| 摘要 |
PURPOSE:To highly accurately maintain a gap between a photosensitive drum and a developing roller by providing a pressure means that presses space maintaining rings, which are provided on both edge part of each developing roller, and a developing unit to the photosensitive drum side and making the space maintaining rings abut on the periphery of the photosensitive drum. CONSTITUTION:The space maintaining rings 32 and 32, which are rotetably provided on both edge part of a developing roller 30, and the supporting part 18 of an unit supporting body 14 are provided with leaf springs 33 as the pressure means energizing and pressing a cyan developing unit 15 against the photosensitive drum 1 side. Hence, the leaf spring 33 is elastically brought into contact with the rear surface of the cyan developing unit 15, which is rotated unitclockwise centering around a supporting shaft 23 and energized, and the space maintaining rings 32 and 32 are made abut on the peripheral surface of the photosensitive drum 1, whereby the space (d) is maintained between the developing roller 30 and the peripheral surface of the photosensitive drum. Thus, the space between the developing roller 30 and the photosensitive drum 1 can be stably and highly accurately maintained, and uniform picture quality without developing unevenness can be obtained. |
