Abstract: A fixing unit includes a rotary member that includes a conductive layer, a magnetic core inserted in an interior space of the rotary member, and an energizing coil that includes a conductor and that is wound helically around a circumference of the magnetic core. In a case where a distance between a first cross section of the conductor in a plane along the longitudinal direction and a second cross section of the conductor in the plane and adjacent to the first cross section in the longitudinal direction is L1 (mm), and a distance between the conductor and the magnetic core in a radial direction orthogonal to the helical axis is L2 (mm), following inequalities are satisfied, L1>0.1 and 0.1<L2<2.0.

Abstract: A fixing apparatus includes a rotary member including a heat-generation layer with a plurality of rings, a temperature detecting portion configured to detect a temperature of the rotary member, a conduction detecting unit configured to detect a conduction failure in an opposing ring that is one of the plurality of rings of the heat-generation layer and that opposes the temperature detecting portion, and a controller configured to control the supply of power to the magnetic field generator. The conduction detecting unit includes a first magnetic core, a second magnetic core, and a current detecting portion that includes a detection coil. A length of one of the first magnetic core and the second magnetic core around which the detection coil is wound is less than a length of another of the first magnetic core and the second magnetic core around which the detection coil is not wound.

Abstract: The power supply apparatus of a synchronous rectification systems includes a current detection unit configured to detect a current for charging a secondary-side smoothing element, and a driving unit configured to drive a rectification unit based on a detection result by the current detection unit.

Abstract: A fixing apparatus includes a rotary member including a heat-generation layer with a plurality of rings, a temperature detecting portion configured to detect a temperature of the rotary member, a conduction detecting unit configured to detect a conduction failure in an opposing ring that is one of the plurality of rings of the heat-generation layer and that opposes the temperature detecting portion, and a controller configured to control the supply of power to the magnetic field generator. The conduction detecting unit includes a first magnetic core, a second magnetic core, and a current detecting portion that includes a detection coil. A length of one of the first magnetic core and the second magnetic core around which the detection coil is wound is less than a length of another of the first magnetic core and the second magnetic core around which the detection coil is not wound.

Abstract: An image heating apparatus including a sleeve having divided heat generating layers, an exciting coil provided in an inside space of the sleeve, a magnetic core provided inside the exciting coil, a temperature detecting element opposing one of the divided heat generating layers, and a current monitoring sensor. An induced current is generated in the divided heat generating layers by passing an alternating current through the exciting coil, and the divided heat generating layers generate heat. An image on the recording material is heated by the divided heat generating layers. The current monitoring sensor is configured to monitor a current flowing through the above-described one of the divided heating generating layers.

Abstract: An image heating apparatus includes an electroconductive cylindrical member, an opposing member thereto, a nip forming member cooperating with the opposing member to form a nip configured to nip and feed a recording material, a magnetic field generating device, a converter, a temperature detector for the rotatable member, and a converter controller. The magnetic field generating device includes an excitation coil in an inside space of the rotatable member so that a helicity axis of the excitation coil is in parallel with an axial direction of the rotatable member to produce an induced current in a circumferential direction of the rotatable member. The converter applies a high frequency voltage to the coil. The controller controls the temperature of the rotatable member by controlling at least one of a pulse period, a pulse-on time, a burst period, and a burst-on time.

Abstract: The power supply apparatus of a synchronous rectification systems includes a current detection unit configured to detect a current for charging a secondary-side smoothing element, and a driving unit configured to drive a rectification unit based on a detection result by the current detection unit.

Abstract: An image heating apparatus includes a electroconductive cylindrical member; an opposing member thereto; a nip forming member cooperating with said opposing member to form a nip configured to nip and feed a recording material; a magnetic field generating device including an excitation coil in an inside space of said rotatable member so that a helicity axis of said excitation coil is in parallel with an axial direction of said rotatable member to produce an induced current in a circumferential direction of said rotatable member; a converter applying a high frequency voltage to said coil; temperature detector for said rotatable member; and a converter controller. The controller controls the temperature of said rotatable member by controlling at least one of a pulse period, a pulse-on time, a burst period, and a burst-on time.

Abstract: An image heating apparatus includes a sleeve including divided heat generating layers, an exciting coil provided in an inside space of the sleeve, a magnetic core provided inside the exciting coil, and a temperature detecting element opposing one of the divided heat generating layers. An induced current is generated in the divided heat generating layers by passing an alternating current through the exciting coil, and the divided heat generating layers generate heat. An image on the recording material is heated by the divided heat generating layers. The image heating apparatus further comprises a current monitoring sensor configured to monitor a current flowing through the above-described one of the divided heating generating layers.

Abstract: The power supply apparatus having a current resonance circuit includes a charge unit connected to a primary winding of a transformer, and storing electric charge, and a connection unit connected in series with the charge unit, and configured to switch the charge unit between a connecting state in which one of charging and discharging is enabled, and a non-connecting state, and after making the connection unit into the connecting state, while a current is flowing into either one of the first diode and the second diode, the first control unit performs transition from a halt period to an operating period of a switching operation by turning ON the switching element of the one of the first diode and the second diode, the current being flowing into the one of the first diode and the second diode.

