JPH0584944A - Thermal head and production thereof - Google Patents

Abstract

PURPOSE:To prevent an unnecessary organometallic material film from remaining on the surface of an insulating substrate when a heating resistor or electrode composed of an organometallic material is formed on the surface of the insulating substrate. CONSTITUTION:In a thermal head wherein a plurality of heating resistors 3 arranged along a main scanning direction X, the common electrode 4 extending in the main scanning direction X to be connected to the respective heating resistors 3 and a plurality of individual electrodes 5 connected to the heating resistors 3 at the leading end parts thereof and arranged along the main scanning direction X are formed to the surface of an insulating substrate 2, the insulating substrate 2 is constituted of an insulating substrate main body 2a, the partial under glaze 2b formed to the surface of the insulating substrate glass layer 2c covering the partial under glaze 2b and the surface of the insulating substrate main body 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head used in a thermal printer, a facsimile or the like as an output device of a word processor, a personal computer or the like, and a manufacturing method thereof.

[0002]

2. Description of the Related Art The thermal head has been widely used since it has advantages such as low noise during printing and easy handling because no developing / fixing process is required. As the thermal head, in the manufacturing process, a thick film paste along the main scanning direction is applied in a strip shape on the surface of the insulating substrate by a thick film technique such as screen printing, dried, and fired to form a strip-shaped heating resistor. A thick film type thermal head and a resistive layer formed on the entire surface of the insulating substrate by thin film technology such as vapor deposition and sputtering was formed with a plurality of individual heating resistors along the main scanning direction using photolithographic etching technology. A thin film type thermal head is known.

[0003]

The thick-film type thermal head using the strip-shaped heat generating resistor has low equipment cost, high productivity, and low cost. However, the thick film of the electrode and the heat generating resistor causes heat generation. There is a problem that the heat capacity of the element is large and the thermal response is inferior, and that the heating resistor is a sintered body of powder of the order of μm, so that the resistance value greatly varies. Further, since it is necessary to form the electrode density to be twice the density of the heating elements (that is, the density of print dots), it is difficult to increase the density of the heating elements.

Further, the thin film type thermal head can form the electrodes, the heating resistors and the abrasion resistant layer having a uniform composition, and the arrangement density of the electrodes and the heating resistors can be the same as the density of the heating elements. However, although uniform and high-density printing dots can be obtained, there is a problem that the manufacturing facility becomes large and the cost becomes high.

Therefore, the present applicant has previously proposed a method capable of manufacturing a thermal head having the advantages of a thin film type thermal head by using an inexpensive thick film technology of a manufacturing facility, that is, a MOD (Metallo Organic Deposition) method. is suggesting. 13 to 14B show a first conventional example of a thermal head including a heating resistor formed by the MOD method. As shown in FIG. 13, the thermal head Ho of the first conventional example includes a support plate 01.
An insulating substrate 02 is attached to the surface of 1 by an adhesive. The insulating substrate 02 is composed of a ceramic insulating substrate body 02a and a belt-shaped partial underglaze 02b formed on the surface thereof along the main scanning direction X. The partial underglaze 02b is provided to improve the contact between the thermal head and the recording paper. A large number of heating resistors 03 are provided in an island shape along the main scanning direction X on the surface of the partial underglaze 02b. In addition, as shown in FIG.
As shown in A, the common electrode 04 is composed of a strip-shaped common electrode body portion 04a and a large number of common electrode connecting portions 04b protruding from the common electrode body portion 04a in a comb-like shape in the sub-scanning direction Y.
And a large number of individual electrodes 05 facing the large number of common electrode connection portions 04b at a predetermined distance.
The common electrode connection portions 04b and the individual electrodes 05 are connected by the heating resistor 03 provided on the surface of the insulating substrate 02. The surface of the insulating substrate 02 on which the heating resistor 03 and the electrodes 04 and 05 are formed is covered with a wear resistant layer Go made of glaze (the wear resistant layer Go is not shown in FIG. 13). I'm done.).

When the heating resistor 03 is formed on the surface of the partial underglaze 02b of the insulating substrate 02 by using the MOD method, if the resistance film for forming the heating resistor is printed only on the surface of the partial underglaze 02b. Since the width of the partial underglaze 02b is as narrow as about 1 mm, it is difficult to obtain a uniform film thickness. Therefore, a method is employed in which a resistance film is formed on the entire surface of the insulating substrate 02 and then etched with an etching solution such as hydrofluoric nitric acid.

