| 摘要 |
PURPOSE:To eliminate the defect of an image caused by the contamination of an exposure device and a carrying guide by scattered toner by preventing the scattering of toner based on the rotating action of a rotary developing device. CONSTITUTION:A black developing device 144 is arranged between the exposure device 3 on the upstream side and the rotary developing device 4 on the downstream side in the rotating direction of a photoreceptor drum 1 (direction shown by an arrow R1), and the upper part of the developing device 4 is covered. The disposing position of the rear end T of the lower part of a developing unit 144 is set at a position distant from the center 0 of the rotation of the device 4 by the half or more of the maximum radius (r) of the rotation. The rotating directions (shown by arrows R4 and R5) of the device 4 and an intermediate transfer body 5 are made reverse and the opposed parts of both of them are moved in the same direction so as to form rotation wind W1 and W2 guiding the scattered toner between both of them. The rotation wind becomes the rotation window W0 when it passes a gap S between the lower part of the developing unit 144 and the upper part of the developing device 4, and impinges at the lower part of the developing unit 144, where the scattered toner adheres. Thus, the toner is prevented from being scattered further. |
