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 heating device to heat an endless rotary body with radiant heat, a power source to supply power to the heating device, a first heat source to heat a region on the endless rotary body corresponding to a width of the small size sheet, and a second heat source to heat regions on the endless rotary body corresponding to both widthwise ends of the large size sheet outside the width of the small size sheet. The power source supplies power only to the first heat source when the small size sheet is printed and to both the first and second heat sources when the large size sheet is printed. The power source supplies more power to the first heat source when the small size sheet is printed than when the large size sheet is printed within a maximum power available to the fixing device.

Abstract: A fixing device includes a heat roller and an opposing component. The heat roller extends in an axial direction and includes a cylindrical-shaped roller section and a coil. The heat roller section has an inner circumferential surface and an outer circumferential surface. The coil is spirally wound along the inner circumferential surface and including a first portion and a second portion other than the first portion, the first portion being configured of such a number of turns of the coil, the number being a natural number greater than zero, the first portion having a first coil pitch length in the axial direction, and the second portion being configured of at least one turn of the coil and having a second coil pitch length in the axial direction greater than the first coil pitch length. The opposing component confronts the outer circumferential surface of the roller section and is exclusively superposed with an entire first portion via the roller section.

Abstract: A surface processing apparatus includes a heater and a controller for controlling a heating of a sheet. The controller determines a difference between a position, on the sheet, of an image indicated by original image information and a position, on the sheet, of the actually formed image on the sheet indicated by outer configuration information of the sheet and the actual image information. The controller corrects inputted heating position information, for the heater, on the basis of information of the difference, and controls the heating of the heating means in accordance with the corrected heating position information.

Abstract: An image forming apparatus includes an image forming device, a fixing device, a first fan configured to supply air to a first area of the fixing device, a second fan configured to supply air to a second area of the fixing device, a first temperature detector for detecting a temperature of the first area, a second temperature detector for detecting a temperature of the second area, and a control unit configured to start to operate the first fan and the second fan, wherein, when a displacement amount of a recording material with respect to a conveyance reference is a predetermined amount or larger and when the recording material is displaced toward the first area, the control unit sets a temperature for starting to drive the second fan to be lower than a temperature that is set when the positional displacement amount is less than the predetermined amount.

Abstract: A fixing unit includes a first heat source configured to heat a roller, and a second heat source configured to heat the roller. The maximum value of a total amount of heat generated in the second heat source is smaller than that of the first heat source. The second heat source has an amount of heat generated higher in ends of the second heat source than in a center thereof in a distribution of the amount of heat generated in the axial direction. The second heat source has a rate of the amount of heat generated in the ends of the second heat source to that in the center thereof higher than a rate of the amount of heat generated in the ends of the first heat source to that in the center thereof.

Abstract: An image forming apparatus includes a fixing device that has: a fixing roller heated by induction and a pressing roller brought into press-contact with the fixing roller to fix a toner image borne on a paper sheet conveyed toward the fixing device by a conveyor unit. When a paper sheet having a width smaller than a width of a maximum-width recording medium that can be passed through the fixing device is passed through the fixing device, a non-paper passing region is formed at each end portion of each of the fixing and pressing rollers. Sirocco fans cool the non-paper passing region at a part of an outer peripheral surface of the pressing roller. The pressing roller is disposed opposed to the outer side of the main body of the image forming apparatus.

Abstract: A fixing device which heats a heating object through induction heating by using a plurality of coils includes a plurality of coil drivers that drive the plurality of coils respectively, a drive circuit that controls ON/OFF states of a plurality of switching elements simultaneously to control the drive of the plurality of coil drivers, a control unit that controls a voltage supplied to each of the plurality of coils in accordance with the control of the ON/OFF states of the plurality of switching elements by the drive circuit, and a plurality of voltage control circuits that individually change the voltages supplied to the plurality of coils in accordance with the voltage control of the control unit.

