| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus and the like with suppression of decline in an image forming speed caused by the time for switching over polarities of an output voltage of a bias power supply.SOLUTION: A transfer bias power supply 27 included in an image forming apparatus includes: a negative voltage generation unit 200 for generating a negative voltage transfer bias; a positive voltage generation unit 210 for generating a positive voltage cleaning bias; a threshold setup circuit 220 for setting a threshold voltage Vth corresponding to a limit current Ip in the case of supplying a negative voltage transfer bias; a current detection circuit 230 for detecting current flowing via a power feed roll; and an output control circuit 240 for lowering an absolute value of the negative voltage supplied from the negative voltage generation unit 200 in a case where the current detected by the current detection circuit 230 exceeds the limit current Ip set by the threshold voltage Vth. |
