JPS5857975A - Thermal head - Google Patents

Abstract

PURPOSE:To make it possible to conduct a high speed and high revolving power printing onto a printing paper of large area by providing a plurality of specified partial ceraic layer at a thin filmed thermal head. CONSTITUTION:A number (e.g. 7 dots) of heating member 28 are equipped on an insulting substrate 24 along the direction of the paper feeding, and for the heating member 28, three partial ceramics 25, 27, 26 are equipped in this order on the substrate 24 in a single-file lined dot type thin filmed thermal head formed by connecting electrodes 21, 21 for power supply, moreover the partial ceramic 27 is constructed higher than the partial ceramics 25, 26, and at the top thereof, the heating member 28 is equipped so as to form the thermal head.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal head that includes a plurality of partial glazes and has a heat generating section in the high partial glaze near the center.

An object of the present invention is to provide a thermal printer with good printing quality.

Another object of the present invention is to provide a thermal head that prints with low power.

Still another object of the present invention is to provide a thermal head capable of printing on a large area at high speed and with high resolution.

Thermal printing is a method in which colored recording is performed by transmitting the Joule heat generated by passing a pulsed current through a heating resistor to thermal recording paper, or by transferring ink from a thermal ribbon onto plain 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 has been used in a wide range of fields from large line printers to ultra-compact and lightweight 117 printers. It has been applied to many applications, and is becoming indispensable in the information processing field, not only for facsimiles but also for peripheral computers.

Various types of thermal recording paper have been devised, and they are also being considered for image recording methods such as multicolor recording, simultaneous copying recording, gradation recording, etc. In particular, the thermal transfer method solves the problem of storage stability, which was considered to be a drawback of the conventional thermal printing method, and the printing quality is also 90% clear, making it highly anticipated that it will continue to develop.

There are thin film, thick film, and semiconductor methods for the heating resistor, or thermal head, which is the lifeblood of the thermal printing method, but currently there are many problems such as decomposition layers, printing speed, long-term reliability, and cost. The superiority of the thin film method has been proven.In order to explain a thin film thermal head, an outline of one example is shown in FIG.

FIG. 1 is a diagram showing a cross section of a thin film thermal head. A glass glaze layer 2 forming a smooth surface on an insulating substrate l made of alumina or the like is coated with 40 to 60 μm of N. 8. A heating resistor film 3 such as M is formed. 'W, on which a power source 115 for supplying power to the heat generating section 4 is patterned. On top of that, there is an oxidation-resistant and protective layer 6 of about 2 μm, and a wear-resistant layer 7 of about 10 μm.
μ is always formed. Normal oxidation-resistant protective layer 6 is 8% O snow
The wear-resistant layer 7 is formed by sputtering Ta and O, respectively.

FIG. 1 shows an example of a thin-film thermal head, and many improvements have been made to the structure, shape, material, etc. in order to achieve even higher performance.

Fig. 2 shows an example of a structure for achieving good printing quality.A glaze layer 9f is formed on an insulating substrate 7 made of alumina or the like only at a portion The structure of the upper part of the partial glaze layer 9 is the same as the example shown in FIG. A protective layer 12 and a wear-resistant layer 13 are formed and patterned.

The arrangement of heating elements and patterning of the cholera printers differ depending on their use.

For facsimile machines, line printers, etc., horizontal single-row drum heads are used. This is perpendicular to the paper feed direction.
It is an arrangement of the pieces. Serial printers that print alphanumeric characters, kanji, katakana, etc. use heads made of vertical dots, with dots arranged in the same direction as the paper feed direction.

For serial printers, dot matrix type, gutter and segment heads are also used.

FIG. 3 shows an example of "II-row dot type head". Current is supplied to one heat generating part 15 in which a large number of heat generating parts 15 are formed perpendicularly to the paper feeding direction indicated by the arrow on the insulating substrate 14. An electrode 16 is formed on the insulating substrate 14, and a connection terminal 17 for connecting to an external circuit is formed at the end of the insulating substrate 14.In one case, a partial glaze layer 18 is formed as shown by the dotted line to improve printing quality. You can also try to disguise it.

FIG. 4 shows an example of a vertical single-row dot type head, in which a large number of heat generating parts 20 are formed on an insulating substrate 19 in parallel in the paper feeding direction indicated by the arrow. An electrode 21 is formed to supply a 20KV current to the heating section, which is usually a 7-point structure, and a connection terminal 22 for connecting to an external circuit is formed at the end of the insulating base 1!119. . In some cases, attempts have been made to improve printing quality by forming a partial glaze layer 23 as shown by the dotted line.

