JPS6189870A - Manufacture of thermal head - Google Patents

Abstract

PURPOSE:To enable all electrode layers to be provided by a series of manufacturing steps, by sequentially laminating electrode layers on one side of a substrate so as to face each other through a glass layer. CONSTITUTION:A conductor is applied to a surface of the substrate 1 by printing, followed by firing to provide a conductor layer 30, which is etched as shown to provide the first electrode layer 3 (selective electrode layer 3). A high melting point glass or the like is provided on the electrode layer 3 by printing and firing. An electrode layer 4 (common electrode layer 4) is connected to an electrode pattern 5 after passing over a glass layer 6. To protect the selective electrode layer 3 and the common electrode layer 4, a glass layer 7 is provided by printing and firing on the surface of the substrate 1 except a lead part. The substrate thus laminated and wired is cut at the position of a straight line (a). Heating resistors 2 are separated by laser cutting. Accordingly, the plurality of electrode layers 3, 4 are laminated on one side of the substrate so as to face each other through the glass layer 6 or the like.

Description

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

[Conventional technology]

Conventionally, thermal heads such as those disclosed in Japanese Patent Publication No. 40-6040 and Japanese Patent Publication No. 48-38265 are known as thermal heads in which a heating resistor is formed at the end of a substrate. FIG. 12 is a block diagram showing an outline of such a thermal head. The thermal head shown in the figure has a heating resistor 2 formed at the end of a substrate 1, and emits i! ! ! Resistor 2
The electrode layers 3 and 4 are stacked so that they partially overlap. In the thermal head formed in this manner, the heat-generating portion of the heat-generating resistor 2 comes into reliable contact with the recording paper, etc., so that a thermal head with good thermal efficiency can be obtained. In addition, since it is easier to process the end portion of the substrate 1 into a flat surface than the flat portion, a plurality of heat generating resistors 2 are formed.
PAM can be applied evenly to iJE, etc., and high print quality can be obtained.

[Problem that the invention seeks to solve]

However, in such a thermal head,
Since the electrode layer 3.4 is formed on both sides of the substrate 1, it has a defect such as blowing.

[B] Since electrode layers must be formed on one side of the substrate 1, alignment of the electrode layers 3 and 4 is not easy.

(b) If a ceramic substrate, which is difficult to process through holes, is used as the substrate 1, wiring such as lead wiring must be done on a separate substrate, and the driving IC and other elements must be built in. It's difficult.

(c) The size of the printed dot (the length of the heating resistor 2) is determined by the thickness of the substrate 1, so in order to achieve high resolution recording, the substrate 1 must be made thinner. The mechanical strength of the substrate 1 cannot be obtained, and manufacturing becomes difficult.

(d) Since the heat generating resistor 2 is formed so as to wrap around the edge of the substrate 1, there is a possibility that the heat generating resistor 2 is bent and broken at the edge of the substrate 1.

An object of the present invention is to eliminate the drawbacks of the conventional apparatus as described above, to realize a thermal head that is easy to manufacture, and is suitable for high resolution, and a method for manufacturing the same.

[Means for solving problems]

The thermal head and the manufacturing method thereof of the present invention include sequentially forming electrode layers of Pi number on one surface of a substrate so as to face each other with an electrical insulating layer and a glass layer serving as a thermal resistance layer interposed therebetween. Each layer included in the electrode layer is cut into a straight line, and a heating resistor is formed on the exposed end surface of each electrode layer.

[For production]

In this way, if a plurality of electrode layers are formed on one side of the substrate, all the electrode layers can be formed through a series of manufacturing steps, and the manufacturing process is easy. Lead wiring processing such as lossover, which is necessary when mounting other elements, can be performed simultaneously and within the same substrate. If wiring is done in three or four layers, wiring for driver elements can also be done within the same substrate. In addition, the length of the heating resistor is determined by the thickness of the glass layer formed between the electrode layers, so by adjusting this thickness, the length of the heating resistor can be freely controlled. A high-resolution thermal head can be realized without affecting strength. moreover,
Since the end of the substrate is cut and the heating resistor is formed at the exposed end of the electrode layer, the heating resistor only needs to be formed on one surface, and there is no bending. , a highly reliable heating resistor can be obtained.

〔Example〕

Hereinafter, one embodiment of the thermal head of the present invention and its manufacturing method will be described following manufacturing process 11.

In the figure, the same parts as in FIG. 12 are designated by the same reference numerals.

1 and 2 show the steps of forming a first electrode layer on a substrate 1. FIG. The substrate 1 is, for example, a ceramic substrate, and its surface is coated with gold (Au) and silver palladium.

