Abstract: A control circuit executes voltage adjustment processing of adjusting a voltage output from a transfer power source so that a current detected by a detection circuit becomes a predetermined current value. The voltage adjustment processing is executed before a toner image is transferred from at least one of a first image bearing member and a second image bearing member to an intermediate transfer belt. A processor determines whether the second transfer member is in a state of contact or is in a state of separation on the basis of behavior of the current detected by the detection circuit in a period in which the control circuit is executing the voltage adjustment processing.

Abstract: A control circuit executes voltage adjustment processing of adjusting a voltage output from a transfer power source so that ae current detected by a detection circuit becomes a predetermined current value. The voltage adjustment processing is executed before a toner image is transferred from at least one of a first image bearing member and a second image bearing member to an intermediate transfer belt. A processor determines whether the second transfer member is in a state of contact or is in a state of separation on the basis of behavior of the current detected by the detection circuit in a period in which the control circuit is executing the voltage adjustment processing.

Abstract: An image forming apparatus includes a voltage adjustment portion having a voltage adjustment member connected to a contact member contacting an endless belt, the voltage adjustment portion changing a current flowing from a current supply member contacting the belt at a position different from a position, at which an image bearing member contacts the belt with respect to a rotating direction of the belt, to the voltage adjustment member via the belt according to a control signal input from a control portion outputting a control signal, thereby changing a size of a transfer potential to transfer a toner image borne by the image bearing member onto the belt at a part at which the belt contacts the image bearing member.

Abstract: Provided is a fixing apparatus for fixing a toner image on a recording material while conveying the recording material on which the toner image has been formed at a nip portion that includes a roller, a heating unit configured to heat the roller from outside the roller, the heating unit receiving power supplied from a power supply, a backup unit forming the nip portion with the roller, and a power shutdown member configured to operate in response to an abnormal temperature of the backup unit and shut down power supply to the heating unit.

Abstract: An image forming apparatus includes a voltage adjustment portion having a voltage adjustment member connected to a contact member contacting an endless belt, the voltage adjustment portion changing a current flowing from a current supply member contacting the belt at a position different from a position, at which an image bearing member contacts the belt in a rotating direction of the belt, to the voltage adjustment member via the belt according to a control signal input from a control portion outputting a control signal, thereby changing a size of a transfer potential—a surface potential—to transfer a toner image borne by the image bearing member onto the belt at a part at which the belt contacts the image bearing member.

Abstract: Provided is a fixing apparatus for fixing a toner image on a recording material while conveying the recording material on which the toner image has been formed at a nip portion that includes a roller, a heating unit configured to heat the roller from outside the roller, the heating unit receiving power supplied from a power supply, a backup unit forming the nip portion with the roller, and a power shutdown member configured to operate in response to an abnormal temperature of the backup unit and shut down power supply to the heating unit.

Abstract: Provided is a fixing apparatus for fixing a toner image on a recording material while conveying the recording material on which the toner image has been formed at a nip portion that includes a roller, a heating unit configured to heat the roller from outside the roller, the heating unit receiving power supplied from a power supply, a backup unit forming the nip portion with the roller, and a power shutdown member configured to operate in response to an abnormal temperature of the backup unit and shut down power supply to the heating unit.

Abstract: The power supply apparatus for obtaining a direct current from an alternating voltage source includes a first DC/DC converter for outputting a first direct current and a second DC/DC converter for a second direct current lower than the first direct current from the first DC/DC converter, and the output voltage of the first DC/DC converter is changed to a lower direct current and the second DC/DC converter is driven in a continuously-conducting state.

Abstract: Provided is a fixing apparatus for fixing a toner image on a recording material while conveying the recording material on which the toner image has been formed at a nip portion that includes a roller, a heating unit configured to heat the roller from outside the roller, the heating unit receiving power supplied from a power supply, a backup unit forming the nip portion with the roller, and a power shutdown member configured to operate in response to an abnormal temperature of the backup unit and shut down power supply to the heating unit.

Abstract: A switching power supply includes a transformer, a switching unit configured to switch a voltage input to the primary side of the transformer, a control unit configured to control the operation of the switching unit, and a detection unit configured to detect as a voltage a current flowing through the primary side of the transformer and supply the voltage to the control unit, wherein the detection unit controls the voltage to be supplied to the control unit based on the operating state of the switching unit.