By the way, when the resistance film formed on the glaze is etched, the glass component of the resistance film is first attacked, and then the lower amorphous glass is etched. Therefore, other than the glass component of the upper resistance film also peels off,
The resistive film is etched without remaining. However, in the first conventional example, since the surface of the insulating substrate 02 other than the partial underglaze 02b does not have a glass component, the above-described etching is difficult. Therefore, the insulating substrate 02 other than the partial underglaze 02b
An unnecessary resistance film may remain on the surface. The unnecessary residual resistance film may form irregularities on the surface of the insulating substrate 02, which may hinder the formation of a uniform electrode film.

Next, a second conventional example of the thermal head will be described with reference to FIGS. 15A and 15B. Since the thermal head of the second conventional example has basically the same configuration as the first conventional example, detailed description thereof will be omitted. The constituent elements corresponding to those of the first conventional example are marked with '(dash) on the right shoulder. In this second conventional example, both electrodes 0
4 ', 05' by the MOD method described above, the heating resistor 03 '
Are formed by the lift-off method. That is, a metal organic material for forming both electrodes is applied and baked on the entire surface of the insulating substrate 02 'to form an electrode film (MOD method), and then this is photolithographically etched.
4 ', 05' are formed. Next, the both electrodes 04 ', 0
A resist layer is formed on the entire surface of the insulating substrate 02 'on which 5'is formed, and a large number of openings for forming a heating resistor are formed in the resist layer along the partial underglaze 02b', and unsintered in the openings. After the resistor is filled, it is fired to form an island-shaped heating resistor 03 '(lift-off method).

According to the above method, since the heating resistor is formed only on the surface portion of the partial underglaze 02b ', an unnecessary resistance film remains on the surface of the insulating substrate 02' other than the partial underglaze 02b '. The problems of the conventional example are solved. However, both electrodes 04 ', 0
The following problems occur when forming 5 '. That is,
Since the thickness of the electrode film formed on the entire surface of the insulating substrate 02 'becomes thicker at the step portion So between the partial underglaze 02b' and the surface of the insulating substrate body 02a ', when the electrode film is patterned by photolithography etching. This step So
Unnecessary electrode film is likely to remain in the vicinity.

In view of the above-mentioned circumstances, it is an object of the present invention to prevent unnecessary heating resistors or electrodes from remaining on the insulating substrate surface when forming the heating resistors or electrodes on the insulating substrate surface. ..

[0011]

In order to solve the above-mentioned problems, a thermal head according to the first invention of the present application has a plurality of heating resistors arranged in a row along the main scanning direction and a plurality of heating resistors in the main scanning direction. A common electrode extended and connected to each of the heat generating resistors, and a plurality of individual electrodes whose tip is connected to the heat generating resistors and arranged in a row along the main scanning direction are formed on the surface of the insulating substrate. In the formed thermal head, the insulating substrate covers the insulating substrate body, the partial underglaze formed on the surface of the insulating substrate body, the partial underglaze and the surface of the insulating substrate body. And a non-crystallizable glass layer.

Further, in the method for manufacturing a thermal head according to the second invention of the present application, a plurality of heating resistors 3 arranged in a row along the main scanning direction X and the heating resistors 3 extended in the main scanning direction X are provided. A common electrode 4 connected to each heating resistor 3 and a plurality of individual electrodes 5 having their tips connected to the heating resistor 3 and arranged in a row along the main scanning direction X are provided on the surface of the insulating substrate 2. In the method of manufacturing the formed thermal head, a partial underglaze 2b is formed on the surface of the insulating substrate main body 2a, and then the amorphous undercoat 2b and the surface of the insulating substrate main body 2a are covered. The insulating layer 2 is manufactured by forming the glass layer 2c, and then the electrode film 40 is formed on the surface of the amorphous glass layer 2c.
It is characterized by including a step of forming a common electrode 4 and an individual electrode 5 by photolithographically etching 0.

