JPS5859864A - Thermal head - Google Patents

Abstract

PURPOSE:To improve reliability and the quality of print, by a method wherein a substrate is provided with a partial glaze comprising the upper part which is made of a low fusing material and the lower part which is made of a high fusing material, and said substrate is further provided thereon a heating section comprising a thin film resistant layer and an electrode layer that supplies power to said resistant layer. CONSTITUTION:First a high fusing glass layer 25 is printed and burned. Next, a low fusing glass frit paste is printed and burned at lower temperature than the high fusing glass layer is burned. As a result, the low fusing glass layer 26 is formed without giving any damage to said high fusing glass layer 25, thereby providing a very smooth surface of the partial glaze having neither unevenness nor pin holes. Further, since the skirt part of the glaze is covered by the reasonable flow of the low fusing glass, the surface of the partial glaze is connected with the surface of the substrate with no radical distinction nor angle. Thus, accuracy of pattern and good quality of print are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal head including a partial glaze i11 whose upper part is made of a low melting point material and whose lower part is made of a high contact point material.

An object of the present invention is to provide a highly reliable thermal head.

Another object of the present invention is to provide a thermal head that can print clearly and with good print quality.

Still another object of the present invention is to provide a thermal head capable of printing with low power.

Thermal printing is a method in which Joule heat generated by passing a pulsed current through a heating resistor is transferred to thermal recording paper to create color recording, or ink from a thermal ribbon is transferred to paper using heat. be.

The thermal printing method has many advantages such as a simple mechanism, high reliability, low cost, and low noise, so it can be applied to a wide range of fields from large line printers to ultra-compact and lightweight printers. has been done,
It is becoming indispensable in the information processing field, including facsimile machines and personal computer peripherals.

Various types of PA recording paper have been devised, allowing multicolor recording.

It is also seen as promising as an image recording method such as simultaneous copy recording and two-tone recording. In particular, the thermal transfer method solves the problems of the conventional thermal printing method and its poor shelf life, and the print quality is clear, so it is expected to continue to develop in the future.

The heating resistor, or thermal head, is the lifeblood of the thermal printing method, and there are thin film, thick film, and semiconductor methods, but currently resolution and printing speed are limited.

The superiority of the thin film method has been proven in many respects, including long-term reliability and cost. In order to explain the thin film thermal head, an example of the thermal head is shown in Figure 1.

FIG. 1 is a diagram showing a cross section of a thin film thermal head.

An insulating substrate 1 made of alumina or the like is coated with a glass glaze layer 2 with a thickness of 40 to 60 μm to form a smooth surface.
Moreover, a heating resistor film 5 such as VCT a@N is formed. Furthermore, an electrical connection 5 made of Au or the like for supplying power to the heat generating part 4 is patterned on it. Besides, i! The oxidation-resistant protective layer 6 has a thickness of approximately 2μ, and the wear-resistant layer 7
The normal oxidation-resistant protective layer 6 has a groove of about 10μ.
top.

The wear-resistant layer 7 is formed of TIklOB by a sputtering method.

Figure 1 shows an example of a thin film thermal head.
Furthermore, the structure and shape are designed to satisfy Takayoshi p4Bt.

Figure 2 shows an example of a structure for improving printing quality.Thermal paper is made by forming a glaze layer 9 entirely on an insulating substrate 7 made of alumina or the like, only in a portion corresponding to the bottom S of the heat generating part 8. The structure of the upper part of the 0-part glaze layer 9, which makes contact with the tube well and efficiently transfers heat to the thermal paper and improves printing quality, is the same as the example shown in FIG. 1, and the heating resistor film 10111E pole 11
．． Oxidation-resistant protective layer 12. A wear-resistant layer 15 is formed and patterned.

These thermal printers have different arrangement and patterning of heating elements depending on their use.

Facility printers, line printers, and the like use dot-type heads in horizontal rows. This is an arrangement of dots perpendicular to the paper feed direction. Alphanumeric characters.

Nreal printers that print kanji, katakana, etc.
A vertical dot type head is used in which dots are arranged in the same direction as the paper feeding direction. For serial printers, dot matrix type heads, segment type heads, etc. are also used.

FIG. 5 shows an example of a horizontal single-row dot type head.

A large number of heat generating parts 15 are formed on the insulating substrate 14 perpendicular to the paper feeding direction shown by the arrow. Electrodes 16 are formed to supply current to the heat generating parts 15, and at the ends of the insulating substrate 14, A connection terminal 17 with an external circuit is formed. In some cases, it is attempted to form a partial glaze layer 18 in a leather-like manner as shown by the dotted line to improve printing quality.

