JPH09234895A - Thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To heighten stable travelling by providing a heat resistant resin material having a specified hardness in between a partial glaze layer and a reinforcing conductor layer, in a thermal head wherein a partial glaze layer having a mountainous cross section with a plurality of heating resistors attached on its top face and a reinforcing conductor layer are arranged almost in parallel on an insulating base plate. SOLUTION: On an insulating base plate 1, a partial glaze layer 2 formed of glass is formed in a covering manner. On its top face, a plurality of heating resistors 3 formed of a tantalum nitride are arranged in a covering manner. At one end of each heating resistor 3, an individual electrode 4 is connected. To other end of each heating resistor 3, a common electrode 5 which is arranged on the insulating base plate 1 and is to be connected to a reinforcing conductor layer 6 lower than the layer 2 is connected in common. At an area between a slant face of the reinforcing conductor layer of the partial glaze layer 2 and the reinforcing conductor layer 6, a heat resistant resin material 8 having a hardness of 6H or below in pencil scratch test is put in a covering manner. The top part of the resin material 8 is positioned in between the top face of the partial glaze layer 2 and the top face of the reinforcing conductor layer 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head incorporated as a printer mechanism for a word processor, a facsimile or the like.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a thermal head incorporated as a printer mechanism such as a word processor has a partial glaze layer 12 and a reinforcing conductor layer 16 on an upper surface of an insulating substrate 11 made of alumina ceramics or the like. The heat generating resistors 13 are arranged so as to be substantially parallel to each other, and a plurality of heat generating resistors 13 are deposited and arranged on the partial glaze layer 12, and the individual electrodes 14 are provided at one end of each heat generating resistor 13.
And a common electrode 15 electrically connected to the reinforcing conductor layer 16 at the other end, respectively. A predetermined electric power is applied between the individual electrode 14 and the common electrode 15 in response to a print signal. Is applied to selectively generate Joule heat in the heating resistor 13 and conduct the generated heat to the thermal recording paper or the like to form a predetermined print image on the thermal recording paper or the like, thereby functioning as a thermal head.

The reinforcing conductor layer 16 is the common electrode 15
This is for effectively preventing a large voltage drop from occurring in the common electrode 15 when a large current is applied to the common electrode 15, and is formed with a thickness of 15 μm to 32 μm by a conductive material such as silver.

[0004]

However, in this conventional thermal head, the partial glaze layer 12 and the reinforcing conductor layer 16 are arranged substantially parallel to each other, and the depression A is formed between them. For this reason, when the thermal head is used for a long period of time, a large amount of paper dust such as thermal recording paper accumulates in the above-mentioned depression A, and these solidify and adhere firmly. This is because the binder contained in paper dust such as thermal recording paper is polyvinyl alcohol (P
This is because when the heat from the heat generating resistor 13 is transferred to this binder, it is extremely easily softened and adheres to the vicinity of the heat generating resistor 13. As a result, the heat-sensitive recording paper or the like generates heat. There is a drawback that paper scraps attached in the vicinity of the resistor 13 are caught and stable running is impossible.

[0005]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and a partial glaze layer having a mountain-shaped cross section having a plurality of heating resistors attached to the upper surface of an insulating substrate, A thermal head comprising a reinforcing conductor layer, which is commonly connected to each of the plurality of heating resistors and has a height lower than that of the partial glaze layer, arranged substantially parallel to each other. JIS K 5400 between the conductor layer
A heat-resistant resin material having a hardness of 6H or less according to the specified pencil scratch test was applied, and the top of the heat-resistant resin material was positioned between the upper surface of the partial glaze layer and the upper surface of the reinforcing conductor layer. Is characterized by.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an embodiment of a thermal head of the present invention, and FIG. 2 is a sectional view taken along line XX of FIG.
1 is an insulating substrate, 2 is a partial glaze layer, 3 is a heating resistor,
6 is a reinforcing conductor layer, and 8 is a heat resistant resin material.

The insulating substrate 1 is made of an electrically insulating material such as alumina ceramics, and has an upper surface for supporting the heating resistor 3 and the like.

The insulating substrate 1 is made of an organic solvent suitable for a ceramic raw material powder such as alumina, silica, and magnesia;
A ceramic green sheet is formed by adding and mixing a solvent to form a slurry and adopting a conventionally known doctor blade method, calendar roll method, etc.
Thereafter, the ceramic green sheet is manufactured by stamping into a predetermined shape and firing at a high temperature.

A partial glaze layer 2 made of glass or the like is deposited on the insulating substrate 1 so as to have a thickness of 30 μm to 60 μm. The partial glaze layer 2 has a heating resistor 3 formed thereon.
The heat generated by is accumulated so as to have an appropriate temperature, and serves to maintain the thermal response characteristics of the thermal head in good condition.

