| 摘要 |
PURPOSE:To perform multicolor changeover copying operation by revolving two developing devices in a parallel state and setting one developing device at a development position by a revolving unit, and making an image formation process speed faster when the 2nd developing device is set at the development position than when the 1st developing device is set. CONSTITUTION:At least one set of the 1st developing device 27c composed of a single developing device part and at least one set of the 2nd developing device 27d consisting of at least two developing device parts in one body are revolved while held in the parallel state and one developing device is selected by the revolving unit. A contacting/separating means is provided which allows the developing device selected by the revolving unit 28 to contact or leave an image carrier 12 and the image formation process speed is made faster when the 2nd developing device 27d is set at the development position nearby the carrier 12 than when the 1st developing device 27c is set. |
