| 摘要 |
PURPOSE:To selectively perform normal development in copying mode and reversal development in printer mode with such a simple operation as changing polarities of charging only, by using a photoreceptor which has photosensitivity to positive and negative charging. CONSTITUTION:The 1st charger 2 charges a photosensitive drum 1 having, for example, an amorphous silicon photosensitive surface positively, an original image is exposed by a ''SELFOC '' lens 15, and the image is developed with negatively charged toner in a developing device 6, thus taking a copy of an original. When this device is used as a printer, for example, a liquid-crystal optical shutter 16 is driven selectively by image signals from a facsimile equipment and a computer to expose the drum 1 to light from a lamp 17, a latent image is formed on a photosensitive surface charged negatively by the 2nd charger 3, and reversal development is performed by using the negatively charged toner in the developing device 6, thus obtaining a positive copy from the negative image signal. |
