| 摘要 |
PROBLEM TO BE SOLVED: To recover the two component developer without unnecessarily deteriorating linearlity of both, in the case the detected toner concentration in a developing device is differing from the real toner concentration. SOLUTION: A addional time S for adding on the reference agitating time variable is set in accordance with the value (voltage) deducting the toner concentrationβdetected at the previous time from the toner concentrationαin the developing device detected at this time, being stored in a nonvolatile memory. Then, the agitating time S for adding on the agitating time becoming to reference is stored in the non-volatile memory. The two component developer in the developing device is agitated at the image forming time, and the time is extended in accordance with the length of agitating time stored by the non- volatile memory (step S61, S62 and S64). However, the upper limit of 30 minutes are set to the extension time (step S63). |
