Abstract: A fixing device includes a first rotator, a second rotator pressed against the first rotator, and a heater to heat the first rotator. The heater includes an elongated substrate extending in an axial direction of the first rotator, a heat generator disposed on a surface of the substrate facing the first rotator, at a position downstream in a rotational direction of the first rotator, a plurality of first conduction paths connected to the heat generator and grounded downstream of the heat generator in the rotational direction of the first rotator, and a second conduction path on which the plurality of first conduction paths are grounded. The heat generator has a heat-generating area divided into a plurality of sub-heat-generating areas in the axial direction of the first rotator. The plurality of sub-heat-generating areas are grounded on the second conduction path via the plurality of first conduction paths.

Abstract: A fixing device includes a fixing rotary body inside which a heat generator is disposed and an exciting coil unit disposed opposite the heat generator via the fixing rotary body. A first moving mechanism is connected to one of the heat generator and the exciting coil unit to move the one of the heat generator and the exciting coil unit between a first position where the exciting coil unit is disposed away from the heat generator and a second position where the exciting coil unit is disposed closer to the heat generator. The exciting coil unit heats a first heat generation layer of the fixing rotary body at the first position, and heats both the first heat generation layer of the fixing rotary body and a second heat generation layer of the heat generator at the second position.

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 device includes a rotatable fixing member to rotate while contacting an unfixed image; a pressure member to form a fixing nip with the fixing member; a heating member having a plurality of heating elements divided in a direction perpendicular to a conveyance direction of a sheet; a heat performance sensor to detect heating performance of each heating element of the heating member, and an controller to control the heating member. The controller controls each heating element independently such that a temperature of a portion of the fixing member corresponding to a blank area becomes lower than the temperature of a portion of the fixing member corresponding to an image area; and controls the temperature to be maintained at each heating element based on the detection result of the heating performance of each heating element detected by the heat performance sensor.

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 rotatable, endless fixing belt; a rotatable contact member configured to contact a circumferential surface of the fixing belt to form a nip in association with the fixing belt; and a heating member disposed at an interior surface of the fixing belt, configured to heat the fixing belt. The heating member includes a multiple heat sources arranged along the width of a sheet of recording media in a direction perpendicular to a sheet conveyance direction. A controller changes an area to be heated by each heat source based on image data and corresponding to an unfixed image on the sheet. The fixing belt is heated by the heating member so that the unfixed image on the sheet that has been conveyed to the nip is fixed onto the sheet at least with heat. The heating member is disposed at a portion other than the fixing nip.

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 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 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 an endless belt formed into a loop and rotatable in a given direction of rotation. An opposed rotary body contacts the endless belt to form a fixing nip therebetween through which a recording medium bearing a toner image is conveyed. A heater is disposed in proximity to an irradiation span spanning on an inner circumferential surface of the endless belt in a circumferential direction thereof to emit light that irradiates and heats the irradiation span of the endless belt. A shield is interposed between the heater and the irradiation span of the endless belt in a diametrical direction thereof to shield the irradiation span of the endless belt from heated air surrounding 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 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 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 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 rotatable fuser member a heater, a rotatable pressure member, a thermometer, and a feedback controller. The rotatable fuser member is subjected to heating. The heater heats the fuser member to a heating temperature. The rotatable pressure member is disposed opposite the fuser member. The fuser member and the pressure member are pressed against each other to form a fixing nip therebetween, through which the recording medium is conveyed, so as to fix the toner image in place under heat and pressure. The thermometer is disposed adjacent to the pressure member to detect an operational temperature of the pressure member. The feedback controller is operatively connected with the thermometer to control the heating temperature according to the detected operational temperature, so that the recording medium exhibits a substantially constant post-fixing temperature downstream from the fixing nip regardless of the heat capacity of the recording medium.

Abstract: A fixing device includes a rotatable fuser member, a rotatable pressure member, a heater, a rotary driver, a thermometer, and a controller. The rotatable fuser member is subjected to heating. The rotatable pressure member is disposed opposite the fuser member. The heater heats the fuser member. The rotary driver imparts torque to at least one of the fuser and pressure members. The fuser member and the pressure member are pressed against each other to form a fixing nip therebetween. The thermometer is disposed external to the fixing nip to detect a temperature outside the fixing nip. The controller is operatively connected with the thermometer to control an amount of heat applied to the recording medium through the fixing nip according to the detected temperature, so that the recording medium exhibits a substantially constant post-fixing temperature downstream from the fixing nip.

Abstract: A fixing device includes a fixing rotary body inside which a heat generator is disposed and an exciting coil unit disposed opposite the heat generator via the fixing rotary body. A first moving mechanism is connected to one of the heat generator and the exciting coil unit to move the one of the heat generator and the exciting coil unit between a first position where the exciting coil unit is disposed away from the heat generator and a second position where the exciting coil unit is disposed closer to the heat generator. The exciting coil unit heats a first heat generation layer of the fixing rotary body at the first position, and heats both the first heat generation layer of the fixing rotary body and a second heat generation layer of the heat generator at the second position.

Abstract: A heating apparatus which can increase the temperature of a heating element to a target temperature in a short time and ensures temperature uniformity of the heating element. In the heating apparatus, when the specific resistance of a material of a heat generating layer of a heating roller is ? (???cm), the average thickness of the heat generating layer is 5? (?m) or more but not more than 15? (?m), and the thickness error is 1.2? (?m) or less. For instance, when the heat generating layer is copper having a specific resistance of 1.7 (???cm), the average thickness of the heat generating layer is 8-25 (?m), and the thickness error is 2 (?m) or less. Thus, the heating roller having a short heat increasing time and excellent temperature uniformity is provided.