Abstract: A fixing device including a fixing member, an opposing member, a plurality of heat sources, and a voltage detector. The opposing member is disposed opposite the fixing member to contact the fixing member to form a nip portion at which an unfixed image on a recording medium is fixed. The plurality of heat sources heats the fixing member. The voltage detector detects an applied voltage of at least one of the plurality of heat sources. Upon detection of the applied voltage of the heat sources by the voltage detector, a voltage is applied to at least one of the heat sources.

Abstract: An image forming apparatus includes: a fixing member; a moving section that moves the fixing member in a sheet width direction; a temperature detection section disposed at a position corresponding to an end portion of the fixing member, the temperature detection section moving together with the fixing member to detect a temperature of the end portion; and a control section that performs a first movement control and a second movement control on the basis of a result of a detection by the temperature detection section, the first movement control being intended to move the fixing member in the sheet width direction in a reciprocating manner with a predetermined cycle, the second movement control being intended to move the fixing member in the sheet width direction so that the temperature of the fixing member falls within a predetermined temperature range.

Abstract: According to an embodiment, provided is a fixing device that includes: a rotatable fixing member that heats a recording medium on a side carrying an unfixed image; a rotatable pressing member that is pressed and is contacted with the fixing member to form a nip portion between the pressing member and the fixing member; a heat source heating the fixing member; a relay switch provided in an energizing path for the heat source; a temperature detection sensor detecting a temperature of the fixing member; and a control unit that controls energization of the heat source according to the temperature detected by the temperature detection sensor. The control unit keeps the relay switch in an off state if the temperature of the fixing member is equal to or more than a predetermined temperature when the fixing member has stopped rotation.

Abstract: An image forming apparatus includes: an image formation portion; a fixing portion that includes an exciting coil for inductively heating member and a temperature detection member: a main control portion that stops a printing operation when a temperature abnormality is recognized; a notification portion; a power supply portion that supplies power to the exciting coil; and a heating control portion that controls power supply to the exciting coil and detects the power abnormality. When the heating control portion detects a power abnormality, the heating control portion stops the induction heating, provides stop notice; when the main control portion determines, based on the history of the stop notice, whether the temperature abnormality is due to the stop of the induction heating or is not due to the stop of the induction heating.

Abstract: An image forming apparatus includes an image forming station for forming an unfixed image on a recording material; a fixing portion for heating and fixing an unfixed image formed on the recording material, the fixing portion including a fixing rotatable member, and a pressing roller cooperative with the fixing rotatable member to form a nip for nipping and feeding the recording material; an ambient condition sensor for detecting an ambient temperature and an ambient humidity; and a controller for controlling the fixing portion; wherein the controller sets such a warming-up time for warming up the fixing portion that a temperature of the pressing roller at the time when the recording material enters the nip is a temperature calculated on the basis of the ambient temperature and the ambient humidity.

Abstract: A fixing device for thermally fixing an unfixed image on a recording sheet, comprising: a heating rotor including a cylindrical resistance heating layer, and fixing an unfixed image on a recording sheet by thermal fusion bonding using heat generated by the resistance heating layer supplied with power; a power supply unit supplying power to the resistance heating layer; an elongated heat sensitive resistor extending along an entire length of an axis of the resistance heating layer, located to face a portion of a circumferential surface of the resistance heating layer, and exhibiting a change in resistance according to a temperature of the portion of the resistance heating layer; and an abnormal heat determination unit determining whether the temperature of the portion has reached an abnormal temperature by detecting the change in resistance of the heat sensitive resistor, the abnormal temperature possibly causing damage to the resistance heating layer.

Abstract: A fixing device according to the invention comprises a first belt in an endless form, a first heat source for heating the first belt, a first reflection member reflecting heat from the first heat source toward the first belt, and a first temperature detecting member for detecting temperature of the first reflection member by contacting the first reflection member, wherein the first reflection member is disposed between the first heat source and the first temperature detecting member. The fixing device is able to accurately detect the temperature of the member heated by the heat source.

