Abstract: An image forming apparatus includes an operating key, an illuminance sensor, and a controller. The operating key contains a lamp. The illuminance sensor detects an ambient illuminance. The controller controls turning on and off of the lamp. The operating key functions as a first trigger for return from a power-saving mode to a normal mode. The controller turns the lamp off when the ambient illuminance detected by the illuminance sensor in the power-saving mode is equal to or more than a first threshold value, and the controller turns the lamp on when the ambient illuminance detected by the illuminance sensor in the power-saving mode is less than the first threshold value.

Abstract: An image forming apparatus includes an operating key, an illuminance sensor, and a controller. The operating key contains a lamp. The illuminance sensor detects an ambient illuminance. The controller controls turning on and off of the lamp. The operating key functions as a first trigger for return from a power-saving mode to a normal mode. The controller turns the lamp off when the ambient illuminance detected by the illuminance sensor in the power-saving mode is equal to or more than a first threshold value, and the controller turns the lamp on when the ambient illuminance detected by the illuminance sensor in the power-saving mode is less than the first threshold value.

Abstract: After a fixed period of time has passed with no operation received by an operating unit, a control unit switches the operation mode to a first power saving mode when the brightness detected by a brightness detection unit is greater than or equal to a given brightness, and switches the operation mode to a second power saving mode when the brightness detected is less than the given brightness. The control unit extends the detection range of a human detection unit in the second power saving mode to a range broader than the range used in the first power saving mode.

Abstract: After a fixed period of time has passed with no operation received by an operating unit, a control unit switches the operation mode to a first power saving mode when the brightness detected by a brightness detection unit is greater than or equal to a given brightness, and switches the operation mode to a second power saving mode when the brightness detected is less than the given brightness. The control unit extends the detection range of a human detection unit in the second power saving mode to a range broader than the range used in the first power saving mode.

Abstract: A total-current control unit is configured to add a fuser current of a fuser unit to a load current of the load to thereby obtain a total current to be supplied from a commercial power supply to the image forming apparatus, the total-current control unit being configured to control the total current to be at a predetermined limit value or less. An auxiliary power supply is configured to supply an auxiliary current to the load. The total-current control unit is further configured to provide first control to control the total current to be at the limit value or less and allow the auxiliary power supply to supply the auxiliary current to the load, thereby supplying, to the load, a current obtained by adding the auxiliary current to the load current, if an increase in the load current causes the total current to exceed the limit value.

Abstract: A total-current control unit is configured to add a fuser current of a fuser unit to a load current of the load to thereby obtain a total current to be supplied from a commercial power supply to the image forming apparatus, the total-current control unit being configured to control the total current to be at a predetermined limit value or less. An auxiliary power supply is configured to supply an auxiliary current to the load. The total-current control unit is further configured to provide first control to control the total current to be at the limit value or less and allow the auxiliary power supply to supply the auxiliary current to the load, thereby supplying, to the load, a current obtained by adding the auxiliary current to the load current, if an increase in the load current causes the total current to exceed the limit value.

Abstract: An image-forming apparatus includes: a fixing unit; a load; a power source circuit section; a fixation electrical current detecting body; a total electrical current detecting body; a storage unit; and a fixation control unit. The fixing unit fixes a toner image using a heat generator. The power source circuit section supplies electric power to the load. The storage unit stores electrical current change amount data establishing an amount of change in the magnitude of the total electrical current relative to an amount of change in a phase for each value of the power factor of the fixing unit. The fixation control unit finds the power factor of the fixing unit, and alters the phase at which the heat generator starts to be energized on the basis of the power factor thus found and the electrical current change amount data, so that the total electrical current value approaches a target value.