| 摘要 |
PURPOSE:To maintain a stable cleaning function for a long period without causing any deterioration in picture quality such as decreases in image density and visibility by supplying low-resistance powder to toner caught by a magnet roller successively. CONSTITUTION:Part of residual toner on a photosensitive body 1 is caught directly by the magnet roller and the remainder is scraped off by a cleaning blade 3 and caught by the roller 4. Then the low-resistance material of <=10OMEGAcm which consists of low-resistance toner, strontium titanate, conductive carriers, etc., is supplied from a container 7 to the upstream side of a cleaning device 2 through a supply roller 8 so that >=0.5% of the powder is mixed with the toner layer formed on the roller 4. The nonmagnetic sleeve 8b of the roller 8 is applied with a bias 9 obtained by superposing a direct current on an alternating current to select the powder and bias properly according to the polarity of the residual toner, thereby sticking the powder on the photosensitive body. Consequently, the mean potential of the toner layer on the roller 4 never decreases to destroy a photosensitive layer.
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