| 摘要 |
PURPOSE:To correct image density and to prevent the generation of fogging and staining by providing a non-volatile memory, which maintains the output of a toner concentration detecting means even during the period that a power source is being turned off, and controlling toner replenishment by using the voltage maintained by the non-volatile memory when a control board is replaced. CONSTITUTION:Even during the period that the power source is being turned off, the non-volatile memory M which maintains the output of the toner concentration detecting means T is provided, and when the control board B is replaced, the toner replenishment is controlled by using the voltage maintained by the non-volatile memory M. Namely, since there is no difference between the toner concentration before the control board B replacement and the toner concentration after the replacement, the toner replenishing condition must be the same. Therefore, the output of the toner concentration detecting means T must be fixed before and after the replacement of the control board B. The correct toner replenishment is carried out by adjusting the output voltage of the toner concentration after the control board B replacement to be equal to the output voltage of the toner concentration detecting means T before the replacement. Thus, the generation of fogging and staining is prevented and the image density is corrected. |
