| 摘要 |
PURPOSE:To miniaturize the device main body and to preclude color mixing in developer multiple transfer by setting the surface of an OPC belt at a distance of more than a constant development gap from a magnet roller when the belt surface is not opposite a developing device. CONSTITUTION:When an electric latent image of image data of specific color, e.g. yellow is formed by exposure, a developing gap adjusting roller 11 is so set at a position alpha opposite developing device 20a as to maintain the constant development gap phi with the magnet roller 20a1. At this time, the intervals between other developing devices 20a2 and 20a3 and the OPC belt surface are increased above the constant development gap. Thus, a yellow developer sticking on the magnet roller 20a1 by magnetic brush development is exposed (stuck on) to the OPC belt 12. Consequently, the simple, size-reduced device of space saving structure is obtained and the color mixing in developer multiple transfer is securely precluded. |
