JPH0252758A - Protective device for thermal head - Google Patents

Abstract

PURPOSE:To prevent the accumulation of static electricity by a changer having small power capacity while inhibiting the corrosion of an aluminum pattern in a thermal head by installing the changer supplying a platen roller with one side of a recording power supply while being interlocked with the open/close of a door operated when recording paper is exchanged. CONSTITUTION:A sensor 7 for detecting the open/close of a door detecting the open/close of a recording-paper exchanging door 6, and a changer 3 connecting one electrode of a recording power supply 4 and a platen roller 2 by the sensor 7 when the door is closed are mounted on subjected device. When the recording-paper exchanging door 6 is opened, the safety at the time of the exchanger of recording paper can be ensured by interrupting the potential of the platen roller 2 from the recording power supply 4 by the changer 3. When the recording-paper exchanging door 6 is closed, the generation of an electric field between a thermal head 1 and the platen roller 2 is prevented by connecting the potential of the platen roller 2 to recording supply voltage by the changer 3 while static electricity between the recording paper 5 and the platen roller 2 is discharged, and the title protective device can be constituted of the changer having small power capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal head protection device, and more particularly to a thermal head protection device for preventing corrosion of an aluminum pattern inside a thermal head/yield used in facsimile machines and the like.

[Conventional technology]

In a hot and humid environment, if the recording paper remains sandwiched between the thermal head to which recording power is supplied and the platen roller made of conductive material for a long time, 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 when feeding the recording paper, corrosion is accelerated by the electric field generated between the thermal head and the platen roller.

Therefore, in conventional thermal head protection devices, a switching device such as a relay is installed between the recording power source and the thermal head, and only when recording is performed, the switching device is connected to supply power and wait for the electric field to be generated. I kept it to the minimum necessary.

[Problem to be solved by the invention]

The above-mentioned conventional thermal head protection device has a disadvantage in that it requires a switch with a correspondingly large power capacity because the thermal power consumption is large.

[Means to solve the problem]

The thermal head protection device of the present invention includes a thermal head connected to one side of a recording power source, a conductive platen roller that brings recording paper into contact with the printing surface of the thermal head with a predetermined pressure, and a conductive platen roller that operates when the recording paper is replaced. and a switching device that opens and closes supplying one of the recording power sources to the platen roller in conjunction with opening and closing of the door.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention.

In this embodiment, a thermal head 1 connected to one electrode of a recording power source 4, a platen roller 2 made of a conductive material that presses a recording paper 5 against the printing surface of the thermal head 1 with a predetermined pressure, and a replacement of the recording paper 5. Recording paper exchange door 6 that operates at the same time
A sensor 7 for detecting opening/closing of a door (hereinafter referred to as a sensor) detects the opening/closing of the door 6, and a switch 3 that connects one electrode of the recording power source 4 and the platen roller 2 by the sensor 7 when the door 6 is closed. and configure.

In this way, when the recording paper exchange door 6 is opened, the switching device 3 disconnects the potential of the platen roller 2 from the recording power source 4, thereby ensuring safety when exchanging the recording paper. When the door 6 is closed, the switch 3 connects the potential of the platen roller 2 to the recording power supply voltage to prevent the generation of an electric field between the platen roller 2 of the thermal head 1 and to prevent the generation of an electric field between the recording paper 5 and the platen of the thermal head 1. Static electricity generated by friction between rollers 2 is recorded using power source 4.
Since it discharges sequentially to prevent static electricity from accumulating, it can be configured with a switch with a small power capacity.

〔Effect of the invention〕

As explained above, the present invention installs a switching device between the platen roller and the recording power source and connects the platen roller to the recording power source only when the recording paper exchange door is closed, thereby using a switching device with a small power capacity. This has the effect of preventing static electricity from accumulating and suppressing corrosion of the aluminum pattern inside the thermal head.

Furthermore, when the recording paper exchange door is opened, the platen roller and the recording power source are in an open state, which has the effect of ensuring operational safety when exchanging the recording paper.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. 1... Thermal head, 2... Platen roller, 3
...Switcher, 4...Recording power source, 5...Recording paper, 6
... Recording paper exchange door, 7... Sensor for detecting door opening/closing.

Claims (1)

[Claims] A thermal head connected to one side of the recording power source, a conductive platen roller that brings the recording paper into contact with the printing surface of the thermal head with a predetermined pressure, and a conductive platen roller that contacts the printing surface of the thermal head with a predetermined pressure. A thermal head protection device comprising: a switch that opens and closes supplying one of the power sources to the platen roller.