Abstract: An image forming apparatus includes an image forming unit, a heating member configured to heat the sheet for fixing the image onto the sheet, a temperature detection unit configured to detect a temperature of a predetermined position of the heating member, a controller configured to control the heating member, a heating region control unit configured to control the heated region of the heating member, wherein the heating region control unit controls a first and a second heated region, wherein the first heated region includes the predetermined position, and wherein the second heated region in the width direction includes the first heated region and an outer heated region outside the first heated region, and a cooling unit configured to cool the heated region, wherein if the heating region control unit changes the heated region from the first heated region to the second heated region, the cooling unit cools the predetermined position.

Abstract: A fixing device includes a nip forming member disposed inside a fixing member and pressed against a pressing member via the fixing member to form a nip portion between the pressing member and the fixing member through which a recording medium bearing a toner image passes. A heat generator disposed inside the fixing member heats the fixing member outside the nip portion and has variable heat distribution over a width of the fixing member. A first temperature detector disposed inside the fixing member contacts an end portion of the heat generator in the width direction of the fixing member, opposite a surface facing the fixing member, to detect a temperature of the heat generator. A second temperature detector disposed inside the fixing member contacts a center of an inner circumferential surface of the fixing member in the width direction, to detect the temperature of the fixing member.

Abstract: An image heating rotatable member for heating an image on a recording material, comprising a base layer; a heat generation layer, provided on the base layer, for generating heat by being supplied with electric power; an electrode layer, provided outside of the heat generation layer with respect to a widthwise direction and having an electric resistance which is smaller than that of the heat generation layer, for supplying the electric power to heat generation layer; an elastic layer provided on the electrode layer and having a length longer than that of the electrode layer measured in the widthwise direction; and a parting layer provided on the elastic layer and having a length which is substantially equal to the length of the electrode layer measured in the widthwise direction.

Abstract: A fusing device for an image forming apparatus that heats an infused image on a printing medium by an electromagnetic induction heating method includes a heated member having a metallic layer; a plurality of main cores disposed to be spaced apart a predetermined distance from a surface of the heated member, the plurality of main cores arranged to be spaced apart a predetermined interval from each other in a length direction of the heated member; and a main coil wound to surround the plurality of main cores.

Abstract: A fixing device includes a metal thermal conductor provided inside a loop formed by a fixing rotary body to heat the fixing rotary body; a heater provided inside the metal thermal conductor to heat the metal thermal conductor; a pad support provided inside the metal thermal conductor; and a reflector provided between the heater and the pad support to reflect heat emitted by the heater thereto toward an inner circumferential surface of the metal thermal conductor. The reflector includes a center reflection portion provided at a center of the reflector in a longitudinal direction thereof and a plurality of end reflection portions provided at respective lateral ends of the reflector. A plurality of reflector moving assemblies is connected to the plurality of end reflection portions of the reflector, respectively, to tilt the plurality of end reflection portions toward the center reflection portion.

Abstract: A fixing device includes a coil disposed along an outer surface of a heating member and configured to generate magnetic flux for heating the heating member through induction heating; and a core unit being configured to constitute a part of a magnetic path around the coil. The core unit includes a plurality of core bodies arranged in a width direction of a recording medium to be conveyed, the core bodies being made of magnetic material; and a shaft having an outer surface on which the core bodies are arranged, a length of the outer surface being longer than a sum of lengths of the core bodies arranged thereon, the core body lengths including axial tolerances of the core bodies. A gap is provided between any adjacent ones of the core bodies.

Abstract: A fixing device includes a heating rotating member that generates heat by induction heating; an induction coil that generates magnetic flux for induction heating; and a magnetic member core section forming a magnetic path and including a first core section, a second core section, a magnetic flux shielding member, and third core sections. The magnetic flux shielding member is disposed at a side of an end portion of the first core section opposite to the second core section and separated from the end portion, and disposed at a position that is separated from the outer surface of the heating rotating member by a separation distance. The third core sections are disposed at a side of the magnetic flux shielding member facing the end portion of the first core section. At least one of the third core sections is movable to a first position and to a second position.

