Abstract: An image forming apparatus includes a charging device configured to uniformly charge a surface of a photoconductive element; an image writing device configured to write an image in the charged photoconductive element by light to form an electrostatic latent image; a developing device configured to visualize the formed electrostatic latent image as a toner image; a transfer device configured to transfer the toner image to a sheet recording medium; a fixing device configured to fix the transferred toner image onto the medium; and a surface information detecting device configured to detect surface information of a fixing member of the fixing device. The surface information detecting device radiates optical spots on a surface of the fixing member in a direction crossing a conveying direction, receives reflected light of each optical spot, and detects the surface information of the fixing device based on the detection results of the reflective lights.

Abstract: A thermally-actuated switch includes a movable member that is provided between a second electrode and a displacement member so as to be movable in a first direction, is pushed at one end by the displacement member in a concave state to push the second electrode at the other end to bring a second contact into contact with a first contact, and is moved in the first direction by an urging force acting on the second electrode due to convex displacement of the displacement member, and a regulating member that regulates movement of the movable member in a second direction orthogonal to the first direction from a transmittable position where a pushing force from the displacement member is capable of being transmitted to the second electrode, and releases the regulation such that the movable member moved in the first direction by the urging force is removed from the transmittable position.

Abstract: A fixing device includes a fixing member, an induction heating unit, a pressing member, and a damage detection unit. The fixing member heats a toner image on a recording medium to fix the toner image onto the recording medium. The induction heating unit heats the fixing member by electromagnetic induction. The pressing member presses the fixing member to form a fixing nip portion. The fixing member includes a heat insulating elastic layer and a sleeve layer. The sleeve layer is located outside the heat insulating elastic layer and is provided with an outer conductive layer that generates heat from a magnetic flux generated by the induction heating unit. The damage detection unit is connected to the outer, conductive layer.

Abstract: An image heating apparatus includes: a rotatable cylindrical belt; a heater, provided inside the belt, for heating the belt; and an overheating preventing element, including a circuit which is opened when abnormal temperature rise occurs, for interrupting electric power supply to the heater. The overheating preventing element is provided at a position, inside the belt, where the overheating preventing element is free from direct heat radiation emitted from said heater.

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: An image forming apparatus which is capable of reducing the number of times a second member is separated from a first member upon entry into power-save mode, thereby minimizing failures of a separation unit. A pressure-roller separating mechanism is provided so as to abut and separate a pressure roller and a fixing roller against/from each other. The image forming apparatus is controlled to change to a power-save mode in which power consumption of the image forming apparatus is reduced. The pressure-roller separating mechanism is controlled to separate the pressure roller and the fixing roller from each other in the power-save mode based on a measurement result measured by a timer, and the power-save mode is maintained after the pressure roller and the fixing roller are separated from each other.

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: 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: First, a first temperature difference and a second temperature difference are calculated. The first temperature difference is a difference between (a) a first detected temperature that is a current temperature of the fixing member and (b) a difference of a control target temperature for the fixing member. The second temperature difference is a difference between (a) the first detected temperature and (b) a past temperature of the fixing member which past temperature was detected a predetermined time earlier than the current time. Then, by reading out, from a table prepared in advance, an amount of power to be supplied to a heating member which amount corresponds to a combination of the first temperature difference and the second temperature difference, the amount of power to be supplied to the heating member is determined. In accordance with this amount of power determined, an actual amount of power supplied to the heating member is controlled.

Abstract: Methods include moving a fuser assembly with respect to a medium at a fusing nip. The fuser assembly may be moved back and forth, axially in a media cross process direction for registration distribution. The system may be configured to move the fuser assembly different distances based on a deduction of a current location of a fuser member in view of a known driving motor speed, and a time elapsed after a change in signal state. Systems may incorporate one or two sensors, and may be configured for axial movement over a distance of 2 mm or a distance of 55 mm. signature.

Abstract: An image forming apparatus having an image forming unit and a fixing unit. The image forming unit may form an image on a sheet based on image data by using a recording agent. The fixing unit may fix the recording agent on the sheet. The image forming apparatus may include a control unit to receive the image data and transmit the received image data to the image forming unit and a determination unit to determine a type of an interface via which the image data has been received. The control unit additionally determines whether to start raising a temperature of the fixing unit before the image data becomes ready to be transmitted to the image forming unit based on the type of the interface determined by the determination unit.