FIG. 4 shows an example of a vertical single-row doublet type head.

A large number of heat generating parts 20 are formed on the insulating base 19 in parallel to the paper feeding direction indicated by the arrow. In most cases, the number of heat generating parts 20 is 7 dots. An electric pole 21 is formed for supplying a t' current to the heat generation @20, and a connection terminal 22 for connecting to an external circuit is formed at the end of the insulating substrate 19. In some cases, attempts have been made to improve printing quality by forming a partial glaze layer 25 as shown by the dotted line. After forming the required pattern shape on a substrate such as alumina using a method, it is fired at a predetermined temperature to scatter the binder, and is melted by VC to form a glass-like surface with a smooth surface.Normally stiff glass. The firing temperature is 500°C to 700°C. These firing temperatures and degrees are determined by the proportion of low melting point components such as lead oxide contained in the glass.

For purposes of partial glaze layers, a height of at least 40 μm is required, which must maintain a certain degree of simplicity. Therefore, glass with a low melting point will flow during firing and it is difficult to maintain the height. Therefore, in order to maintain the height, a high melting point glass with a melting point of 600° C. or higher is used. However, in this case as well, operations are performed to prevent the flow and maintain the height. For this reason, unevenness and pinholes remain on the surface of the partial glaze layer, which tends to cause problems in patterning the heating resistor layer.
In other words, even at the boundary with the substrate, there is a large angle between the surface of the substrate, which is made of ceramic which originally has a poor surface N degree due to poor wettability with the substrate, and especially when turning the electrode lead wire at 75, the pattern There was a phenomenon where the disc was cut off.

The present invention solves these disadvantages, improves printing quality by increasing the height of the partial glaze layer, improves reliability by improving pattern accuracy, and improves adhesion to thermal recording paper. This enables printing with low power.

That is, in the present invention, high melting point glass is used in the lower layer of the partial glaze layer, and low melting point glass is used in the upper layer.

An embodiment of the present invention is shown in FIG. 5, where a high melting point glass layer 25 is placed on an alumina substrate 24. A partial glaze layer consisting of a low melting point glass layer 26 is formed.

As a measure to realize this *X, first, a high melting point glass layer is marked 11 and fired, and then a low melting point glass frit paste is stamped 11 and fired at a temperature lower than the previous firing temperature. By doing this, a low melting point glass layer is formed without any deterioration of the previous high melting point glass layer, and the surface of the partial glaze layer becomes extremely smooth.
Irregularities and pinholes are removed, and the low melting point glass flows out even at the base, so the surface of the partial glaze layer and the surface of the substrate are connected without abrupt discontinuities or steep angles, and the pattern is Defects such as cutting no longer occur, pattern accuracy has improved, good printing is possible, and resolution has also improved.

According to the present invention, a thermal head that can perform clear printing with low power and with high reliability has been completed.

That is, printing of kanji characters that can be clearly distinguished is made possible by this embodiment of the vertical format, which is equipped with a heat generating part of 20 or more dots. Further, although the heat-generating portion normally requires more than 2 millijoules of energy per dot, according to this embodiment, it was possible to print with less than 1 millijoule. Furthermore, at this time, there were no defects caused by cutting of the pattern part of the electrode lead part.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a cross section of a thin film thermal head. FIG. 2 is a cross-sectional view of a thin film thermal head with a partial glaze layer. FIG. 5, 4WA is a diagram showing an example of a thermal head having a partial glaze layer. FIG. 5 is a diagram showing an embodiment of the present invention. 1...l [base fi! 2...Glass glaze layer 3...Heating resistor film 4...Heating part 5
...Electrode 6...Oxidation-resistant protective layer 7...
- Wear-resistant layer 8... Heat generating part 9... Glaze layer 10... Heat generating resistor film 11... Electrode
12... Oxidation-resistant protective layer 1S... Wear-resistant layer
14... Insulating substrate 15... Heat generating part
16... Electrode 17... Connection terminal 18...
-Partial glaze layer 19...insulating group 17B 20
... Heat generating part 21 ... Electrode 22 ... Connection terminal 25 ... Partial glaze layer 24 ... Alumina base plate 25 ... High melting point glass 26 ... Low melting point glass or higher Applicant Corporation Suwa Seikosha agent Patent attorney Mogami Tsutomu N1 diagram? Figure 2

Claims (1)

[Claims] In a thermal head that is equipped with a thin film resistance layer on a substrate provided with a partial glaze and a heat generating part that is connected to an electrode layer that supplies power to the thin film resistance layer, the upper part of the partial glaze is made of a low melting point material and the lower part is made of a high melting point material. Thermal head is made of melting point material.