JPS59204857A - Electrostatically charging device on brush of copying machine - Google Patents

Abstract

PURPOSE:To prevent deterioration of a photosensitive body and sagging of a conductive brush, and to prevent deterioration of electrostatic charging characteristics by forming a non-contact part with the brush, on the circumferential part of the photosensitive body which stops at a position of the brush, when a copying operation stops. CONSTITUTION:A conductive brush 2 which contacts with the surface of a photosensitive body 1 and charges electrostatically it uniformly is provided on the circumferential part of the photosensitive body 1. Also, a slit 3a is formed on the circumferential surface part of the photosensitive body 1 which stops at a position of the brush 2, when copying stops. Therefore, when copying stops, the tip of the brush 2 is separated from the surface of the photosensitive body 1, and it is prevented that both of them contact with each other for a long period of time, deterioration of the surface of the photosensitive body 1 and sagging of the brush are prevented, and also deterioration of charging characteristics is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a brush charging device for a copying machine that charges the surface of a photoreceptor using a conductive brush.

Prior Art Conventional corotrons using discharge wires made of tungsten or the like are often used as charging devices in conventional electronic copying machines, but they generate ozone during discharge and toner adheres to the discharge wires, deteriorating charging characteristics. Therefore, there are problems that require a lot of effort for maintenance and inspection, such as the need for periodic cleaning.

To solve this problem, a brush charging device using a conductive brush has recently been proposed. As shown in Figure 1, this brush charging device charges the photoconductor by bringing the conductive brush α into contact with the photoconductor, so there is little damage to the photoconductor surface due to ozone generation due to discharge or spark discharge, and it is easy to maintain. It has characteristics such as being easy to use.

However, since the conductive brush α is in contact with the surface of the photoconductor even when copying is paused, the surface of the photoconductor may deteriorate or the conductive brush α may become damaged due to external force applied to the conductive brush α (see Fig. 2). As shown in Figure 2, there were problems such as deterioration of charging characteristics due to stagnation.

Purpose of the Invention The present invention has been made for the purpose of improving the above-mentioned problems.The conductive brush is separated from the surface of the photoreceptor when copying is stopped, thereby preventing the surface of the photoreceptor and the conductive brush from deteriorating. The present invention aims to provide a brush charging device for a copying machine.

Structure of the Invention A non-contact portion with the conductive brush is formed along the axial direction of the conductive brush on the circumferential surface of the photoreceptor that stops at the position of the conductive brush when the copying operation is stopped. By preventing long-term contact between the conductive brush and the electroconductive brush, deterioration of the charging characteristics due to deterioration of the photoreceptor or fatigue of the conductive brush is prevented.

EXAMPLES Hereinafter, examples of the present invention will be described in detail with reference to the drawings shown in FIGS. 3 and 4. In the figure, reference numeral 1 denotes a photoreceptor of an electronic copying machine, which has a drum shape.A brush charging device such as a conductive brush 2 is provided around the photoreceptor 10. As shown in FIG. The conductive brush 2 has a large number of brush bodies 26 made of conductive fibers planted on the surface of a roll 2α.
As α rotates, the tip of the brush body 2b comes into contact with the surface of the photoreceptor 1, thereby uniformly charging the surface directly on the photoreceptor.

On the other hand, when the copying body is stopped, a slit 3α shown in FIG. 3 and a groove 3b shown in FIG. A non-contact portion 3 is formed so that the tip of the brush body 2b of the conductive pusher 2 does not come into contact with the surface of the photoreceptor 1 when the copying operation is stopped.

Effects of the Invention As described in detail above, the present invention includes a slit 3α and a groove 3b along the axial direction of the conductive brush 2 in the circumference of the photoreceptor 1 that stops at the position of the conductive brush 2 when the copying operation is stopped. Since the non-contact portion 3 is formed, the tip of the brush body 2b of the conductive brush 2 is separated from the surface of the photoreceptor 1 when the copying operation is stopped. It is possible to eliminate problems such as deterioration of the brush body 2b or deterioration of charging characteristics due to the brush body 2b becoming flattened, and since no mechanical evacuation mechanism is required, it can be implemented easily and inexpensively.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams showing defects in a conventional brush charging device, and FIG. 3 is an explanatory diagram showing an embodiment of the present invention.
FIG. 4 is an explanatory diagram showing another embodiment. 1 is a photoreceptor, 2 is a conductive brush, and 3 is a non-contact part. Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto @Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] In a device in which the surface of the photoreceptor 1 is uniformly charged with a conductive brush 2, a charger is applied along the axis of the conductive brush 2 to the circumferential surface of the photoreceptor I that stops at the position of the conductive brush 2 when the copying operation is stopped. A brush charging device for a copying machine in which a non-contact part 3 with a conductive brush 2 is formed.