JPH05254166A - Thermal head and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a thermal head with a surface which is so smooth as to allow high-quality prints to be obtained without polishing. CONSTITUTION:A smooth layer forming process provided is for forming a low softening fillerless glass paste layer on an insulating substrate 1 after the formation of a common electrode 3, discrete electrodes 4 and a thermal element 2a on the surface of the insulating substrate 1, and baking the fillerless glass paste layer at higher than a working point. The forming sequence of an abrasion-resistant layer 6 and a smooth layer 7 on the insulating substrate 1 is optional, whichever is the first to be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head for a thermal recording device 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 Conventionally, as the thermal head,
A thin film type thermal head in which electrodes and heating elements are formed by using a thin film technology, a thick film type thermal head in which heating elements are formed by a thick film technology such as a lift-off method, and the like are known.

The conventional thin film thermal head and thick film thermal head will be described with reference to FIGS. First, an example of the conventional thin film thermal head (hereinafter referred to as "conventional example 1") will be described with reference to FIGS. 12A and 12B. The thermal head Ho of the conventional example 1 includes an insulating substrate 01. This insulating substrate 01
A resistor layer 02 is formed on the surface of the. On the upper surface of the resistor layer 02, a strip-shaped common electrode body portion 03a extending along the main scanning direction X and a large number of common electrode connecting portions 03 protruding in the sub-scanning direction Y in a comb shape from the body portion 03a.
a common electrode 03 having b and a large number of individual electrodes 04 whose tip portions 04a are arranged to face the common electrode connecting portion 03b.
And are formed.

A heating element 02a is formed by the portion of the resistor layer 02 that is disposed between the common electrode connecting portion 03b and the individual electrode tip portion 04a. The heating element 0
A large number of 2a are formed along the main scanning direction X. On the surfaces of the heating element 02a and the electrodes 03 and 04,
A protective layer 05 for improving the heat resistance of the heating element 02a, a wear resistant layer 06 for preventing contact wear due to the thermal recording paper P, and the like are formed. The surface of the portion of the abrasion resistant layer 06 that covers the heating element 02a contacts the heat-sensitive recording paper P, the ink donor film, or the like to transfer heat.
6a. Then, the heating element 02
a, both electrodes 03, 04, protective layer 05, and wear resistant layer 0
6 and the like are formed by using a thin film technique such as sputtering or CVD.

In the thermal head Ho of the above-mentioned conventional example 1, when a voltage is selectively applied to the individual electrode 04, the selected individual electrode 04 and the common electrode connecting portion 03b facing it are connected. A current flows through the heating element 02a in the range, and the heating element 02a generates heat. Therefore, when the thermal recording paper P is pressed against the surface portion of the wear resistant layer 06 covering the heat generating portion of the heating element 02a, that is, the printing portion 06a as shown in FIG. 12B, or when the printing paper is pressed through the ink ribbon, The thermal recording paper P that comes into contact with the printing portion 06a develops color, or ink is transferred to the printing paper to perform thermal recording (printing).

In the thermal head Ho of Conventional Example 1 shown in FIGS. 12A and 12B, since the abrasion resistant layer 06 is formed by using the thin film technique, the step below the abrasion resistant layer 06 (that is, the heating element 02a and The step formed by both electrodes 03 and 04) is reproduced as it is up to the surface of the wear resistant layer 06, so that the stepped portion So is generated on the surface of the wear resistant layer 06. Therefore, when printing, the thermal recording paper P or
The abrasion-sensitive layer 06 is scraped by being scratched by o to generate paper dust on the peripheral portion of the printing portion 06a.
Print quality was deteriorated.

Further, since the printing portion 06a of the abrasion resistant layer 06 is recessed from the other portions of the abrasion resistant layer 06 due to the thickness of the electrodes 03 and 04, the thermal recording paper P or the ink ribbon is interposed in the printing portion 06a. It is difficult to press the printing paper sufficiently by pressing, resulting in insufficient printing. This also contributes to the deterioration of print quality.

