JPH01118450A - Thermal head substrate and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a thermal head substrate at a low cost which enable high speed printing of high precision to be executed at small power consumption, by providing an insulating substrate and a glaze layer which is a porous SiO2 particulate layer formed on the insulating substrate. CONSTITUTION:At first, a mixed particulate layer 12 of a line state is formed on an alumina substrate 11. In this case Au particulate 12a and SiO2 particulate 12b are generated in an aerosol state by heating objective matter in an inert gas atmosphere, and a mixed particulate layer 12 is formed by a gas deposition method in which those particulates of an aerosol state are sprayed at a high speed onto the alumina substrate 11 from a nozzle or the like to deposit the Au particulate 12a and SiO2 particulate 12b abovementioned on the alumina substrate 11. Then, the alumina substrate 11 having the particulate layer 12 is dipped into a mixed aqueous solution of, for instance, KI (100g/l) and I2(10g/l), and the Au particulate 12a is removed by etching to form a porous SiO2 particulate layer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a substrate for a thermal head and a method for manufacturing the same.

[Conventional technology]

For example, as shown in FIG. 2, a conventional thermal head substrate is one in which a glaze layer 2 as a heat insulating layer is directly provided on an alumina ceramic substrate 1, and this glaze layer 2 is made of glass. There is something.

[Problem that the invention seeks to solve]

However, as the basic requirements for communication systems, such as reliability, immediacy, and labor-saving, have recently become more and more demanded, thermal heads are also required to have higher definition,
There is a demand for performance that enables faster printing with less power. In order to achieve this kind of performance, sufficient heat must be stored in the board when electricity is applied to the heat generating part, and
There is a need for a thermal head structure that allows heat to be absorbed into the substrate sufficiently quickly when the current is turned off.

In conventional thermal head substrates, the thickness of the glaze layer is set sufficiently large to provide sufficient heat retention, and once heat is stored in the substrate, printing is performed using a small amount of electric power. In this case, after the power to the heat generating part is turned off, the temperature does not decrease quickly enough, resulting in poor thermal isolation and smearing between each pixel. There were problems with high-definition printing and high-speed printing, such as tailing during high-speed printing.

On the other hand, if an attempt was made to make the glaze layer thinner to improve its thermal response and enable high-definition and high-speed printing, a problem arose in that a large amount of electric power would be required for printing. In other words, from the viewpoint of improving thermal efficiency, the glaze layer has the following properties:
There were mutually contradictory demands: a thicker one is preferable, and a thinner one is preferable from the viewpoint of improving thermal response.

Therefore, a countermeasure for solving the above-mentioned problems is proposed in Japanese Utility Model Application Publication No. 148640/1983. This proposal involves attaching a porous glass body to a substrate, and provides a thermal head with excellent heat retention and heat separation properties, but manufacturing requires a thin porous glass body. Another problem is that the above difficulty increases manufacturing costs.

Therefore, the present invention was made to solve the above-mentioned problems of the prior art, and its purpose is to inexpensively produce a thermal head substrate that enables high-definition and high-speed printing with low power consumption. It is about providing.

[Means for solving problems]

In order to achieve the above object, a thermal head substrate according to the present invention includes an insulating substrate and a craze layer formed on the insulating substrate, and the glaze layer has a porous 5i02
It is characterized by a particle-through layer.

Further, the method for manufacturing a thermal head substrate according to the present invention includes a step of forming a mixed fine particle layer containing metal fine particles and SiO2 fine particles on an insulating substrate, and a step of removing the metal fine particles in the mixed fine particle layer by etching. It is characterized by including.

[For production]

In the present invention having the above configuration, the glaze layer is
Composed of a porous 5i02 fine particle layer, it has excellent heat resistance,
Moreover, it has a property of having low thermal conductivity. Due to its low thermal conductivity, the craze layer has = 3- large heat retention properties, and therefore, by simply applying a small amount of electric power to the heat generating part, the surface temperature of the craze layer can reach the predetermined temperature required for printing. This results in better thermal efficiency. On the other hand, even if the craze layer is thinned to the extent that the thermal conductivity of the glaze layer is low, sufficient heat retention can be ensured, so the heat capacity of the glaze layer itself can be reduced, and therefore heat can be quickly transferred to the board by the printed adhesive. It has the function of quickly lowering the surface temperature.

