| 摘要 |
PURPOSE:To prevent mixing of colors, to obtain a high quality image with excellent gradation and to improve image quality by providing multiple color and monochromatic modes, combining most suitably latent images in first, color second and subsequent colors, with developing biases, and carrying out exposure by means of binary writing and multivalue writing respectively. CONSTITUTION:As for a developing means 7 in the second and subsequent colors by applying a DC bias in the case of the multiple color mode, mixing of the colors, which is caused by reverse flying of the first toner on an electrostatic latent image carrier 1, is prevented. By applying periodically varying bias in the monochromatic made, a high quality image with excellent gradation can be obtained. Further, in the case where exposure by the use of laser beams 3 and 6 is carried out, a latent image which has area gradation obtained by the binary writing in the multiple color made or has multivalue gradation obtained by the multivalue writing in the monochromatic mode is exposed. Thus, the high quality image can be obtained. |
