Abstract: A fixing unit includes a film including a tubular shape and configured to rotate, a heater arranged inside the film and including a heating resistor configured to generate heat by passing alternating current therethrough and an insulator configured to cover the heating resistor, a sliding member arranged between the heater and the film and configured to be in sliding contact with an inner surface of the film, the sliding member having electric conductivity, a pressing member configured to be in pressure contact with the sliding member across the film to form a nip portion between the sliding member and the pressing member, and a conductive member electrically connected to a ground potential via at least one impedance element. The sliding member is electrically connected to the conductive member.

Abstract: A power control device includes a heater, a zero-cross detecting unit, a triac, a supplying unit, and a controlling unit. The supplying unit discharges an electric charge when a control signal is outputted in a half-wave of each of a first polarity and a second polarity and charges the electric charge when the control signal is not outputted in the half-wave of the first polarity. The controlling unit outputs: in a first half-wave, a first control signal on the basis of the zero-cross point and a second control signal in a first phase different in timing from the first control signal, and in a second half-wave, a third control signal on the basis of the zero-cross point and a fourth control signal in a second phase different in timing from the second control signal. The first phase and the second phase are different from each other.

Abstract: A fixing unit includes a film including a tubular shape and configured to rotate, a heater arranged inside the film and including a heating resistor configured to generate heat by passing alternating current therethrough and an insulator configured to cover the heating resistor, a sliding member arranged between the heater and the film and configured to be in sliding contact with an inner surface of the film, the sliding member having electric conductivity, a pressing member configured to be in pressure contact with the sliding member across the film to form a nip portion between the sliding member and the pressing member, and a conductive member electrically connected to a ground potential via at least one impedance element. The sliding member is electrically connected to the conductive member.

Abstract: A fixing unit includes a film including a tubular shape and configured to rotate, a heater arranged inside the film and including a heating resistor configured to generate heat by passing alternating current therethrough and an insulator configured to cover the heating resistor, a sliding member arranged between the heater and the film and configured to be in sliding contact with an inner surface of the film, the sliding member having electric conductivity, a pressing member configured to be in pressure contact with the sliding member across the film to form a nip portion between the sliding member and the pressing member, and a conductive member electrically connected to a ground potential via at least one impedance element. The sliding member is electrically connected to the conductive member.

Abstract: A fixing unit includes a film with a tubular shape, a nip forming unit including a heater and configured to be in sliding contact with an inner surface of the film, the heater including a substrate made of metal, an insulating layer formed on the substrate, and a heating element arranged on the insulating layer and configured to generate heat when a first AC voltage is applied from an AC power supply connected thereto, a pressing member opposed to the nip forming unit with the film interposed therebetween and configured to form a nip portion with the film, and a voltage application circuit configured to apply a second AC voltage to the substrate with a waveform that takes a voltage value of an opposite polarity to the first AC voltage when the first AC voltage takes a peak value.

Abstract: A fixing unit includes a film with a tubular shape, a nip forming unit including a heater and configured to be in sliding contact with an inner surface of the film, the heater including a substrate made of metal, an insulating layer formed on the substrate, and a heating element arranged on the insulating layer and configured to generate heat when applied first AC voltage from an AC power supply connected thereto, a pressing member opposed to the nip forming unit with the film interposed therebetween and configured to form a nip portion with the film, and a voltage application circuit configured to apply second AC voltage to the substrate with a waveform that takes a voltage value of an opposite polarity as the first AC voltage when the first AC voltage takes a peak value.

Abstract: In a case where a drive instruction signal in a high level for placing a first triac provided to correspond to a heat generation member in a conduction state is output from a CPU, the first triac is placed in a conduction state after a second triac provided to correspond to a heat generation member is prohibited from being in a conduction state. In a case where a drive instruction signal in a low level for placing the second triac in a non-conduction state is output from the CPU, the state in which the second triac is prohibited from being in the conduction state is released after the first triac is placed in the non-conduction state.

Abstract: In a case where a drive instruction signal in a high level for placing a first triac provided to correspond to a heat generation member in a conduction state is output from a CPU, the first triac is placed in a conduction state after a second triac provided to correspond to a heat generation member is prohibited from being in a conduction state. In a case where a drive instruction signal in a low level for placing the second triac in a non-conduction state is output from the CPU, the state in which the second triac is prohibited from being in the conduction state is released after the first triac is placed in the non-conduction state.