Therefore, the thermal recording paper P is printed on the printing portion 06a.
In order to sufficiently press the heat generating element 02a into a meandering shape, the space between the electrodes 03 and 04 is increased, or a partial underglaze layer is formed on the surface of the insulating substrate 01. Both electrodes 03,
The heating element 02a portion in the range where 04 is connected is raised. By doing so, the printing pressure on the thermal recording paper P of the printing unit 06a can be increased and the printing quality can be improved. However, due to the improvement of resolution or the requirement of halftone printing by dividing in the sub-scanning direction, the interval between the electrodes 03 and 04 is further narrowed as compared with the conventional one, and the sub-scanning of the heating element 02a in the range connecting the 03 and 04 is performed. When the width in the direction Y is reduced, the heating element 0 between the electrodes 03 and 04 is formed even if the partial underglaze layer is formed as described above.
It becomes impossible to raise the surface of 2a close to the surface of both electrodes 03 and 04. Therefore, the printing pressure on the thermal recording paper P in the printing section 06a could not be sufficiently increased.

Therefore, in order to solve the problems of the prior art example 1, a thin film type thermal head described in JP-A-53-57045 is proposed. Next, FIG.
A, 13B, the thin film thermal head described in JP-A-53-57045 (hereinafter referred to as "Prior art example 2").
Ho) will be described. The thermal head Ho ′ of Conventional Example 2 is different from that of Conventional Example 1 in that a wear layer 07 made of a substance having a hardness smaller than that of the wear resistant layer 06 and easily worn is formed on the surface of the wear resistant layer 06. It is different from the thermal head Ho. In this case, wear layer 0
The surface of the portion of No. 7 that covers the heating element 02a is formed as a printing portion 07a. The other structure is the same as that of the thermal head Ho of the prior art example 1.

In the thermal head Ho 'of the prior art example 2, since the wear layer 07 made of a substance having a hardness smaller than that of the wear resistant layer 06 and easily worn is formed on the surface of the wear resistant layer 06, this wear is caused. Step S generated on the surface of layer 07
o wears out while using the thermal head Ho '. Therefore, with the use of the thermal head Ho ', the surface of the wear layer 07 is not dented, the paper contact is improved, and the printing quality is improved.

14A and 14B are views showing an example of a conventional thick film thermal head (hereinafter referred to as "conventional example 3"). The thermal head Ho ″ according to Conventional Example 3 includes an insulating substrate 01, and a belt-shaped common electrode main body 03a extending along the main scanning direction X is provided on the surface of the insulating substrate 01.
And a common electrode 0 having a large number of common electrode connecting portions 03b protruding in a sub-scanning direction Y from the main body portion 03a.
3 and a large number of individual electrodes 04 whose tip portions 04a are arranged so as to face the common electrode connecting portion 03b.
Each common electrode connecting portion 03b and each individual electrode tip portion 0
4a are connected by a large number of island-shaped individual heating elements 02a 'formed along the main scanning direction X on the surface of the insulating substrate 01. The surfaces of the electrodes 03, 04 and the heat generating element 02a 'are covered with a wear resistant layer 06, and the surface of the part of the wear resistant layer 06 covering the heat generating element 02a' serves as a printing portion 06a '. Has been formed. The heating element 02a 'is formed by a lift-off method which is a kind of thick film technology (a resist layer is formed on the surface of an insulating substrate, a heating element forming opening is formed in the resist layer, and a resistor paste is formed in the opening. Fill it and dry it,
It is formed by a method of forming a heating element by firing after grinding.

In the thermal head Ho "of the prior art example 3, since the printing portion 06a 'of the abrasion resistant layer 06 is higher than the other portions of the abrasion resistant layer 06, the thermal recording paper P of the printing portion 06a' is printed. Since the printing pressure can be increased, a relatively simple linear image such as a character can be printed well.