Abstract: A fixing device for fixing an unfixed toner image on a recording sheet by passing the recording sheet through a fixing nip and applying heat and pressure to the recording sheet, the fixing device comprising: a heater including a resistance heater part and a supporting member, the resistance heater part having a positive resistance-temperature characteristic in a temperature range above a predetermined level, and the supporting member being insulative and supporting the resistance heater part such that the resistance heater part applies heat to the recording sheet; a current detector detecting a current supplied to the resistance heater part; and an abnormality determiner determining whether the resistance heater part has an abnormality, based on an initial current detected by the current detector at a predetermined time after a beginning of power supply to the resistance heater part and before the temperature of the resistance heater part reaches the predetermined level.

Abstract: A fixing device includes a rotary fixing member, a sensor, a grinder, and a controller. The rotary fixing member fixes an image on a recording medium. The sensor detects a surface state of the rotary fixing member. The grinder is disposed opposite the rotary fixing member to slide against a surface of the rotary fixing member and grind the surface of the rotary fixing member. The controller controls the grinder to contact or separate from the rotary fixing member, in accordance with a detection result of the surface state detected with the sensor in a recording medium edge passage area of the rotary fixing member over which an edge of a recording medium passes in a direction perpendicular to a feed direction of the recording medium fed with rotation of the rotary fixing member.

Abstract: A thermal fixing device includes a fixing member, a flexible endless belt, a flexible endless belt, a rotary pressure member, a heating unit, and a rotation detector. The flexible endless belt is disposed on an outer circumferential surface of the fixing member. The rotary pressure member is disposed parallel to and pressing against the fixing member via the endless belt. The heating unit heats the endless belt. The rotation detector detects a rotation speed of the endless belt. The heating unit is powered off when the rotation speed of the endless belt detected by the rotation detector is at or below a predetermined threshold value.

Abstract: A fixing device that fixes a toner image carried on a transfer sheet onto the transfer sheet includes a fixing belt that relatively moves, with its surface being in contact with the toner image during the fixing operation, with respect to the transfer sheet, surface information detecting devices that determine surface information of the fixing belt, a surface condition changing roller that is arranged so as to be capable of coming into contact with and separating from the fixing belt and abrades the surface of the fixing belt in contact with the fixing belt, and a surface condition changing controller that controls the contact and separation of the surface condition changing roller with and from the fixing belt based on detection results obtained by the surface information detecting devices.

Abstract: A fixing device includes a fixing rotator formed into a loop and rotatable in a predetermined direction of rotation and a pressure rotator disposed outside the loop formed by the fixing rotator and pressed against the fixing rotator to form a fixing nip therebetween through which a recording medium bearing a toner image is conveyed. A stay is disposed opposite the pressure rotator via the fixing rotator. A heater is disposed opposite an inner circumferential surface of the fixing rotator to heat the fixing rotator. A pressurization member is pressed against the heater via the fixing rotator. A housing is interposed between the stay and the heater. A temperature detector is mounted on the housing to detect a temperature of the heater.

Abstract: An image heating device includes a belt, a wire stretched from one widthwise end to the other widthwise end of the belt near a peripheral surface of the belt, a moving member movably fixed to one end of the wire, a biasing member, a detection unit, and a control unit. The belt heats an image on a sheet. The biasing member biases the moving member. The detection unit detects, from a biasing force of the biasing member provided when the wire is cut, that the moving member is moved. The control unit controls, according to an output of the detection unit with regard to detecting that the moving member is moved, whether or not to prohibit an image heating process.

Abstract: The image forming apparatus can be used in areas having different power supply voltages, in which a failure of the apparatus can be detected so that reliability of the apparatus is improved. The apparatus includes a connection state switching part which switches connection of a first heat generating member and a second heat generating member, which generate heat by electric power supplied from a commercial power supply through a power supply path, between a serial connection state and a parallel connection state, and a current detection part which detects current flowing in the power supply path. The current detection part is disposed in the power supply path after branching toward the first heat generating member and the second heat generating member in the parallel connection state.

Abstract: An image forming apparatus includes a fixing member, at least one reflective optical sensor, a heat shielding member, and a processor. The fixing member fixes an image on a recording medium moving in a first axis direction. At least one reflective optical sensor emits light toward the fixing member and receives light reflected by the fixing member. The heat shielding member is arranged between the fixing member and the at least one reflective optical sensor, has a light passing part through which light directed to the fixing member from the at least one reflective optical sensor and light reflected by the fixing member and directed to the at least one reflective optical sensor passes, and prevents heat transfer from the fixing member to the at least one reflective optical sensor. The processor is configured to obtain a surface state of the fixing member on the basis of an output signal from the at least one reflective optical sensor.

Abstract: A belt failure detecting mechanism includes a rocking arm connected to a ground contact portion and an urging member configured to urge one end of the rocking arm against an inner surface of an end of a heating belt. When the end of the heating belt is not broken, the end of the rocking arm is in contact with the inner surface of the end of the heating belt, and the other end of the rocking arm does not contact to a detection switch so that an electric power is supplied to a heating device. When the end of the heating belt is broken, the end of the rocking arm is displaced to an outer side of the heating belt so that the other end of the rocking arm contacts to an electric element so that a fuse is blown to stop the electric power supplied to the heating device.

Abstract: In an image-forming apparatus, a sheet detector detects the recording sheet conveyed from the sheet accommodating unit by the pickup roller. A fixing unit includes a heating member configured to heat the recording sheet. A power supply unit supplies the heating member with electric power. A control device is configured to: output a signal controlling the pickup roller to convey the recording sheet from the sheet accommodating unit; determine, based on a detection result of the sheet detector, whether the pickup roller succeeds in conveying the recording sheet from the sheet accommodating unit; control the power supply unit to supply the heating member with the electric power such that the electric power per unit time does not exceed an upper limit; and set the upper limit depending on a determination result of whether the pickup roller succeeds in conveying the recording sheet from the sheet accommodating unit.

Abstract: A fixing unit controlling apparatus that includes a switching unit of a power supplier to supply power to a fixing unit according to a power supply controlling signal to control a temperature of the fixing unit, and a switching unit of a power shutter to shut off power supplied to the fixing unit when the fixing unit controlling apparatus operates abnormally, wherein the switching units of the power supplier and the power shutter are both connected to a snubber circuit of the power shutter.

Abstract: A fixing device includes a fixing roller, a single heating member that heats the fixing roller, a pressure roller, a first temperature detecting element that detects the temperature of the contact region, of the fixing roller, that comes into contact with the recording paper transported, and a second temperature detecting element that detects the temperature of the noncontact region of the fixing roller. The fixing device carries out energization control of the heating member based on the temperature detected by the first temperature detecting element and stops energization control of the heating member when the temperature detected by the second temperature detecting element reaches a prescribed temperature.

Abstract: Image forming apparatus including: fixing device thermally fixing unfixed image on recording sheet by causing recording sheet to pass through nip formed by pressing member pressing against outer circumferential surface of heating rotating body having resistance heating layer; temperature measuring unit measuring temperatures of resistance heating layer in measurement regions set by sectioning outer circumferential surface of heating rotating body along rotational axis; information obtaining unit obtaining information indicating temperature changes in measurement regions in one rotational period of heating rotating body, by sampling measured temperatures; and abnormality judging unit judging whether abnormality has occurred in resistance heating layer based on result of comparison of information that is made between measurement regions in each combination, wherein one or more combinations of measurement regions have been set for each of paper-passing and non-paper-passing regions in nip by using all measuremen

Abstract: A status detection device includes a heater, a first power line for supplying power to one end of the heater, a second power line for supplying power to the other end of the heater, a switch portion disposed in the first power line, an overheat protection portion for disconnecting the second power line when temperature exceeds a predetermined temperature, and a zero cross signal generation portion which outputs a zero cross signal in accordance with a waveform of an AC power supply, and outputs zero cross signals having different output values in a case where voltage of the first power line is higher than voltage of the second power line and in a case where the voltage of the second power line is higher than, the first power line.

