Abstract: A fixing device includes a fixing rotary body, an opposed member, a heater, and a heating controller. The opposed member opposes the fixing rotary body to form a nipping portion therebetween. The heater includes heat generators arranged in a width direction of a recording medium. When the recording medium fed to the nipping portion has an image area and a non-image area, the heating controller controls the outputs of the heat generators based on image information so that a first heat generator of the heat generators corresponding to the image area is higher in temperature and a second heat generator of the heat generators corresponding to the non-image area is lower in temperature. Based on information other than the image information, the heating controller temporarily shifts an area of the fixing rotary body corresponding to the non-image area to a temperature differing from a normal temperature.

Abstract: A fixing device includes a fixing rotary body, an opposed member opposing the fixing rotary body to form a nipping portion, and a heater to heat the fixing rotary body. The heater includes heat generators arranged in a width direction of a recording medium and separately supplied with power. When an unfixed image on the medium has an image area and a non-image area, power supplied to each of the heat generators is controlled so that, of the heat generators, a first heat generator corresponding to the image area becomes a higher temperature and second heat generators corresponding to the non-image area becomes a lower temperature. When the second heat generators are adjacent to each other, power supplied to one of the second heat generators closer to the image area is set to be greater than power supplied to another of the second heat generators farther from the image area.

Abstract: A fixing device includes a heat conductive member; a flexible fixing belt looped around the heat conductive member, an inner circumference of the flexible fixing belt slidably contacting a portion of an outer circumferential surface of the heat conductive member; a rotary pressing member disposed opposing the heat conductive member; heat sources disposed in a circumferential direction of the fixing belt at a predetermined interval to heat the heat conductive member; and temperature detectors provided to detect a surface temperature of the fixing belt at a detection position at which heating intensity of a corresponding one of the heat sources is not affected by any other one. In operation, the inner circumferential surface of the fixing belt contacts the heat conductive member at a position at which each temperature detector contacts the fixing belt as the detection position or a position proximal to the detection position of each temperature detector.

Abstract: A fixing device temperature control method includes selectively energizing at least one of a plurality of heaters that heats a fixing rotary body according to an image area on a recording medium where a toner image is formed on the recording medium, detecting a temperature of a pressing rotary body pressed against the fixing rotary body, and controlling the energized, at least one of the plurality of heaters based on the detected temperature of the pressing rotary body so as to heat the fixing rotary body to a target temperature. The image area on the recording medium corresponds to a plurality of axial heating spans on the fixing rotary body.

Abstract: A fixing device includes a first alternating electric current power supply that outputs a first alternating electric current having a first frequency that causes a magnetic flux generated by an exciting coil to reach a first heat generation layer of a fixing rotary body; a second alternating electric current power supply that outputs a second alternating electric current having a second frequency that is lower than the first frequency and causes the magnetic flux to reach the first heat generation layer of the fixing rotary body and a second heat generation layer of a heat generator; and a switch circuit connected to the exciting coil, the first alternating electric current power supply, and the second alternating electric current power supply to selectively connect the first alternating electric current power supply or the second alternating electric current power supply to the exciting coil.

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 fixing device temperature control method is performed by a fixing device including a heat conductor contacting and heating an unfixed toner image formed on a recording medium, a heater disposed opposite and heating the heat conductor, and a pressing roller pressed against the heat conductor to form a fixing nip between the heat conductor and the pressing roller through which the recording medium is conveyed. The method includes detecting a temperature of the pressing roller and controlling an input voltage to the heater based on the detected temperature of the pressing roller to maintain a temperature of the recording medium discharged from the fixing nip at a target temperature.

Abstract: A fixing device includes a fixing member, a pressing member, a stationary member, a metal member, flanges, a first heater, and a second heater. The pressing member is rotatably pressed against an outer circumferential surface of the fixing member to form a nip therebetween. The metal member is fixedly disposed opposite an inner circumferential surface of the fixing member over an area other than the nip. The flanges are disposed at axial edges of the metal member in contact with an inner circumferential surface of the metal member. The first heater is disposed opposite the inner circumferential surface of the metal member to heat an axial middle portion of the metal member. The second heater is disposed opposite the inner circumferential surface of the metal member to heat axial end portions of the metal member. The first heater is disposed farther from the nip than the second heater.

Abstract: A fixing device includes a fixing member, a pressing member, a stationary member, a metal member, flanges, a first heater, and a second heater. The pressing member is rotatably pressed against an outer circumferential surface of the fixing member to form a nip therebetween. The metal member is fixedly disposed opposite an inner circumferential surface of the fixing member over an area other than the nip. The flanges are disposed at axial edges of the metal member in contact with an inner circumferential surface of the metal member. The first heater is disposed opposite the inner circumferential surface of the metal member to heat an axial middle portion of the metal member. The second heater is disposed opposite the inner circumferential surface of the metal member to heat axial end portions of the metal member. The first heater is disposed farther from the nip than the second heater.