Furthermore, in the manufacturing method of the present invention, metal fine particles and Si
Since the O2 fine particles are made into an aerosol and deposited by spraying them onto the insulating substrate from, for example, a nozzle, it is possible to easily form a uniform mixed fine particle layer. Thereafter, by etching, only the metal fine particles in the mixed fine particle layer are eluted and removed, thereby forming a porous SiO2 fine particle layer in which pores are uniformly distributed.

〔Example〕

The present invention will be explained below based on illustrated embodiments. 1st
Figures (a) and (b) are process explanatory diagrams showing a method for manufacturing a thermal head substrate according to the present invention. In the same figure, 1
1 is an alumina substrate as an insulating substrate, 12 is a mixed fine particle layer formed directly on the alumina substrate 11, 12a and 1
2b is Au fine particles and SiO constituting the mixed fine particle layer 12.
2 fine particles, 13 is Au coarse particles 1 from the mixed fine particle layer 12
Porous Si as a craze layer formed by removing 2a
This is an O2 fine particle layer.

Next, IJ! of the thermal head substrate of the present invention! i! I will explain how to send it. First, in the first step, the process shown in Figure 1 (a
), a line-shaped mixed fine particle layer with a width of 1n+m, a thickness of 2μm, and a length of 50fflIn is formed on an alumina substrate 11 using a cast deposition device (manufactured by Shinjo Yakin Co., Ltd., model G-D-RA-2). form 12.

This gas deposition device heats a target object in an inert gas atmosphere to generate Auli particles 12a and SiO2 fine particles 12b in the form of an aerosol, and these aerosol-like fine particles are deposited onto the alumina substrate 11 at high speed through a nozzle or the like. A mixed fine particle layer 12 is formed by a cass deposition method in which the Au fine particles 12a and the SiO2 fine particles 12b are deposited on the alumina substrate 11 by spraying. In addition, in this example, Au fine particles 12a and SiO2 particles 1
The average particle size of all of 2b was about 5001.

Further, the mixing ratio of the Au fine particles 12a and the SiO2 fine particles 12b was set to 20-b for the AIJ fine particles 12a. In addition, in the case of particles having a particle size of submicron size, they are sometimes called not only fine particles but also ultrafine particles.

In the next step, the alumina substrate 11 having the mixed fine particle layer 12 formed in the above step is, for example, KI (100
By immersing it in a mixed aqueous solution of g/, Q ), I2 (10 g/, Q ) and removing the Au fine particles 12a by etching, a porous 5I02 as shown in FIG. 1(b) is obtained.
A fine particle layer 13 was formed.

Incidentally, in the above embodiment, only the case where the alumina substrate 11 is used as the insulating substrate is explained; however, the present invention is not limited thereto, and materials that maintain strength and heat resistance, such as ceramics such as AIN and SiC, may be used. A substrate, a metal substrate whose surface is insulated, a quartz substrate, or the like may be used.

Further, in the above embodiment, a case was explained in which Au fine particles were used as the metal fine particles, but the present invention is not limited thereto, and other metals such as Cu, Fe, Ni, AU, and Aj may be used.

Furthermore, the particle size of the SiO2 fine particles and metal fine particles is not limited to the above-mentioned 500A, but any suitable particle size may be used depending on the required heat retention properties, mechanical strength, etc. of the substrate.

Furthermore, in the above example, a case was explained in which the KI 10-2 solution was used as the etching liquid when there were ALI particles, but the present invention is not limited to this, and other cyan-based etching liquids may be used. You can. Furthermore, when using other metals, an appropriate etching solution may be used.