Abstract: A fixing device includes a heat rotational member that fixes a toner, a pressure rotational member that presses the heat rotational member, a magnetic-flux generation unit, a detector, and a fixing controller. The magnetic-flux generation unit includes a switch unit for switching of power supply to a resonant circuit. The resonant circuit includes a coil that generates a magnetic flux for causing the heat rotational member to generate heat by induction heating, and a capacitor. The detector detects power consumption of the magnetic-flux generation unit. The fixing controller recognizes the power consumption in response to an instruction of target power, sets a switching frequency of the switch unit in accordance with the target power, and causes the switch unit to stop the power supply if a difference between the set switching frequency and the adjusted switching frequency exceeds a predetermined change width.

Abstract: A heating control device which is capable of detecting an abnormality of an object to be heated accurately. A power-supply unit applies the electric power to the electromagnetic induction heating coil. A magnetic flux detecting unit detects a magnetic flux emitted from the electromagnetic induction heating coil across the object, and outputs a voltage corresponding to the detected magnetic flux. A changing unit changes at least one of the detected magnetic flux voltage value and an abnormality detection threshold value based on relationship between an electric power set value that defines the electric power and an input voltage inputted to the power-supply unit. A determination unit compares the detected magnetic flux voltage value changed by the changing unit to the abnormality detection threshold value, and determines an abnormality of the object when the detected magnetic flux voltage value is larger than the abnormality detection threshold value.

Abstract: A fixing device for fixing an unfixed toner image on a recording medium includes a rotatable fixing member heated by a heater to contact the recording medium bearing the unfixed toner image while rotating, with the heater disposed inside a hollow of the fixing member and turned on and off intermittently at a start of a fixing process to heat the fixing member intermittently, a first pressing member disposed opposite the fixing member to press against and rotate the fixing member to define a fixing nip through which the recording medium passes to fix the unfixed toner image with heat and pressure, and a temperature detector to detect a change in the temperature of the fixing member when the heater turns on and off intermittently. When the temperature detector detects the change in the temperature of the fixing device, the heater is turned on continuously.

Abstract: A fixing device includes a fixing belt, a pressuring rotation body, a drive transmission member, a detected member, and a rotation detecting part. The fixing belt rotates around a rotation axis. The pressuring rotation body comes into pressure contact with the fixing belt to form a fixing nip. The drive transmission member is held by one end part of the fixing belt. The detected member is held by another end part of the fixing belt. The rotation detecting part detects the rotation of the detected member. The fixing belt is configured to co-rotate with the rotation of the drive transmission member by friction force between the one end part of the fixing belt and drive transmission member. The detected member is configured to co-rotate with the rotation of the fixing belt by friction force between the other end part of the fixing belt and detected member.

Abstract: A fixing device includes a fixing belt, a pressuring rotation body, a drive source, a heat source, detected members, rotation detecting parts, a storing part and a controlling part. The storing part stores standard condition for occurrence difficulty of a slip between the fixing belt and detected members co-rotated with rotation of the fixing belt. The controlling part stops heating of the fixing belt by the heat source on a condition that both rotation detecting parts do not detect the rotation of the detected members within a first time when the drive source rotates the fixing belt in a situation unsatisfying the standard condition. The controlling part stops the heating on a condition that at least one of the rotation detecting parts does not detect the rotation of the detected members within a second time when the drive source rotates the fixing belt in a situation satisfying the standard condition.

Abstract: An image forming apparatus includes a fixing device. The fixing device includes a rotatable endless fixing member, a nip forming member arranged inside the fixing member, a pressing member in contact with the nip forming member via the fixing member, and a heating source configured to heat the fixing member. When an abnormality occurs in at least one of the fixing device and other devices included in the image forming apparatus, a rotation of the fixing member is stopped prior to stopping a rotation driving of a discharging unit and, after stopping, the fixing member is controlled to rotate.

Abstract: A fixing device for fixing a toner image on a recording medium includes a fixing roller, a pressing roller, and at least one of a sheet guide, a sheet separation plate, and an electric component module. The fixing roller rotates in a predetermined direction of rotation. The pressing roller rotates and contacts an outer circumferential surface of the fixing roller to form a nip between the pressing roller and the fixing roller through which the recording medium bearing the toner image passes to fix the toner image by heat and pressure. The position of the pressing roller is changeable relative to the fixing roller. At least one of the sheet guide, the separation plate, and the electric component module moves in conjunction with movement of the pressing roller as a single integrated unit without changing relative positions with respect to the pressing roller.