Abstract: A fixing device for fixing an image on a recording medium includes an endless flexible fixing member formed into a loop, a heat conductive member disposed within the loop formed by the fixing member, a heater disposed near the heat conductive member to heat the heat conductive member, a pressing member pressing the fixing member against the heat conductive member to form a fixing nip, a temperature sensor detecting a temperature of the fixing member, and a lubricant disposed between the fixing member and the heat conductive member. The heater heats the heat conductive member to heat the lubricant with the fixing member stopped. The fixing member rotates after heating of the heat conductive member by the heater.

Abstract: A fixing device includes a switch circuit that selectively connects an alternating electric current power supply to a first exciting coil and a second exciting coil. When the switch circuit connects the alternating electric current power supply to both the first exciting coil and the second exciting coil, the first exciting coil and the second exciting coil together generate a first magnetic flux having a first density that reaches only a first heat generation layer of a fixing rotary body. When the switch circuit connects the alternating electric current power supply to the first exciting coil only, the first exciting coil generates a second magnetic flux having a second density greater than the first density that reaches both the first heat generation layer of the fixing rotary body and a second heat generation layer of a heat generator.

Abstract: A fixing device includes a fixing member, a pressing member, a stationary member, a metal member, flanges, a first heater, and a second heater. The pressing member is rotatably pressed against an outer circumferential surface of the fixing member to form a nip therebetween. The metal member is fixedly disposed opposite an inner circumferential surface of the fixing member over an area other than the nip. The flanges are disposed at axial edges of the metal member in contact with an inner circumferential surface of the metal member. The first heater is disposed opposite the inner circumferential surface of the metal member to heat an axial middle portion of the metal member. The second heater is disposed opposite the inner circumferential surface of the metal member to heat axial end portions of the metal member. The first heater is disposed farther from the nip than the second heater.

Abstract: A fixing device capable of shifting to a sleep state includes a heat source; a rotatable fixing member that is partly heated by the heat source to heat an unfixed image carrying surface of a recording medium; a rotatable pressing member that is in pressure contact with the fixing member to form a nip portion between the pressing member and the fixing member; a rotation drive unit that directly or indirectly rotates the fixing member; a temperature detecting unit that detects a temperature of the fixing member; and a controller configured to prohibit the fixing device from shifting to the sleep state when the temperature of the fixing member in a region facing the heat source is equal to or more than a predetermined temperature T1 at a point when a predetermined time period t1 has elapsed from the stop of rotation drive of the rotation drive unit.

Abstract: A fixing device includes a flexible endless fixing member; a metal member; and a pressing member. “A” is equal to or less than “Bmax” and greater than “Bave” (“Bmax”?“A”>“Bave”), where “A” represents an amount of a clearance at the time of normal temperature between the fixing member and the metal member, “Bmax” represents a maximum amount of deformation generated in the metal member when heating is started by the heating member from a normal temperature state, and “Bave” represents an amount of stable deformation generated in the metal member when the temperature of the entire metal member becomes even.

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: 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 device includes a heat generator including a first non-conductive portion having a first width in an axial direction of the heat generator and a second non-conductive portion spaced apart from the first non-conductive portion in a circumferential direction of the heat generator and having a second width in the axial direction of the heat generator that is smaller than the first width of the first non-conductive portion. The heat generator is movable between a first heating position where the first non-conductive portion is disposed opposite an exciting coil unit and a second heating position where the second non-conductive portion is disposed opposite the exciting coil unit.

Abstract: A temperature control method of calculating a temperature of a recording medium after fixing and used in a thermal fixing device includes separating calculations of calculating the temperature of the recording medium after fixing into first-stage calculations to be performed before start of printing and second-stage calculations to be performed in real time during the printing, performing the first-stage calculations, and performing the second-stage calculations to calculate a result of the temperature of the recording medium after fixing. Further, the result of the temperature of the recording medium after fixing is used to control obtaining a desired temperature of the recording medium after fixing, and the temperature of the recording medium after fixing is calculated without directly measuring the temperature of the recording medium after fixing.

Abstract: A fixing control device includes a power distribution controller that adjusts a power distribution time period when the power is distributed to plural heater elements per control cycle, a turn on time determining member that determines a time when each of the plural heater elements is turned on based on a duty ratio between the power distribution time period and the control cycle, and a soft operation controller that either gradually starts or stops heating each of the plural heater elements during a soft start or stop period, respectively. One of the soft start and stop periods for one of the plural heater elements is decreased not to overlap with another one of the plural heater elements.

Abstract: A fixing device includes a first alternating electric current power supply that outputs a first alternating electric current having a first frequency that causes a magnetic flux generated by an exciting coil to reach a first heat generation layer of a fixing rotary body; a second alternating electric current power supply that outputs a second alternating electric current having a second frequency that is lower than the first frequency and causes the magnetic flux to reach the first heat generation layer of the fixing rotary body and a second heat generation layer of a heat generator; and a switch circuit connected to the exciting coil, the first alternating electric current power supply, and the second alternating electric current power supply to selectively connect the first alternating electric current power supply or the second alternating electric current power supply to the exciting coil.