[0013]

According to the thermal head of the first invention of the present application having the above-mentioned structure, the insulating substrate is provided with the insulating substrate body, the partial underglaze formed on the surface of the insulating substrate body, and the partial underlayer. It is composed of a glaze and an amorphous glass layer covering the surface of the insulating substrate body. Therefore, the partial underglaze improves the contact between the thermal head and the recording paper. Further, when the heating resistor, the electrode, etc. are formed on the surface of the insulating substrate, the heating resistor forming material or the electrode forming material is formed on the surface of the amorphous glass layer. The layer surface is also etched. Therefore, unnecessary heating resistor forming material or electrode forming material does not remain on the surface of the insulating substrate after photolithographic etching. Further, the step portion between the partial underglaze and the surface of the insulating substrate main body is covered with the amorphous glass layer, so that the surface of the amorphous glass layer corresponding to the step portion becomes gentle. Therefore, the film thickness of the electrode film formed on the surface of the insulating substrate does not become thick locally and becomes uniform. Therefore, when there is a thick portion in the electrode film, that portion does not remain during etching. The method of manufacturing a thermal head according to the second invention of the present application can manufacture a thermal head in which an unnecessary metal organic material film does not remain on the surface of the insulating substrate.

[0014]

Embodiments of the thermal head and the method for manufacturing the same according to the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 11B. As shown in FIG. 1, the thermal head H for performing thermal recording on the thermal recording paper P conveyed along the outer periphery of the platen roll R includes a support plate 1. An insulating substrate 2 is attached to the surface of the support plate 1 on the right side portion in FIG. 1 with an adhesive. This insulating substrate 2 comprises an insulating substrate body 2a made of ceramic such as alumina, a strip-like partial underglaze 2b formed on the surface thereof with a width of about 1 mm and a thickness of about 50 to 60 μm along the main scanning direction, and the partial underlayer. It comprises a glaze 2b and an amorphous glass layer 2c covering the surface of the insulating substrate body 2a. As shown in FIG. 3, a plurality of heating resistors 3 are provided in an island shape along the main scanning direction X on the surface of the partial underglaze 2b.

On the surface of the insulating substrate 2, there are formed a strip-shaped common electrode body 4a and a large number of common electrode connecting portions 4b protruding from the common electrode body 4a in a comb-like shape in the sub-scanning direction Y. The common electrode 4 and the multiple common electrode connection portions 4b
A large number of individual electrodes 5 facing each other at a predetermined distance are formed in the. The common electrode connecting portions 4b and the individual electrodes 5 are connected by the heating resistors 3 arranged on the surface of the insulating substrate 2. Further, the base end portion (the left end portion in FIG. 1) of the individual electrode 5 is formed as an IC connection terminal 5a for connecting to a drive IC described later.

A printed wiring board 6 is attached to the left side portion of FIG. 1 by an adhesive on the surface of the support board 1, and external connection wiring 7 is formed on the surface of the printed wiring board 6. .. The external connection wiring 7 is connected to a socket 9 as a drive signal input terminal via a lead wire 8 penetrating the printed wiring board 6 on the input end side (left side in FIG. 1). A drive IC is arranged in a portion of the printed wiring board 6 close to the insulating substrate 2,
The driving IC is connected to the IC connection terminal 5a of the individual electrode 5 and the external connection wiring 7 by bonding wires 10 and 11. The IC and the bonding wires 10 and 11 are covered with a protective resin 12, and the heat generating resistor 3, the common electrode 4, the individual electrode 5 and the like have wear resistant layers G (see FIGS. 3, 4 (A), (B)). )reference)
(The wear resistant layer G is omitted in FIGS. 1 and 2). Further, the protective resin 12 is protected by a cover 13 made of aluminum. And
The thermal head H is composed of the components indicated by the reference numerals 1 to 13 and the reference numeral G and the driving IC.

Next, a method of manufacturing the thermal head H having the structure shown in FIGS. 4 (A) and 4 (B) will be described with reference to FIGS. 5 (A) to 11 (B). FIG. 5 (A),
In (B), the upper surface of the ceramic insulating substrate body 2a is 1 mm wide and 50 to 60 μm thick in the main scanning direction X.
A band-shaped partial underglaze 2b of m is formed. By printing and baking amorphous glass on the entire surface of the insulating substrate body 2a, a thickness of 2 to 2 is obtained as shown in FIGS. 6 (A) and 6 (B).
An amorphous glass layer 2c of 10 μm is formed. Then, from the components indicated by the reference numerals 2a, 2b, and 2c to the insulating substrate 2,
Is formed.

