| 摘要 |
PROBLEM TO BE SOLVED: To provide a tandem image forming apparatus employing intermediate transfer system, configured to prevent reduction in primary transfer rate due to developer deterioration in second control mode (K-color mode) which uses one image carrier (K-color photoreceptor), while preventing reduction in image quality in first control mode (all-color mode) which uses a plurality of image carriers.SOLUTION: In K-color mode, a primary transfer bias is corrected so as to reduce a primary transfer current of K-color, by use of a correction amount according to a degree of deterioration of K-color developer. In all-color mode, the primary transfer bias of K-color is not corrected according to the degree of deterioration of the K-color developer or corrected by use of a correction amount less than the correction amount in the K-color mode. |