[0013]

By the way, in the thermal head Ho 'of the prior art example 2, the wear layer 07 is worn during use, and there is no dent from the surface of the printing portion 07a (that is, wear). The print quality cannot be improved (until the surface of layer 07 is smooth). Further, from the beginning of using the thermal head Ho ′, in order to smooth the surface of the wear layer 7 and improve the printing quality, the surface of the wear layer 07 must be polished.
There is a problem that the manufacturing process of o'is increased.

Further, the thermal head H of the prior art example 3 is used.
In the case of o ″, since the step portion So ′ (the height of the step portion So ′ is about 10 μm) is generated on the surface of the abrasion resistant layer 06, the thermal recording paper P or the like is caught on the step portion So ′. In that case, there is a problem that the image quality is deteriorated, and in particular, when the halftone image such as a picture is printed, the deterioration of the image quality is conspicuous. Therefore, also in the case of Conventional Example 3, in order to perform high-quality printing, it is necessary to make the surface of the abrasion resistant layer 06 smooth as in the case of Conventional Example 2. In order to make the surface smooth, the surface must be polished, and there is a problem that the number of manufacturing processes increases.

In view of the above circumstances, it is an object of the present invention to provide a thermal head having a smooth surface so that good printing can be obtained without polishing.

[0016]

Next, the constitution of the invention of the present application devised to solve the above-mentioned problems will be described. The constituent elements of the present invention are the constituent elements of the embodiment described later. In order to facilitate correspondence, the reference numerals of the constituent elements of the embodiment are shown in parentheses. The reason why the present invention is described in association with the reference numerals of the embodiments described below is to facilitate understanding of the present invention and not to limit the scope of the present invention to the embodiments.

In order to solve the above problems, the first aspect of the present application
In the thermal head of the invention, a common electrode (3) extending along the main scanning direction (X) and a tip portion (4a) are arranged in a row along the main scanning direction (X) and the common electrode (3).
A plurality of individual electrodes (4) arranged to face each other, a heating element (2a, 2a ') connecting the common electrode (3) and the individual electrode tip portion (4a), and the both electrodes (3, 3). 4) and a wear resistant layer (6) covering the surface of the heating element (2) are formed on the surface of the insulating substrate (1), the electrodes (3, 4) and the heating element (2) A smooth layer (7) made of low-softening fillerless glass, which is softened during firing to generate fluidity, is formed on the surface side of the. Either the abrasion resistant layer (6) or the smooth layer (7) may be an upper layer or a lower layer.

In the method of manufacturing a thermal head according to the second invention of the present application, the common electrode (3) extending along the main scanning direction (X) and the tip portion (4a) along the main scanning direction (X). A plurality of individual electrodes (4) arranged in a row and facing the common electrode (3), and the common electrode (3)
And a heating element (2) for connecting the individual electrode tip (4)
a, 2a ') and a wear resistant layer (6) covering the surfaces of the electrodes (3, 4) and the heating element (2a) are formed on the surface of the insulating substrate (1). At the surface of the insulating substrate (1), the both electrodes (3,
4) and the heating element (2a) are formed, and then a low-softening fillerless glass paste layer is formed on the surface of the insulating substrate (1), and then the fillerless glass paste layer is fired at a working point or higher. Is provided. The abrasion-resistant layer (6) and the smooth layer (7) may be formed first or later.