Furthermore, in this example, Au in the mixed fine particle layer 12
The case where the mixing ratio of the fine particles 12a is 20 to 80 mo1% has been described, but when the mixing ratio of the Au fine particles 12a is large, the number of pores increases, so the mechanical strength of the porous SiO2 fine particle layer 13 tends to weaken. There is. On the other hand, those with a small mixing ratio of Au fine particles 12a have SiO2 fine particles 12
Since there is a large amount of b, the Au fine particles 12a may not be completely etched. Therefore, the mixing ratio of the AuR particles 12a should be set to an appropriate ratio in consideration of the type of metal used, the mechanical strength required of the glaze layer, etc.

Next, the performance of the thermal head substrate formed by the manufacturing method of this example will be explained. Here, in order to compare with a conventional substrate, the mixing ratio of Au fine particles is 1'! IO
Porous 5i02 of the above example made from mixed microparticles of 30, 40, 50, 60°701′lOI% at 1%
Using a glazed alumina substrate and a glazed alumina substrate with a conventional glass glaze layer (manufactured by Nippon Tokushu Tokugyo Co., Ltd.),
A thermal head was constructed for each, and the relationship between its input power and peak temperature of heat generation was measured. This result is the third
As shown in the figure. Here, the glaze layers are all 1 width, 20
The heating element size of the thermal head is 50 x 75 mm thick.
It is a rectangle of μm, and the driving of the heating element is 0.8 + 11 during the pulse.
SeC (pulse cycle: 511 seconds), and the peak temperature was measured with an infrared thermometer.

As can be seen from the figure, the thermal bed using the substrate according to the present invention can reach a higher temperature with less power than that of the conventional configuration with the same thickness of heat insulation layer, and this tendency is observed in AUFI! This becomes noticeable when the mixing ratio of one particle 12a is large. Furthermore, since the glaze layer manufactured in this example has lower thermal conductivity than conventional glaze layers made of glass, it is possible to make the glaze layer thinner than conventional glaze layers and still have the same heat retention properties. It is possible. Furthermore, since the thermal head substrate according to the present invention allows the glaze layer to be made thinner, the heat capacity of the glaze layer itself can be reduced, which allows the substrate to quickly absorb heat and reduce the surface temperature. Thermal separation performance can be improved quickly.

〔Effect of the invention〕

As explained above, by using the thermal head substrate of the present invention, printing can be performed using less power than conventional substrates. Furthermore, according to the present invention, it is possible to make the glaze layer thinner, so in order to print with the same power, it is only necessary to form a thinner glaze layer. This has the effect that high-speed and high-definition printing is possible because the trailing is reduced.

Furthermore, according to the manufacturing method of the present invention, it is possible to form an extremely thin glaze layer, for example, without going through a difficult process such as depositing ultra-thin porous glass on an insulating substrate. The substrate can be manufactured through a simple process, and since the craze layer is directly formed on the substrate, reliability can be improved.

[Brief explanation of the drawing]

1(a) and 1(b) are process explanatory diagrams showing an embodiment of the method for manufacturing a thermal head substrate according to the present invention, FIG. 2 is a side sectional view of a conventional thermal head substrate, and FIG. 3 is Au
The mixing ratio of fine particles is 30.40.50.60.701Il
1 is a graph showing the relationship between applied power and peak temperature of a thermal head constructed using the thermal head substrate of this example in which a craze layer was formed with a craze layer of 1%. 11...Alumina substrate, 12...Mixed fine particle layer, 12a--AIJ fine particles, 12b-SiO2 fine particles, 13...Porous SiO2 fine particle layer. Patent applicant Oki Electric Industry Co., Ltd. Agent Patent attorney Former 1) Actual

Claims (1)

[Claims] 1. A substrate for a thermal head, comprising: an insulating substrate; and a glaze layer formed on the insulating substrate, the glaze layer being a porous SiO_2 fine particle layer. 2. A thermal head substrate comprising the steps of forming a mixed fine particle layer containing metal fine particles and SiO_2 fine particles on an insulating substrate, and removing the metal fine particles in the mixed fine particle layer by etching. Production method.