| 摘要 |
PURPOSE:To obtain a sharp multicolor image having no color mixture by setting the surface potential of an image part formed on an upstream side higher than the bias voltage of a downstream-side developing sleeve. CONSTITUTION:A 2nd image light 7 is projected for a 2nd exposure to form a 2nd negative latent image, and the surface potential of a charge erasure part is lowered almost to 0V. A 2nd development is carried out while a developing bias Vb2 is applied to a developing sleeve 81 similarly to a 1st development, black toner which is charged electrostatically to the positive polarity sticks on a 2nd image part X2, and a 2nd toner image is formed over a 1st toner image. The background X0 of a photosensitive drum 1 is given the fatigue degree of the same level with a 1st image part X1 by an eraser lamp 5, so the 1st image part X1 and background part X0 have nearly the same attenuation tendency after a 2nd electrostatic charging. Consequently, the surface potentials of not only the background part X0, but also the 1st image part X1 exceed the bias voltage Vb2 of a developing sleeve 81 and a 2nd toner on the developing sleeve 81 never sticks on the 1st image part X1, thereby obtaining the image without any color mixture. |