Abstract: An image heating apparatus includes a rotatable image heating member for heating an image on a recording material, a magnetic flux generator for generating magnetic flux for heating the image heating member, an adjustor for adjusting the magnetic flux distribution so that the magnetic flux acting on an end portion region of the image heating member with respect to a rotational axis direction of the image heating member is decreased, a changing portion for changing a sheet passing position of the recording material with respect to the rotational axis direction within a set range, and a switching portion for switching, when the adjustor is actuated and sheets of the recording material are continuously passed, the set range from a range in which the sheet passing position does not overlap with the end portion region to a range in which the sheet passing position overlaps the end portion region.

Abstract: A fixing device for performing a thermal fixing for fixing an unfixed image onto a recording sheet by passing the recording sheet through a fixing nip formed by a fixing rotator and a pressing member pressing the fixing rotator. The fixing device obtains a value indicating an amount of paper dust attached to the fixing rotator, and when the amount of paper dust indicated by the obtained value is equal to or larger than a permissible amount, performs a control so that a larger amount of heat is supplied to the recording sheet in the thermal fixing than when the amount of paper dust indicated by the obtained value is smaller than the permissible amount.

Abstract: A fuser device includes a first motor for rotatably driving one of a heating member and a pressure-applying member, a second motor rotating either in a forward direction or a reverse direction in order to switch a pressure-application-switching mechanism between an applied-pressure state and a released-pressure state, a first detector for detecting whether the first motor is rotating, and a second detector for detecting the forward-direction or reverse-direction rotation of the second motor. The first detector has a first sensor for detecting the rotation of the first detector plate caused to rotate by the first motor. The second detector has a second sensor for detecting changes in the rotational state of the second detector plate caused to rotate in the forward and reverse directions by the second motor. A single sensor constitutes the first sensor and the second sensor.

Abstract: An area calculating unit calculates an image area of a toner image formed on a sheet recording member. A behavior detecting unit detects behavior of the recording member fed out of a conveying nip formed by a pair of conveying members. A thickness obtaining unit obtains thickness information of the recording member. An index calculating unit calculates an index value indicating windability of the recording member with respect to the conveying members based on the image area, the behavior, and the thickness information.

Abstract: An image forming system includes a first image forming apparatus and a second image forming apparatus, the first image forming apparatus including: a first image forming section which performs image formation on a sheet; a first fixing section which performs image fixation on the sheet on which the first image forming section performs the image formation; and a first control section which makes, when the first image forming apparatus and the second image forming apparatus perform the image formation and the image fixation on different sides of a sheet to perform double-sided printing, thereby performing tandem outputting, a tandem-outputting target fixing temperature of the first fixing section lower than a first fiducial temperature which is a non-tandem-outputting target fixing temperature of the first fixing section for when the first image forming performs the image formation and the image fixation alone.

Abstract: A fixing device includes a rotary, endless fuser belt, a heater, a thermometer, and a controller. The fuser belt is subjected to heating, on which the recording medium is conveyed to fuse the toner image thereon. The heater is located adjacent to the fuser belt for heating the belt. The thermometer is located adjacent to the fuser belt to detect an operational temperature of the belt. The controller is operatively connected to the thermometer and the heater to deactivate the heater upon detecting an abnormal condition in which the operational temperature detected remains below a setpoint temperature after lapse of a warm-up time limit since activation of the heater. The controller includes a historical data recorder and a processor. The historical data recorder records historical usage data of the fixing device since installation. The processor adjusts the warm-up time limit according to the historical usage data recorded.

Abstract: A heating device capable of accurately determining a change in the state of a to-be-heated member, caused in a narrow area. An induction heating coil generates magnetic flux by flow of electric current therethrough. The fixing belt generates heat by the action of the magnetic flux generated by the induction heating coil. A first antenna is disposed at a location where the magnetic flux generated by the induction heating coil can be detected assuming that there is no fixing belt. A second antenna is disposed such that at least some area of the second antenna overlaps the first antenna. A control circuit determines whether or not a state of the fixing belt has changed, based on a result of detection by the first antenna and a result of detection by the second antenna.

