JPH0241261A - thermal head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermal head used in a thermal recording device such as a printer or facsimile.

BACKGROUND OF THE INVENTION Conventional thermal recording devices such as printers and facsimile machines use thermal heads to perform thermal recording on thermal paper or plain paper overlaid with an ink sheet. FIG. 3 shows a cross-sectional configuration diagram of a conventional thick film type thermal head. A glass glaze layer 2 is formed on an alumina substrate 1, a common electrode 3 and individual electrodes 4 are formed on this substrate so as to be arranged alternately, and a heating resistor 6 made of ruthenium oxide is formed on this electrode. Then, a wear-resistant layer 6 is further formed.

On the other hand, thin film thermal heads have electrodes and resistors.

Although the material of the wear-resistant layer is different, the substrate material and structure are almost the same as the thick-film thermal head.

In thermal recording, the efficiency of recording density is determined by how well the heat generated energy per unit volume of the heating resistor of the thermal head is transmitted to the thermal paper without loss. However, the heating energy of one heating resistor is.

Because thermal energy is taken away by the substrate on which the heating resistor is formed and the wear-resistant layer, materials other than the heating resistor become important.

Problems to be Solved by the Invention The present invention particularly relates to the problem of a substrate constituting a thermal head.

When using an alumina substrate, the thickness of the alumina substrate affects the characteristics of the thermal head.

The composition and thickness of the glass glaze layer have a major influence.

Alumina has a high specific gravity and relatively good thermal conductivity, so it is preferable to have a thickness as thin as possible, but the thickness of the alumina substrate and the composition of the glass glaze layer are limited due to the relationship with mechanical strength and coefficient of thermal expansion. Furthermore, alumina substrates have problems such as poor shape precision, and are by no means the best substrate for thermal heads.

In view of the above problems, it is an object of the present invention to provide a low-cost, highly reliable thermal head.

Means to solve problems The present invention provides an electrode on the surface of a glass ceramic substrate.

This is a thermal head formed with a resistor and a wear-resistant layer.

Function: The present invention does not suffer from the limitations of an alumina substrate, allows the heat generated energy of the heating resistor to be transmitted to the thermal recording paper without loss, and has good mechanical strength and shape accuracy of the substrate. can provide something.

Embodiment FIG. 1 is a sectional view of a thick film type thermal head according to an embodiment of the present invention. Note that elements common to those in FIG. 3 are given the same numbers. A common electrode 2 made of a gold conductor electrode (thickness 0.6~1.0fi1!1) is placed on a glass ceramic substrate 1.
Then, individual electrodes 3 were formed so as to be arranged alternately, a common heating element 4 made of ruthenium oxide was formed in the shape of these electrodes, and a wear-resistant layer 6 was further formed.

As a comparative example, an electrode, a resistor, and a wear-resistant layer were formed using an alumina glaze substrate in the same manner as in this example.

Here, the glass ceramic substrate refers to one made of crystallized glass, and the crystal structure is L120.2si02, Li2O.mu1□03.4sio2, and even
Some are made of fluorine mica.

In addition, there is also so-called mica ceramic, which is made by bonding fine mica powder with glass, but this is not preferred for the present invention because its density is not perfect, it is non-uniform, and it also has directionality.

Compared to alumina substrates, materials with these crystal structures have 1) greater mechanical strength, 2) higher altitude and lower specific gravity, and 2) the ability to freely control the expansion coefficient. ■High electrical insulation, ■Low shrinkage due to heat treatment, and ■Complete airtightness. The table shows a comparison of the characteristics of the glass ceramic substrate used in the present invention and a conventional alumina glaze substrate.

(Margins below) In this way, glass-ceramic substrates have lower specific gravity than aluminum 2 glaze substrates, and their thermal conductivity is equivalent to that of the glaze layer of alumina substrates, so they have better properties than alumina glaze substrates. It will be done.

Figure 2 shows the thermal efficiency characteristics of the thermal head, and as can be seen from this figure, it can be seen that the thermal head using the glass-ceramink substrate has better thermal efficiency than the alumina glaze substrate. In particular, the thermal efficiency of Example 2 using fluorine mica was excellent. This is thought to be because fluorine mica grows needle-like or plate-like microcrystals three-dimensionally and randomly in the glass matrix phase, forming a homogeneous and dense phase. In addition, better results than the alumina glaze substrate were obtained in the evaluation of the PALNU life of the thermal head.

The glass ceramic substrate of the present invention preferably has a thickness of 0.6-2. An OH substrate is better.

In this embodiment, a thick film type thermal head has been described, but the present invention is not limited thereto, and can also be applied to a thin film type thermal head or a thin film-thick film type thermal head.

Effects of the Invention According to the present invention, the thermal energy of the heat generating resistor of the thermal head can be transferred to the thermal recording paper without loss, resulting in excellent thermal efficiency and power saving. Further, it is possible to provide a highly reliable thermal head at low cost.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the configuration of a thermal head according to an embodiment of the present invention, Fig. 2 is a graph of thermal efficiency characteristics of the thermal head according to the embodiment of the present invention and a conventional example, and Fig. 3 is a configuration of a conventional thermal head. FIG. 1... Glass ceramic substrate, 2, 3...
...Electrode, 4...Heating resistor, 6...
Abrasion resistant layer. Name of agent: Patent attorney Shigetaka Awano and 1 other person No. 3
Figure 0θ6 a, to 6.15 tap
Electric power (W)

Claims (2)

[Claims] (1) A thermal head consisting of a glass ceramic substrate with electrodes, resistors, and a wear-resistant layer formed on the surface. (2) The thermal head according to claim 1, wherein the glass ceramic has a fluorine mica crystal structure.