Next, a metal-organic material for forming a heating resistor is screen-printed on the surface of the amorphous glass layer 2c (that is, the surface of the insulating substrate 2), and then this is fired, and the result is shown in FIG.
A band-shaped resistor-forming resistor film 30 having a thickness of 0.2 to 1.0 μm is formed as shown in FIGS.

Next, a metal organic material for electrode formation is solid-printed by screen printing on the surface of the insulating substrate 2 on which the resistance film 30 is formed, followed by firing, as shown in FIGS. Such an electrode forming electrode film 40 is formed.

Next, a resist layer is formed on the electrode film 40, and then exposure and development are performed to obtain a resist pattern for forming an electrode. Subsequently, using this resist pattern as a mask, an iodine-potassium iodide solution ( Etching is performed using an etching solution (photolithographic etching step).
An electrode pattern 40a as shown in (A) and (B) is formed.

Next, when the resistor film 30 is etched with a hydrofluoric nitric acid solution (etching solution) using the electrode pattern 40a as a mask, islands under the electrode pattern 40a as shown in FIGS. The heating resistor 3 having a shape of a circle is formed.

Next, the electrode pattern 40a is photolithographically etched to form a common electrode 4 and an individual electrode 5 as shown in FIGS. 11A and 11B. The method of forming the resistor film 30 and the electrode film 40 is the MOD method. Finally, the surface of the insulating substrate 2 on which the heating resistor 3 and the electrodes 4 and 5 are formed is covered with a wear resistant layer G, and the thermal head H shown in FIGS.
To get

According to the first embodiment described above, the resistance film 30 and the electrode film 40 made of the metal organic material film formed on the surface of the insulating substrate 2 are formed on the surface of the amorphous glass layer 2c. When the resistance film 30 and the electrode film 40 are etched, the surface of the amorphous glass layer 2c is also etched. Therefore, an unnecessary metal organic material film does not remain on the surface of the insulating substrate 2 after the photolithography etching. Further, since the surface of the amorphous glass layer 2c covering the surface of the insulating substrate main body 2a on which the partial underglaze 2b is formed is gentle and has no step, the film thickness of the electrode film 40 formed on the surface is partial. It is uniform without thickening. Therefore, when there is a thick portion in the electrode film, that portion does not remain during etching.

Next, a second embodiment of the thermal head of the present invention will be described with reference to FIGS. 12 (A) and 12 (B).
In the following description, the same components as those in the first embodiment will be designated by the same reference numerals and detailed description thereof will be omitted.
The second embodiment differs from the first embodiment in that the heating resistor 3'is formed not by the MOD method but by the lift-off method. That is, the amorphous glass layer 2 of the insulating substrate 2
After forming the common electrode 4 and the individual electrode 5 on the surface c by the MOD method, a resist layer is formed on the entire surface of the amorphous glass layer 2c on which the electrodes 4 and 5 are formed. afterwards,
A large number of openings for forming heating resistors are formed in the resist layer along the partial underglaze 2b. Next, an unsintered resistor is filled in the opening and fired to form an island-shaped heating resistor 3 '. In addition, this second embodiment also uses both electrodes 4,
Since 5 and the heating resistor 3'are formed on the surface of the amorphous glass layer 2c, the same action and effect as those of the first embodiment can be obtained.

Although the embodiments of the thermal head and the method for manufacturing the same according to the present invention have been described in detail above, the present invention is not limited to the above embodiments, and deviates from the invention described in the claims. It is possible to make various small design changes without doing so.

For example, it is possible to first form a large number of heating resistors by photolithographic etching on the surface of the amorphous glass layer of the insulating substrate, and then form both electrodes by photolithographic etching.

