. 15 and 16, the upper surface of the head substrate 1b. , A plurality of dot-shaped heating resistors 2b are formed in a line, and a common conductor pattern 3a and an individual conductor pattern 4a are connected to each of the dot-shaped heating resistors 2b at appropriate pitch intervals. , Each dot heating resistor 2
b is designed to generate heat separately.

[0004]

In the former continuous dot type, however, a large number of dot heating resistors are formed all at once by forming the heating resistors 2a in a line on the head substrate 1a. The advantages are that the manufacturing method is simple and can be manufactured at low cost, and the density of the dot heating resistors (the number of dot heating resistors that can be provided per unit length) can be increased. Have.

However, on the other hand, the resistance value of each dot heating resistor is set to a predetermined value by impressing a current on the dot heating resistor via the common conductor pattern 3a and the individual conductor pattern 4a. When the adjustment (trimming) is performed as described above, the adjustment current is simultaneously applied to the two dot heating resistors connected to one individual conductor pattern 4a. In other words,
Since the resistance value of each dot heating resistor is adjusted with respect to the two dot heating resistors, there is a problem that imbalance easily occurs in the resistance value between the dot heating resistors and the print quality is low.

On the other hand, in the latter independent dot type, since the resistance value adjustment for each dot heating resistor 2b can be performed separately for each dot heating resistor 2b, the resistance value varies. While it has the advantage that the attachment is small and the printing quality is high, a plurality of dot heating resistors 2b are separately and independently formed on the upper surface of the head substrate 1b. There was a problem that I could not do it.

Therefore, recently, in the independent dot type, the "lift-off method" or the "etching method" is adopted to form a large number of dot heating resistors at high density. However, the "lift lift method" is used, for example, in the 4th Microelectronics Symposium (M
ES'91), Tokyo, May 1991, 45P, "Technology for forming a heating element for a thermal head by a lift-off method", which requires extremely complicated steps, resulting in a significant increase in manufacturing cost. To do.

On the other hand, in the "etching method", a heating resistor is formed on the upper surface of the head substrate so as to extend linearly,
Next, after covering this line-shaped heating resistor with a photoresist film, an opening is formed by mask exposure and development in each part of this photoresist film between each individual conductor pattern, and the whole is etched in this state. By processing, the line-shaped heating resistor is dissolved and divided into a large number of dot heating resistors by an etching solution.However, when the heating resistor is cut by dissolution by the ethigun solution, it is extremely difficult. In addition to having to use a special etching solution, this etching solution must be post-processed, and moreover, a thick film heating resistor,
Since it takes a considerably long time to divide into a large number of dot heating resistors by dissolving the etching solution,
In addition, the manufacturing cost was significantly increased.

The present invention is based on the latter independent dot type of the two thick film type thermal print heads described above.
It is a technical object to provide a method that can be manufactured at low cost with a simple process.

[0010]

In order to achieve this technical object, the present invention forms a common conductor pattern and an individual pattern on the upper surface of a head substrate, and a heating resistor
It is formed so as to extend in a line shape across both the common conductor pattern and the individual conductor pattern, and then a photoresist film is formed on the upper surface of the head substrate so as to cover at least the heating resistor. Mask exposure / development is performed on the photoresist film to form openings in each of the portions of the photoresist film between the individual conductor patterns, and then fine abrasive particles are formed on the portion of the heating resistor. Was sprayed to divide the linear heating resistor into dot heating resistors for each individual conductor pattern.

[0011]

[Operation] In this way, a photoresist film covering the heating resistor is formed on the upper surface of the head substrate, and an opening is formed in each of the portions of the photoresist film between the individual conductor patterns. By spraying fine abrasive particles onto the body, the abrasive particles penetrate through the opening formed in the photoresist film and directly collide with the portion of the heating resistor inside the opening. As a result, since the heating resistor in that portion is polished and cut, the line-shaped heating resistor can be divided into the dot heating resistors for each of the individual conductor patterns.

[0012]

As described above, according to the present invention, the heating resistor formed in a line shape is divided into a large number of dot heating resistors by spraying fine abrasive particles. It can be carried out in a much shorter time than the separation by dissolving the liquid, and very ordinary abrasive particles can be used, and further, the abrasive particles can be used repeatedly, so that the production cost thereof can be reduced. ,
Compared with the above-mentioned "lift-off method" and "etching method", it has the effect of being able to reduce significantly.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. First, as shown in FIG. 1, a head substrate 10 having a glaze layer 11 formed on its upper surface is prepared.
A metal paste, such as gold, is applied in a thin film on the upper surface of the glaze layer 11 to form a metal film 12, and then the metal film 12 is subjected to conventionally known photoetching. Thus, as shown in FIG. 2, the common conductor pattern 13 and the individual conductor pattern 14 are formed.