Abstract: A fixing device includes a heating element disposed inside a flexible fusing member, a nip member disposed to contact with a surface of the flexible fusing member and to allow the flexible fusing member to slide along the nip member, a reflecting plate for reflecting radiant heat from the heating element toward the nip member, and a backup member for nipping the flexible fusing member with the nip member. The reflecting plate includes a central reflecting portion extending along a longitudinal direction of the heating element at least in a region corresponding to along a heat generating portion of the heating element, and end reflecting portions stationarily provided on both ends of the central reflecting portion. The end reflecting portions are disposed in positions longitudinally outward of the heat generating portion and each has a reflecting surface tilted with respect to the longitudinal direction of the heating element.

Abstract: A fixing apparatus includes a heating roller, a fixing roller, a fixing belt that is wound around the heating roller and the fixing roller and circulates between the heating roller and the fixing roller, a pressing roller to press the fixing roller through the fixing belt, a first heater that is included in the heating roller and mainly heats a center part of the heating roller, a second heater that is included in the heating roller and mainly heats a peripheral part of the heating roller, and a temperature control unit to control a temperature of the heating roller by an on/off control of the first heater and the second heater, and the temperature control unit performs the on/off control in which when one of the first heater and the second heater is turned on, the other is turned off.

Abstract: A fixing device includes a fixing member including a heating unit, and a pressure member, the heating unit includes a sub-heater having a heat generating portion in a region smaller than a minimum paper width, a main heater having a heat generating portion at outside of the sub-heater, a first temperature detector to detect a temperature of the fixing member at the heat generating portion of the main heater, and a second temperature detector to detect the temperature at the heat generating portion of the sub-heater. The main heater and the sub-heater can be switched selectively, and the initial duty ratio at the start of PID temperature control by the sub-heater is determined in accordance with a difference between temperatures detected by the respective temperature detectors at the start of PID temperature control and a target temperature so that the temperature is not overshooting and dropped.

Abstract: A fixing device of an image forming apparatus includes a magnetic core forming a magnetic path composed of a first path for induction-heating a specified area of a heating member and a second path for induction-heating only a smaller area as a reduction of the specified area and the magnetic field being composed of a common magnetic field region where both the first and the second paths pass and an uncommon magnetic field region where only the first path passes; and a magnetism adjusting member arranged at least over the uncommon magnetic field region and permitting the passage of magnetic fluxes propagating toward the heating member from the magnetic core in the uncommon magnetic field region when the magnetic path is switched to the first path while suppressing the passage of the magnetic fluxes in the uncommon magnetic field region when the magnetic path is switched to the second path.

Abstract: Provided is a fixing device comprising: a fixing rotating body; a magnetizing coil; a pressing member forming a fixing nip through which a recording sheet passes; a demagnetizing coil unit set including a pile of demagnetizing coil units each including demagnetizing coils of different sizes, and canceling out part of magnetic flux generated by the magnetizing coil in a non-sheet-passing region; a sheet information acquisition unit acquiring sheet information including information relating to a width of the recording sheet; and an operation control unit controlling each demagnetizing coil according to the width, wherein in each demagnetizing coil unit, the demagnetizing coils are arranged such that a smaller demagnetizing coil is surrounded by a larger demagnetizing coil and the demagnetizing coils are in a same plane extending along a surface of the magnetizing coil, and a combination of sizes of the demagnetizing coils differs among the demagnetizing coil units.

Abstract: An image heating apparatus includes a rotatable image heater including: an electroconductive layer; a pressor, press-contacting the heater, for forming a nip in which an image on a recording material is to be heated; an urging member, provided inside the heater, for urging the heater toward the pressor; and an excitation coil for induction-heating the electroconductive layer. When the length of the heater with respect to a rotational axis direction thereof is Lb, the length of the pressor with respect to the rotational axis direction is Lr, the outside distance of bent portions of the coil at both end portions thereof with respect to the rotational axis direction is LcoilA, and the inside distance of the bent portions with respect to the rotational axis direction is LcoilB, the lengths Lb and Lr and the distance LcoilA and LcoilB satisfy the following relationship: LcoilA>Lb>Lr>LcoilB.

