| 摘要 |
PURPOSE:To improve the efficiency of cleaning of the surface of a photosensitive body using a magnetic brush by extending the width of contacting between the magnetic brush and the photosensitive body. CONSTITUTION:A developer 2 consisting of a carrier and a toner is carried by a nonmagnetic sleeve 4 rotated around the outside peripheral part of a magnetic roll 3 where plural magnetic poles are provided cylindrically. A gap (d) between the nonmagnetic sleeve 4 and a control member 5 which can set variably this gap (d) to optional larger and smaller values is set to the smaller value, and the quantity of the carried developer 2 is controlled and is made uniform in this state, and the developer 2 is carried to a developing magnetic pole 7 in the position facing a photosensitive body 6 which is set a gap l apart from the nonmagnetic sleeve 4, and the developer 2 is crested to a brush shape there and rubs lightly an electrostatic latent image on the photosensitive body 6 to develop this image. When the cleaning function of the surface of the photosensitive body 6 is used, the control member 5 is set variably to set the gap (d) to the larger value, and the gap (d) is made equal to or wider than the gap l, and the developer 2 is carried for a certain period similarly to development in the state where the electrostatic latent image is not formed on the photosensitive body 6. Since the width of contacting between the developer 2 and the surface of the photosensitive body 6 is extended to increase the rubbing force, the cleaning effect of the surface of the photosensitive body 6 is improved. |
