| 摘要 |
PURPOSE:To prevent sheet clogging without providing a dedicated sensor by forming a toner pattern on a transferring belt, reading a transferring belt position from the pattern by means of a sensor and controlling image recording operation. CONSTITUTION:A driven roller 26 around which the transferring belt 21 is wound is formed movably between an operation position and an operation cancellation position. A transferring sheet and a photosensitive body 14 come in touch with the operation position. A photosensor 28 is disposed near the roller 26, and standard pattern concentration for controlling toner supply is read in order; the concentration is transferred by recording devices 13C, M, Y and BK, and toner concentration control is performed. The sensor 28 tests whether the transferring belt 21 is in cancellation position or not and generates a signal. Besides, the signal from the sensor 28 and a set standard are compared by means of the detecting signal of the opening and closing detecting switch of an image forming device when a door switch is on and when the door switch is changed from on to off. Since image recording operation or cancellation can be controlled based on data obtained from said comparison, the image recording can be performed with the transferring belt 21 canceled and the sheet clogging can be prevented. |
