IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide an image forming apparatus which, even after the process speed thereof is switched, can correctly determine the necessity for cleaning of a corona wire. SOLUTION: When printing, the image forming apparatus 20 determines, on the basis of a threshold voltage according to the process speed in the printing, whether or not the corona wire 221 of a charger 22 needs to be cleaned. On the basis of whether or not a monitoring voltage corresponding to the current value of a charged bias, which is applied to the corona wire 221 by a charged-bias high-voltage power supply 222, is equal to or more than the predetermined threshold voltage according to the process speed, the image forming apparatus 20 determines whether or not the corona wire 221 needs to be cleaned. COPYRIGHT: (C)2011,JPO&INPIT