JPH0624022A - Manufacture of thermal head - Google Patents

Abstract

PURPOSE:To provide a method for manufacturing a thermal head which eliminates completely separation of protective layers from the surfaces of a heating resistor and a couple of conductive layers, protects the heating resistor and a couple of conductive layers by the protective layers perfectly and provide the given printing of high printing quality for a long period of time. CONSTITUTION:An insulated base 1 with a heating resistor and a couple of conductive layers formed on its upper face and a target material 6 are disposed face to face in a sputtering device 7, and power satisfying following conditions is applied simultaneously to the insulated base 1 and the target material 6 to scatter a part of the target material 6 and accumulate the same on the upper face of the heating resistor and on the surfaces of a couple of conductive layers on the upper face of the insulated base 1 to form protective layers. 7<=(power applied to the target material/power applied to the insualted base)<=17.

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 thermal head incorporated in a printer mechanism such as a word processor or a facsimile.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a thermal head incorporated in a printer mechanism such as a word processor has a heat storage layer 12 made of glass or the like deposited on the upper surface of an insulating substrate 11 made of alumina ceramics or the like. A heating resistor 13 made of tantalum nitride or the like on the layer 12
And a pair of conductive layers 14 made of aluminum or the like and a protective layer 15 made of silicon nitride or the like are sequentially deposited, and a predetermined electric power is applied between the pair of conductive layers 14. The heating resistor 13 causes Joule heat to a predetermined temperature required for printing, and the generated heat is conducted to thermal paper or the like to form a printed image on the thermal paper or the like, thereby functioning as a thermal head.

The protective layer 15 has a function of protecting the heating resistor 13 and the pair of conductive layers 14 from oxidative corrosion due to contact with moisture in the atmosphere and abrasion due to sliding of thermal paper. .

The conventional thermal head is usually
The protective layer 15 is formed on the surfaces of the heating resistor 13 and the pair of conductive layers 14 on the upper surface of the insulating substrate 11 by the following method.

That is, (1) First, the heating resistor 13 and the pair of conductive layers 1 are formed on the upper surface.
An insulating substrate 11 having No. 4 and a target material made of silicon nitride or the like are prepared.

(2) Next, the insulating substrate 11 and the target material are disposed opposite to each other in the sputtering apparatus, and then an inert gas such as argon is introduced into the sputtering apparatus and the inside of the sputtering apparatus is vacuumed. Evacuate to a specified pressure with a pump or the like.

(3) Next, a predetermined electric power is applied to the target material through an electrode to scatter a part of the target material, and the scattered target material is combined with a heating resistor 13 and a pair on the upper surface of the insulating substrate 11. On the surface of the conductive layer 14, and thereby the protective layer 15 is adhered and formed on the surfaces of the heating resistor 13 and the pair of conductive layers 14 on the upper surface of the insulating substrate 11.

[0008]

However, in this conventional method of manufacturing a thermal head, a predetermined electric power is applied to the target material to scatter a part of the target material, and one of the scattered target materials. When the protective layer 15 is deposited on the surfaces of the heating resistor 13 and the pair of conductive layers 14 by depositing a portion on the upper surfaces of the heating resistor 13 and the pair of conductive layers 14, the heating resistor 13 on the insulating substrate 11 is covered. Since there is a step between the heat generating resistor 13 and the pair of conductive layers 14, a step is also formed in the protective layer 15 attached to the surfaces of the heating resistor 13 and the pair of conductive layers 14. When printing is performed on a thermal paper or the like using this thermal head, a large stress is generated in the step portion of the protective layer 15 due to the sliding of the thermal paper or the like, and the protective layer 15 causes the protective layer 15 or the pair of heat generating resistors 13 or of Had a drawback that peeling from the conductive layer 14.

[0009]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to eliminate the peeling of a protective layer from the surface of a heating resistor and a pair of conductive layers, and It is an object of the present invention to provide a method for manufacturing a thermal head, which can completely protect the conductive layer by protecting the printed matter and can obtain predetermined printing with high printing quality for a long period of time.

[0010]

According to a method of manufacturing a thermal head of the present invention, an insulating substrate having a heating resistor and a pair of conductive layers on an upper surface thereof and a target material are arranged to face each other in a sputtering apparatus. A protective layer is formed by applying power satisfying the following conditions to both the insulating substrate and the target material at the same time to scatter a part of the target material and deposit it on the heating resistor on the upper surface of the insulating substrate and the surfaces of the pair of conductive layers. It is characterized by

7 ≦ (power applied to target material / power applied to insulating substrate) ≦ 17

[0012]

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

FIG. 1 is a sectional view of a thermal head manufactured according to an embodiment of the present invention, in which 1 is an insulating substrate, 2 is a heat storage layer, 3 is a heating resistor, 4 is a pair of conductive layers, and 5 is a protective layer. The heat storage layer 2, the heating resistor 3, the conductive layer 4, and the protective layer 5 are sequentially deposited on the insulating substrate 1.

The insulating substrate 1 is made of an electrically insulating material such as alumina ceramics, supports the heating resistor 3 and the like on the upper surface thereof, and needs the temperature of the thermal head to form a good printed image on thermal paper or the like. It controls the temperature.

When the insulating substrate 1 is made of, for example, alumina ceramics, a suitable organic solvent or solvent is added to and mixed with ceramic raw material powder such as alumina, silica, magnesia, etc. to form a sludge, and this is formed by a conventionally known doctor blade. Method and calender roll method are used to form a ceramic green sheet.
It is manufactured by punching the ceramic green sheet into a predetermined shape and firing it at a high temperature (about 1600 ° C.).

A heat storage layer 2 made of glass or the like is deposited on the upper surface of the insulating substrate 1 to a thickness of about 80 μm, and the heat storage layer 2 brings the heat generated by the heating resistor 3 to an appropriate temperature. As described above, it has the function of maintaining good thermal response characteristics of the thermal head.

The heat storage layer 2 is formed by applying a glass paste obtained by adding and mixing an appropriate organic solvent and a solvent to glass powder on the upper surface of the insulating substrate 1 by employing a conventionally known screen printing method or the like. After that, set this to a high temperature (about 120
It is deposited on the insulating substrate 1 by baking at 0 ° C.

On the upper surface of the heat storage layer 2, a heating resistor 3 is also provided.
, And a pair of conductive layers 4 with a constant space therebetween are further deposited on the heating resistor 3.

Since the heating resistor 3 is made of, for example, tantalum nitride or the like and has a predetermined electric resistivity, it generates Joule heat when electric power is applied through the pair of conductive layers 4. Heat is generated at a temperature required to form a printed image, for example, a temperature of 250 to 400 ° C.

The pair of conductive layers 4 deposited on the heating resistor 3 is made of a metal such as aluminum, and the conductive layer 4 has a predetermined amount necessary for causing the heating resistor 3 to generate Joule heat. It acts to apply electric power.

The heating resistor 3 and the pair of conductive layers 4 deposited on the heat storage layer 2 are deposited on the heat storage layer 2 with a predetermined thickness by employing a conventionally known sputtering method or the like. Further, it is processed into a predetermined pattern by adopting photolithography technology.

On the surface of the heating resistor 3 on the upper surface of the insulating substrate 1 and the surfaces of the pair of conductive layers 4, silicon nitride and sialon (S) are also formed.
A protective layer 5 made of IALON or the like is deposited to a thickness of about 3 μm, and the protective layer 5 protects the heating resistor 3 and the pair of conductive layers 4 from abrasion due to sliding with thermal paper or the like, and is exposed to the atmosphere. It acts to protect against oxidative corrosion due to the contact of the contained water.

The surface of the protective layer 5 is a pair of conductive layers 4.
Has a taper shape from the upper surface of the end portion to the upper surface of the heating resistor 3, so that when printing on thermal paper or the like,
The thermal paper is smoothly slid against the protective layer 5 so that the protective layer 5
No large stress is generated in the protective layer 5, and as a result, the protective layer 5 is never separated from the surfaces of the heating resistor 3 and the pair of conductive layers 4.

Thus, the above-described thermal head applies a predetermined electric power between the pair of conductive layers 4 in response to an external electric signal to cause the heating resistor 3 to generate Joule heat to a predetermined temperature and sense the generated heat. It functions as a thermal head by forming a printed image on thermal paper or the like by conducting it to paper or the like.

Next, in the above-mentioned thermal head,
A method of depositing the protective layer 5 on the surfaces of the heating resistor 3 and the pair of conductive layers 4 on the upper surface of the insulating substrate 1 will be described.

(1) First, an insulating substrate 1 having a heating resistor 3 and a pair of conductive layers 4 on its upper surface and a target material 6 made of silicon nitride or sialon are prepared.

(2) Next, as shown in FIG. 2, the insulating substrate 1 and the target material 6 are attached to the electrodes 8 and 9 in the sputtering apparatus 7, respectively, and the upper surface of the insulating substrate 1 is set in the sputtering apparatus 7. And the surface of the target material 6 are opposed to each other.

(3) Next, an inert gas such as argon is introduced into the sputtering device 7, and the inside of the sputtering device 7 is approximately 5 × 10 5 by a vacuum pump or the like.
Evacuate to a pressure of ^-3 torr.

