| 摘要 |
PURPOSE:To enable only one sheet of a printing paper to be reliably conveyed even if a friction force between printing papers changes dur to a change in ambient temperature, by a method wherein dynamic torque of a turn-over roller for returning a sheetform medium to a medium storing part is variably controlled according to ambient temperature. CONSTITUTION:When ambient temperature is low, the width of the pulse of a control signal fed to a transistor 26 is narrow, and the amount of a current flowing to an electromagnet 21 is small. Thus, a contact force between a plate 19 and a felt 25 decreases, and dynamic torque, applied to a turn-over roller 12 through members 17-19, 21, 23, and 25 forming a clutch mechanism, decreases. However, when ambient temperature is low, a friction force between printing papers 7 is low, and thereby only one sheet of the printing paper may be reliably conveyed. Meanwhile, when ambient temperature is high, the width of the pulse of a control signal fed from a pulse modulating circuit 31 to a transistor 26. Thus, dynamic torque, applied on the turn-over roller 12, increases,and in this case also, only one sheet of a printing paper may be reliably conveyed. |