[0019]

Next, the operation of the present invention having the above-mentioned features will be described. The thermal head of the first invention of the present application having the above-mentioned characteristics is provided with the both electrodes (3, 4) and the heating element (2).
On the surface side of (a), a smooth layer (7) made of low-softening fillerless glass which is softened during firing to generate fluidity is formed. Therefore, whether the smooth layer (7) or the abrasion resistant layer (6) is the uppermost layer, the unevenness of the surface is extremely small. Therefore, unevenness in the paper feeding due to the unevenness of the surface of the thermal head and insufficient printing pressure in the printed portion of the surface of the thermal head are less likely to occur. In such a thermal head,
When a voltage is applied between the common electrode (3) and the individual electrode (4), the heating element (2a, 2) that connects the selected individual electrode (4) and the common electrode (3) facing it
An electric current flows through a ') and the heating elements (2a, 2a') generate heat. When printing is carried out while the recording paper or the like is pressed against the surface of the abrasion resistant layer (6) or the smooth layer (7) covering the heating elements (2a, 2a '), the printing pressure is uniform. Good printing can be obtained because of the high paper feeding speed.

The method of manufacturing the thermal head according to the second invention of the present application having the above-mentioned characteristics is the insulating substrate on which the electrodes (3, 4) and the heating element (2) are formed during the manufacturing process. The surface of (1) has irregularities. However,
When the low-softening fillerless glass paste layer is formed on the uneven insulating substrate surface and then the fillerless glass paste layer is fired at a working point or higher, the fillerless glass softened at a working point or higher has the uneven surface Flows to the lower part (recess) and the unevenness is reduced. Therefore,
It is possible to manufacture a thermal head having less surface irregularities without providing a step of polishing the surface.

[0021]

Embodiments of the thermal head of the present invention will be described below with reference to the drawings. First, Embodiment 1 of the thermal head H of the present invention will be described with reference to FIGS. 1 is a perspective view of an essential part of the thermal head H, FIG. 2A is a plan view of an essential part of the thermal head H, and FIG. 2B is IIB-IIB of FIG. 2A.
3A to 6B are sectional views taken along the line, and are diagrams for explaining a method of manufacturing the thermal head H. Although only a part of the thermal head H of this embodiment is shown in FIGS. 1, 2A and 2B, the thermal head H actually has a resolution of 8 dot / mm and the width in the sub-scanning direction Y is approximately. It has a size of 50 μm.

As shown in FIGS. 1, 2A and 2B, the thermal head H of this embodiment is a ceramic substrate main body 1a.
An insulating substrate 1 having a surface on which a glaze layer 1b made of amorphous glass is formed is provided. A resistor layer 2 is formed on the surface of the insulating substrate 1. On the upper surface of the resistor layer 2, there are provided a strip-shaped common electrode body 3a extending along the main scanning direction X and a large number of common electrode connecting portions 3b protruding from the body 3a in the sub-scanning direction Y in a comb shape. Common electrode 3 having
And a large number of individual electrodes 4 whose tip 4a is arranged so as to face the common electrode connecting portion 3b.

The common electrode connecting portion 3 of the resistor layer 2
The heating element 2a is formed by the portion disposed between b and the individual electrode tip portion 4a. A large number of the heating elements 2a are formed along the main scanning direction X. The surface of the insulating substrate 1 on which the heating element 2 and the electrodes 3 and 4 are formed is covered with a protective layer 5 made of glaze. The protective layer 5 is a layer for improving the heat resistance of the heating element 2. The surface of the protective layer 5 is covered with a wear resistant layer 6 made of glaze.

The wear resistant layer 6 is for protecting the heat generating element 2 and both electrodes 3 and 4 from contact wear caused by the thermal recording paper P. It is also possible to configure the abrasion resistant layer 6 to have the effect of the protective layer 5, and in that case, the protective layer 5 can be omitted. The surface of the wear-resistant layer 6 is softened by baking at a working point (a temperature at which the viscosity becomes about 300,000 cm poise) or more, so that the surface of the wear-resistant layer 6 is smoothed by filling the steps due to the unevenness. The smooth layer 7 made of low softening fillerless glass is formed. The surface of the portion of the smoothing layer 7 that covers the heating element 2a between the electrodes 3 and 4 has a thermal recording paper P.
It is formed as a printing portion 7a which transfers heat by coming into contact with an ink donor film or the like.

