| 摘要 |
PURPOSE:To obtain excellent images and to prevent a constitution from becoming complex by providing a simple carrier mixture preventing means to the 2nd developing device. CONSTITUTION:The 1st developing device 2 has a two-component developer 3 consisting of carriers and toner, and contacts and leaves a photosensitive drum 1, and an electrostatic latent image on the photosensitive drum 1 is allowed to contact and developed by a developing brush formed on a developing roller during the contacting. The 2nd developing device 6 coats the developing roller 8 with an internal single-component developer 7 having no carrier in a thin-layer state and the electrostatic latent image formed on the photosensitive drum 1 is developed without contacting. The 2nd developing device 6 is provided with the carrier mixture preventing means 10 on the downstream side of the rotation of the developing roller 8. This carrier mixture preventing means 10 scraps off carriers by a scraping member 10a to a carrier collecting means 11 provided below in synchronism with the rotation of the developing roller 8 only when the 2nd developing device 6 is used. |
