| 摘要 |
PURPOSE:To make it possible to avoid a long abnormal operation of a copying machine to prevent a drive section and peripheral mechanisms from being damaged, by carrying out abnormality diagnostic operations having different limited times in accordance with the time of on-copying operation or the time of paper supply. CONSTITUTION:A control circuit in an elevator tray control section determines, in accordance with the condition of output of a paper position detecting switch 8, whether an elevator tray is under the condition of paper supply or the condition of on-copying operation. An elevator drive circuit is controlled to rotate a motor 3 for elevating a tray until a level adjusting switch 7 detects the coming- up of papers 1 which are therefore always held at a predetermined paper supply position. Further, in the case of that the operating time of elevation of the tray from the start to termination of elevation is not carried out within a limited time period or in the case of the on-copying operation, a different limited time period is set, and if the adjustment of level of the elevator tray is not completed within such a set time period, it is determined as abnormal so that the operation is rapidly stopped. Accordingly, it is possible to prevent the drive section and peripheral mechanisms from being damaged. |
