| 摘要 |
PROBLEM TO BE SOLVED: To restrain the change of toner condition inside a developing device before and after a long term use so as to prevent image quality from being deteriorated before and after the long term use. SOLUTION: Developing process for faithfully reproducing an original is performed by a first developing device 4 by using black developer, and reversal red toner and reverse polarity additive agent are developed by a second developing device 7 on an area which is on the black solid part of the developing area developed by the device 4 and which is smaller than solid part. Thus, the reversal toner and the reverse polarity additive agent inside the device 7 are positively developed so as to restrain the change of the toner condition inside the device 7. |
