An image forming apparatus includes a photosensitive member, a charging member, a developing member, a first contacting member contacting to the developing member, and first to third power sources. The first power source generates a first voltage lower and supply to the charging member. The second power source generates a second voltage lower than the first voltage from the first voltage and applies to the first contacting member. The third power source generates a third voltage lower than the second voltage from the second voltage and applies to the developing member.

A discharge circuit for a decoupling capacitor to stabilize a voltage supplied from a first power supply unit to a first load includes a first capacitor, a first switch, and a discharge control circuit. The first capacitor is charged by power supplied from a second power supply unit that supplies power to a second load that is different from the first load. The first switch is arranged between the decoupling capacitor and ground. The discharge control circuit discharges, in a case where power supplied from the second power supply unit to the second load is cut off, charges of the decoupling capacitor to the ground by driving the first switch using charges stored in the first capacitor.

According to an embodiment, an image forming apparatus includes: a motor that drives a fixing device; and a controller. The motor outputs a signal corresponding to a driving current value of the motor. The controller performs a first operation where a magnitude value of the signal has fallen out of a first range while driving the motor in a first operation mode. The controller performs a second operation where the magnitude value of the signal has fallen out of a second range while driving the motor in a second operation mode.

In an image processing apparatus, a power switcher starts supplying power in a second mode in which the power is supplied to a controller but not supplied to an image processor, when a state in which the power switcher receives no power is changed to a state in which the power switcher receives power. When a state in which no power is supplied to the controller is switched to a state in which power is supplied to the controller in the second mode and when the power switcher is receiving no power from a commercial power source, the controller, based on particular information, switches, before a first processing, a power supply mode from the second mode to a first mode in which no power is supplied or switches the power supply mode from the second mode to the first mode after the first processing.

An image forming apparatus includes a photosensitive member, a charging member, an exposing device, a developing device, a transfer member, a brush, a voltage applying portion, and a control portion controlling a surface potential of the photosensitive member at the brush contacting position. When a value of subtracting a value of the surface potential of the photosensitive member in the brush contacting position from a value of the brush voltage is defined as a contacting position potential difference, the control portion controls the surface potential of the photosensitive member in the brush contacting position so that the contacting position potential difference is changed from a first potential difference to a second potential difference in a predetermined direction which is either one of an increasing direction or a decreasing direction, and then the contacting position potential difference is changed from the second potential difference to a third potential difference in the predetermined direction.

An image forming apparatus including a normal power mode and a power saving mode includes a fixing unit configured to bring first and second rotary members into contact with each other to form a nip portion and fix a toner image onto a sheet with a pressing force of the nip portion. The image forming apparatus executes a rotation operation or a separation operation to separate the first and second rotary members from each other in order to prevent a deformation of the nip portion in the fixing unit. The image forming apparatus measures a time during which the first and second rotary members are in contact with each other without rotating. The image forming apparatus determines whether to execute the separation operation or the rotation operation based on a result of the power mode determination and the measured time.

A image forming apparatus includes a power control unit, an operation mode control unit, and a first timer. The power control unit performs control so as to switch between a normal power state for supplying the operation power supply voltage to the image forming unit, a first power saving state for not supplying the operation power supply voltage to the image forming unit, and a second power saving state having less power consumption than the first power saving state. The operation mode control unit performs control so as to switch a normal mode corresponding to a normal power state, a first power saving mode corresponding to a first power saving state, and a second power saving mode corresponding to a second power saving state.

A power supply apparatus to supply power to an image forming device, the power supply apparatus includes an amplifier to amplify an input AC power by a general amplification or a double amplification, a converter to receipt the input AC power amplified by the general amplification or the double amplification and output a DC power with a determined size. A controller control applying the general amplification or the double amplification to the converter, in response to an operating mode of the image forming device.

Method of heating control includes preheating a heater to a first target temperature when an image forming device is powered on, is woken up from sleep, or receives a task to be processed; determining a voltage parameter of the heater or a characteristic of temperature change of a heating process of the heater, under the current environment of the power supply, according to a prior-preheating temperature, a post-preheating temperature, and a time length of the preheating; and according to the voltage parameter or the characteristic of temperature change under the current environment of the power supply, determining a heating start time of a second heating for the preheated heater and triggering the second heating at the heating start time, to allow a temperature of the heater to reach a second target temperature within a set time before an image to-be fixed arrives at the fixing assembly.

An image forming apparatus includes a fixing device, and a processor. The fixing device fixes an image formed on a recording medium at a fixing temperature. The fixing device includes a heater to heat the fixing device with power from a power supply. The processor detects a voltage value of the power supply, sets a standby temperature of the fixing device based on the detected voltage value of the power supply, and controls operation of the heater to heat the fixing device from the standby temperature to the fixing temperature in response to receiving an instruction for forming an image.