| 摘要 |
PURPOSE:To immediately and automatically detect abnormal electric discharge, namely transfer omission caused by leakage or the like. CONSTITUTION:At a transfer time, a transfer voltage value VTC for obtaining the most excellent transfer is set by a set part 40. Simultaneously, a transfer guarantee voltage VAC for guranteeing the transfer is set. A constant-current source 50 controls constant-current control so that the transfer voltage of the set value is impressed on a transfer electrifier 30 and a constant transfer current (iT) flows. Thus, a paper CP is electrified into the polarity inverse to the electrifying charge of toner TN by corona discharge by the electrifier 30 and a toner image is transferred onto the paper. Then, a voltage VT impressed on the electrifier 30 is detected by a voltage detection part 60 and the detected voltage VT is compared with the transfer guarantee voltage VA by a comparison part 80. When the voltage VT is smaller than the voltage VA, an alarm ALM 1 is issued by regarding that the abnormal electric discharge such as the leakage is generated and the transfer omission is occurred. |
