| 摘要 |
PURPOSE: An image forming apparatus and a method thereof are provided to suppress or reduce the degradation of a throughput of an image forming apparatus by appropriately controlling timing to switch a development unit based on the size of each color image to be formed. CONSTITUTION: A yellow development unit(20Y), a magenta development unit(20M), a cyan development unit(20C), and a black development unit(20B) are supported by a development rotary(23), which is a rotatable development unit. The development rotary can rotate and is capable of switching the development unit from one color development unit to another color development unit, of development units for a plurality of colors. The development rotary can contact a photosensitive drum(15). By contacting the photosensitive drum, the development rotary serially forms and develops images on the photosensitive drum. In addition, the development rotary serially transfers the developed images onto an intermediate transfer belt(9), which is an example of an intermediate transfer member. The development rotary forms color images by multiple transfer. The formed color images are transferred on a transfer material(2), which has been fed from a paper feed unit(1). Thus, the color images are formed on the transfer material. The transfer material having the color images formed thereon is conveyed to and fixed by a fixing unit(25). Then, the transfer material having the color images fixed thereon is discharged by a paper discharge roller(36) to a paper discharge portion(37), which is provided on a top portion of the color image forming apparatus. |
