| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device capable of calculating a proper constant current value by accurately detecting the resistance value of a bias-applied member with simple constitution. SOLUTION: A forward transfer bias applying circuit 72 which applies a forward transfer bias under constant current control during transfer and a reverse transfer bias applying circuit 73 which applies a reverse transfer bias under constant voltage control during cleaning of a transfer roller 31 are connected in series to constitute a transfer bias applying power source 71. When the constant current control is carried out, the resistance value Z on the side of the transfer roller 31 is calculated from Z=(αVe-Ri<SB>1</SB>)/i<SB>1</SB>on the basis of the output voltage Ve of a forward transfer output voltage detecting circuit 75, the voltage ratioαof a secondary coil 85 and an auxiliary coil 86 of a transformer 82 of a forward transfer voltage boosting/smoothing rectifying circuit 74, the resistance value R of a discharge resistance 103 of a reverse transfer voltage boosting/smoothing rectifying circuit 91, and a constant current set value i<SB>1</SB>and the forward transfer bias is applied successively to the transfer roller 31 on the basis of the resistance value Z. COPYRIGHT: (C)2004,JPO
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