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.

Abstract: A boosting circuit includes a switch element, a first coil, a second coil, and a capacitor. The switch element generates a first alternating current voltage having a first frequency from a direct current voltage. The first coil generates a magnetic field around the first coil with a flow of the first alternating current voltage having the first frequency in the first coil. The first coil also induces an eddy current in the object with the magnetic field to inductively heat the object. The second coil is cumulatively connected to the first coil. The capacitor is connected to the first coil and the second coil in a parallel manner.

Abstract: A fixing device includes a substantially cylindrical metal member, a heater, an endless, flexible fixing member, a rotary pressing member, a stationary member, a first temperature detector, and a second temperature detector. The first temperature detector is disposed upstream from a nip in a rotation direction of the fixing member to detect a surface temperature of the fixing member. The second temperature detector is disposed downstream from the nip in a rotation direction of the pressing member to detect a surface temperature of the pressing member. When a difference between a surface temperature of the fixing member detected by the first temperature detector and a surface temperature of the pressing member detected by the second temperature detector after a predetermined time has elapsed since the first temperature detector detects the surface temperature of the fixing member is greater than a predetermined threshold, the heater stops heating the metal member.

Abstract: A fixing device includes a protected object disposed opposite an outer circumferential surface of a pressing rotary body and upstream from a fixing nip formed between the pressing rotary body and a fixing rotary body in a direction of rotation of the pressing rotary body; a stationary duct disposed upstream from the protected object in the direction of rotation of the pressing rotary body, the stationary duct including a blowoff outlet disposed opposite the outer circumferential surface of the pressing rotary body through which airflow impinges on the outer circumferential surface of the pressing rotary body; and a shield interposed between the blowoff outlet of the stationary duct and the protected object in the direction of rotation of the pressing rotary body to protect the protected object against airflow from the blowoff outlet.

Abstract: An image forming apparatus includes a reading unit, a receiving unit, an image forming unit, a fixing unit, and a control unit. The reading unit generates generated image data indicating the image. The receiving unit receives external image data. The image forming unit forms, by using a recording agent, an image on a sheet based on the generated or external image data. The fixing unit fixes the recording agent on the sheet. The control unit controls to start raising a temperature of the fixing unit at a first timing, where a copy process is executed. The control unit controls to start raising the temperature of the fixing unit at a second timing, which is later than the first timing, where a printing process is executed.

Abstract: An image forming apparatus comprises: a sensor that includes a light-emitting part for emitting light to a moving body and a light-receiving part; a light-incidence adjusting mechanism that is able to alternatively select from a first state where the light-incidence adjusting mechanism causes light which have been emitted from the sensor and then reflected by the moving body to enter the sensor and a second state where the light-incidence adjusting mechanism causes a reflected light of light emitted from the sensor not to enter the sensor; and a processing unit that causes the sensor to emit light, and corrects output of the sensor when the light-incidence adjusting mechanism is in the first state on the basis of output of the sensor when the light-incidence adjusting mechanism is in the second state.

Abstract: An image forming device including: an image forming unit; a heating body; a power supply unit; a temperature sensing member; and a controller. The image forming unit is configured to form an image on a recording sheet. The heating body is configured to heat the recording sheet on which the image is formed. The power supply unit is configured to supply power to the heating body. The temperature sensing member is configured to detect a temperature of the heating body. The controller is configured to: control the power supply unit based on the detected temperature; determine whether or not a high-power output state of the power supply unit has continued for a first duration under a print control process; and judge that the temperature sensing member is in an abnormal state when determination is made so that the high-power output state has continued for the first duration.

Abstract: A fixing device includes a fixing unit with a nip, two rollers, a guide member, a detection unit and an urging unit. The detection unit is disposed substantially parallel to the guide member opposite to the guide member across a recording medium conveyed between the nip and the two rollers. The detection unit detects jamming of the recording medium on the basis of a pressure greater than a predetermined value applied by the recording medium between the nip and the two rollers. The distance between the guide member and the detection unit is greater than the distance between the guide member and the recording medium passing between the nip and the two rollers while being urged by the urging unit.