Next, a method of manufacturing the thermal head H having the above structure will be described with reference to FIGS. First, as shown in FIGS. 3A and 3B, TaSiO 2 is deposited on the entire surface of the insulating substrate 1 by sputtering to form a resistor forming film La having a thickness of 0.1 μm, and then the resistor forming film La is formed. By vacuum deposition on the entire surface, Ti, Pd,
Au is deposited to a thickness of 0.1 μm, 0.1 μm, and 0.8 μm to form an electrode forming film Lb. Next, the resistor forming film La and the electrode forming film Lb are etched by photolithography to form a film on the surface of the insulating substrate 1.
The heating element 2 and the electrode formation pattern Lbp as shown in A and 4B are formed. In this case, the electrode formation pattern L
The bp is formed so as to overlap the surface of the resistance layer 2. In addition,
The resistor forming film La may be left on the entire surface of the insulating substrate 1 without being etched. In that case, the step of etching the resistor forming film La can be omitted. Next, only the electrode forming pattern Lbp is etched by photolithography to form a pattern on the surface of the resistance layer 2 as shown in FIGS.
The common electrode 3 and the individual electrode 4 as shown in B are formed. Then, the heating element 2a is formed by the portion of the resistance layer 2 that connects the common electrode 3 and the individual electrode 4. A large number of heating elements 2a are formed along the main scanning direction X.

Next, the heating element 2a and both electrodes 3,
6A is formed by forming a protective layer 5 on the entire surface of the insulating substrate 1 on which Ta 4 is formed, and then depositing Ta 2 O 5 on the entire surface of the protective layer 5 at a film forming temperature of 400 ° C. by using a sputtering technique. , 6B to form a wear-resistant layer 6 having a thickness of 3 μm. Next, a fillerless glass paste (for example, Noritake glass paste NP7240 (trade name)) is screen-printed on the entire surface of the abrasion resistant layer 6, and then fired at a working point (600 ° C.) or higher, A thermal head H having a smoothing layer 7 with a thickness of 3 μm as shown in 1 and 2 is manufactured.

In the thermal head H of FIGS. 1 and 2 manufactured by the above steps, the step S formed on the surface of the smoothing layer 7 is formed.
Was 0.2 μm or less. When the level difference S on the surface of the smoothing layer 7 is 0.2 μm or less as in the thermal head H of this embodiment, the paper contact with the thermal recording paper P is good at the time of printing without polishing. High-quality printing can be performed.

Next, a second embodiment of the thermal head of the present invention will be described with reference to FIGS. 7A is a partial plan view of the thermal head H'of the second embodiment, and FIG. 7B is a plan view of FIG.
VIIB-VIIB line sectional view of A, FIG. 7C is VIIC of FIG. 7A
8C is a cross-sectional view taken along line VIIC, and FIGS. 8A to 10B are views for explaining a method of manufacturing the thermal head H '. 7A to 7
Although only a part of the thermal head H'of this embodiment is shown in C, this thermal head H is actually 300
It has a resolution of dpi. The thermal head H'of this embodiment is different from that of the first embodiment in that it has a heating element 2a 'formed by a lift-off method.

That is, as shown in FIGS. 7A to 7C, the common electrode 3 and the individual electrode 4 having the same pattern as that of the first embodiment are formed on the surface of the insulating substrate 1. The common electrode connecting portions 3b and the individual electrode tip portions 4a are connected to each other by individual heating elements 2a 'arranged in a row along the main scanning direction X. The surface of the insulating substrate 1 on which the electrodes 3, 4 and the heating element 2a 'are formed is covered with a wear resistant layer 6 made of glaze, and the surface of the wear resistant layer 6 is the same as in the first embodiment. A smoothing layer 7 having the same structure as that of is formed. A printing portion 7a 'is formed by the surface of the smoothing layer 7 which covers the heating element 2a' connecting the electrodes 3 and 4.

