| 摘要 |
PROBLEM TO BE SOLVED: To enable the time, which can be used for switching developing means, to be taken long by starting the development of the developing means arranged on an upstream side in the rotating direction of an image carrier first and executing the development by the developing means arranged on a downstream side, next. SOLUTION: The development is switched to that by the downstream-side developing roller 34 from that by the upstream-side developing roller 35 in the rotating direction of a photoreceptor drum 26. When the back end of a previous image is defined as a B point, a non-image area is the distance of one circumference of the drum 26. Therefore, time required for moving the front end (B' point) of the next image to a position where it is closely opposed to the next roller 34 after the back end (B point) of the previous image is passed through a position where it is closely opposed to the previous roller 35 corresponds to the time required for advancing the image by the distance L2. Besides, the time required for advancing the image by the distance L2 corresponds to the time Ta which can be used for switching the developing means. By starting the development of the upstream-side developing means first, the time Ta, which can be used for switching the developing means, is made sufficient. |