[0027]

As described above, in the thermal head of the first invention of the present application, the insulating substrate is the insulating substrate body, the partial underglaze formed on the surface of the insulating substrate body, and the partial underlayer. -A glaze and an amorphous glass layer covering the surface of the insulating substrate body. Therefore, due to the partial underglaze, the contact between the thermal head and the printing paper is good. Further, when a resistance film or electrode film made of a metal organic material film is formed on the surface of the insulating substrate, the resistance film or electrode film is formed on the surface of the amorphous glass layer. An unnecessary metal organic material film does not remain on the surface of the insulating substrate after etching. Further, since the amorphous glass layer covers the stepped portion between the partial underglaze and the surface of the insulating substrate body, the surface of the amorphous glass layer corresponding to the stepped portion becomes gentle. Therefore, the film thickness of the electrode film formed on the surface of the insulating substrate does not become thick locally and becomes uniform. Therefore, when there is a thick portion in the electrode film, that portion does not remain during etching.

The thermal head manufacturing method of the second invention of the present application can manufacture a thermal head in which an unnecessary metal organic material film does not remain on the surface of the insulating substrate.

[Brief description of drawings]

FIG. 1 is an overall explanatory view of a first embodiment of a thermal head of the present invention.

FIG. 2 is a perspective view of a main part of the first embodiment.

FIG. 3 is an enlarged view of a portion indicated by an arrow III in FIG.

FIG. 4 is an explanatory diagram of a main part of the first embodiment.

FIG. 5 is an explanatory view of a method of manufacturing a main part of the first embodiment.

FIG. 6 is an explanatory diagram of a method of manufacturing the main part of the first embodiment, which is an explanatory diagram of the next step of FIG. 5;

FIG. 7 is an explanatory diagram of the method of manufacturing the main part of the first embodiment, which is an explanatory diagram of the next step of FIG. 6;

FIG. 8 is an explanatory diagram of the method of manufacturing the main part of the first embodiment, which is an explanatory diagram of the next step of FIG. 7;

FIG. 9 is an explanatory diagram of the method of manufacturing the main part of the first embodiment, which is an explanatory diagram of the next step of FIG. 8;

FIG. 10 is an explanatory view of a method of manufacturing the main part of the first embodiment,
It is explanatory drawing of the process of the following FIG.

FIG. 11 is an explanatory view of a method of manufacturing a main part of the first embodiment,
FIG. 11 is an explanatory diagram of a step subsequent to that of FIG. 10.

FIG. 12 is an explanatory diagram of a main part of a second embodiment of the present invention.

FIG. 13 is a perspective view of a first conventional example of a thermal head.

14 is an explanatory diagram of a portion XIVA as viewed in the direction of the arrow in FIG. 13;

FIG. 15 is an explanatory diagram of a second conventional example of a thermal head.

[Explanation of symbols]

 2 Insulating substrate 2a Insulating substrate body 2b Partial underglaze 2c Amorphous glass layer 3 Heating resistor 3'Heating resistor 4 Common electrode 5 Individual electrode 40 Electrode film 40a Electrode pattern

Claims (2)

[Claims] 1. A plurality of heating resistors (3) arranged in a row along a main scanning direction (X), and extending in the main scanning direction (X) and being provided on each heating resistor (3). The connected common electrode (4) and a plurality of individual electrodes (5) whose tips are connected to the heating resistor (3) and which are arranged in a row along the main scanning direction (X) are insulating substrates ( 2) In the thermal head formed on the surface, the insulating substrate (2) comprises an insulating substrate body (2a) and a partial underglaze (2b) formed on the surface of the insulating substrate body (2a). A partial underglaze (2b) and an amorphous glass layer (2c) covering the surface of the insulating substrate body (2a). 2. A plurality of heating resistors (3) arranged in a row along the main scanning direction (X), and a plurality of heating resistors (3) extending in the main scanning direction (X) and arranged on each heating resistor (3). The connected common electrode (4) and a plurality of individual electrodes (5) whose tips are connected to the heating resistor (3) and which are arranged in a row along the main scanning direction (X) are insulating substrates ( 2) In a method of manufacturing a thermal head formed on the surface, a partial underglaze (2) is formed on the surface of the insulating substrate body (2a).
After forming b), this partial underglaze (2b)
And an amorphous glass layer (2c) covering the surface of the insulating substrate body (2a) is formed to manufacture the insulating substrate (2), and then an electrode film (40) is formed on the surface of the amorphous glass layer (2c). After being formed, the electrode film (40) is photolithographically etched to form a common electrode (4) and an individual electrode (5).
A method of manufacturing a thermal head, comprising the step of forming: