| 摘要 |
PURPOSE:To prevent of fog and surface stain and to obtain a satisfactory image, by using a photosensitive body of a photoconductive body having photoconductivity for change of both positive and negative polarity, and switching the polarity of bias voltage applied to a developer holding member, into a copying mode and a printer mode. CONSTITUTION:The titled device is provided with a copying exposure device 4 and a printer optical image scanning device 5, and converts an electrostatic latent image on a photosensitive body 1 to a visible image by a single developing device 6, and since the polarity of the electrostatic latent image is positive in a copying mode and negative in a printer mode, a switch 39 is switched to a positive polarity voltage source 37 and a negative polarity voltage source 38 when switching the mode. When executing this switching, it is desirable that it is executed at a single stroke by being interlocked with switching of operations of the first corona discharger 2 and the second corona discharger 3, and switching of operations of the copying exposure device 4 and the printer optical image scanning device 5. |