Abstract: An image forming apparatus includes a fixing unit, a power supply switch, a timer unit, a backup memory, and a controller. The backup memory is configured to nonvolatilely store an accumulated time, the accumulated time being a total period of time during which a heater is energized for detection of disconnection of a temperature-detecting unit after the power supply switch is turned on. The controller is configured to: recognize temperature of a heated member based on an output from the temperature-detecting unit, control the energization of the heater, and start the energization of the heater when the power supply switch is turned on. The controller is configured to determine that a disconnection of the temperature-detecting unit has occurred if the temperature recognized based on the output from the temperature-detecting unit remains in a predetermined low-temperature zone when the accumulated time has become a predetermined detecting-execution time period.

Abstract: An apparatus is capable of switching between a mode in which a first resistance heating element and a second resistance heating element are connected in series and a mode in which they are connected in parallel. When a temperature increase rate detected by a temperature detection unit is smaller than a threshold rate although a current detected by a current detection unit is greater than a threshold current, a notification of a failure is issued.

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: 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 according to the present disclosure includes: a printing unit configured to perform printing on a recording medium; a multiple-sheet-feed detecting unit configured to detect a multiple sheet feed of the recording medium; an image holding unit configured to hold an image expected to print on the recording medium on which the multiple sheet feed is detected (i.e. the multi-fed medium); and a print control unit configured to control the printing unit. The print control unit is further configured (a) to cancel printing on the multi-fed medium, and (b) to cause the printing unit to print the held image on another recording medium, which (b1) is in transfer after the multi-fed medium, (b2) is nearest in a transferring order to the multi-fed medium, and (b3) has a property same as that of the multi-fed medium.

Abstract: An apparatus, system, and method of predicting failure of a fixing device of an image forming apparatus are provided. Based on a plurality of sheet transfer time values of the fixing device, a first characteristic value that is an average value of the plurality of sheet transfer time values, and at least one of a second characteristics value that indicates the variance of the plurality of sheet transfer time values and a third characteristics value that indicates the maximum value of the plurality of sheet transfer time values are calculated. Using a determination result generated based on the first characteristics value and the at least one of the second and third characteristics values, failure of the fixing device is predicted.

Abstract: An image forming device includes a plurality of power consumption parts that operate by power supply from a power source. The image forming device includes a failure detection part that detects occurrence of an unrecoverable failure, and a main controller that suppresses an amount of power supplied to the plurality of power consumption parts in response to detection by the failure detection part of the occurrence of an unrecoverable failure.

Abstract: There is disclosed an image forming apparatus where at suitable positions in a power supply path of a first heat generating member and a second heat generating member which can be switched to a series connection condition and a parallel connection condition, there are arranged a current detection section including a circuit which detects a current subjected to rectification of a positive half wave and a circuit which detects a current subjected to rectification of a negative half wave, and an applied voltage detection section including a circuit which detects a voltage subjected to full-wave rectification. Consequently, in the image forming apparatus which can be used in districts using different power supply voltages, failure of the apparatus can be detected, and reliability of the apparatus can be enhanced.

Abstract: A fixing device in an image forming apparatus includes a conveyance member to convey a recording medium at a fixing nip where an image carried on the recording medium is fixed onto it; a plurality of temperature detectors to detect temperature of the conveyance member, the detectors being disposed at both end portions of the conveyance member outside an area where a maximum-sided recording medium passes through; a guide member to guide the recording medium toward the fixing nip; and a guide plate displacing unit to displace a part of the guide member in a direction orthogonal to a conveyed surface of the recording medium to be conveyed at the fixing nip, based on temperature difference detected by the plurality of temperature detectors.

Abstract: An image heating apparatus, including: a rotary member; a heating member configured to heat the rotary member, the heating member being held in contact with the rotary member; a temperature detecting element configured to detect temperature of the rotary member or the heating member; a protection element configured to interrupt power supply to the heating member, the protection element being activated when sensing abnormal rise in temperature of the heating member; and a control portion configured to control the image heating apparatus, wherein, when the temperature detected by the temperature detecting element exceeds a threshold value, the control portion stops rotation of the rotary member.