Abstract: An image forming apparatus including a fixing device using an induction heating method determines a driving frequency for a switching element configured to drive an induction coil, according to a difference between a detected temperature of an electrically conductive heating element provided in the fixing device and a target temperature. When the determined frequency is a predetermined minimum frequency and a current flowing through the induction coil is at a predetermined value or less, the image forming apparatus generates a signal indicating the abnormality of electric power supplied to the induction coil.

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: The present invention provides a fixing apparatus including: a pair of rotating bodies that transports a recording medium on which an image is formed by using an image forming material, by sandwiching the recording medium; a heating section that heats at least one of the pair of rotating bodies; a moving section that moves the pair of rotating bodies between a position at which they mutually contact and a position at which they are mutually separated; a temperature detecting section that detects a surface temperature of at least one of the pair of rotating bodies without contacting the rotating bodies; and a twine generation determining section that determines whether the recording medium has twined around either one of the pair of rotating bodies based on a rate of temperature increase after a temperature decrease of the surface temperature detected by the temperature detecting section.

Abstract: An apparatus to protect a half or full bridge circuit including a first switching unit and a second switching unit in an image forming apparatus performing induction heating, the apparatus including a switching control unit to control operations of the first switching unit and the second switching unit by generating and outputting a first driving signal to turn on or off the first switching unit and a second driving signal to turn on or off the second switching unit; and an arm-short detecting unit to output a disable signal to stop operation of the switching control unit in response to the first driving signal and the second driving signal simultaneously being signals to turn on the first switching unit and the second switching unit.

Abstract: A heating device includes: an alternating current (AC) power supply line configured to supply AC current from an AC power supply; a heat generation unit configured to generate heat in accordance with the AC current; an energization regulation unit configured to regulate energization time of the AC current to the heat generation unit; a switching unit configured to switch a connection state between the AC power supply and the heat generation unit; and a high-voltage protection unit, which is connected between the AC power supply line at a rear stage of the switching unit, and which is configured to protect the energization regulation unit against an abnormal input high voltage.

Abstract: An image-forming apparatus includes a power-source part, a fixing device, a power-source switch, a memory part, a fixing motor, and a drive-transmitting part. The power-source part generates and supplies voltage. The fixing device includes a rotating heating body, a heater, and a rotating pressing body. The power-source switch turns off a power source of the image-forming apparatus. The memory part stores recorded data that the power source was turned off due to the operation of the power-source switch. When the recorded data is stored in the memory part, electric power is applied to the fixing motor so as to initiate rotation at a first torque, and when the recorded data is not stored, electric power is applied to the fixing motor so as to initiate rotation at a second torque, which is less than the first torque.

Abstract: A fixing device comprises a rotatable fixing member to apply heat to a recording medium bearing an unfixed image thereon, a heat source to heat the fixing member, and a rotatable pressing member pressing against the fixing member forming a nip therebetween. A driving source rotates and drives the fixing member and the pressing member. An overheat safety device has a relay to open and close a power supply path connected to the heat source. A temperature detector is connected to both the relay and the control unit to detect temperature of the fixing member. The overheat safety device turns off the relay and cuts off power supply to the heat source when the fixing member is overheated. The fixing member is allowed to radiate heat and cool down when the temperature detected by the temperature detector is more than a prescribed level.

Abstract: A fixing apparatus that conveys a printing medium to a fixing nip portion formed by rotating members, and fixes an image onto the printing medium by heat from heating elements. The fixing apparatus also includes a safety element, a rotation detection circuit, and a limiting circuit. The safety element is in a power supply path to supply electrical power to the heating elements and to shut off the path in response with an abnormal temperature. The rotation detection circuit detects a rotation state of the rotating members. The limiting circuit limits a drive of a second driving circuit per a rotation detection circuit output. A first driving circuit detects that the circuit drives a first heating element per a control signal, regardless of the rotating members rotation state, and the second driving circuit drives a second heating element per a control signal and the output from the rotation detection circuit.

Abstract: Disclosed are a heating unit and its malfunction determining method, an image fixing device including the heating unit, and an image forming apparatus including the image fixing device. The method comprises a temperature detection step of detecting temperature of a heating body in the heating unit; a first malfunction determination step of obtaining a temperature rise time of the heating body, and then determining whether there is malfunction in the heating unit; and a second malfunction determination step of calculating a temperature increase rate of the heating body, and then determining whether there is malfunction in the heating unit.

