| 摘要 |
PURPOSE:To eliminate the need for an energization device and to set the developing sleeve of each developing device with a correct space between the sleeve and an image forming body surface by constituting each developing sleeve of the developing device unit in such a manner that a fixed space between the sleeve and the image forming body surface is held. CONSTITUTION:The developing device unit 100 has such a shape that it is deformed slightly inward and contracted so that the developing sleeves 361, 371, 381, and 391 of respective developing devices are uniformly brought into contact with a periphery, whose curvature is slightly smaller than that of the periphery of the photosensitive drum 30, at the time of a single body. When butting rollers 361A, 371A, 381A, and 391A provided on the same axis of corresponding developing sleeves so as to place them on the position facing the periphery of the photosensitive drum 30, are brought into press-contact with the periphery of the photosensitive drum 30, the developing unit 100 expands to the right and left to cause butting rollers to be uniformly brought into contact with the periphery of the photosensitive drum 30 with uniform pressure; consequently, respective developing sleeves 361, 371, 381 and 391 can be set in a position with a correct space for development to the image forming body by using a considerably simple means. |