Abstract: The power supply apparatus having a current resonance circuit includes a charge unit connected to a primary winding of a transformer, and storing electric charge, and a connection unit connected in series with the charge unit, and configured to switch the charge unit between a connecting state in which one of charging and discharging is enabled, and a non-connecting state, and after making the connection unit into the connecting state, while a current is flowing into either one of the first diode and the second diode, the first control unit performs transition from a halt period to an operating period of a switching operation by turning ON the switching element of the one of the first diode and the second diode, the current being flowing into the one of the first diode and the second diode.

Abstract: A cylindrical fixing member for use with a fixing device includes a heat generating layer and an electrode layer contacting the heat generating layer. The electrode layer is smaller in volume resistance value than the heat generating layer. The electrode layer is formed in a helical shape so that a helical axis thereof extends in a direction along a generatrix direction of the fixing member. One end and the other end of the electrode layer are electrically open.

Abstract: The power supply apparatus includes a detecting unit that has a first detecting device, a second detecting device and a third detecting device, detects a current flowing into the primary winding, and outputs a voltage corresponding to the current, and a control unit that controls a switching operation of the switching element, an output voltage which the detecting unit outputs to the control unit includes a first output voltage at which the control unit stops an operation of the switching element at a time of the second state, a second output voltage at which the control unit stops the operation of the switching element at a time of the first state, a third output voltage at which the second detecting device is brought into a conducting state, and a fourth output voltage at which the third detecting device is brought into a conducting state.

Abstract: A cylindrical fixing member for use with a fixing device includes a heat generating layer and an electrode layer contacting the heat generating layer. The electrode layer is smaller in volume resistance value than the heat generating layer. The electrode layer is formed in a helical shape so that a helical axis thereof extends in a direction along a generatrix direction of the fixing member. One end and the other end of the electrode layer are electrically open.

Abstract: The power supply apparatus includes a detecting unit that has a first detecting device, a second detecting device and a third detecting device, detects a current flowing into the primary winding, and outputs a voltage corresponding to the current, and a control unit that controls a switching operation of the switching element, an output voltage which the detecting unit outputs to the control unit includes a first output voltage at which the control unit stops an operation of the switching element at a time of the second state, a second output voltage at which the control unit stops the operation of the switching element at a time of the first state, a third output voltage at which the second detecting device is brought into a conducting state, and a fourth output voltage at which the third detecting device is brought into a conducting state.

Abstract: Disclosed is a cylindrical rotary member including a conductive layer; a coil disposed inside the rotary member, the coil including a helical portion having a helical axis that is substantially parallel to a generatrix direction of the rotary member, the coil forming an alternating magnetic field to generate heat in the conductive layer by electromagnetic induction; a core disposed inside the helical portion, the core inducing a line of magnetic force of the alternating magnetic field; a roller coming in contact with an outer surface of the rotary member to form a fixing nip portion; and a metal stay disposed inside the rotary member, in which an image on a recording material is fixed to the recording material by being heated at the fixing nip portion and the stay is disposed outside the coil and has a shape that does not form an electrical loop around the coil.

Abstract: An image heating apparatus configured to heat an image formed on a recording material includes a cylindrical rotatable member including a conductive layer, a magnetic core inserted through the rotatable member, a coil helically wound around an outer side of the magnetic core within the rotatable member, and an inverter configured to supply an alternating current to the coil. A frequency of the alternating current supplied from the inverter is within a range of 20.5 to 100 kHz. The conductive layer generates heat by electromagnetic induction due to an alternating magnetic field produced from the alternating current supplied to the coil. The coil is wound at an interval of 1 mm or longer.

Abstract: A fixing device configured to fix an image on a recording material, includes: a rotary member including an electroconductive layer; a coil which has a spiral shaped portion and is disposed in the inside of the rotary member; and a core disposed in the spiral shaped portion; with magnetic resistance of the core being, with an area from one end to the other end of the maximum passage region of the image on the recording material regarding the generatrix direction, equal to or smaller than 30% of combined magnetic resistance made up of magnetic resistance of the electroconductive layer and magnetic resistance of a region between the electroconductive layer and the core.

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: An image heating apparatus configured to heat an image formed on a recording material includes a cylindrical rotatable member including a conductive layer, a magnetic core inserted through the rotatable member, a coil helically wound around an outer side of the magnetic core within the rotatable member, and an inverter configured to supply an alternating current to the coil. A frequency of the alternating current supplied from the inverter is within a range of 20.5 to 100 kHz. The conductive layer generates heat by electromagnetic induction due to an alternating magnetic field produced from the alternating current supplied to the coil. The coil is wound at an interval of 1 mm or longer.