For the partial glaze layer 2, a glass paste obtained by adding and mixing an appropriate organic solvent and an organic resin to a predetermined glass material is printed and applied on the upper surface of the insulating substrate 1 by screen printing to a thickness of 30 μm to 60 μm. Then, evaporate a part of the organic solvent contained in the glass paste, and then bake it at a high temperature of about 1000 ° C to 1200 ° C to remove the organic components (organic solvent, organic resin). Is deposited on the upper surface of the insulating substrate 1.

A plurality of heating resistors 3 made of tantalum nitride or the like are deposited and arranged on the upper surface of the partial glaze layer 2, and an individual electrode 4 is individually provided at one end of each heating resistor 3. A common electrode 5 that is connected and is electrically connected to a reinforcing conductor layer 6 described later is commonly connected to the other end of each heating resistor 3.

The heating resistor 3 is made of, for example, tantalum nitride or the like, and has a predetermined electric resistivity, so that when electric power is applied through the individual electrode 4 and the common electrode 5, the joule is formed. Heat is generated, and heat is generated at a predetermined temperature necessary for forming a printed image, for example, a temperature of 200 ° C to 350 ° C.

The individual electrodes 4 and the common electrode 5 connected to both ends of the heating resistor 3 are made of metal such as aluminum, and the individual electrodes 4 and the common electrode 5 generate Joule heat in the heating resistor 3. It has an effect of applying a predetermined electric power required for the operation.

The plurality of heating resistors 3, the individual electrodes 4 and the common electrode 5 are formed on the upper surface of the partial glaze layer 2 with a predetermined pattern and a predetermined thickness (heating resistance) by adopting the well-known sputtering method and photolithography technique. The body 3 is applied to a thickness of 0.01 to 0.5 μm, and the individual electrode 4 and the common electrode 5 are applied to a thickness of 0.5 to 2.0 μm). Further, on the insulating substrate 1 to which the partial glaze layer 2 and the like are adhered, the reinforcing conductor layer 6 having a height lower than that of the partial glaze layer 2 is formed.
Are arranged substantially parallel to the partial glaze layer 2 with a thickness of 15 μm to 32 μm.

The reinforcing conductor layer 6 is electrically connected to the common electrode 5 on the upper surface thereof, and acts to effectively prevent a voltage drop in the common electrode 5 when a large current flows through the common electrode 5. A well-known thick film method, that is, a predetermined conductive paste obtained by adding and mixing an organic solvent or the like to a metal powder such as silver or copper is applied to a predetermined area on the upper surface of the insulating substrate 1 by a well-known screen printing or the like. For example, it is formed by printing and coating to a thickness of 15 μm to 32 μm, and then baking it at a temperature of 500 to 700 ° C., and electrically connecting to the common electrode 5 by attaching the common electrode 5 to the upper surface thereof. To be done.

A protective film 7 made of silicon nitride or the like is deposited on the upper surfaces of the heating resistor 3, the individual electrodes 4 and the common electrode 5 by a sputtering method or the like. Oxidation and corrosion due to contact with moisture contained therein and abrasion due to sliding contact of heat sensitive recording paper etc.
Etc. are protected.

Furthermore, in the region between the reinforcing conductor layer 6 side slope of the partial glaze layer 2 and the reinforcing conductor layer 6, JIS
K 5400 has a hardness of 6 according to the specified pencil scratch test.
A heat-resistant resin material 8 (softening temperature: 120 ° C. or higher) whose temperature is H or lower and whose top is located between the upper surface of the partial glaze layer 2 and the upper surface of the reinforcing conductor layer 6 is applied. By attaching the heat-resistant resin material 8 between the inclined surface of the partial glaze layer 2 on the reinforcing conductor layer 6 side and the reinforcing conductor layer 6,
The depression formed between the two is filled.

Therefore, even if the thermal head is used for a long period of time, after the paper dust adheres to the surface of the heat-resistant resin material 8, the thermal recording paper or the like is worn away by sliding contact, so that the paper is sequentially removed from the insulating substrate 1. As a result, the large pieces of paper dust do not adhere to the vicinity of the heating resistor 3.
Therefore, the thermal recording paper or the like can be stably run, and the printing quality can be improved.

If the hardness of the heat-resistant resin material 8 by the pencil scratch test specified in JIS K 5400 is larger than 6H, the abrasion due to the sliding contact of the heat-sensitive recording paper is reduced and the paper dust is removed from the insulating substrate 1. Cannot be removed satisfactorily. Therefore, the hardness of the heat-resistant resin material 8 by the pencil scratch test specified in JIS K5400 is specified to be 6H or less.

