JPH0516405A - Thermal head - Google Patents

Abstract

PURPOSE:To provide a low-cost and highly reliable thermal head without deteriorating the printing quality. CONSTITUTION:On a heat accumulating glaze layer 2 is formed a wiring electrode layer 3 by the printing method. At least one end of the layer 3 opposed to the glaze layer 2 is inclined downward to the glaze layer 2. A heat generating resistance layer 4 is formed on the layer 3 by the thin film method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head.

[0002]

2. Description of the Related Art A conventional thermal head technology will be described with reference to FIGS.

The conventional thermal head starts with a thin film method in which a thin film heating resistor layer is formed by a spattering method or a vacuum vapor deposition method and a thin film wiring electrode layer is formed thereon, and screen printing or gravure printing. There is a printing method in which a wiring electrode layer is formed on the substrate and a heating resistor layer is formed on the wiring electrode layer by printing.

[0004] thin film method, for example, as shown in FIG. 3, FIG. 4, for example ceramic, glass, mainly provided heat storage glaze layer 2 made of SiO ₂ on a substrate 1 made of epoxy or the like, on the top, for example a cermet A thin-film heating resistor layer is formed from a system heating resistor material by a spattering method or a vacuum deposition method, and a heating resistor array 6 is formed by photolithography. On top of it, for example, Cu, Cr,
A thin wiring electrode layer is formed from an electrode material made of Al, Au or the like by a sputtering method or a vacuum deposition method, and individual electrodes 7a and a common electrode 7b are formed by photolithography. At this time, the portion sandwiched between the individual electrode 7a and the common electrode 7b becomes an individual heating element. A protective layer 5 made of, for example, SiON, SiC, SiN or the like is formed on the upper part thereof by a spattering method, a vacuum deposition method or a chemical vapor deposition method so as to cover the electrodes and the heating element.

On the other hand printing method, for example as shown in FIGS. 5 and 6, such as ceramic, glass, on a substrate 1 made of epoxy or the like mainly provided heat storage glaze layer 2 made of SiO _2, for example, Au on top Print using resinate
The individual electrode 8a and the common electrode 8b are formed by baking / photolithography, and the heating resistor 9 made of, for example, Ru resinate is printed / baked on the upper part of the individual electrode 8a and the common electrode 8b. At this time, the portions sandwiched by the two adjacent common electrodes 8b become individual heating elements. In this method, since the resistance value of the heating resistor 9 varies, it is necessary to perform pulse trimming in order to correct the variation in the resistor array. After that, a protective layer 10 made of, for example, lead borosilicate was printed and baked on the upper portion so as to cover the electrodes and the heating element.

[0006]

Among the above-mentioned conventional techniques, the thin film method requires a vacuum apparatus such as spattering and vacuum deposition, and a photolithography process, which requires a large-scale facility and many processes, resulting in high productivity. ， There was a problem in terms of economy. On the other hand, in the printing method, since the shape of the heating resistor 9 protrudes as shown in FIG. 5, the flatness is poor and the printing quality is inferior to the thin film method. It is an object of the present invention to provide a low-cost and highly reliable thermal head without deteriorating print quality by using the above-mentioned technical advantages.

[0007]

In order to achieve the above object, the present invention is a wiring method in which a wiring is formed on a heat storage glaze layer by a printing method in which at least the opposite end is inclined downward toward the heat storage glaze layer side. An electrode layer is formed, and a heating resistor layer is formed on the electrode layer by a thin film method.

[0008]

If the wiring electrode layer is formed by the printing method and the heating resistor layer is formed thereon by the thin film method, for example, if the wiring electrode layer is formed by the gravure printing, a vacuum device or a photolithography process is performed. A wiring electrode layer equivalent to a thin film can be obtained without the need.

The thin film resistor layer formed by, for example, spattering and photolithography does not require pulse trimming because the film thickness and resistance are uniform. Further, since the thin film resistor layer does not protrude, the number of steps and cost can be reduced without lowering the printing quality, and a low cost and highly reliable thermal head can be provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a flat type thermal head will be described below with reference to FIGS.

As shown in FIGS. 1 and 2, a heat storage glaze layer 2 mainly made of SiO is provided on an alumina substrate 1 of a flat type thermal head made of, for example, ceramic, glass, epoxy or the like, and printing is first performed on the heat storage glaze layer 2. According to the method, the wiring electrode layer 3 is formed by using a printing resinate containing Cu, Al, Au, Ag or the like as a main component. As an electrode pattern forming method, a method of forming a wiring electrode layer 3 on the entire surface by a screen printing method, baking and then forming a pattern by a photolithographic etching method, and a method of forming a wiring electrode layer 3 patterned by a gravure printing method are used. There is a method of forming by printing and firing directly. In this case, as shown in FIGS. 1 and 2, the opposite side 3C of the wiring electrode layer 3 has an appropriate curve or straight line toward the heat storage glaze layer 2 side in order to avoid disconnection of the thin film resistor provided thereon. It is inclined. In the gravure printing method, the surface tension acting on the resinate during printing / baking can naturally incline, but in the screen printing method, a curve or a straight line can be formed by etching two or more times during photolithographic etching.

Next, a heating resistor layer 4 composed of, for example, three layers is continuously formed on the layer by a spattering method, a vacuum deposition method or the like. First, a first heating element layer containing silicon carbide as a main component is provided, a second heating element layer made of a mixture of titanium carbide and silicon oxide is further provided thereon, and a third heating element made of silicon is further provided thereon. Provide a body layer. The heating resistor layer 4 is patterned by the photolithographic etching method. After forming the patterns of the heating resistor layer 4 and the wiring electrode layer 3, a protective layer 5 made of silicon oxynitride or silicon carbide is formed by a spattering method, a chemical vapor deposition method or the like.

[0013]

As described above, according to the present invention, the portion facing the wiring electrode layer in the vicinity of the heating element forming portion is provided with the inclination toward the heat storage glaze layer side by the printing method, and between the inclinations. The thin-film method forms a heating resistor layer with a uniform resistance value, which complements the defects of both and improves the man-hour, yield, and productivity without degrading printing quality.
It is possible to provide a low cost and highly reliable thermal head.

[Brief description of drawings]

FIG. 1 is a sectional view of a heating resistor portion showing an embodiment of a thermal head of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a sectional view of a thermal head using a conventional thin film method.

FIG. 4 is a plan view of FIG.

FIG. 5 is a sectional view of a thermal head using a conventional printing method.

6 is a plan view of FIG.

[Explanation of symbols]

 1 Alumina substrate 2 Heat storage glaze layer 3 Wiring electrode layer 4 Heating resistor layer 5 Protective layer

Claims (1)

1. A substrate, a heat storage glaze layer provided on at least an upper surface side of the substrate, and a wiring electrode layer provided on the heat storage glaze layer so as to face each other by a printing method. The end portions of the wiring electrode layers facing each other are shaped to have a downward slope toward the heat storage glaze layer side, and a heating resistor layer formed of a thin film is provided between the slope portions. head.