(4) Next, an electric power of about 5.5 W / cm ² is applied to the target material 6 through the electrode 9 so that the surface of the target material 6 is bombarded with argon ions. A part of the scattered target material 6 is scattered from the surface and the insulating substrate 1
About 1 μm on the surface of the heating resistor 3 on the upper surface and the pair of conductive layers 4
To the thickness of.

(5) Next, the condition “7 ≦ (power applied to the target material 6 / power applied to the insulating substrate 1) ≦ is applied to both the insulating substrate 1 and the target material 6 via the electrodes 8 and 9. 17 ", for example, 0.
Electric power of 4W / cm ² and 3.3W for the target material 6
/ Cm ² of electric power is applied at the same time, and argon ions are made to collide with both the surface of the target material 6 and the surface of the insulating substrate 1 to further generate the target material 6 on the surface of the heating resistor 3 on the upper surface of the insulating substrate 1 and the surface of the pair of conductive layers 4. Is partially deposited to a thickness of about 2 μm, and a protective layer 5 having a predetermined thickness is formed on the surfaces of the heating resistor 3 and the pair of conductive layers 4 on the upper surface of the insulating substrate 1.

In this case, the argon ions colliding with the surface of the target material 6 scatter a part thereof from the surface of the target material 6, and at the same time the upper surface of the heating resistor 3 and the pair of conductive layers 4 on the insulating substrate 1. On the other hand, the argon ions colliding with the surface of the insulating substrate 1 form a step on a part of the target material deposited on the upper surface of the heating resistor 3, especially on the surface. When it is, the corners of the step are selectively shaved and scattered again.

When the protective layer 5 is applied to the surfaces of the heating resistor 3 and the pair of conductive layers 4 on the insulating substrate 1 by simultaneously applying electric power to both the insulating substrate 1 and the target material 6, protection is performed. Even if a step is formed on the surface of the layer 5, since the corners of the step are selectively shaved off by the argon ions, the obtained protective layer 5 has no step on the surface and has a gentle taper as shown in FIG. Become a state.

Therefore, when printing is performed on the thermal paper or the like using this thermal head, the thermal paper or the like does not slide smoothly on the protective layer 5 and a large stress is not generated on the protective layer 5. As a result, The protective layer 5 is never peeled off from the surfaces of the heating resistor 3 and the pair of conductive layers 4.

Further, when the "power applied to the target material 6 / power applied to the insulating substrate 1" becomes smaller than 7, the deposition rate of the target material 6 deposited on the insulating substrate 1 becomes extremely slow and the thermal head When the manufacturing efficiency of No. 2 is significantly reduced and is more than 17, the scraping off of the target material 6 deposited on the surfaces of the heating resistor 3 and the pair of conductive layers 4 becomes weak, and a step is formed on the surface of the protective layer 5. It is easy to be done. Therefore, "target material 6
Power applied to the substrate / power applied to the insulating substrate 1 ”is specified in the range of 7 to 17.

The present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the gist of the present invention.

[0036]

According to the method of manufacturing a thermal head of the present invention, the condition "7.ltoreq.power applied to target material / applied to insulating substrate" is applied to both the insulating substrate and the target material which are arranged to face each other in the sputtering apparatus. The protective layer is formed on the surfaces of the heating resistor and the pair of conductive layers on the insulating substrate by simultaneously applying the electric power satisfying the electric power ≦ 17 ”, so that the step is formed in the protective layer. The surface is tapered without any. Therefore, when printing is performed using this thermal head, the thermal paper, etc., will smoothly slide on the surface of the protective layer, and no large stress will be generated in the protective layer. Can be firmly adhered to the upper surface of the insulating substrate for a long period of time.

[Brief description of drawings]

FIG. 1 is a sectional view of a thermal head manufactured by a manufacturing method of the present invention.

FIG. 2 is a schematic view for explaining the manufacturing method of the present invention.

FIG. 3 is a sectional view of a conventional thermal head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating substrate 2 ... Heat storage layer 3 ... Heating resistor 4 ... A pair of conductive layers 5 ... Protective layer 6 ... Target material 7 ... Sputtering device 8, 9 ... ·electrode

Claims (1)

[Claims] 1. An insulating substrate having a heating resistor and a pair of conductive layers on an upper surface thereof and a target material are arranged to face each other in a sputtering apparatus, and both the insulating substrate and the target material satisfy the following conditions. Apply power at the same time,
A method of manufacturing a thermal head, characterized in that a part of a target material is scattered and deposited on the surfaces of a heating resistor and a pair of conductive layers on the upper surface of an insulating substrate to form a protective layer. 7 ≦ (power applied to target material / power applied to insulating substrate) ≦ 17