JPH01310375A - Transfer charger of electrophotographic printer - Google Patents

Abstract

PURPOSE:To prevent the deterioration of an OPC drum by covering the aperture for discharge of a transfer charger body with an insulating sheet according to the width of printing paper and limiting the discharge range to the printing paper. CONSTITUTION:The transfer charger body 6 consists of a combination of a conductive wire 7a for impressing a high voltage and an electrode 7b having a U-shaped section. The aperture 7c for discharge is provided to the front surface of the electrode 7b, which surfaces faces the paper. The aperture 7c is set at the size corresponding to the width of the paper of the max. size among the various sizes of the paper to be used. A band-shaped insulating sheet 5 covering the aperture 7c is provided and one end thereof is coupled to a reel 4 of a motor 3 for un-winding and winding. The sheet 5 is un-wound from the reel 4 and is wound thereto, by which the aperture 7c is covered over a required length and the effective width thereof is changed. The discharge to the OPC drum in the part where there is no paper is shut off in this way and the deterioration of the drum is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to electrophotographic printers, and more particularly to transfer chargers.

[Conventional technology]

Conventionally, this type of transfer charger has a discharge capacity corresponding to the printable paper width.

[Problem to be solved by the invention]

The conventional transfer charger described above has a discharge capacity corresponding to the printable paper width, but its discharge range is fixed, so even if the width of the paper is narrow, the transfer charger discharges beyond the width of the paper. The OPc drum has the disadvantage that in areas where there is no paper, the OPc drum is directly subjected to electric discharge without passing through the paper, which accelerates the deterioration of the OPc drum in those areas.

An object of the present invention is to provide a transfer charger for an electrophotographic printer that solves the above problems.

[Means to solve the problem]

In order to achieve the above object, 1 in the transfer charger for an electrophotographic printer according to the present invention, the discharge opening of the transfer charger main body of the electrophotographic printer is covered with an insulating sheet according to the width of the printing paper to limit the range of discharge to the printing paper. It has a mechanism to do this.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention.

In the figure, the transfer charger main body 6 consists of a combination of a conductive wire 7a for applying a high voltage and a cross-sectional opening type electrode 7b, and a discharge opening 7c is provided on the front surface of the cross-sectional opening type electrode 7b facing the paper. ing. The opening 7c for weight release is set to a size corresponding to the paper width of the largest size paper among the papers used.

The present invention includes a band-shaped insulating sheet 5 that covers the discharge opening 7c of the transfer charger main body 6, and one end of the insulating sheet 5 is connected to the reel 4 of the feeding/winding motor 3, and the sheet 5 is transferred from the reel 4. By rolling it out or winding it up, the discharge opening 7C is covered over a necessary length to change its effective width.

FIG. 2 is a block diagram for controlling the insulating sheet 5 of the present invention. The paper width sensor 1 reads the paper width, and the motor controller 2 controls the paper width based on the read paper width.
controls the drive of the motor 3 for feeding and winding the insulating sheet. That is, when printing paper with a paper width a is sent, the paper width sensor 1 reads the paper width a, and the motor control unit 2 drives and controls the motor 3 to feed the insulating sheet 5 from the reel 4 and transfer it to the transfer charger. The discharge opening 7c of the main body 6 covers the paper width portion b while leaving the paper width portion a.

Therefore, the discharge occurs between the conductive wire 7a to which high voltage is applied and the electrode 7b, but the OPC drum receives the discharge only in the paper width a, and in the part b where there is no paper, the insulating sheet 5 Because it is covered, it is not directly exposed to electrical discharge.

〔Effect of the invention〕

As explained above, by changing the effective width of the discharge opening of the transfer charger main body according to the width of the paper to be printed, the present invention can cut off discharge to the OPC drum in areas where there is no paper, and It has the effect of preventing the deterioration of

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a block diagram for controlling the feeding and winding operations of the insulating sheet. 1...Paper width sensor 2...Motor control section 3
...Feeding/winding motor 4...Reel 5...Insulating sheet 6...Transfer charger body 7a...
・Conductive wire 7b...N-type electrode 7c...
・Discharge opening

Claims (1)

[Claims] (1) A transfer charger for an electrophotographic printer, characterized in that it has a mechanism for covering the discharge opening of the main body of the transfer charger with an insulating sheet according to the width of the printing paper to limit the range of discharge to the printing paper.