Abstract: A magnetic core includes a plurality of first core portions arranged to surround a coil in a direction perpendicular to a conveying direction of a recording medium, and a second core portions disposed closer to a heating member than the first core portion on both end portions in the direction perpendicular to the conveying direction of the recording medium in a hollow portion formed by a coil loop. The second core portion has thermal capacity smaller than that of the first core portion. Curie temperature of the second core portion is a temperature of the second core portion or higher when the heating member becomes a fixable temperature and is a cooling set temperature of the coil or lower.

Abstract: An image heating apparatus includes: a rotatable heating member; a driving mechanism; a rotatable pressing member; a first contact-and-separation mechanism; a rotatable externally-heating member; a second contact-and-separation mechanism; a detecting portion configured to detect information corresponding to a drive load exerted on the driving mechanism; and a controller configured to actuate, when the information is detected by the detecting portion, the driving mechanism for a predetermined time in a state in which the rotatable externally-heating member is press-contacted to the rotatable heating member and in which the rotatable pressing member is spaced from the rotatable heating member. The controller controls, depending on an output of the detecting portion, whether or not image heating is prohibited.

Abstract: An apparatus and method of protecting a fuser unit and an image forming apparatus having the same include a fuser drive motor portion to drive the fuser unit, a power detecting portion to detect power that is supplied to the fuser unit, and a power cutoff portion to cut off the power supplied to the fuser unit when a motor rotation signal is not output from the fuse drive motor portion and the power detecting portion detects the power that is supplied to the fuser unit. The fuser unit protecting apparatus and method and the image forming apparatus including the fuser unit protecting apparatus are configured to detect rotation of a fuser drive motor and supply of an alternating current required for a temperature rise and cut off the power supply when abnormal conditions occur, to prevent a continuous rise in a temperature of the fuser unit as well as deformation thereof.

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: The present invention provides a low-cost and safe image forming apparatus that has a first state in which first and second resistance heating bodies of a heater are connected in series, a second state in which the first and second resistance heating bodies are connected in parallel, and a third state in which a first switching unit shuts off a power supply path and a second switching unit is connected to a first power source terminal to block power supply to the heater.

Abstract: A fixing device includes a fixing rotation body heating and fixing an unfixed image onto a recording medium; a pressing rotation body pressing the recording medium to the fixing rotation body; and a temperature detection unit detecting a temperature of the pressing rotation body. Further, when a predetermined time period elapses since a warm-up operation has started before a temperature detected by the temperature detection unit is equal to or greater than a predetermined temperature or when the temperature detected by the temperature detection unit is equal to or greater than the predetermined temperature before the predetermined time period elapses since a warm-up operation has started, the fixing device determines that the warm-up operation is finished.

Abstract: The invention provides an image forming apparatus, having: an apparatus main body; a fixing unit fixing an image onto a recording material at a fixing nip portion, the fixing unit including a pressure-applying portion applying a pressure to the fixing nip portion and a pressure-releasing portion releasing the pressure; an opening/closing member disposed in the apparatus main body; an engaging portion engaging with the pressure-releasing portion of the fixing unit in a state of being mounted to the apparatus main body for moving the pressure-releasing portion, the engaging portion moving in conjunction with an opening/closing action of the opening/closing member; and a phase adjusting portion adjusting a phase of the pressure-releasing portion to a phase of the engaging portion when the opening/closing member is opened, in conjunction with a mounting action of the fixing unit to the apparatus main body.

Abstract: An infrared temperature sensor including: a sensor case made of metal and including a first airspace (a light guiding region) that guides infrared rays entering from an infrared entrance window, and a second airspace (a light shielding region) that is adjacent to the light guiding region via a partition wall, and where an upper wall that blocks entrance of the infrared rays is formed on an entrance side of the infrared rays; a film that absorbs the infrared rays reaching the film through the light guiding region, and converts the infrared rays to heat; a sensor cover that is made of metal and arranged opposing the sensor case via the film; an infrared detection element and a temperature compensation element arranged on the film, wherein the light guiding region and the light shielding region have substantially symmetrical forms with respect to the partition wall.