Next, as shown in FIGS. 3, 4 and 5,
On the upper surface of the glaze layer 11 on the head substrate 10,
The heating resistor 15 is formed such that the heating resistor 15 extends in a line shape across both the common conductor pattern 13 and the individual conductor pattern 14. In this case, in another embodiment, the glaze layer 1 on the head substrate 10 is
The heating resistor 15 may be first formed in a line shape on the upper surface of 1, and then the common conductor pattern 13 and the individual conductor pattern 14 may be formed so as to be continuous with the line heating resistor 15. Of.

Then, as shown in FIG. 6, a photoresist film 16 having an appropriate thickness is formed on the upper surfaces of the photoresist film 16 so as to cover the entire surface, and then the photoresist film 16 is subjected to mask exposure and development. As shown in FIGS. 7 and 8, openings 16a are formed in the photoresist film 16 between the individual conductor patterns 14, respectively.

Then, with respect to the opening 16a, as shown in FIG.
And, as shown in FIG. 8, fine abrasive particles are blown together with air from the nozzle 17. Then, nozzle 1
Abrasive particles ejected together with air from 7 penetrate through the opening 16a formed in the photoresist film 16 and directly collide with a portion of the heating resistor 15 inside the opening 16a. As a result, the heating resistor 15 in that portion is ground and cut, and the groove 18 is formed in the opening 16a of the heating resistor 15 as shown in FIG. Line-shaped heating resistor 15
Can be divided into the dot heating resistors 15a for each of the individual conductor patterns 14.

According to an experiment conducted by the present inventor, the width S of the opening 16a in the photoresist film 16 is set to 1
In the case of 5 microns, the line-shaped heating resistor 15 can be polished and divided into a number of todd heating resistors 15a by spraying abrasive particles having a particle size of 5 microns. In this case, the photoresist film 16 is Due to the soft material, the erosion of the photoresist film 16 due to the spraying of the abrasive particles was hardly recognized.

Further, in another embodiment, as shown in FIG. 9, the line-shaped heating resistor 15 is not completely divided into a large number of dot heating resistors 15a as shown in FIG. By making the depth of the groove 18 shallow, an incomplete divided state may be obtained. In this way
The line-shaped heat generating resistor 15 includes a large number of dot heat generating resistors 1.
When divided into 5a, the photoresist film 16 is removed by etching or the like, and then the overcoat glass 19 is applied and formed on the entire surface.
Also, an independent dot type thick film type thermal print head as shown in FIG. 12 can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a head substrate in a method of the present invention.

FIG. 2 is a perspective view showing a state in which a common conductor pattern and individual conductor patterns are formed on the head substrate.

FIG. 3 is a perspective view showing a state where a heating resistor is formed in a line on the head substrate.

4 is an enlarged sectional view taken along line IV-IV of FIG.

5 is an enlarged sectional view taken along line VV of FIG.

FIG. 6 is a perspective view showing a state in which a photoresist film is formed on the head substrate.

FIG. 7 is a perspective view showing a state where an opening is formed in the photoresist film on the head substrate.

FIG. 8 is an enlarged sectional view taken along line VIII-VIII of FIG. 7.

FIG. 9 is a cross-sectional view showing a state in which the line heating resistor is divided into a large number of todd heating resistors.

10 is a cross-sectional view showing another example of FIG.

FIG. 11 is a perspective view of the completed thick film thermal print head.

12 is an enlarged sectional view taken along line XII-XII of FIG.

FIG. 13 is a perspective view of a conventional continuous dot type thermal print head.

14 is an enlarged sectional view taken along line XIV-XIV of FIG.

FIG. 15 is a plan view of a conventional independent dot type thermal print head.

16 is an enlarged sectional view taken along line XVI-XVI of FIG.

[Explanation of symbols]

 10 Head Substrate 11 Glaze Layer 13 Common Conductor Pattern 14 Individual Conductor Pattern 15 Linear Heating Resistor 16 Photoresist Film 16a Opening 17 Abrasive Particle Spraying Nozzle

Claims (1)

[Claims] 1. A common conductor pattern and an individual pattern are formed on an upper surface of a head substrate, and a heating resistor is formed so as to extend in a line shape across both the common conductor pattern and the individual conductor pattern. Then, a photoresist film is formed on the upper surface of the head substrate so as to cover at least the heating resistor, and then the photoresist film is subjected to mask exposure / development so that each of the individual conductors of the photoresist film is exposed. An opening is formed in each of the portions between the patterns, and then fine abrasive particles are sprayed on the portion of the heating resistor to form the line-shaped heating resistor.
A method for manufacturing a thick film type thermal print head, characterized by dividing the individual conductor patterns into dot heating resistors.