| 摘要 |
PROBLEM TO BE SOLVED: To prevent developer from being replaced unwittingly, and to maintain the property of the developer over a long term, by replacing the developer corresponding to the extent of deterioration of the developer. SOLUTION: This device decides a replacing quantity (recovering quantity and feeding quantity) of the developer, by measuring the deterioration extent of the developer, and comparing a measurement value A with the preliminaryly set value A0, when the developer deterioration is judged, as the result of comparison between the measuring value and the preliminaryly prescribed set value. The developer replacing operation is controlled by following the above namely, the releasing time of the shutter 43 is controlled so as to recover the decided recovering quantity, and the operation for controlling the roller rotation time is executed after completion of recovering, so that the developer feeding roller 38 feeds the same quantity as the recovered quantity. Moreover, the replenishment quantity or the replenishment time can be varied, by varying the set value variable based on such as deterioration state of the photoreceptor and the exposure condition, and correcting the measuring value variably. |
