Configured to enhance toner collecting efficiency and toner redepositing

Abstract

An image forming apparatus includes a cleaning member for collecting toner left on an image carrier after image transfer, and then redepositing it on the carrier, so that a developing unit can collect the redeposited toner to reuse it. Even when the frictional charging ability of the cleaning member falls due to aging or varying environment, the charge of the toner left on the image carrier is regulated to preselected polarity before the toner reaches the cleaning member, thereby enhancing a toner collecting efficiency and a toner redepositing efficiency. The charge of the toner redeposited on the image carrier and moved away from the cleaning member is regulated to preselected polarity while being increased, thereby reducing a load to act on the developing unit. The toner is redeposited on the image carrier efficiently without regard to the polarity of the toner collected by the cleaning member. The developing unit is allowed to collect all the toner redeposited on the image carrier, thereby freeing the background of an image from contamination. When the cleaning member collects the toner from the image carrier, the toner is prevented from being transferred from the cleaning member to the image carrier, thereby obviating defective cleaning. An image forming speed is increased by reducing the interval between consecutive image forming areas. A pressure is caused to act uniformly between the cleaning member and the image carrier in the axial direction of the roller, further enhancing the toner collecting efficiency and toner redepositing efficiency while obviating background contamination.