| 摘要 |
PROBLEM TO BE SOLVED: To prevent a toner image from being directly transferred to a transfer belt. SOLUTION: Since a photoreceptor drum 1Y and the transfer belt 14 are already rotated and transfer bias is already applied when supply of transfer material P is started from a resist roller 21, a transfer current flows. When the transfer material P reaches the transfer point N of yellow, the transfer bias is controlled in terms of constant voltage so that the transfer current is decreased. By monitoring the change of the transfer current, the arrival of the transfer material P at the transfer point N is recognized. Since time required to move the transfer material P from the roller 21 to the transfer point N can calculated in advance, a situation that the transfer material P has not been carried is detected when the transfer current does not change even if the calculated time comes. |