Next, a method of manufacturing the thermal head H'having the above structure will be described with reference to FIGS. First, the common electrode is formed on the surface of the insulating substrate 1 by a conventional electrode forming technique such as a thin film technique or a MOD method (a method of forming an electrode pattern by photolithographic etching after forming a metal organic material layer for forming an electrode on the insulating substrate surface). The electrode 3 and the individual electrode 4 are formed. Next, the both electrodes 3,
A resist layer Re is formed on the surface of the insulating substrate 1 on which 4 is formed, and individual heating element forming openings P as shown in FIGS. 8A and 8B are formed in this resist layer Re. Next, FIG.
As shown in A and 9B, a resistor forming paste Pe containing ruthenium oxide inside the heating element forming opening P is formed.
Is filled so as to be higher than the surface of the resist layer Re, and then it is dried. Next, the surface of this dry paste is lapped until it becomes flush with the surface of the resist layer Re and then baked to obtain a thickness of 10 μm for connecting the electrodes 3 and 4 as shown in FIGS. 10A and 10B. The individual heating elements 2a 'are formed.

Next, the electrodes 3, 4 and the heating element 2
The abrasion resistant layer 6 is formed on the surface of the insulating substrate 1 on which a'is formed in the same manner as in the first embodiment. In that case, a step of about 1 μm remained on the surface of the abrasion resistant layer 6. Next, in the same manner as in Example 1, after the fillerless glass paste (for example, glass paste NP7240 (trade name) manufactured by Noritake) was screen-printed on the entire surface of the abrasion resistant layer 6, a working point (600 ° C) or higher was obtained. Baking in 3μ thick
The smooth layer 7 of m is formed. Then, a thermal head H'having the structure shown in FIGS. The surface of the thermal head H'of the second embodiment also has a step difference of 0.2 μm or less, like the surface of the thermal head H of the first embodiment.

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, in the thermal head of each of the above-described embodiments, two or more smooth layers may be laminated, and by doing so, a smoother flat surface can be realized. Further, as the glass paste for forming a smooth layer, in addition to the above-mentioned ones, an amorphous fillerless glass as shown in Table 1 of FIG. 11 can be used. , 2 can be obtained. Furthermore, the order of forming the wear resistant layer and the smooth layer can be reversed. Furthermore, in each of the above embodiments, the heating elements 2a and 2a 'are formed by the thin film technique and the lift-off method, respectively.
Method (a method of forming a resistor-forming metal organic material layer on the surface of an insulating substrate and then forming a resistor pattern by photolithography) or a screen printing method. Further, it is also possible to form a protective layer on the lower surface of the wear resistant layer in the second embodiment.

[0033]

As described above, according to the present invention, since a smooth layer made of low-softening fillerless glass, which is softened during firing and has fluidity, is formed on the surface of the insulating substrate of the thermal head, the surface is not required to be polished. Is smooth. Therefore, according to the present invention, it is possible to realize a thermal head that can perform good printing pressure and paper feeding without polishing. According to the present invention as described above, a thermal head that requires good printing pressure and high-precision paper feeding for performing halftone printing, especially a heating element having a narrow width in the sub-scanning direction (a space between the individual electrodes and the common electrode). It is possible to realize a film-type thermal head having a narrow heating element) and a thick-film thermal head in which the heating element is formed by a lift-off method without surface polishing.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a thermal head according to a first embodiment of the present invention.

FIG. 2 is a detailed explanatory view of a main part of the thermal head of the first embodiment, FIG. 2A is a partial plan view of the thermal head of the first embodiment, and FIG. 2B is a sectional view taken along line IB-IB of FIG. 2A. is there.

FIG. 3 is an explanatory diagram of a method of manufacturing the thermal head according to the first embodiment, and FIGS. 3A and 3B are diagrams corresponding to FIGS. 2A and 2B, respectively.

