| 摘要 |
PURPOSE:To preclude jam detection abnormality due to a sensor defect by confirming whether or not paper jams when jamming is misdetected owing to the sensor defect, and deciding the sensor defect and disabling only a composing and both-surface copying function unless there is the jamming paper. CONSTITUTION:When the presence of transfer paper is detected by sensors 33 and 34 in a conveyance path for both-surface copying and composition after copying operation in composition or both-surface copying mode is started, the copying operation is stopped. Then a conveying mechanism is driven and discharging operation is performed for a specific time; if a paper discharge signal is outputted by neither a paper discharge sensor 30 nor a discharge sensor 31 even after the discharging operation is performed for the specific time, a sensor defect is judged and the function of both-surface copying is disabled. Consequently, jamming is prevented from being misdetected owing to the defect of the sensor 33 or 34. |
