JPS58111062A - Opposite-polarity toner removing method of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To prevent a non-image part of a copy from being stained owing to the sticking of opposite-polarity toner to a non-image part of a photoreceptor during development, by removing the opposite-polarity toner from a developer by the use of equipment installed in an electrophotographic copying machine. CONSTITUTION:A developing machine 4 has a developing roll 11 provided in a housing 10; the developing roll 11 is applied with a bias from bias power sources 12 and 13 selectively through a switch 14 and the bias potential has the same polarity with the surface potential of the photoreceptor 1. In normal copying process, the developing roll 11 is connected to the bias power source 12 having a low potential V1. When copying is not in operation, the photoreceptor 1 is raced and the switch 14 is changed over to connect the developing roll 11 to the bias power source 13 having a higher potential V2 than the non-image part potential of the photoreceptor. Further, when the photoreceptor 1 is not charged, toner having the opposite polarity sticks to the surface of the photoreceptor 1, so it is removed and recovered by the blade 7a of a cleaning machine 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing toner of opposite polarity from a developer in an electrophotographic copying machine.

Conventionally, the developer in the tax gR device of an electrophotographic copying machine contains:
Due to developer deterioration and toner paste complaints, toner charged with opposite polarity (hereinafter referred to as reverse polarity toner) increases, and this reverse polarity toner adheres to the non-image sK of the photoreceptor during development, and the non-1i16 portion of the copy becomes toner. This causes a smudging and fogging phenomenon, resulting in an unsightly copy.

The present invention was developed in view of the above-mentioned circumstances, and its purpose is to provide fj
& To provide a method for removing toner of opposite polarity in a secondary electron double-zero machine by making it possible to remove toner of opposite polarity from a toner.

The present invention will be described in detail below with reference to the figures.

FIG. 1 is a schematic explanatory diagram of an electrophotographic copying machine.
Around the are charging @ (charging corotron) 2, exposure machine 3, developing machine 4, transfer 'I# machine (transfer corotron) 5, static elimination @ (static elimination corotron) 6, cleaning machine 7, static elimination machine (static elimination lamp) 8
etc., and the paper is conveyed through the paper path 9.

The dust mitter 4 has a developing roll 11 in the housing 10, which becomes the next mag brush dust**, and the developing roll 11 has V+.
Application of either one of the bias power supply 12 and the bias power supply 13 of v2 (Vl<Vl) is controlled by the switch 14, and the polarity of the bias potential is determined depending on the photoreceptor 10.
It has the same polarity as the surface.

Therefore, during the normal copying process, the switch 14 turns on the bias power supply which is 1jt so roll Ilt'iVz.
Connected to 2.

On the other hand, a potential Vs is applied to the image area IB lm of the photoreceptor 1, and an electrostatic charge is formed, and the non-image area 1b is Vs.
A potential of 4 is applied.

Here, Vl<Vm and Vt=V4.

For this reason, as shown in FIG. 2, the positive polarity toner a is attracted to the electrostatic charge of the photoreceptor 1 and forms a toner image.

At this time, each device normally operates according to the duplication process to transfer the toner image onto the paper and make a copy.

Also, when not copying, such as during warm-up of the duplicator, photoreceptor 1 is rotated idly (idle scan) and 1 switch +4
is connected to the bias power source 13 of 3JIm roll 11tVg, and the charging device 2, transfer device 5, and static eliminator 6 are not operated so that the photoreceptor 1 is not charged. As a result, the entire surface of the photoreceptor 1 becomes a non-image area 1b, and since V2>V4, as shown in FIG. It is removed and recovered by the blade 7a of the machine 7.

According to the present invention, as described above, the toner of opposite polarity in the rinsing agent can be removed using a device installed in the electronic three-photocopying machine.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a schematic diagram of an electronic four-photo copying machine, and FIG. #! Figure 3 is a diagram showing the operation. 1 is a photoreceptor, 2 is a charging machine, 3 is a dew generator, 4 is a genrin machine, 5
1 is a transfer machine, 7 is a cleaning machine, and 11 is a developing roll.

Claims (1)

[Claims] A charging machine 2, an exposure machine 3, a developing machine 4, a transfer machine 5, a cleaning machine 7, etc. are arranged around the photoreceptor 1, and a current roll 11 of the developing machine 4 is arranged.
In an electrophotographic copying machine that applies a bias voltage to
When not copying, the photoreceptor 1 is rotated idly, a bias voltage higher than the potential of the photoreceptor is applied to the developing roll 11, and the photoreceptor 1 is not charged with electric charge. How to remove reverse polarity toner from a photo duplicator.