JPS61179483A - Preventing device for fatigue of photosensitive body - Google Patents

Abstract

PURPOSE:To prolong the life of a photosensitive drum by placing the front end of the side piece of a corona discharger which is positioned in the front in the rotating direction of the photosensitive drum closer to the drum surface than the front end of a side piece which is positioned at the back and also forming a cut at part of the cover. CONSTITUTION:The corona discharger 2 is provided at the periphery of the photosensitive drum 1, the discharger consists of a U-sectioned charger unit 20 which is parallel to the rotating shaft of the drum and a charger wire 21 which is extended in parallel to the rotating shaft of the drum, and the opening part of the unit 20 is provided opposite the drum 1. Further, the front end of the side piece 20 a which is positioned in the front in the rotating direction A of the drum is set closer to the drum surface than the front end of the side piece 20b which is positioned at the back. The cut part 20d in a long-hole shape is formed in a horizontal piece 20c. Consequently, an ozone gas layer is prevented from being formed at the periphery of the photosensitive drum, whose life is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an apparatus for preventing fatigue of a photoreceptor used in an image forming apparatus such as an electrophotographic copying machine.

<Prior art and its drawbacks> In devices that use a corona discharger to charge the surface of a photoreceptor, there is a problem that ozone gas generated by corona discharge spreads around the photoreceptor, and this ozone gas accelerates fatigue of the photoreceptor. There is. Therefore, in the past, fans were installed at appropriate locations in the device so that a force stronger than the corona wind generated during discharge, or a force stronger than the force generated when the photoreceptor drum rotated to suck in the gas around the drum, was applied. was installed to discharge ozone gas to the outside from the bottom of the corona discharger.

However, in such a device, since it is necessary to provide a fan or the like within the device, an increase in cost cannot be avoided, and there are disadvantages that hinder miniaturization. Also, a device has been proposed in which a hole is opened in the corona discharger to allow ozone gas to escape without installing a fan or the like.
With this method, it was not possible to obtain a sufficient effect on fatigue of the photoreceptor.

<Object of the Invention> The object of the present invention is to provide a photoreceptor fatigue prevention device that can eliminate the above-mentioned disadvantages simply by devising the shape of the corona discharger, and can prevent acceleration of photoreceptor fatigue caused by ozone gas at a low cost. <Configuration and Effects of the Invention> The present invention constitutes a part of the corona discharger cover, and the tip of the side piece located at the front with respect to the rotational direction of the photoreceptor drum is connected to the tip of the side piece located at the rear. It is characterized in that it is located closer to the drum surface than the tip, and that a portion of the cover is cut out.

With this configuration, according to the present invention, when the photoreceptor drum rotates, the layer of ozone gas taken in around the drum is separated outward from the surface of the photoreceptor drum by the side piece located in front of the corona discharger. It works like this,
Further, since the gas is released from the notch of the corona discharger to the outside, ozone gas on the surface of the photoreceptor drum can be easily removed.

<Embodiment> The figure is a partial configuration diagram around a photoconductor drum of an electrophotographic copying machine to which a photoconductor fatigue prevention device according to an embodiment of the present invention is applied.

In the figure, 1 is a photosensitive drum having a photosensitive layer formed on its surface, and a corona discharger 2 is arranged around this photosensitive drum.

The corona discharger 2 includes a charger unit 20 that is parallel to the drum rotation axis and has a U-shaped cross section, and a charger line 21 that is stretched parallel to the drum rotation axis. It is facing 1. In this charger unit 20, the tip of the side piece 20a located at the front with respect to the photosensitive drum rotation direction A is closer to the drum surface than the tip of the side piece 20b located at the rear. The gear rough G between the side piece 20a and the drum surface is set to be sufficiently smaller than the gap 20H between the side piece 20b and the drum surface, and the size of the gap G is about 2 to 311 degrees. Further, the horizontal piece 20c has a long hole-shaped notch 20.
d is formed.

With the above configuration, when the photosensitive drum 1 rotates in the direction of arrow A, the corona discharger 2 is activated, and ozone gas 3 is generated and moves in the direction shown by the dotted line.

However, this ozone gas is pulled upward from the surface of the photoreceptor drum by the side piece 20a of the charger unit 20 and discharged upward through the notch 20d, thereby preventing the formation of an ozone gas layer on the surface of the photoreceptor drum l. It can be prevented. With such a very simple structure, formation of an ozone gas layer around the photoreceptor drum can be prevented, and the life of the photoreceptor can be extended.

[Brief explanation of drawings]

The figure is a diagram showing a part of the structure around the photoreceptor drum of an electrophotographic copying machine to which a photoreceptor fatigue prevention device according to an embodiment of the present invention is applied. 1-photosensitive drum, 2-corona discharger, 3-ozone gas.

Claims (2)

[Claims] (1) In a device in which a corona discharger with a U-shaped cross section is arranged around the photoreceptor drum, a side piece that forms part of the corona discharger cover and is located in front with respect to the photoreceptor drum rotation direction. A device for preventing fatigue of a photoreceptor, characterized in that the tip is closer to the drum surface than the tip of the side piece located at the rear, and a portion of the cover is cut out. (2) The photoconductor fatigue prevention device according to claim 1, wherein the tip of the side piece located forward with respect to the photoconductor drum rotation direction is inclined toward the drum rotation direction.