| 摘要 |
PURPOSE:To perform an excellent development process even if a defective developing material is mixed, by collecting the defective developing material from a magnet roll through a conductive roller whose surface potential is controlled by a bias power source. CONSTITUTION:A magnetic developer on the bucket roller 5 of a developing device 2 is attracted through the magnet roll 4 to form a magnetic brush of the magnetic developer on a developing sleeve 3, developing a latent image on a photosensitive drum 1. When this magnetic brush is rubbed against the surface of the conductive roller 10, a defective developer containing insulating toner which does not hold enough charge for development by an electric field produced by the roller 10 whose surface potential is controlled by the bias power source 11 to a lower value than the sleeve 3 is attracted to the roller 10 and collected before development process. Therefore, excellent development process free of fogging is carried out regardless of the mixing of the defective developer. |
