JPH01286880A - Protective device for thermal head - Google Patents

Abstract

PURPOSE:To make it possible to prevent accumulation of static electricity by means of a switch with a low power capacity and to inhibit corrosion of an aluminum pattern in a thermal head by connecting a switch between a platen roller and a casing earth, and connecting the platen roller and the casing earth to each other only at the time of feeding recording paper. CONSTITUTION:A thermal head 1, a platen roller 2 made of a conductive material, a switch 3 (with a low power capacity), a recording power supply 4 and recording paper 5 are provided. At the time of not feeding the paper 5, the switch 3 is opened to separate the potential of the platen roller 2 from a casing earth, thereby preventing an electric field from being generated between the thermal head 1 and the platen roller 2. At the time of feeding the paper 5, the switch 3 is closed to connect the platen roller 2 to the casing earth so that static electricity generated due to friction between the paper 5 and the head 1 as well as the platen roller 2 is successively discharged, whereby accumulation of static electricity is prevented. The successive discharge permits the use of a switch with a low power capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to corrosion protection of aluminum patterns inside a thermal head.

[Conventional technology]

If the recording paper remains sandwiched between the thermal head, which is supplied with recording power, and the platen roller made of conductive material for a long time in a hot and humid environment, moisture may build up between the thermal head, the recording paper, and the platen roller. Through this moisture, ions emitted from the components of the recording paper may enter through pinholes or cracks in the coating of the thermal head and corrode the aluminum pattern inside the thermal head. This corrosion is significantly accelerated in the presence of an electric field.

However, since the platen roller is connected to the casing ground in order to release static electricity generated by friction during feeding of recording paper, corrosion is accelerated by the electric field generated between the thermal head and the platen roller.

Therefore, in conventional technology, a switching device such as a relay is installed between the recording power source and the thermal head, and the switching device is closed and power is supplied only when recording is performed, thereby minimizing the time during which the electric field is generated. .

[Problem to be solved by the invention]

The above-described conventional technology has the drawback that the thermal head consumes a large amount of power, and therefore requires a switch with a correspondingly large power capacity.

[Means to solve the problem]

The thermal head protection device of the present invention includes a thermal head to which recording power is constantly supplied, and a platen roller made of a conductive material that brings the recording paper into contact with the thermal head with appropriate pressure.
A switch for selecting whether or not to ground the potential of the platen roller to the casing ground, and means for closing the switch when feeding the recording paper and grounding the potential of the platen roller to the casing ground. do.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

The embodiment of the present invention is a thermal head 1. Platen roller made of conductive material 2. Switcher 3 (low power capacity), recording power source 4. It is composed of recording paper 5.

When recording paper is not being fed, the switch 3 is opened to separate the potential of the platen roller 2 from the housing ground, thereby preventing the generation of an electric field between the thermal head 1 and the platen roller 2.

When feeding the recording paper, the switch 3 is closed and the platen roller 2 is connected to the casing ground, and the static electricity generated by the friction between the recording paper 5, the thermal head 1, and the platen roller 2 is sequentially transferred to the casing ground. Discharges and prevents static electricity from accumulating. Since it is a sequential discharge, it can be configured with a switch with a small power capacity.

〔Effect of the invention〕

As explained above, the present invention connects a switch between the platen roller and the casing ground, and connects the platen roller to the casing ground only when recording paper is fed, thereby reducing static electricity using a switch with a small power capacity. This has the effect of preventing corrosion of the aluminum pattern inside the thermal head.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. 1...Thermal head, 2...Platen roller, 3...Switcher, 4...Recording power supply, 2...Recording paper. Agent Patent Attorney Oto Uchihara

Claims (1)

[Claims] A thermal head to which recording power is constantly supplied, a platen roller made of a conductive material that brings the recording paper into contact with the thermal head with appropriate pressure, and a switch that selects whether or not the potential of the platen roller is grounded to the housing ground. and means for closing the switching device and grounding the potential of the platen roller to the casing ground when feeding out recording paper.