By printing and firing a conductor such as platinum or copper, the one shown in Figure 1 is -
This is an integrally formed selection electrode connected to each of the heating resistors arranged in a row, and later etched into a pattern as shown in FIG. 3). Here, the number of fine patterns processed by etching is 10/
In the case of obtaining an electrode density of mm or more, and in the case of a relatively low density, it is also possible to directly form an electrode pattern as shown in FIG. 2 by printing. 5 is common which will be explained later.
? This is an electrode pattern for taking a return from fll+. The film thickness of these conductor layers is generally 3 to 5.
It is about μm.

FIG. 3 shows a step of forming a glass layer 6, which will serve as an electrical insulating layer and a thermal resistance layer, on the selection electrode layer 3.

As shown in the figure, high melting point glass or the like is printed on the selective electrode layer 3 and fired. The film thickness after firing is 50 to 1 if necessary.
00 μm. In addition, although the thickness of the thick film glass layer after firing is generally 20 to 30 μm, it becomes necessary by repeating the same process.

FIG. 4 shows a step of forming the second electrode layer 4 on the glass layer 6. In this case, the electrode layer 4 (hereinafter referred to as common electrode layer 4) passes over the glass layer 6 and is then connected to the electrode pattern 5 described above.

FIG. 5 shows a step of printing and baking a glass layer 7 on the surface of the substrate 1 except for the lead extraction portions in order to protect the selection electrode layer 3 and the common electrode layer 4.

The material of this protective glass layer 7 is the same high melting point glass as the glass layer 6 described above. This protective glass layer 7 is used to prevent the electrode layers 3 and 4 from peeling off during the next cutting of the edge of the substrate. Furthermore, it is also effective to add, for example, aluminum oxide (A1.O,) powder to this glass layer in consideration of wear resistance, thermal conductivity, and the like.

FIG. 6 shows a step of cutting the end portion of the substrate 1 to form an end surface to which the heating resistor 2 is to be attached. Songbook Figures 1 to 512
The substrate 1, which has been successively laminated and wired as shown in FIG. 1, is cut at the position of straight line a in the figure. FIG. 7 shows the state of the end face. As shown in the figure, the end has a selective 0iK93 (
The selection type ai31-38) and the common electrode layer 4 are now exposed, and moreover, these electrodes are facing each other with the glass m6 interposed therebetween.

Incidentally, if the degree of surface compatibility of the end face after cutting is lower than a predetermined standard, polishing is performed to give the surface a mirror finish.

The end face formed in this way is coated with tantalum nitride (Ta,
A resistive material such as N), nichrome (Ni-Cr) is deposited by sputtering or vapor deposition to form the heating resistor 2. The film thickness of the heating resistor 2 in this case is determined in relation to its resistance value, and is approximately 0.1 μm.
That's about it.

Now, by the above process, the heating resistor 2 is of the selective type 8i3
The heating resistors 2 are uniformly formed on the exposed end surfaces of the selected electrodes 1 to 38 and the common electrode layer 4 and are electrically connected to these electrodes.Next, it is necessary to separate the heating resistor 2 for each of the selected electrodes 31 to 38.

FIG. 8 shows a state in which the heating resistor 2 is separated into shapes corresponding to the selection electrodes 31-38. In the illustrated example, the heating resistor 2 is separated using laser cutting.
8 is a locus of laser cutting.

The width of the laser cut (the line width of the locus 8) is determined by the spot diameter of the laser beam, and the minimum width can be up to about 30 μm, making it easy to form high-density heating resistors.

Further, as shown in the figure, the length of the heating resistor 2 is determined by the thickness of the glass layer 6 interposed between the selection electrodes 31 to 38 and the common electrode layer 4. By adjusting the length of the heating resistor 2, the length of the heating resistor 2 can be arbitrarily controlled.

When the heating resistor 2 is separated in this way, silicon oxide (Sin,
), tantalum pentoxide (Ta*O-), boron nitride (BN), silicon carbide (Sac), etc., are deposited by sputtering or vapor deposition. 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, gold Ir
& The film mainly uses nickel, and by adding aluminum oxide, boron nitride, diamond, etc. as a dispersant, thermal conductivity and publication Jm! Abrasion resistance can be improved.

