| 摘要 |
<P>PROBLEM TO BE SOLVED: To output an appropriate charging bias even when the resistance of a charging roller is changed, and also, even when current-voltage characteristics of a photoreceptor are changed. <P>SOLUTION: A first bias correction operation and a second bias correction operation are performed by a bias correcting means. Regarding the first bias correction operation, a first charging current value detected when a first charging bias as an initial set value is applied is compared with a target charging current value, and a first operation to obtain a second charging bias is performed based on the comparison result, next, a second charging current value detected when the second charging bias is applied is compared with the target charging current value, and a second operation to obtain a third charging bias is repeatedly performed a prescribed number of times. The second bias correction operation to correct the charging bias obtained from the result of the first bias correction operation is performed based on photoreceptor information on photoreceptor temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT |
