| 摘要 |
PURPOSE:To improve image quality by simplifying the detection of toner image density and improving detecting-accuracy, in an image forming device provided with plural photosensitive drums. CONSTITUTION:Plural image forming stations Pm, Pc, Py and Pk, each of which is provided with the photosensitive drum, electrifying device, exposing means, developing device and transfer device, are disposed, and a transfer belt 9a which carries a transfer material P to them in order is also disposed. A density sensor 13 is arranged at the furthest downstream photosensitive drum 1K. A density detection toner image formed at image forming stations 1M, 1C, 1Y situated upstream is once transferred to the transfer belt 9a or a transfer material P. Thereafter it is again transferred to the photosensitive drum 1K by the transfer device 6K acting as a retransfer mechanism. Since the density sensor 13 detects the density of the toner image, the single sensor is enough and, in addition, satisfactory detecting accuracy is obtained. |
