JPS62109663A - Thermal head - Google Patents

Abstract

PURPOSE:To equalize the temperature distribution of a heat-generating section, and to improve the quality of printing by forming heating resistor layers divided into several sections on according to the shape of the first or second electrode layer an end surface, at which first and second electrode layers are exposed. CONSTITUTION:In a glazed substrate 10, first electrode layers 2 as selecting electrodes are fitted on one surface, and second electrode layers 4 as common electrodes are mounted on the other surface. Cover glass layer 5 are printed and backed on the electrode layers 2, 4 with the exception of lead leading-out sections. The end section of the glazed substrate 10 coated with the first and second electrode layers 2, 4 is cut, and the end surface coated with heating resistor layers 6 is formed. A resistance material, such as tantalum nitride, nichrome, etc. is applied onto the end surface through a sputtering method or an evaporation method, thus shaping the heating resistor layers 6. The heating resistor layers 6 are divided into a plurality of heat generating sections so as to correspond to the shapes of the first electrode layers 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head in which a heating resistor is formed in the direction of an end surface of a substrate.

[Conventional technology]

Conventionally, as a thermal head in which a heating resistor is formed on the end surface of a substrate, there is a device already published by the applicant of the present invention in Japanese Patent Application No. 59-213116. FIG. 4 is a block diagram showing an outline of this thermal head. , the thermal head shown in the figure has a first electrode layer 2 on one side of a substrate 1.
．． Glass layer serving as an electrical insulation layer and a thermal resistance layer 3. Second electrode m4. and a protective glass layer 5 are sequentially laminated, and each layer including the substrate 1 is cut in a straight line, so that a heating resistor layer 6 is formed on the exposed end surface of each electrode layer 2°. . Further, the heating resistor layer 6 is divided into a plurality of parts according to the shape of the first electrode layer 2 constituting the selection electrode.

In the thermal head formed in this manner, the heat generating resistor layer 6 (heat generating portion) comes into reliable contact with the recording paper, etc., so that a thermal head with good thermal efficiency can be obtained. Furthermore, since the end surface of the substrate 1 can be processed to be flat more easily than the flat surface, the plurality of heat generating parts can be brought into even contact with the recording paper, etc., and high printing quality can be obtained. Furthermore, since the length of the heat generating part in the heat generating resistor layer 6 is determined by the thickness of the glass layer 3 formed between the electrode layers, the length of the heat generating part can be freely controlled by adjusting this thickness. , without affecting the strength of the substrate 1, etc.
A high-resolution thermal head can be realized.

[Problem that the invention seeks to solve]

However, in such a thermal head,
As the glass layer 3 formed between the first and second electrode layers 2.4, a high melting point glass fired at a temperature of 1200° C. or higher is used. Therefore, this glass layer 3
Metal materials with low melting points cannot be used for the first electrode layer 2 formed below, and common gold (Au),
Silver (KS), copper (Cu), aluminum (AI), etc. can no longer be used.

The present invention eliminates the above-mentioned drawbacks of conventional devices, improves heat generation characteristics by forming a heat generating part on a glass layer, and provides a thermal head that does not require a high melting point material for the electrode material. The purpose is to realize this with a simple configuration.

[Means for solving problems]

The thermal head of the present invention has first and second electrodes on both sides of a glazed substrate, which has glass layers baked on both sides and whose thickness is equal to or less than the thickness of the glass layer. A heating resistor layer is formed on the end face where the first and second electrode layers are exposed, and at least mll symbol 5 of the heating resistor layer is provided.
The heating resistor layer portion located on the second layer is divided into a plurality of parts depending on the shape of the first or second'' electrode layer.

[For production]

In this way, by forming a heat generating resistor layer on the end face of the glazed substrate and separating it to form multiple heat generating parts, it is possible to form the heat generating parts only on the glass layer through a simple process. This makes it possible to improve the heat generation characteristics of the thermal head. In addition, the base of the heating resistor layer is usually a glass layer, but since a substrate part with high thermal conductivity is sandwiched between the glass layers, the temperature distribution of the heating part is made uniform. , high print quality can be obtained.

Furthermore, since the first and second electrode layers are formed on the glass layer that has already been fired, they are not exposed to high temperatures after their formation, and use common metal materials with relatively low melting points. be able to.

〔Example〕

The thermal head of the present invention will be explained below using drawings.
Ru. In the figure, the same parts as those in Figure 4 are designated by the same reference numerals.

FIG. 1 is a configuration diagram showing an embodiment of the thermal head of the present invention. In the figure, 10 is a glazed substrate in which glass layers 12 are baked on both sides of a substrate portion 11 made of, for example, alumina. Note that the substrate portion 11 of the glazed substrate 10 is formed thinly by a manufacturing method such as, for example, spreading a liquid raw material thinly on a flat surface, drying and sintering it, and the thickness of the substrate portion 11 is equal to the thickness of the glass layer 12. (50
µm to 200 µm), the same or lower (30 µm)
m to 200 μm).

First, in the glazed substrate 10, a first electrode layer 2 serving as a selection electrode, for example, is formed on one surface, and a second electrode layer 4 serving as a common electrode, for example, is formed on the other surface. The first and second electrode layers □2.2 are made by printing a thick film conductive paste of gold, silver palladium, platinum, copper, etc.
It is fired and etched into an arbitrary pattern. Note that fine patterns are processed by printing when obtaining an electrode density of 10 lines/run or more, and in the case of relatively low spring temperatures, the desired electrode pattern is processed directly by printing. “□It is also possible to form.