Abstract: An image forming apparatus and a control method thereof in which occurrence or removal of a paper rolling state in a fusing device is judged based on temperature of the fusing device. The apparatus includes a temperature sensor to sense temperature of the fusing device, a memory to store information about occurrence or removal of the paper rolling state, and a controller to judge occurrence or removal of the paper rolling state. The controller detects an initial temperature of the fusing device when the apparatus is turned off and then on in a state in which the information about occurrence of the paper rolling state is stored in the memory, heats the fusing device by applying power thereto for a predetermined time based on the initial temperature, and judges occurrence or removal of the paper rolling state based on temperature of the fusing device detected after power application.

Abstract: An image forming apparatus includes a fixing device. The fixing device includes a rotatable endless fixing member, a nip forming member arranged inside the fixing member, a pressing member in contact with the nip forming member via the fixing member, and a heating source configured to heat the fixing member. When an abnormality occurs in at least one of the fixing device and other devices included in the image forming apparatus, a rotation of the fixing member is stopped prior to stopping a rotation driving of a discharging unit and, after stopping, the fixing member is controlled to rotate.

Abstract: Disclosed are an image forming apparatus and a fixing unit control method thereof, the image forming apparatus including an image forming unit, a fixing unit, a power supply to supply operating power to the fixing unit, a temperature sensor to sense a temperature of the fixing unit, a first protection unit to compare the sensed result of the temperature sensor with a first predetermined reference value and to output a signal, a switching unit to turn on/off power supplied to the fixing unit in accordance with the signal output from the first protection unit, a second protection unit to compare the sensed result of the temperature sensor with a second predetermined reference value and to output a signal, and a relay unit to turn on/off the operating power supplied to the fixing unit in accordance with the signal output from the second protection unit.

Abstract: A voltage detection apparatus is configured to detect a voltage value applied to a first or second current path of a heater. The voltage detection apparatus detects a first period during which the voltage value of the first or second current path exceeds a threshold voltage as well as a second period during which electric power is supplied to the first current path or the second current path to control the electric power supplied to the first and second current paths. The voltage detection apparatus uses a detection result to detect a state where over-power is supplied to the heater.

Abstract: An image forming apparatus includes a fixing roller to fix a toner on a recording medium; a heater to heat the fixing roller; an alternating current (AC) power source to generate an AC electric power such that the heater heats the fixing roller according to the AC electric power; a unit interposed between the heater and the AC power source to selectively supply the AC electric power from the AC power source to the heater so as to control the heater to heat the fixing roller; a relay including a first relay contact point disposed on a first AC power supply line between the AC power source and the unit and a relay coil to open and close the first relay contact point; the relay selectively supplying the AC electric power from AC power source to the heater and the power control switch; a direct current (DC) power supplier to supply a DC power to the relay coil; and a thermoswitch interposed on a DC power supply line between the DC power supplier and the relay coil to control the supply of the AC electric power fr

Abstract: An image heating device includes a belt, a wire stretched from one widthwise end to the other widthwise end of the belt near a peripheral surface of the belt, a moving member movably fixed to one end of the wire, a biasing member, a detection unit, and a control unit. The belt heats an image on a sheet. The biasing member biases the moving member. The detection unit detects, from a biasing force of the biasing member provided when the wire is cut, that the moving member is moved. The control unit controls, according to an output of the detection unit with regard to detecting that the moving member is moved, whether or not to prohibit an image heating process.

Abstract: An image heating device includes a belt, a light emitting portion, a light receiving portion, and a control portion. The belt heats an image on a sheet in an image heating operation. The light emitting portion emits light from one widthwise end of the belt to the other widthwise end of the belt such that the light passes near a peripheral surface of the belt. The light receiving portion receives the light from the light emitting portion. The control portion controls, according to an output of the light receiving portion, whether or not to prohibit the image heating operation.

Abstract: An area calculating unit calculates an image area of a toner image formed on a sheet recording member. A behavior detecting unit detects behavior of the recording member fed out of a conveying nip formed by a pair of conveying members. A thickness obtaining unit obtains thickness information of the recording member. An index calculating unit calculates an index value indicating windability of the recording member with respect to the conveying members based on the image area, the behavior, and the thickness information.

