| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to apply an optimum transfer bias even if temperature and humidity environment change and to shorten a first print-out time. SOLUTION: At no-image formation time which is not right before image forming operation, the output voltage when a transfer high-pressure power source 11 performs fixed-voltage control over a transfer roller 2 is varied, the output current at this time is detected, and a transfer bias to be applied from the transfer high-pressure power source 11 to the transfer roller 2 in transfer operation is predicted according to the detection result; and the predicted transfer bias is corrected on the basis of temperature and humidity environment inputted from an environment sensor 10 and resistance variation information on the transfer roller 2 inputted from a RAM 10b in a DC controller 10 and the optimum transfer bias is determined. Consequently, an excellent image can be obtained by preventing scattering and the generation of a plus memory and the first print-out time can be shortened. |