Abstract: A reception unit sequentially receives input of voltage values indicating an AC input voltage from an AC power supply. A ROM stores a power control table in which a power control parameter corresponding to the AC power supply voltage is matched with each group of the voltage values indicating the same AC power supply voltage. A decision unit determines to which group the received voltage values belong among the plurality of groups, whenever the reception unit receives the input of the voltage value and decides the group, to which a predetermined number of voltage values belongs among the plurality of voltage values sequentially received by the reception unit, among the plurality of groups using the determination result. A power control unit controls power supply according to the power control parameter matched with the decided group.

Abstract: An image forming apparatus includes a heating element that generates heat, a temperature detector that detects a temperature of the heating element, a resistor that divides a detection result of the temperature detector and a predetermined reference voltage, a disconnection detector that detects a disconnection of the temperature detector, a converter that converts the divided voltage value into a digital signal and outputs the digital signal to a controller, a comparing unit that inverts its output on the basis of a predetermined threshold, a delay circuit that delays an increase in an output voltage of the comparing unit, a discharge circuit that quickly discharges the output voltage of the comparing unit, a latch circuit connected to an output of the discharge circuit, and a power supply path connecting and disconnecting unit that is connected to the latch circuit and connects and disconnects a power supply path to the heating element.

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 toner fixing system for fixing toner onto a receiver medium includes rotatable fixing drum partially filled by a heating liquid, so that a stationary-drum liquid level is defined. The heating liquid is warmed above a toner glass transition temperature. The fixing drum rotates fast enough to draw the heating liquid to substantially cover an inner surface thereof. The moving receiver medium contacts an outer surface of the fixing drum in a contact region above the stationary-drum liquid level. Heat is transferred through the rotating fixing drum from the drawn warmed heating liquid to heat the toner above its glass transition temperature. A sensor detects stoppage of the receiver medium in contact with the fixing drum. A controller automatically stops the rotation of the fixing drum when a stoppage is detected, so that the heating liquid is pulled by gravity away from the stopped receiver medium.

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: 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 failure predictor for predicting failure of a fixing device including a first characteristics value extractor to extract a first characteristics value representing a time interval between each implementation of repair of a surface of one of a pair of rotary bodies, a second characteristics value extractor to extract a second characteristics value representing a change in a degree of glossiness on the surface of one of the pair of rotary bodies during a period of time between before and after repair of the surface of one of the pair of rotary bodies, a third characteristics value extractor to extract a third characteristics value representing a change in a current value of a drive motor, and a determination device to predict failure of the fixing device caused by the condition of the surface of one of the pair of rotary bodies using the extracted first, second, and third characteristics values.

Abstract: A method for determining abnormality of a temperature sensor and the image forming apparatus, the method comprises: detecting an actual temperature of a fixing apparatus and an input voltage; calculating an actual temperature variation amount in a predetermined time period; comparing the detected input voltage and a predetermined voltage; comparing the calculated actual temperature variation amount and a first reference temperature variation amount if the input voltage is greater than the predetermined voltage; determining that the temperature sensor is abnormal if the actual temperature variation amount is less than the first reference temperature variation amount; comparing the calculated actual temperature variation amount and a smaller second reference temperature variation amount if the input voltage is equal to or less than the predetermined voltage; determining that the temperature sensor is abnormal if the actual temperature variation amount is less than the second reference temperature variation amou

Abstract: There is provided an image forming apparatus including: a forming section that, based on image forming data including image data of an image to be formed on paper and paper data relating to the paper, forms a toner image according to the image data on paper; a fixing section that fixes the toner image formed on the paper; a switching section that on operation switches a fixing pressure of the fixing section; a control section that, when the fixing pressure is switched by the switching section from a first fixing pressure to a second fixing pressure prior to a predetermined condition being satisfied after the fixing pressure has been switched to the first fixing pressure by the switching section, controls to prohibit image forming on paper corresponding to the second fixing pressure different from the first fixing pressure.

Abstract: An optical fixing apparatus includes a transport unit that transports a recording medium in a first direction in a first fixing process and a second fixing process subsequent thereto and transports the recording medium in a second direction after the first fixing process and before the second fixing process; a light irradiating unit that irradiates the recording medium with light having a predetermined intensity while the recording medium is transported in the first and second fixing processes; a controller that performs a control so that the intensity of the light is lower than the predetermined intensity in a first period before the end of the first fixing process and a second period after the start of the second fixing process, and so that an area of the recording medium irradiated in the first period and an area of the recording medium irradiated in the second period overlap.

