Abstract: A controller obtains a first duty cycle of a first current to be supplied to a first heater and a second duty cycle of a second current to be supplied to a second heater and controls the first switch and the second switch after the reduction control period, such that the temperature of a fixing unit maintains a target temperature for fixing the image by the fixing unit.

Abstract: A heater 600 includes a substrate 610 and a plurality of heat generating elements 623a to 623f which are provided on both surfaces of the substrate 610 and which generate heat, and heats a fixing belt in contact with an inner peripheral surface of the fixing belt. The plurality of heat generating elements 623a to 623f are different from each other in length with respect to a widthwise direction, and a plurality of the heat generating elements are provided on a front surface of the substrate 610 which is a side where the heater 600 contacts the inner peripheral surface of the fixing belt 600, and at least one of the heat generating elements is provided on a back surface.

Abstract: The power source device comprises a transformer, a voltage detection unit, a CPU and a drive circuit. Through an applying of a DC voltage, the transformer generates an AC voltage for development of an amplitude corresponding to the voltage value and an applying time of the DC voltage. The voltage detection unit detects a voltage value of the DC voltage. The CPU sets a reference value and generates PWM signals for controlling the applying time in accordance with a difference between the voltage value detected in the voltage detection unit and the reference value. The reference value is a voltage value of the DC voltage when an amplitude of the AC voltage reaches a predetermined value in a predetermined applying time. Controlling the applying time of the DC voltage to the transformer in accordance with the PWM signals, the drive circuit suppress variation in amplitude of the AC voltage.

Abstract: A fixing device includes first and second rotatable members, a heating portion, a detecting portion configured to detect a temperature of the first rotatable member, a controller configured to control supplied electrical power to the heating portion depending on the detected temperature, and a setting portion configured to set a nip pressure at a first pressure when a recording material of a first kind is subjected to a fixing process and configured to set the nip pressure at a second pressure less than the first pressure when a recording material of a second kind is subjected to the fixing process. The controller controls the supplied electrical power depending on a difference between a target temperature of the first rotatable member and the detected temperature. The supplied electrical power is less when the nip pressure is the second pressure than when the nip pressure is the first pressure.

Abstract: A fixing device includes first and second rotatable members, a heating portion, a detecting portion configured to detect a temperature of the first rotatable member, a controller configured to control supplied electric power to the heating portion depending on the detected temperature, and a setting portion configured to set a nip pressure at a first pressure when the recording material of a first kind is subjected to a fixing process and configured to set the nip pressure at a second pressure smaller than the first pressure when the recording material of a second kind is subjected to the fixing process. The controller controls the supplied electric power depending on a difference between a target temperature of the first rotatable member and the detected temperature. The supplied electric power is smaller when the nip pressure is the second pressure than when the nip pressure is the first pressure.

Abstract: The power source device comprises a transformer, a voltage detection unit, a CPU and a drive circuit. Through an applying of a DC voltage, the transformer generates an AC voltage for development of an amplitude corresponding to the voltage value and an applying time of the DC voltage. The voltage detection unit detects a voltage value of the DC voltage. The CPU sets a reference value and generates PWM signals for controlling the applying time in accordance with a difference between the voltage value detected in the voltage detection unit and the reference value. The reference value is a voltage value of the DC voltage when an amplitude of the AC voltage reaches a predetermined value in a predetermined applying time. Controlling the applying time of the DC voltage to the transformer in accordance with the PWM signals, the drive circuit suppress variation in amplitude of the AC voltage.