Abstract: A fixing device includes a fixing rotary body rotatable in a predetermined direction of rotation and a heater disposed opposite and heating the fixing rotary body. A heat shield is movable in a circumferential direction of the fixing rotary body and interposed between the heater and the fixing rotary body to shield the fixing rotary body from the heater. A driver is connected to the heat shield to drive and move the heat shield within a circumferential moving span in the circumferential direction of the fixing rotary body. An abnormal temperature detector detects an abnormal temperature of the fixing rotary body that is not lower than a predetermined temperature. The abnormal temperature detector is disposed opposite a circumferential outboard span outboard from the circumferential moving span of the heat shield in the circumferential direction of the fixing rotary body.

Abstract: According to one embodiment, a fuser includes a fixing rotating section including a heat generating section, an opposed section configured to form a nip between the opposed section and the fixing rotating section, a first bimetal type thermostat disconnected by heat from the fixing rotating section to cut power supply to a heat generation source that causes the heat generation section to generate heat, and a second bimetal type thermostat present in a position different from the position of the first bimetal type thermostat in a rotating direction of the fixing rotating section and is disconnected by heat from the fixing rotating section to output an indication that the fixing rotating section is in use.

Abstract: A fixing unit controlling apparatus that includes a switching unit of a power supplier to supply power to a fixing unit according to a power supply controlling signal to control a temperature of the fixing unit, and a switching unit of a power shutter to shut off power supplied to the fixing unit when the fixing unit controlling apparatus operates abnormally, wherein the switching units of the power supplier and the power shutter are both connected to a snubber circuit of the power shutter.

Abstract: A fixing device includes a temperature measuring unit, configured to measure the temperature in regions that extend partially along the outer surface of a heating rotating body, which includes a resistance heating layer, in the circumferential direction and are aligned in the direction of the axis of rotation of the heat rotating body, and a control unit configured to sample temperatures, measured by the temperature measuring unit in each of the regions, over the entire outer surface of the heating rotating body in the circumferential direction by causing the heating rotating body to rotate while supplying a predetermined amount of power to the resistance heating layer, and to determine whether an abnormality has occurred in the resistance heating layer based on the difference between the maximum temperature and the minimum temperature among the sampled temperatures in each region.

Abstract: An abnormality detection device for an image forming apparatus detects an abnormality in the image forming apparatus which includes a heating belt looped around a heating roller and a fixing roller. The abnormality detection device for an image forming apparatus includes: thermistors for detecting temperatures of one widthwise end portion and the other widthwise end portion of the heating belt; a temperature difference detection section for determining whether or not a temperature difference between the temperature of the one end portion and the temperature of the other end portion which are detected by the thermistors is greater than a predetermined value; and a judgment section for judging that an abnormality has occurred in the image forming apparatus when it is determined in the temperature difference detection section that the temperature difference is greater than the predetermined value.

Abstract: An image heating apparatus includes an endless belt having a heat generation layer; a driving rotatable member forming a nip; a pressing pad for pressing the endless belt toward the driving rotatable member; an electric energy supply device for supplying electric energy to the heat generation layer; and a shut-off element configured to break electric connection between the electric energy supply device and the heat generation layer when a temperature of the endless belt reaches a predetermined upper limit temperature, wherein the shut-off element is disposed contacted with the endless belt in a region, with respect to a widthwise direction of the endless belt, outside a passing region of a maximum width of the sheet usable with the apparatus and inside of a heat generating region of the heat generation layer.

Abstract: The heating apparatus includes a first detection part which detects whether or not the power supplied to the heat generation member is in an overpower state by detecting a positive phase of a half wave in an alternating voltage of a commercial power supply applied to the first or the second current path of the heat generation member, a second detection part which detects whether the power supplied to the heat generation member is in an overpower state or not by detecting a negative phase of a half wave in an alternating voltage the commercial power supply applied to the first current path or the second current path of the heat generation member, and a control part which controls itself to stop supplying power from the commercial power supply to the heat generation member in a case where an overpower state is detected by the first or second detection part.