Abstract: A fixing device includes a fixing member, a pressure member, and a damage detecting unit. The fixing member includes a heat-insulating elastic layer, to which a conductive thin-film layer is provided. The pressure member presses against the fixing member to form a fixing nip. The damage detecting unit detects the electric resistance of the thin-film layer. The damage detecting unit detects a change in the electric resistance of the thin-film layer, thereby detecting damage to the fixing member. Depending on the extent of the damage, the condition of conveyance of a recording medium to the fixing nip is changed.

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: An image forming apparatus according to the present invention includes: a fixing part having a heater; a control part controlling ON/OFF of power distribution to the heater; a power source part generating a voltage for driving the control part; a main switch for turning ON/OFF power supply from outside to the power source part; and an interrupt signal generation part generating a periodical interrupt signal. The control part, based on the interrupt signal, controls ON/OFF of the power distribution to the heater, turns OFF power supply to the heater upon passage of predetermined time since disappearance of the interrupt signal, and judges that an error has occurred, when the control part is still driving after passage of driving stop time from when the main switch is turned OFF to when the control part stops its driving since the disappearance of the interrupt signal.

Abstract: A disclosed image forming apparatus includes an image transferring unit configured to transfer an image to a recording medium; a fusing unit provided downstream of the image transferring unit and configured to fuse the image transferred by the image transferring unit with the recording medium; a recording medium conveying unit provided between the image transferring unit and the fusing unit and configured to convey the recording medium from the image transferring unit to the fusing unit; a conveyance failure detecting unit configured to detect a conveyance failure of the recording medium; and a recording medium evacuation unit to which the recording medium can be evacuated in the event that the conveyance failure detecting unit detects the conveyance failure. Plural recording medium evacuation units are provided and plural recording media can be evacuated to each of the recording medium evacuation units.

Abstract: An electrophotographic printer is configured such that an infrared heater is installed at a position between a plurality of electrophotographic print units installed in of the flow direction of a recording material, and a part (an inter-unit extension part) situated between print units of the recording material is irradiated with infrared light from the infrared heater to perform a partial evaporative removal of a carrier liquid of the recording material and a partial fixing of a toner.

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 fixing device thermally fixes an unfixed toner image onto a recording sheet and includes: a rotatable heating element that is endless and includes a resistive heating layer that generates heat upon application of voltage; a power source for placing voltage across the resistive heating layer; an ammeter for measuring the electric current flowing through the resistive heating layer, and a controller for determining whether the resistive heating layer has a scratch by monitoring an amount of change between a value of electric current that flows through the resistive heating in absence of a scratch and a value of electric current actually measured by the ammeter. The resistive heating layer exhibits resistivity anisotropy satisfying R1<R2, where R1 and R2 denote a volume resistivity of the resistive heating layer in a direction of voltage application and that in a direction perpendicular to the direction of voltage application, respectively.

Abstract: A fusing unit and an image forming apparatus including the same, and method are provided. The fusing unit senses an error such as local overheating in a surface heater, which uniformly emits heat throughout the surface of a belt member. The fusing unit includes a heating member with a pattern to heat a recording medium, a power supply to supply power to the heating member, a pressing member to transmit rotational force to the heating member while in contact with the heating member and to apply pressure to the recording medium, a driver to rotatably drive the pressing member, a pattern sensor to sense the pattern, and a controller to determine whether there is an error in the rotation of the heating member, based on an output from the pattern sensor.

Abstract: An image forming apparatus forming an image by fixing a developer on a recording medium with heat includes a fixing member, a pressure member, a drive unit, a heat unit, a temperature detection unit, a control unit, and a temperature record storing unit. The fixing member is rotatably supported and heats the recording medium. The pressure member presses against the fixing member. The drive unit rotationally drives the fixing member. The heat unit heats the fixing member. The temperature detection unit detects temperature of the fixing member. The control unit controls the heat unit and the drive unit. The temperature record storing unit stores a temperature record of the temperature detection unit. The control unit controls, based on the temperature record of the temperature record storing unit, a rotation drive of the drive unit in a case of non-fixing.

Abstract: A fusing device of an image forming apparatus including a fusing element in which a heat generation layer is formed and a pressurization element that forms a fusing nip by pressurizing and contacting the fusing element, the fusing device including: a power supplier for supplying a power supply voltage to the heat generation layer to heat the heat generation layer; a current signal detector for detecting a current signal corresponding to a difference between an input current of the heat generation layer and an output current of the heat generation layer; a determination unit for determining whether current leaks out of the heat generation layer by analyzing the current signal detected by the current signal detector; and a power breaker for preventing the power supply voltage, supplied from the power supplier, from being supplied to the heat generation unit, if the determination unit determines that current leaks out of the heat generation layer.