Abstract: A current resonance power supply includes a current detecting unit detecting a current flowing through a primary side of a transformer and a current compensating unit compensating the current detected by the current detecting unit in accordance with a variation in voltage input into the primary side of the transformer. The current resonance power supply detects overcurrent on the basis of an output from the current compensating unit.

Abstract: A power supply apparatus determines that an input AC voltage has reached a voltage at which a power supply control IC can start operating, based on the voltage at an auxiliary winding of a transformer included in a first converter. Note that since the first converter operates so as to maintain a constant voltage at the auxiliary winding, whether the input AC voltage has fallen to an operation lower limit voltage or lower cannot be detected by only monitoring the voltage at the auxiliary winding. The power supply apparatus monitors a second voltage that is proportional to the input AC voltage is generated from the voltage being applied to the primary side of a second converter. Accordingly, the power supply control IC starts and stops operating in accordance with the input AC voltage.

Abstract: A current resonance power supply includes a transformer having a primary winding and a secondary winding, two switching elements connected to one end of the primary winding of the transformer and arranged in series, a resonance capacitor connected to the other end of the primary winding, and a voltage detection unit connected between the one end of the primary winding and the two switching elements and configured to detect that AC voltage input to a primary side of the transformer becomes lower, wherein operations of the switching elements are controlled based on a detection result of the voltage detection unit.

Abstract: The power supply apparatus for obtaining a direct current from an alternating voltage source includes a first DC/DC converter for outputting a first direct current and a second DC/DC converter for a second direct current lower than the first direct current from the first DC/DC converter, and the output voltage of the first DC/DC converter is changed to a lower direct current and the second DC/DC converter is driven in a continuously-conducting state.

Abstract: The power supply apparatus for obtaining a direct current from an alternating voltage source includes a first DC/DC converter for outputting a first direct current and a second DC/DC converter for a second direct current lower than the first direct current from the first DC/DC converter, and the output voltage of the first DC/DC converter is changed to a lower direct current and the second DC/DC converter is driven in a continuously-conducting state.

Abstract: A switching power supply includes a transformer, a switching unit configured to switch a voltage input to the primary side of the transformer, a control unit configured to control the operation of the switching unit, and a detection unit configured to detect as a voltage a current flowing through the primary side of the transformer and supply the voltage to the control unit, wherein the detection unit controls the voltage to be supplied to the control unit based on the operating state of the switching unit.

Abstract: The DC power supply apparatus includes a switching operation control part that is provided between a current detection part to detect a current flowing through a primary coil of a transformer and a control part to control the operation of a switching part and controls the operation of the switching part according to an output voltage so that consumption power in a low-load state can be further reduced.

Abstract: The transformer includes: first and second cores each including a magnetic center leg and a magnetic outer leg positioned outside of the magnetic center leg; a first adhesion part that adheres the magnetic center leg of the first core and the magnetic center leg of the second core to each other; a second adhesion part that adheres the magnetic outer leg of the first core and the magnetic outer leg of the second core to each other; a bobbin inserted through the magnetic center leg of the first core and the magnetic center leg of the second core, a primary coil and a secondary coil being wound on the bobbin; and an elastic member that applies pressure to the magnetic outer leg of the first core and the magnetic outer leg of the second core in a neighborhood of the second adhesion part, in an inward direction of the transformer.

Abstract: A current resonance power supply includes a transformer having a primary winding and a secondary winding, two switching elements connected to one end of the primary winding of the transformer and arranged in series, a resonance capacitor connected to the other end of the primary winding, and a voltage detection unit connected between the one end of the primary winding and the two switching elements and configured to detect that AC voltage input to a primary side of the transformer becomes lower, wherein operations of the switching elements are controlled based on a detection result of the voltage detection unit.

Abstract: A current resonance power supply includes a current detecting unit detecting a current flowing through a primary side of a transformer and a current compensating unit compensating the current detected by the current detecting unit in accordance with a variation in voltage input into the primary side of the transformer. The current resonance power supply detects overcurrent on the basis of an output from the current compensating unit.