When the top of the heat-resistant resin material 8 is higher than the upper surface of the partial glaze layer 2, the heat-sensitive recording paper or the like is caught by the heat-resistant resin material 8 and the heat-sensitive recording paper or the like cannot be stably run. If the height is lower than the upper surface of the reinforcing conductor layer 6, a dent is formed between the partial glaze layer 2 and the reinforcing conductor layer 6, and the same problem as in the conventional example occurs. Therefore, the height of the surface of the heat resistant resin material 8 needs to be set between the top of the partial glaze layer 2 and the upper surface of the reinforcing conductor layer 6.

Further, the heat-resistant resin material 8 has a reinforcing conductor layer 6 such that one end thereof completely covers the upper surface of the reinforcing conductor layer 6.
The thermal recording paper or the like is directly contacted with the reinforcing conductive layer 6 having a rough surface formed by the thick film method and the protective film 7 thinly formed thereon by the sputtering method or the like. Therefore, it is possible to effectively prevent the formation of scratches on the surface of the thermal recording paper or the like and suppress the generation of paper dust. Therefore, it is preferable that one end of the heat resistant resin material 8 is extended to above the reinforcing conductor layer 6.

Incidentally, as such a heat resistant resin material 8,
An epoxy resin having a softening temperature of 130 ° C. to 140 ° C. and a pencil hardness of 6H, a polyimide resin having a softening temperature of about 300 ° C. and a pencil hardness of 3H, and more specifically, IR-650GC manufactured by Sanwa Chemical Industry Co., Ltd. (Product name) etc. are used,
A precursor (varnish) of such a resin material is applied using a dispenser or the like to form a deposit on a predetermined region. For example, when a plurality of thermal heads are simultaneously manufactured from one large substrate, as shown in FIG. 3, two partial glaze layers 2 are arranged on the large insulating substrate 1 so as to face each other. A heat-resistant resin precursor (varnish) 8 ′ is formed in the region between the partial glaze layers 2 by a dispenser or the like.
Then, the surface of the varnish 8 ′ is leveled by leaving it for a predetermined time, and then the varnish 8 ′ is added to 100-1.
It is formed by heat curing at a temperature of 20 ° C.

Thus, in the above-mentioned thermal head, a predetermined electric power is applied between the individual electrode 4 and the common electrode 5 in accordance with the print signal to selectively cause the heating resistor 3 to generate Joule heat and generate the heat. It functions as a thermal head by conducting heat to thermal paper or the like and forming a predetermined print image on the thermal paper or the like.

The present invention is not limited to the above embodiment, and various changes and improvements can be made without departing from the scope of the present invention. For example, metal particles in the heat resistant resin material can be used. By including the above components, it is possible to effectively release static electricity generated by sliding contact with the heat-sensitive recording paper, and prevent the heating resistor from being destroyed by the static electricity. When the heat resistant resin material having such conductivity is formed, the volume specific resistance of the heat resistant resin material is 1 or less.
It is preferable to adjust so as to be 0 ⁸ to 10 ¹⁰ Ω · cm.

[0026]

According to the present invention, even if the thermal head is used for a long period of time, after the paper dust adheres to the surface of the heat-resistant resin material, it is sequentially insulated by the abrasion due to the sliding contact of the thermal recording paper or the like. Since it is removed from the substrate, a large lump of paper dust is effectively prevented from adhering to the vicinity of the heating resistor. Therefore, the thermal recording paper or the like can be stably run, and the printing quality is improved.

Further, according to the present invention, if the heat resistant resin material is extended onto the reinforcing conductor layer, the thermal recording paper or the like will not come into contact with the reinforcing conductor layer having a rough surface. Therefore, the formation of scratches on the thermal recording paper is effectively prevented, and the generation of paper dust can be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a thermal head of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a diagram illustrating a method of manufacturing the thermal head of FIG.

FIG. 4 is a sectional view of a conventional thermal head.

[Explanation of symbols]

 1 ... Insulating substrate 2 ... Partial glaze layer 3 ... Heating resistor 6 ... Reinforcing conductor layer 8 ... Heat-resistant resin material

Claims (1)

[Claims] 1. A partial glaze layer having a mountain-shaped cross section having a plurality of heating resistors mounted on an upper surface of an insulating substrate, and a plurality of heating resistors which are commonly connected to each other and have a height of A thermal head comprising a reinforcing conductor layer lower than the partial glaze layer and arranged substantially parallel to each other, wherein JIS K is provided between the partial glaze layer and the reinforcing conductor layer.
Hardness 6H by the pencil scratch test specified in 5400
A thermal head characterized in that the following heat-resistant resin material is deposited and the top of the heat-resistant resin material is located between the upper surface of the partial glaze layer and the upper surface of the reinforcing conductor layer.