As mentioned earlier, the partial glaze layer improves adhesion to the thermal paper, improves print quality, and reduces energy consumption, but the height of the glaze layer is usually several tens of microns. Therefore, even if you use a partial glaze layer with such a large effect, you may not be able to make the most of its effect at all.Especially in recent years, printers have become capable of printing on large areas and with high resolution. Therefore, there is an inevitable tendency for thermal heads to become larger.Sometimes, in line printers such as facsimiles, the thermal head itself is characterized by the minimum width of the printing paper, especially when compared to thermal paper or thermal ribbon. When the width in the direction of movement increases, the height of the partial glaze layer on the thermal head becomes very high (it is difficult to achieve its effect due to interference with the undulation of the thermal paper, etc.). However, there is a limit to how thick a partial glaze layer can be made, and difficulties arise with increasing the thickness. Attempts have also been made to bring out the original effect of the thermal head.However, simply creating two partial glaze layers usually has no meaning unless they are placed near both ends of the thermal head; is concentrated at either end, making it difficult to arrange the electrode lead wires, making it difficult to pattern them, and adding resistance to the electrode lead wires in some areas.

The present invention eliminates these disadvantages. That is, three or more partial glaze layers are provided, a heat generating part is formed in the partial glaze layer near the center, and the height of the partial glaze layer where the heat generating part is formed is increased by height machining. It was made more expensive. Due to the structure of the present invention, even if the thermal head becomes larger, the original effect of the partial glaze layer, which is the adhesion to the thermal paper, is not impaired. It is possible.

FIGS. 5a and 5b show an embodiment in which the present invention is applied to a dot type head in a single vertical row. FIG. 5 α is a front view of the thermal head, and FIG. 5B is a sectional view. Partial glaze layer 251 partial glaze B26, partial glaze (27) on alumina substrate 24
is formed, and a heat generating portion 28 is formed near the top of the partial glaze C27 near the center. Partial glaze C28ei on which the heat generating portion 28 is formed Other partial glaze layer 26
゜Partial glaze B27 will be discussed.

For example, the partial glaze Bti is 30 microns, and the partial glaze C is 60 microns. With this configuration, even if the width of the elythermal head substrate 24 becomes 2c111 or more, the original effect of the partial glaze layer is exhibited, the printing quality is good, the thermal response is excellent, and defects such as trailing do not occur. Ta. Although FIG. 5 shows an example in which the present invention is applied to a vertical single-row dot type, it goes without saying that the present invention can also be similarly applied to a horizontal single-row dot type.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a cross section of a thin film thermal head. The second factor is a diagram showing a cross section of a thin film thermal head with a partial glaze layer. FIG. 3 is a diagram showing an example of a horizontal single row dot 4 type head. FIG. 4 is a diagram showing an example of a vertical single-row dot type head. Figures W and 5 are diagrams illustrating an embodiment of the present invention. 1: Insulating substrate 2 Glass layer 3: Heat generating resistor film 4: Heat generating part 5: 1! Pole 6: Oxidation-resistant protective layer 7: Wear-resistant layer 8: Heat-generating portion 9: Glaze layer lO2 heating resistor film 11: Electrode 12: Oxidation-resistant protective layer 13: Wear-resistant layer
14: Insulating substrate 15: Heat generating part 16
: Electrode 17: Connection terminal 18 = Partial dales floor 19:
Insulating substrate 20: Heat generating part 21: Electrode
22 Two connection terminals 23: S-minute glaze layer 24: Alumina substrate 25 Two-part glaze 26 = Partial glaze B27 Two-part glaze C28: Yaetsubu Applicant Suwa Seikosha Co., Ltd. Fig. 1 γ, C2 1 u
)p3rd F;! Kei, -? j Figure 4

Claims (1)

[Claims] (1) A thermal head is equipped with a heat generating part consisting of a thin film resistive layer and an electrode layer for feeding power to the thin film resistive layer on a substrate provided with a partial glaze layer, and a plurality of the greases are provided and a small number of (This is a metal head in which the height of the partial glaze layer on which the heat generating part is formed is higher than the other partial glaze layers from the substrate surface. 2. The thermal head according to claim 1, wherein the thermal head is provided with a heat generating part, and the glaze layer having a high height is arranged near the center of the plurality of glaze layer groups.