| 摘要 |
PURPOSE:To obtain copied images of different reproducibilities, by providing plural developing devices of different developing agent carrying quantities to a developing area around an electrostatic latent image carrier and performing development by selectively switching the developing devices. CONSTITUTION:A negative image is exposed and a negative electrostatic latent image is formed on the surface of a photosensitive drum 1 after the drum surface is electrostatically charged at -600V at the upstream side of its rotating direction (arrow a) and the latent image is selectively developed by either one of developing devices 10 and 20. At the time of development, a developing bias of -500V is applied across the developing sleeve 11 or 21 of the selected developing device 10 or 20 and negatively charged toner adheres the image part of the latent image, and thus, a positive developed picture is formed. The developed image is transferred to copying paper by means of the positive discharge of a transferring charger provided on the downstream side in the direction shown by the arrow (a). Switching between the developing devices 10 and 20 to be used for development is performed through a changeover switch on an operation panel. |
