Abstract: A main controller controls a capacitor charger to charge a capacitor as necessary. A sub-controller controls a power saving mode and stops a power supply to the main controller when shifting to the power saving mode. A charge control circuit compares a terminal voltage of the capacitor with a predetermined value by a comparator circuit. If the terminal voltage is lower than the reference value, an AND circuit takes a logical product of an output signal of the comparator circuit and a power saving signal indicating the shift to the power saving mode, and outputs a control signal indicating an instruction to charge the capacitor, to the capacitor charger.

Abstract: An image forming apparatus includes a fixing unit that thermally fixes a toner image, a power control unit that controls a power supply from an auxiliary power supply to the fixing unit, a job-turnaround-time predicting unit that predicts a job turnaround time for executing an image forming job, a charging-time predicting unit that predicts a charging time for charging the auxiliary power supply, and a control unit that controls a charging operation for the auxiliary power supply and execution of the image forming job based on the job turnaround time predicted and the charging time predicted, such that the job turnaround time for the image forming job is minimized.

Abstract: A main controller controls a capacitor charger to charge a capacitor as necessary. A sub-controller controls a power saving mode and stops a power supply to the main controller when shifting to the power saving mode. A charge control circuit compares a terminal voltage of the capacitor with a predetermined value by a comparator circuit. If the terminal voltage is lower than the reference value, an AND circuit takes a logical product of an output signal of the comparator circuit and a power saving signal indicating the shift to the power saving mode, and outputs a control signal indicating an instruction to charge the capacitor, to the capacitor charger.

Abstract: An image forming apparatus includes a fixing unit that thermally fixes a toner image, a power control unit that controls a power supply from an auxiliary power supply to the fixing unit, a job-turnaround-time predicting unit that predicts a job turnaround time for executing an image forming job, a charging-time predicting unit that predicts a charging time for charging the auxiliary power supply, and a control unit that controls a charging operation for the auxiliary power supply and execution of the image forming job based on the job turnaround time predicted and the charging time predicted, such that the job turnaround time for the image forming job is minimized.