FIG. 4 is an explanatory diagram of a method of manufacturing the thermal head according to the first embodiment, and FIGS. 4A and 4B are diagrams showing a state of a process after the processes of FIGS. 3A and 3B.

FIG. 5 is an explanatory diagram of a method of manufacturing the thermal head according to the first embodiment, and FIGS. 5A and 5B are diagrams showing a state of steps after the steps of FIGS. 4A and 4B.

FIG. 6 is an explanatory diagram of a method of manufacturing the thermal head according to the first embodiment, and FIGS. 6A and 6B are diagrams showing a state of a step after the steps of FIGS. 5A and 5B.

FIG. 7 is a detailed explanatory view of a main part of a second embodiment of the thermal head of the present invention, FIG. 7A is a partial plan view of the thermal head of the second embodiment, and FIG. 7B is a sectional view taken along line VIIB-VIIB of FIG. 7A. FIG. 7C is a sectional view taken along line VIIC-VIIC of FIG. 7A.

FIG. 8 is an explanatory diagram of a method of manufacturing the thermal head according to the second embodiment, and FIGS. 8A and 8B are diagrams corresponding to FIGS. 7A and 7B, respectively.

FIG. 9 is an explanatory diagram of a method of manufacturing the thermal head according to the second embodiment, and FIGS. 9A and 9B are diagrams showing a state of a step after the steps of FIGS. 7A and 7B.

FIG. 10 is an explanatory diagram of a method of manufacturing the thermal head of the second embodiment, and FIGS. 10A and 10B are the same as FIGS.
It is a figure which shows the state of the process after B.

FIG. 11 is a table showing fillerless glass materials usable in the present invention.

12A and 12B are explanatory views of Conventional Example 1 of a thermal head, FIG. 12A is a partial plan view thereof, and FIG. 12B is FIG. 12A.
FIG. 4 is a sectional view taken along line XIIB-XIIB of FIG.

13A and 13B are explanatory views of Conventional Example 2 of a thermal head, FIG. 13A is a partial plan view thereof, and FIG. 13B is FIG. 13A.
FIG. 13 is a sectional view taken along line XIIIB-XIIIB in FIG.

FIG. 14 is an explanatory view of Conventional Example 3 of the thermal head, and FIG. 14A is a partial plan view thereof.
14B is a sectional view taken along line XIIIIB-XIIIIB in FIG. 14A, and FIG. 14C
FIG. 14B is a sectional view taken along line XIIIIC-XIIIIC of FIG. 14A.

[Explanation of symbols]

1 ... Insulating substrate, 2, 2 '... Heating element, 3 ... Common electrode, 4
... Individual electrode, 4a ... Individual electrode tip portion, 6 ... Wear resistant layer, 7
… Smooth layer, X… Main scanning direction

Claims (2)

[Claims] 1. A common electrode extending along the main scanning direction,
A large number of individual electrodes whose tip portions are arranged in a row along the main scanning direction and which are arranged to face the common electrode, a heating element which connects the common electrode and the individual electrode tip portions, the both electrodes, and In a thermal head in which a wear-resistant layer that covers the surface of a heating element is formed on the surface of an insulating substrate, on the surface side of the electrodes and the heating element, a low-softening fillerless glass that is softened to cause fluidity during firing The thermal head is characterized in that a smooth layer of is formed. 2. A common electrode extending along the main scanning direction,
A large number of individual electrodes whose tip portions are arranged in a row along the main scanning direction and which are arranged to face the common electrode, a heating element which connects the common electrode and the individual electrode tip portions, the both electrodes, and In a method of manufacturing a thermal head in which a wear-resistant layer that covers the surface of a heating element is formed on the surface of an insulating substrate, in the method of forming both electrodes and the heating element on the surface of the insulating substrate, a low temperature is formed on the surface of the insulating substrate. A method of manufacturing a thermal head, comprising: forming a softened fillerless glass paste layer, and then providing a smooth layer forming step of firing the fillerless glass paste layer at a working point or higher.