| 摘要 |
PURPOSE:To obtain vivid pictures by impressing a DC bias voltage, which has the same polarity as the charge of developed toner particles, to a developing device which does not perform development. CONSTITUTION:The surface of an image forming body 1 rotated in the direction of an arrow is electrostatically charged uniformly by an electrifier 2, and one of image exposure lights 5A-5D is made incident on this electrostatically charged surface through a rotary polygonal mirror 3 and a focusing lens 4 to form an electrostatic latent image. Toner particles are stuck to the exposed part to develop this electrostatic latent image by one of developing devices 6A-6D where toner particles different in color are stored. Latent image formation and development are performed continuously while switching successively the image exposure light and the developing device to image exposure lights 5A-5D and devices 6A-6D respectively. When the toner image formed on the image forming body 1 passes developing areas of developing devices which do not perform development, the DC bias voltage having the same polarity of the charge of toner particles is impressed to a developing sleeve 61 of each of these devices, and the quantity of a carried developer layer of the sleeve 61 is made smaller than that for development. Thus, mixture of toner particles among device 6A- 6D is prevented to form vivid pictures. |