Abstract: A fixing device includes a rotary fixing member, a counter member to contact the rotary fixing member, a first heater to heat the rotary fixing member, a driving unit to rotate the rotary fixing member, a temperature detector to detect a temperature of the rotary fixing member, and a contact-and-separation unit to switch between contact and separation states of the rotary fixing member relative to the counter member. In a temperature-raising operation, the driving unit causes the rotary fixing member to rotate when the temperature detector detects that the temperature of the rotary fixing member has reached a first setting temperature. The contact-and-separation unit causes the rotary fixing member in rotation and the counter member to contact each other when the temperature detector detects that the temperature of the rotary fixing member has reached a second setting temperature that is higher than the first setting temperature.

Abstract: A fuser protection device realizing a protection circuit to protect a fuser by forcibly turning off a heater lamp when the heater lamp is overheated using a sensing signal from a non-contact thermistor to sense surface temperature of a heating roller and an image forming apparatus having the same. The fuser protection device includes a temperature sensing unit to sense a temperature of the heating roller in a non-contact fashion using two sensors provided at different positions, a differential amplifier to amplify a voltage difference between two sensor outputs from the temperature sensing unit, and a comparator to compare an output voltage from the differential amplifier with a reference voltage, wherein power supply to the heater lamp is blocked according to an output signal from the comparator.

Abstract: A fixing device of belt fixing type is provided. A heat generating member that is a heat generating source for heating a fixing belt has a heat generating layer composed of a resistance heat generating element that generates heat due to being energized. The resistance heat generating element includes a paper passing region heating section and a detecting section provided on an end portion in an axial direction of the heat generating member and electrically connected in parallel with the paper passing region heating section. Furthermore, in a vicinity of the detecting section, an overheat preventing element that suppresses energization to the resistance heat generating element when temperature of the detecting section reaches a predetermined value, is provided.

Abstract: A fixing device and an image forming apparatus having the same, and a method of operating the fixing device, the fixing device being provided with a power interruption unit to prevent overheating of the fixing device by physically separating a fuse element from a power line and/or approximating a thermostat to a fixing member of the fixing device.

Abstract: A first feature quantity computing unit that computes a first feature quantity representing an average of a plurality of driving loads recorded by a driving load of a fixing section recording unit of an image forming device that records the driving load acquired by a driving load acquiring unit that acquires the driving load, a second feature quantity computing unit that computes a second feature quantity representing a deviation of the plurality of the driving loads, and a diagnosis unit that performs failure diagnosis including estimation of a cause of a failure of the fixing section using the first feature quantity and the second feature quantity are used.

Abstract: A fixing device includes a fixing unit and a switching unit. The fixing unit includes an emitting unit that emits light and a housing that houses the emitting unit. The fixing unit fixes a toner image to a recording medium by emitting the light to a surface of the recording medium, the recording medium having the toner image formed thereon and having been transported to a predetermined fixing position that is away from the housing. The switching unit switches a state of the fixing device from a first state in which the housing and the recording medium are positioned away from each other to a second state in which the surface of the recording medium at the fixing position is sealed with the housing.

Abstract: An image forming apparatus that is capable of preventing a damage to a fusing belt or hazardous conditions due to the overheating of the fusing belt and a fusing device thereof are disclosed. The image forming apparatus has a fusing device including a fusing belt, a heat source disposed in the fusing belt, a support member to support the fusing belt, the support member having an opening through which heat emitted from the heat source passes to at least a portion of the fusing belt, and a first temperature sensor positioned to measure temperature of the fusing belt at the portion directly heated by radiant heat transmitted through the opening. A control unit of the image forming apparatus controls the heat source based on the temperature measured by the first temperature sensor.

Abstract: A fixing device including a fixing member; a heat source to heat the fixing member; a power supply to supply power to the heat source; a thermostat provided in the middle of a circuit connecting the heat source and the power supply to block power supply from the power supply to the heat source upon detection of a temperature of the fixing member equal to or greater than a predetermined temperature; a support member to contact terminals fixed to the thermostat to support the thermostat; and electrode plates provided opposite the support member with a gap therebetween to form a part of the circuit by connecting to surfaces of the terminals of the thermostat opposite surfaces thereof contacting the support member while the terminals are positioned within the gap. The electrode plates include a first guide part to guide the terminals into the gap.