Further, the film thickness of the first and second w1 electrodes 2.4 is generally about 3 to 5 μm.

A protective glass layer 5 is printed and fired on the soil of the first and second electrode layers 2.4, except for the lead extraction portions, in order to protect these electrode layers 2,4.

For example, thick film crystallized glass is used for this protective glass PjJ5, and its melting point is relatively low.

The protective glass layer 5 is for preventing the first and second electrode layers 2.4 from peeling off when cutting the end surface of the substrate as shown in FIG. In addition, this protective glass layer 5 is made of, for example, aluminum oxide (A
1. It is also effective to add powder of O,).

Next, the first and second electrode layers 2.4 are formed as described above.
The end face of the glazed substrate 10 on which is adhered is cut,
An end face is formed on which the heating resistor layer 6 is to be applied. FIG. 2 shows the state of one side. As shown in the figure, the first and second electrode layers 2.4 are exposed on the end face. Note that if the surface roughness of the end face after cutting is lower than a predetermined standard, polishing or grinding is performed to finish the surface flat.

The end face formed in this way is coated with tantalum nitride (Taj
l) A resistive material such as chromium (Ni-Cr) is deposited by sputtering or vapor deposition to form the heating resistor layer 6. The thickness of the heating resistor layer 6 in this case is determined in relation to the annual resistance value, and is approximately 0.1
．． It is about μm.

Now, as described above, after the heat generating resistor layer 6 is formed on the end surface of the glazed substrate 10, a plurality of heat generating layers are formed so that the heat generating resistor layer 6 corresponds to the shape of the first electrode layer 2. Separated into parts. Laser cutting, photolithography, etc. are used for this separation.

FIG. 3 is a sectional view showing the state of the heat generating section formed in this manner. As shown in the figure, the heating resistor layer 6 is formed across the substrate portion 11 and the glass layer 12. Here, since the thermal conductivity of the substrate portion 11 is about 10 times higher than that of the glass layer 12, the temperature distribution on the surface of the heating resistor layer 6 is
) decreases, and as shown in the upper part of the figure, the distribution, which would normally look like a broken line, is improved and becomes a more uniform distribution. Therefore, a plurality of heat generating parts with uniform temperature distribution can be formed on the end surface of the glazed substrate 10 through a simple process. In the figure, 7 is a protective and wear-resistant layer made of silicon oxide (Sin), tantalum pentachloride (TllsO++), and boron nitride (BN).

An insulating layer such as silicon oxide (SiC) is sputtered or vapor deposited. Furthermore, in consideration of thermal conductivity, a wear-resistant metal layer may be applied by dispersion plating after insulating with silicon oxide or the like. In this case, nickel is mainly used for the metal film, and by adding aluminum oxide, boron nitride, diamond, etc. as a dispersant, thermal conductivity and wear resistance can be improved.

The thermal head of the present invention is formed through the steps described above, and in such a thermal head, the heating portion 1 of the heating resistor layer 6<the glass layer 1 including the substrate portion 11
2, it is possible to obtain appropriate heat retention and uniform temperature distribution, and to obtain good heat generation characteristics.

In addition, since the first and second electrode layers 2 and 4 are formed on the already fired glass layer 12, they are not exposed to high temperatures after they are formed, and are made of electrode materials with relatively low melting points. Low, common metal materials can be used.

Further, since the glass layer 12 is provided on both sides of the thin substrate portion 11, the deflection of the substrate portion 11 due to expansion and contraction of the glass layer 12 can be canceled out, and warpage of the glazed substrate 10 can be reduced.

Note that in the above description, the case where the glazed substrate 10 on which the heating resistor layer 6 is formed is used as is is illustrated, but an aluminum plate, a ceramic plate, etc. When the reinforcing plates made of
It is possible to compensate for the mechanical strength of 0 (substrate portion 11) and to correct the warpage of the substrate.

〔Effect of the invention〕

As explained above, in the thermal head of the present invention, a glazed substrate is formed in which a gas layer is fired on both sides and the thickness of the substrate portion is equal to or less than the thickness of the glass layer. A first and second electrode layer is provided on both sides of the electrode layer, a heat generating resistor layer is formed on the end face where the first and second electrode layers are exposed, and this heat generating resistor layer is attached to the first or second electrode layer. Since the electrode layer is separated into a plurality of parts depending on the shape of the electrode layer, the heat generating part can be formed only on the glass layer by a simple step 2, and a thermal head with good heat generation characteristics can be obtained. Furthermore, since the first and second electrode layers are formed on the glass layer that has already been fired, they are not exposed to high temperatures after they are formed.
A metal material with a relatively low melting point can be used as the electrode material.

[Brief explanation of drawings]

1 to 3 are block diagrams showing an embodiment of the thermal head of the present invention, and FIG. 4 is a block diagram showing an example of a conventional thermal head. DESCRIPTION OF SYMBOLS 1... Substrate, 2, 4... Electrode layer, 3... Glass layer, 5... Protective glass layer, 6... Heating resistor layer, 7...
...Protective layer, 10... Glazed substrate, 11... Substrate portion, 12... Glass layer. Figure 1 Figure 2

Claims (1)

[Claims] A glazed substrate in which glass layers are fired on both sides and the thickness of the substrate portion is equal to or less than the thickness of the glass layer, and first and second glazed substrates provided on both sides of the glazed substrate. an electrode layer and the first and second electrode layers;
A protective glass layer is formed on each of the electrode layers, and the first and second electrode layers are formed on the exposed end surface and are separated into a plurality of layers depending on the shape of the first or second electrode layer. A thermal head comprising a heating resistor layer.