Abstract: An image forming apparatus including: an image forming unit which forms an image; a fixing unit which fixes the image transferred to a printing medium; a power supply which supplies operation power to the fixing unit; a contactless sensor sensing a temperature of the fixing unit and respectively outputting a sensor-sensing voltage and a sensor-compensating voltage; and a contactless-sensing protector which shuts off the power if the sensor-sensing voltage is higher than the sensor-compensating voltage. The fixing unit can be protected from overheating and control error through the contactless-sensing protector for sensing the fixing temperature and shutting off the power.

Abstract: The present invention provides a fixing device that can interrupt power supply to the resistive heat layer more reliably than the conventional technology, for example, at occurrence of abnormality. Electrodes 52a and 52b are provided on a circumferential surface of a fixing roller that includes a resistive heat layer that generates heat by receiving power supply, and power is supplied to the resistive heat layer when power supplying electrodes 54a and 54b that are electrically connected to an electric power source 55 are slidingly in contact with the electrodes 52a and 52b. An insulating tape 522a is attached on the electrode 52a, and the drive controller 59 rotates a motor 58 until the electrode 52a and the insulating tape 522a are in contact with each other, so that power supply to the resistive heat layer is interrupted.

Abstract: An image forming apparatus includes a heat source, a thermal fixing member, a temperature sensing unit, a temperature change determining unit and a halting unit. The heat source generates heat. The thermal fixing member is heated by the heat source and performs a thermal fixing operation by thermally fixing a toner image deposited on a sheet of paper. The temperature sensing unit senses a temperature of the thermal fixing member and outputs temperature data. The temperature change determining unit determines that the temperature of the thermal fixing member decreases based on two pieces of temperature data sensed by the temperature sensing unit at two different timings. The halting unit halts the thermal fixing operation when determination made by the temperature change determining unit is consecutively made for a predetermined number of times.

Abstract: A fuser unit includes: a cylindrical member; a heat generator; a nip member; a backup member, which configures a nip part between the cylindrical member and the backup member with the cylindrical member; a conductive member, which is arranged to cover the heat generator at the inside of the cylindrical member; a temperature detection unit; a wiring; a first frame having insulation, which is arranged at an opposite side to the heat generator with respect to the conductive member being interposed therebetween at the inside of the cylindrical member, and which extends along the conductive member; and a second frame, which is arranged at an opposite side to the conductive member with respect to the first frame being interposed therebetween at the inside of the cylindrical member, and which extends along the first frame, wherein the wiring is arranged between the first frame and the second frame.

Abstract: An image forming apparatus having a temperature detection unit that detects a current interior temperature based on a detection signal from a temperature sensor. A temperature change detection unit calculates a difference between the current interior temperature and an interior temperature detected in a last color misregistration correction processing as a temperature change amount. When the temperature change amount is equal to or higher than a threshold, a determination unit determines that a color misregistration correction operation needs to be executed. A mode setting unit determines whether a monochrome printing processing is currently carried out.

Abstract: An induction heating device includes a resonance circuit including an exciting coil and a resonance capacitor; a switching unit that turns on and off a high-frequency current flowing through the switching unit; a temperature detector that detects a temperature of the heated body; a power amount detector that detects a power amount sent to the exciting coil; a turned-on time setting unit that sets a turned-on time of the switching unit; a timing generation unit that generates a signal indicating a timing when a voltage between both ends of the switching unit is zero; and a timing setting unit that sets a turned-on timing of the switching unit based on the signal generated by the timing generation unit.

Abstract: A belt drive apparatus, including, an endless belt to be laid across in a tensioned condition between supporting rollers and to travel being in pressure contact with or being separated from a body to receive the pressure contact, a pressure contact/separating state detection section to detect whether the endless belt is in the pressure contact with the body or separated therefrom, a belt position detection section to detect a position of the endless belt in a width direction thereof, a belt abnormality judging section to judge whether the endless belt is in an abnormal position based on a detection result obtained by the belt position detection section and one of judgment values which are set correspondingly to the pressure contact/separating state of the endless belt, and a belt drive control section to control a drive of the endless belt.