An image forming apparatus includes a casing accommodating an image forming unit, a fan, a duct member, an electric component, and a sensor unit. The casing includes a cover member, an air inlet opening, and an air outlet opening. The fan is configured to take in air from an upstream side with respect to a second direction and blow out the air to a downstream side with respect to the second direction such that the air flow flowing through the air inlet opening, the fan, the duct member, and the air outlet opening is generated. The sensor unit is arranged within a region between the air inlet opening and a rotational axis of the fan with respect to a first direction, and is arranged on an upstream side of the fan with respect to the second direction.

A power control apparatus includes a power detection circuit to detect DC power converted from AC power supplied from a power supply and to be supplied to a control board of an image forming apparatus. The power control apparatus includes circuitry configured to, in response to a first printing operation performed by the image forming apparatus, calculate fluctuations in the DC power in each preset control period from a start of the first printing operation until stabilization of the DC power. The power control apparatus includes, in response to a printing operation subsequent to the first printing operation performed by the image forming apparatus, determine allocation of the AC power to a fixing device of the image forming apparatus in a next preset control period based on power obtained by adding, to the DC power, an average of the fluctuations in a plurality of preset control periods.

A fixing device includes a first rotator and a second rotator that form a nip therebetween and fix an image on a recording medium that enters the nip. A heater heats at least one of the first rotator or the second rotator. A controller controls the heater to switch between a first heating and a second heating, to switch from the first heating to the second heating before the recording medium enters the nip, to start the second heating at a time prior to a nip entry time at which the recording medium enters the nip by a delay time period taken for the heater to conduct heat to the nip, and to continue the first heating before the second heating for at least one control cycle at a duty cycle of power supplied to the heater. The duty cycle is not greater than 40%.

An intermediate transfer unit includes a seamless intermediate transfer belt, a plurality of primary transfer members and a power supply line. On the intermediate transfer belt, toner images formed on a plurality of image carrying members are sequentially stacked. The primary transfer members are respectively arranged opposite the image carrying members via the intermediate transfer belt, and transfer the toner images formed on the image carrying members onto the intermediate transfer belt. The power supply line branches to at least two or more locations from a transfer voltage power supply which applies a primary transfer voltage to each of the primary transfer members to cause a primary transfer current to flow to each of the primary transfer members. The power supply line and each of the primary transfer members are connected via a high-voltage resistor unit that includes a plurality of resistors having different resistance values.

An intermediate transfer unit includes an intermediate transfer belt, a plurality of primary transfer members, and a plurality of power supply portions that feed a transfer voltage to the corresponding primary transfer members. The power supply portions have a power supply line connected to the source of the transfer voltage and a resistor portion arranged between the corresponding primary transfer member and the power supply line. The resistor portion includes a plurality of resistive elements. The primary transfer member is connected to the power supply line via one or more previously selected resistive elements out of the plurality of resistive elements in the corresponding power supply portion.

An image forming apparatus includes an image forming unit configured to form an image on a recording material, a printed circuit board including a voltage generation unit mounted thereon and configured to generate a voltage to be applied to the image forming unit, a conductive member provided on the printed circuit board, to which the voltage generated by the voltage generation unit is applied, an elastic member including an arm portion configured to be biased toward the conductive member, and configured to connect the conductive member and the image forming unit, and a holding unit configured to hold the arm portion of the elastic member at a position where the arm portion is not in contact with the conductive member.

A metal frame provides a ground potential. An image forming unit forms a toner image on a sheet. A fixing apparatus fixes the toner image on the sheet. The fixing apparatus comprises a heating element for generating heat by being supplied with power from an alternating current power source. An insulating layer covers the heating element. A conductive layer contacts the insulating layer and insulated from the metal frame. A tube-shaped member is heated by the heating element. A pressing member is arranged opposing the tube-shaped member and forms a nip portion in cooperation with the tube-shaped member. A capacitive element whose one end is connected to the metal frame and whose other end is connected to the conductive layer of the fixing apparatus.

A power supply device according to the present disclosure includes an AC voltage output circuit and a DC voltage output circuit. The DC voltage output circuit includes a first voltage dividing resistor provided between a power supply line of a voltage output portion and a ground potential, a second voltage dividing resistor provided between the first voltage dividing resistor and the ground potential, a capacitor provided in parallel with the second voltage dividing resistor, and an operational amplifier. An output of the AC voltage output circuit is connected to the voltage output portion of the DC voltage output circuit. A cutoff frequency of a low-pass filter circuit constituted of the first voltage dividing resistor, the second voltage dividing resistor, and the capacitor is set to be lower than a frequency of the AC voltage output from the AC voltage output circuit.

An image forming apparatus includes a fixing member, a heating portion configured to heat the fixing member by being supplied with electric power, a power source configured to supply electric power to the heating portion, a temperature detector, a controller configured to control power supply from the power source to the heating portion based on the output voltage from the temperature detector, a reference voltage generator configured to generate a reference voltage, and a breaker configured to stop the power supply from the power source to the heating portion. The reference voltage generator is configured to output the reference voltage that changes with time having elapsed since a start of heating at which the power supply to the heating portion was started by the controller.

An image forming apparatus includes a power supply fixed to a casing, a power inlet configured to supply, to the power supply, electric power supplied from an outside via a power cord, and an inlet support member to which the power inlet is fixed, wherein the power supply includes an electric board configured to be supplied with the electric power from the power inlet, and a board support member configured to support the electric board, and wherein the power inlet is fixed to the board support member through intermediation of the inlet support member.