The thermal head of the present invention is formed through the above-described steps. In such a thermal head, one surface of the substrate 1 is formed so that the plurality of electrode layers 3 and 4 face each other with a glass layer 6 or the like interposed therebetween. Since the heating resistor is laminated, manufacturing and wiring processing are easy, and by adjusting the thickness of the glass layer 6 interposed between the selective electrode layer 3 and the common electrode layer 4, the heating resistor 2 can be arbitrarily controlled, and high resolution can be obtained regardless of the thickness of the substrate 1. In addition, since the heating resistor 2 is formed on the exposed end surface of the electrode layer 3.4, the heating resistor 2 only needs to be attached to the end surface, and there is no bending, so it is possible to generate heat with high reliability. The resistor 2 can be formed.Furthermore, since the step of sputtering or vapor depositing the heat generating resistor 2 on the end of the substrate 1 is performed with the substrate 1 upright and the end facing the sputter target, A large number of substrates 1 can be mounted in a sputtering device, etc.
Mass production becomes possible.

Note that in the above description, the first layer is directly applied to the surface of the substrate 1.
However, depending on the smoothness of the surface of the substrate 1, a glass layer may be provided between the substrate 1 and the electrode layer 3 to smooth the base of the electrode layer 3. Good too. Furthermore, although laser cutting has been given as an example of a means for separating the heat generating resistor 2, there are other means for separating the heat generating resistor 2, such as etching by photolithography, mechanical cutting with a blade, and sandblasting. , which can be used as needed.

Furthermore, the heat aperture formed on the heat generating resistor 2 is further increased. The wear layer is not limited to the gold i film, but a glass layer can also be used. In addition, an aluminum plate or ceramic plate is attached on the electrode protective glass layer to maintain mechanical strength and at the same time,
It is also possible to correct warpage of the board.

FIGS. 9 to 11 are configuration diagrams showing other embodiments of the thermal head of the present invention. The thermal head shown in FIG. 9 has a multi-stylus heating resistor 2 used in a line printer, for example, and has a large number of heating resistors 2.
are formed in a row.

The thermal head shown in FIG. 10 has heating resistors 2 arranged in two rows. ．． Glass layer 6. , common electrode layer 4, glass layer 6.2 selection electrode M31. 1ull of protective glass layer 7
Each layer is laminated, and a heating resistor 2 is formed on the cut end surface. That is, by separating the heating resistors 2 attached to the end faces along the thin lines in the figure, two adjacent rows of thermal heads can be obtained.

The thermal head shown in FIG. 11 has selective electrode layers 3.on each side of a substrate 1. , 3. , common electric FfA layer 4. ,
4. .

Glass W6. ．． 6. and protective glass layer7. ,7. By forming the heating resistor 2 in the same process as shown in FIG. 10, two rows of thermal heads having an interval corresponding to the thickness of the substrate 1 can be obtained.

〔Effect of the invention〕

As explained above, in the thermal helad and its manufacturing method of the present invention, a plurality of electrode layers are successively laminated on one surface of a substrate so as to face each other with a glass layer serving as an electrical insulating layer and a thermal resistance layer interposed therebetween. At the same time, each layer including the substrate is cut in a straight line, and a resistor is formed on the exposed end face of each electrode layer, so three- and four-layer wiring and crossover are possible. As a head including a driver, it is possible to reduce the number of parts through miniaturization and commonization, reduce the number of close reading points, and achieve lower costs and improved reliability. Also,
It is possible to easily control the length of the heating resistor, to easily manufacture the thermal head, and to realize a thermal head suitable for high resolution, and a method for manufacturing the same.

[Brief explanation of drawings]

1 to 11 are block diagrams showing embodiments of a thermal head and a method for manufacturing the same according to the present invention, and FIG. 12 is a block diagram showing an example of a conventional thermal head. 1... Substrate, 2... Heat generating resistor, 3.3. ．． 3.・
...Selection electrode layer, 31-38...Selection electrode, 4.4.
．． 4゜00. ti) city? I? if W bow
To 06. The buds are 1, Igu, etc. -() ＾
et al.61...Glass layer, 7.7. ．． 7. ...
Protective glass layer, 8...Laser cut. Fig. 1 U Fig. 2 Fig. 4 Fig. 5 Fig. 6, [7th encyclopedia 171ri Fig. 9> 3 (3I-33), 4 do 2'''-l

Claims (2)

[Claims] (1) A substrate, a plurality of electrode layers sequentially stacked on one surface of the substrate so as to face each other via a glass layer serving as an electrical insulating layer and a heat resistance layer, and the plurality of electrode layers are exposed. A thermal head comprising a heating resistor formed on an end face. (2) A step of sequentially laminating a plurality of electrode layers on one side of the substrate so as to face each other with a glass layer in between, a step of cutting each layer including the substrate into a straight line at its end, and this cutting. A method for manufacturing a thermal head, comprising the step of forming a heating resistor on an end surface where a plurality of electrode layers are exposed in the step.