JPH0241260A - 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 that can be used in various printers, facsimile machines, and the like.

2. Description of the Related Art The thermal head used in conventional facsimile machines, printers, etc. has a typical configuration as shown in FIG. In FIG. 6, 21 is an insulating ceramic substrate, 22 is a heat storage glass layer, 23 is an etching prevention layer, 24 is a resistor, 25 is a pair of electrodes and conductor wiring, 26 is a wear-resistant layer,
Reference numeral 27 represents a driving IC, and 28 represents a cooling board, which are bonded to each other by a bonding layer 29 using an adhesive.

On the other hand, there is a thermal head that does not use a ceramic substrate but uses a substrate whose surface is a metal plate coated with an insulating glass layer.

This has the configuration shown in FIG. 7, in which a metal base material 31 is covered with a glass layer 32, a resistor 34 of an electrode 33 is provided on this glass layer 32, and a part of the resistor 34 is also provided. A wear-resistant layer 36 is provided on the electrode 23. This configuration has high heat dissipation and is said to be effective for use in high-density, high-speed thermal heads.

These thermal heads generate heat by applying a pulsed voltage to a conductive electrode and causing a current to flow through a heating resistor.
Thermosensitive recording is made possible by repeatedly generating heat at a high temperature of 0 to 460°C, and cooling it to around room temperature upon stopping the application of electric power. In order to enable high-density and high-speed printing in these thermal heads, thermal responsiveness is required that allows instantaneous heat generation and cooling as the applied voltage is turned on and off.

Problems to be Solved by the Invention However, in conventional thick-film thermal heads, the volume of the heating resistor is larger than in thin-film thermal heads, so the heat generation efficiency is lower, and it takes more time to obtain the same recording density. It required a lot of electricity.

Furthermore, since the heat generating resistor has a large volume, its heat capacity also becomes large, making it impossible to follow input voltage with a short cycle, making it impossible to perform high-speed printing.

Furthermore, when using an alumina glaze substrate as the substrate, high-density, high-speed printing was possible by adjusting the glaze thickness, but with a substrate made of a metal base coated with an insulating glass layer, the manufacturing method and insulation From the viewpoint of performance, the thickness of the insulating glass layer cannot be freely controlled, and the thickness of the insulating glass layer is as thick as 80 to 150 μm, which has the drawback of poor thermal response during printing.

Therefore, there was a problem in that it was not possible to use a conventional metal substrate coated with an insulating glass layer as a thermal head with good thermal response used in fax machines, which are expected to grow even more in the future. .

The present invention solves these problems and improves the thermal response of a thermal head whose substrate is coated with an insulating glass layer.

Means for Solving the Problems In order to solve the conventional problems, the present invention uses a steel plate in which one or both sides of a metal base material is clad with copper, and electrodes and resistors are attached to this steel plate via an insulating layer.

This is a structure in which a wear-resistant layer is formed.

Effects According to the configuration of the present invention, thermal responsiveness can be improved by the clad copper, high-density and high-speed printing is possible, and a thermal head with excellent heat generation efficiency, thermal responsiveness, and high reliability can be provided. can. Further, the clad copper is insulated from the electrodes and the resistor by an insulating layer.

Embodiment FIG. 1 is a cross-sectional configuration diagram of a thick film type thermal head according to a first embodiment of the present invention. A steel plate 1 in which a metal 1 containing at least one of iron, nickel, and chromium is clad with a copper plate 2
A glass insulating layer 3 is formed on &, a common electrode 6 and individual electrodes 4 made of gold conductor electrodes are formed, a common heating resistor 6 made of ruthenium oxide is formed on these electrodes, and a common heating resistor 6 made of ruthenium oxide is formed on these electrodes. A wear-resistant layer 7 was formed on.

When such a configuration is adopted, thermal efficiency during printing is better than that of a conventional one using a steel plate without cladding with a copper plate.

An important point in the configuration of the present invention is the thickness of the glass insulating layer and the copper plate. The second hole is a graph showing thermal efficiency when changing the thickness of the glass insulating layer. When the glass insulating layer has a thickness of 150 μm or more, the thermal efficiency does not become very high. If the thickness is less than 100 μm, the thermal efficiency will be extremely low, so the optimum thickness is preferably 100 to 150 μm. Figure 2 is a graph showing thermal efficiency depending on the thickness of the copper plate. As the thickness of the copper plate increases, the thermal efficiency decreases.

From the above, it is better to increase the thickness of the glass insulating layer and decrease the thickness of the copper plate.

However, since the printing speed of the thermal head repeats ON-OFF in milliseconds, it is preferable that the temperature of the heating resistor rises as quickly as possible, and when the voltage is OFF, the temperature decreases as quickly as possible. As shown in FIG. 3, in the conventional configuration including only a glass insulating layer, the temperature of the heating element increases as the thickness of the glass insulating layer increases, but the temperature drops slowly. This is because heat is trapped in the glass insulating layer, making the fall worse.

On the other hand, as shown in Fig. 4, the temperature of the heating element according to the present invention is not much different from the one without the copper plate in terms of rise, but the temperature in the case of the present invention is lower in the fall. It's early. In particular, this tendency becomes more pronounced as the copper plate becomes thicker. However, when the thickness of the copper plate exceeds sopm, the heat dissipation characteristics of the copper plate improve, so the temperature of the heating element does not become high, and the thermal efficiency decreases. Therefore, the thickness of the copper plate is preferably 10 to 30 μm.

FIG. 6 shows another embodiment of the present invention, in which the same components as in the first embodiment are given the same reference numerals. This embodiment uses a copper plate only where the heating element is formed, and its characteristics are the same as those of the first embodiment.

As described above, the feature of the present invention is that, in a substrate in which a glass insulating layer is formed on a steel plate, a base material in which a steel plate is clad with a copper plate is used. By adopting such a configuration, it is possible to improve the temperature characteristics of the rise and fall of the heating element.

Although the first embodiment describes a thick film type thermal head, the present invention is not limited to this.
A thin film type thermal head also has similar effects. Also,
The constituent material of the head is also not particularly limited.

Effects of the Invention According to the present invention, it is possible to provide a thermal head with excellent thermal response and capable of high-density, high-speed printing.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional configuration diagram of a thermal head according to an embodiment of the present invention, Fig. 2a is a graph showing the thermal efficiency when the glass insulating layer is changed in a conventional structure that does not use a copper plate, and Fig. 2 Figure 3 is a graph showing the thermal efficiency when the thickness of the copper plate is changed in the configuration of the present invention. Figure 4 is a graph showing the temperature of the heating element when the thickness of the copper plate is changed in the configuration of the present invention, Figure 6 is a cross-sectional configuration diagram of a thermal head according to another embodiment of the present invention, Figures 6 and 7
The figure is a cross-sectional diagram of a conventional thermal head. Name of agent: Patent attorney Shigetaka Awano and 1 other person
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Claims (2)

[Claims] (1) Contains at least one of Fe, Ni, and Cr;
A thermal head made of a steel plate clad with Cu on one or both sides, with an electrode, a resistor, and a wear-resistant layer formed through an insulating layer. (2) The thermal head according to claim 1, wherein the insulating layer is a vitreous coating layer.