JPH0584221B2 - - Google Patents

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 the end surface of a substrate.

[Conventional technology]

Conventionally, as a thermal head in which a heating resistor is formed at the edge of a substrate, the applicant of the present application has disclosed a patent application filed in 1983-
There is a device that has already been filed as No. 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, a glass layer 3 serving as an electrical insulating layer and a heat resistance layer, a second electrode layer 4, and a protective glass layer 5 successively laminated on one surface of a substrate 1. Along with forming;
Each layer including the substrate 1 is cut in a straight line, and a heating resistor layer 6 is formed on the exposed end surface of each electrode layer 2, 4. In addition, the heating resistor layer 6
are separated 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. In addition, since the edges of the substrate 1 are easier to process to be flat than the flat parts,
A plurality of heat generating parts can be brought into even contact with 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. A high-resolution thermal head can be realized without affecting the strength of the substrate 1.

[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 and 4, a high melting point glass fired at a temperature of 1200° C. or higher is used. For this reason, it is not possible to use metal materials with low melting points for the first electrode layer 2 formed under the glass layer 3, and common gold (Au), silver (Ag), copper ( Cu), aluminum (Al), etc. can no longer be used.

The present invention eliminates the above-mentioned drawbacks of the conventional device, improves the heat generation characteristics by forming the heat generating part on the 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 glass layers on both sides of a glazed substrate, in which a glass layer is fired on both sides of the substrate part, and the thickness of the substrate part is equal to or less than the thickness of the glass layer. 2
A heat generating resistor layer is formed on the end face where the first and second electrode layers are exposed by cutting or polishing the end face of the substrate including the respective layers, and at least the above electrode layer is formed in the heat generating resistor layer. The heating resistor layer portion located on the glass layer is divided into a plurality of parts depending on the number of electrodes of the first or second electrode layer.

[Effect]

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. It is possible to improve the heat generation characteristics of the thermal head. In addition, the base of the heating resistor layer is mostly a glass layer, but since a substrate with high thermal conductivity is sandwiched between the glass layers, the temperature distribution of the heating part is made uniform, resulting in high printing quality. You can get quality. 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〕

Hereinafter, the thermal head of the present invention will be explained using the drawings. In the figure, the same parts as in FIG. 4 are designated by the same reference numerals.

FIG. 1 is a block 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 in the glazed substrate 10
For example, by spreading a liquid raw material thinly on a flat surface,
This is formed thinly by a manufacturing method such as drying and sintering, and the plate thickness is equal to or less than the thickness of the glass layer 12 (50 μm to 200 μm) (30 μm to 200 μm). It is.

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. This first and second
The electrode layers 2 and 4 are made by printing and firing a thick film conductive paste of gold, silver palladium, platinum, copper, etc., and etching it into an arbitrary pattern. Note that fine patterns are processed by etching when obtaining an electrode density of 10 lines/mm or more; if the density is relatively low, it is also possible to directly form the desired electrode pattern by printing. be. Further, the film thickness of the first and second electrode layers 2 and 4 is generally about 3 to 5 μm.

A protective glass layer 5 is printed and fired on 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 layer 5, and its melting point is relatively low. The protective glass layer 5 is used to prevent the first and second electrode layers 2 and 4 from peeling off during cutting of the edge of the substrate as described below. Furthermore, it is also effective to add, for example, aluminum oxide (Al ₂ O ₈ ) powder to the protective glass layer 5 in consideration of wear resistance, thermal conductivity, and the like.

Next, the ends of the glazed substrate 10 to which the first and second electrode layers 2 and 4 are attached as described above are cut to form an end surface to which the heating resistor layer 6 is to be attached. . FIG. 2 shows the state of the end face. As shown in the figure, the first and second electrode layers 2 and 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.

A resistive material such as tantalum nitride (Ta ₂ N) or nichrome (Ni-Cr) is deposited on the end face thus formed 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 its resistance value, and is approximately 0.1 μm.

Now, as described above, after the heat generating resistor layer 6 is formed on the end surface of the glazed substrate 10, the heat generating resistor layer 6 is formed so as to correspond to the formation (number of electrodes) of the first electrode layer 2. Separated into multiple heat generating 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 includes a substrate portion 11 and a glass layer 12.
It will be formed across the Here, the thermal conductivity of the substrate portion 11 is 10 compared to that of the glass layer 12.
Since the temperature distribution on the surface of the heating resistor layer 6 is about twice as large, the temperature at the center portion (substrate portion 11) is lowered, and as shown in the upper part of the figure, the distribution that would normally look like a broken line is improved. , the distribution becomes more uniform. 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. At this time,
If the thickness of the substrate portion 11 is too thick, the temperature in the central portion will drop too much and the temperature distribution will not be uniform.
It is desirable that the thickness be equal to or less than the thickness of 2. In addition, in the figure, 7 is a protective and wear-resistant layer, and insulating layers such as silicon oxide (SiO ₂ ), tantalum pentoxide (Ta ₂ O ₅ ), boron nitride (BN), and silicon carbide (SiC) are sputtered or It is vapor deposited. Also,
If thermal conductivity is considered, 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 heat generating portion of the heat generating resistor layer 6 is connected to the substrate portion 1.
1, 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 glass layer 12 that has already been fired, they are not exposed to high temperatures after their formation, and the electrode materials have a relatively low melting point. Common metal materials can be used. Furthermore, since the glass layer 12 is provided on both sides of the thin substrate portion 11, the glass layer 12
The deflection of the substrate portion 11 due to the expansion and contraction of the substrate 2 can be canceled out, and the warpage of the glazed substrate 10 can be reduced.

In addition, in the above description, the heating resistor layer 6
The case where the glazed substrate 10 on which the glazed substrate 10 is formed is used as is is illustrated, but if a reinforcing plate made of an aluminum plate or a ceramic plate is bonded to one or both side surfaces of the glazed substrate 10, a thin glazed It is possible to supplement the mechanical strength of the substrate 10 (substrate portion 11) and correct warpage of the substrate.

〔Effect of the invention〕

As explained above, in the thermal head of the present invention, a glass layer is fired on both sides of the substrate part, and a glazed substrate is formed in which the thickness of the substrate part is equal to or less than that of the glass layer. First and second electrode layers are provided on both surfaces, and a heat generating resistor layer is formed on the end face where the first and second electrode layers are exposed by cutting or polishing the end face of the substrate including each layer, and the heat generating resistor layer is formed on the end face where the first and second electrode layers are exposed. Since the body layer is separated into a plurality of parts according to the number of electrodes in the first or second electrode layer, the heat generating part can be formed only on the glass layer through a simple process, and the heat generating characteristics can be improved. You can get a good thermal head. In addition, since the first and second electrode layers are formed on the already fired glass layer, they are not exposed to high temperatures after they are formed, and metal materials with relatively low melting points are used as electrode materials. can do.

[Brief explanation of the drawing]

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... Heat generating resistor layer,
7... Protective layer, 10... Glazed substrate, 11...
...Substrate part, 12...Glass layer.

Claims (1)

[Claims] 1. A glazed substrate in which a glass layer is fired on both sides of the substrate part and the thickness of the substrate part is equal to or less than the thickness of the glass layer, and a first glazed substrate provided on both sides of the glazed substrate.
and a second electrode layer, and a protective glass layer formed on the first and second electrode layers, respectively;
A heating resistor formed on the end surface where the first and second electrode layers are exposed by cutting or polishing the end surface of the substrate including each of the layers, and separated into a plurality of parts according to the number of electrodes in the first or second electrode layer. A thermal head comprising a body layer.