Abstract: A fixing apparatus which heat-fixes a toner image transferred onto a sheet, including: a heating device configured to generate eddy currents in a conductive heating element using a magnetic core and an exciting coil to produce heat; a core moving unit configured to move the core; a current detecting unit configured to detect a current flowing through the exciting coil; and an abnormal signal output unit configured to output a signal indicating an abnormality when a difference between a first current value and a second current value is smaller than a predetermined threshold value, the first current value being detected by the current detecting unit before the core is moved by the core moving unit, the second current value being detected by the current detecting unit after the core is moved by the core moving unit.

Abstract: A paper wrinkle sign monitoring device includes: at least one timing detecting unit that is set on a transport path of a printing medium, and that detects transport timing of the printing medium; and a sign output unit that detects a sign of paper wrinkle generation in the transporting time of the printing medium based on the transport timing of the printing medium detected by the timing detecting unit, and that outputs the sign.

Abstract: A fixing apparatus capable of performing, even by a short brake, brake assist by which a sheet is stopped at a position where the sheet is visible. Upon occurrence of a wrap jam, brake control for a drive motor and brake assist control are performed. In the brake assist control, a pressing process is performed based on the number of assist operation pulses, which is set in advance. When an edge of a home position sensor signal is detected, a process for stopping the pressing process is carried out, whereby a pressing unit assumes a maximum pressing position.

Abstract: A fixing device includes a heating member that heats an unfixed toner image on a printing medium, a conveyance device that conveys the printing medium launched from the heating member after the heating member heats the unfixed toner image, and a heat temperature detection device that detects heat temperature of the heating member. An excessive temperature rise prevention device is provided to forcibly cut off power distribution to the heating member when the heat temperature reaches an abnormal level. A cooling device is provided to cool the excessive temperature rise prevention device. Further provided is a cooling device use control device that controls the cooling device to cool the excessive temperature rise prevention device when the conveyance device stops a conveyance operation.

Abstract: A fixing device includes a fixing member including a recording medium passing area inside thereof through which the recording medium passes, a first heater disposed in the fixing member to heat the fixing member, a first pressing member disposed opposite the fixing member to press against and rotate the fixing member to fix the unfixed toner image on the recording medium, a second heater disposed outside the recording medium passing area and inside the fixing member to heat the fixing member cyclically in a given cycle of heating, a temperature detector to detect a change in the temperature of the fixing member when the fixing member is cyclically heated by the second heater, and a determination unit to evaluate a condition of rotation of the fixing member based on the cycle of heating by the second heater and the cycle of change in the temperature detected by the temperature detector.

Abstract: According to one embodiment, an image forming apparatus includes an image forming section configured to form a toner image on a medium, a fixing device including a heating member configured to heat the medium and a pressurizing member configured to come into contact with the heating member via the medium and heat the medium, and a control section configured to stop, if the temperatures of the heating member and the pressurizing member deviate from a predetermined temperature range, the image forming operation, separate the heating member and the pressurizing member, and control the respective temperatures within the predetermined temperature range.

Abstract: An image forming apparatus is provided. The image forming apparatus includes a fixing unit to thermally fix an image transferred onto a sheet, a discharge unit to discharge the sheet carried from the fixing unit outside the image forming apparatus through a discharge path, a swingable member to be swung by the sheet being discharged, a swing-detectable sensor to detect swing movement of the swingable member being swung by the sheet, and a judging unit to judge as to whether the sheet is in one-sided alignment, in which the sheet is aligned to one of the widthwise sides in the discharge path based on result detected by the swing-detectable sensor.

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: 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 fixing device includes a heating roller that is internally provided with a heat source member and is rotated by a drive unit; an endless fixing belt that is entrained around the heating roller and heated thereby, and is provided with a surface layer that contacts a recording medium, and the yield stress of a material forming the surface layer is varied according to the temperature of the material; a pressure member that is provided facing the heating roller and presses the recording medium, on which a toner image has been formed, against the fixing belt; a travel direction alteration member that contacts the fixing belt and changes the direction of travel of the fixing belt by bending the fixing belt; and a drive control section that operates the drive unit and rotates the heating roller after the heating roller has been heated such that the endless fixing belt is heated by the heating roller to a predetermined temperature where the yield stress of a material forming the surface layer of the fixing belt is

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: 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.