Abstract: A fixing apparatus includes a transformer, a heater, a temperature acquiring portion, and control portion. A first switching unit allows or cuts off power supply from a primary-side circuit to the heater by supplying power, and a second switching unit allows or cuts off power supply from the primary-side circuit to the temperature acquiring portion by supplying power. The power supply to the heater can be allowed or cut off according to the temperature of the heater acquired by the temperature acquiring portion. In addition, the control portion cuts off power supply from the primary-side circuit to the heater and power supply from the primary-side circuit to the temperature acquiring portion by controlling operations of the first switching unit and the second switching unit with the one signal.

Abstract: A fixing apparatus includes: first switching unit for allowing or cutting off power supply from a primary-side circuit to a heater when power is supplied; and second switching unit for allowing or cutting off power supply from the primary-side circuit to a temperature acquiring portion when power is supplied, and the power supply to the heater can be allowed or cut off according to the temperature of the heater acquired by the temperature acquiring portion. In the fixing apparatus, a control portion cuts off power supply from the primary-side circuit to the heater and power supply from the primary-side circuit to the temperature acquiring portion by controlling operations of the first switching unit and the second switching unit with one signal.

Abstract: A high voltage power supply including a first high voltage output unit that outputs a high voltage having a predetermined polarity, and including second and third high voltage output units that output a high voltage having a polarity opposite to the predetermined polarity. Rectification units that are connected to the first high voltage output unit separate a current path to the second high voltage output unit from a current path to the third high voltage output unit.

Abstract: In a color image forming apparatus, the amount of light of an exposure unit for a weak exposure is changed according to a remaining service life of a photosensitive drum when the weak exposure is performed for the background area of a corresponding photosensitive drum by using the exposure unit.

Abstract: In a color image forming apparatus, the amount of light of an exposure unit for a weak exposure is changed according to a remaining service life of a photosensitive drum when the weak exposure is performed for the background area of a corresponding photosensitive drum by using the exposure unit.

Abstract: In a color image forming apparatus, the amount of light of an exposure unit for a weak exposure is changed according to a remaining service life of a photosensitive drum when the weak exposure is performed for the background area of a corresponding photosensitive drum by using the exposure unit.

Abstract: The high voltage power supply includes a first high voltage output unit that outputs a high voltage having a predetermined polarity, and second and third high voltage output units that output a high voltage having a polarity opposite to the predetermined polarity, wherein rectification units connected to the first high voltage output unit separate a current path to the second high voltage output unit from a current path to the third high voltage output unit.

Abstract: In a color image forming apparatus, the amount of light of an exposure unit for a weak exposure is changed according to a remaining service life of a photosensitive drum when the weak exposure is performed for the background area of a corresponding photosensitive drum by using the exposure unit.

Abstract: A power supply device is disclosed that outputs a voltage of a wider range with a single piezoelectric transformer. The power supply device includes a piezoelectric transformer 101 for applying an output voltage to a transfer member that transfers a toner image formed on an image bearing member onto a recording material. The power supply device further includes a generation unit 110 configured to generate a driving frequency for driving the piezoelectric transformer 101. A control unit 701 controls a spurious voltage by changing driving frequency characteristics of the power supply device in accordance with a target value of an output voltage Vout.

Abstract: A power supply device generates an output voltage by driving a piezoelectric transformer using a frequency signal. The power supply device includes a comparison unit configured to compare an output voltage and a voltage setting signal that sets the output voltage, and a voltage control oscillation unit configured to generate the frequency signal to drive the piezoelectric transformer based on comparison results of the comparison unit. The voltage control oscillation unit generates the frequency signal within a range between the resonant frequency and a spurious resonant frequency closest to the resonant frequency.

Abstract: A power supply unit in an image forming apparatus is provided. The power supply unit includes a piezoelectric transformer, an output voltage detecting circuit which detects the output voltage of the piezoelectric transformer, an output voltage control circuit which controls an output voltage from the piezoelectric transformer, and includes a comparator which receives an output voltage setting signal, together with an output voltage detecting signal fed back from the output voltage detecting circuit, to compare the output voltage setting signal and the output voltage detecting signal. The power supply unit also includes a driving frequency supplying circuit which generates a driving frequency signal of the piezoelectric transformer in accordance with a comparison result by the comparator, and supplies the driving frequency signal to the piezoelectric transformer. The time constant of the output voltage control circuit is longer than the time constant of the output voltage detecting circuit.

Abstract: A power supply device is disclosed that outputs a voltage of a wider range with a single piezoelectric transformer. The power supply device includes a piezoelectric transformer 101 for applying an output voltage to a transfer member that transfers a toner image formed on an image bearing member onto a recording material. The power supply device further includes a generation unit 110 configured to generate a driving frequency for driving the piezoelectric transformer 101. A control unit 701 controls a spurious voltage by changing driving frequency characteristics of the power supply device in accordance with a target value of an output voltage Vout.