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 includes a first member. The first member extends along a first longitudinal axis, and has an external surface whose thickness varies along the first longitudinal axis to define at least one first convex portion and at least one first concave portion. A thickness of the first convex portion is larger than a thickness of the first concave portion. A heating source is disposed in the first member. The heating temperature of an inner circumference side of the first convex portion is higher than the heating temperature of the inner circumference side of the first concave portion.

Abstract: An image heating rotatable member for heating an image on a recording material, includes a base layer, a heat generation layer, provided on the base layer, for generating heat by being supplied with electric power, an electrode layer, provided outside of the heat generation layer with respect to a widthwise direction and having an electric resistance which is smaller than that of the heat generation layer, for supplying the electric power to heat generation layer, an elastic layer provided on the electrode layer and having a length longer than that of the electrode layer measured in the widthwise direction, and a parting layer provided on the elastic layer.

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: In a fixing device, having a sheet portion and an inter-sheet portion, heats and fixes the toner image onto each of sheets by rotationally bringing the sheet portion into contact with each sheet. A heating unit heats the fixing unit. A sensing unit senses a temperature of the fixing unit. A control unit controls a duty ratio of on/off of the heating unit based on a sensing output of the sensing unit, determines whether the sensing unit is sensing the temperature of the sheet portion or the temperature of the inter-sheet portion in a rotation cycle, and controls the temperature of the heating unit by using the adjustment value corresponding to the sheet portion or the inter-sheet portion depending on a determination result.

Abstract: A fixing unit includes a fixing member, a pressing member, a heating device, a sheet width detector, and a heating area adjustor. The pressing member faces the fixing member to form a fixing nip between the fixing member. An un-fixed toner image is fixed on a recording medium when the recording medium passes through the fixing nip. The heating device heats the fixing member while maintaining a non-contact condition with the fixing member. The sheet width detector detects sheet width of the recording medium. The heating area adjustor changes a heating area of the fixing member, heatable by the heating device, based on the sheet width detected by the sheet width detector. The heating area adjustor is moveable in a space between the fixing member and the heating device along a sheet width direction to change a size of the heating area.

Abstract: A fixing apparatus includes: two rotatable members, for forming a nip, including a region where an outer diameter is increased from a longitudinal central portion toward a longitudinal end portion; a heater; and a controller for controlling a heat generation distribution of the heater. The controller is capable of controlling the heater so that the heat generation distribution of the heater is such that a heat generation amount at the longitudinal end portion is larger than that at the longitudinal central portion in a period from start of the heater until the recording material reaches the nip. A ratio of the heat generation amount at the longitudinal end portion to that at the longitudinal central portion is larger when a cumulative amount of use of the fixing apparatus is larger than a predetermined amount than when the cumulative amount of use is smaller than the predetermined amount.

Abstract: A heating roller performs electromagnetic induction heating, and includes a first exciting coil that heats the heating roller, a first degaussing coil that decreases magnetic fields of the first exciting coil, and a first axial direction core that guides magnetic fluxes, to make up a magnetic circuit between the first axial direction core and the heating roller. The width of a heat zone is controlled in agreement with a sheet feeding area. Thus, the capability to control a temperature increase in a non-sheet-feeding area of the heating roller is enhanced. Power can be saved during continual feeding of small recording sheets.

Abstract: A fixing unit for use in an image forming apparatus includes a heating roller, the heating roller being divided into a fixing area and a non-fixing area, in which the fixing area is heated to above a target temperature required for fixing of an image, and the non-fixing area has a temperature lower than the target temperature, a main coil which generates a main magnetic field for generating an induced current, and at least one secondary coil which generates a secondary magnetic field to extend an area of the main magnetic field, where the fixing area of the heating roller, when formed by the main magnetic field, has a width smaller than an entire width of a maximum size paper, and the fixing area, when formed by a combination of the main magnetic field and the secondary magnetic field, is extendable to the entire width of the maximum size paper.

Abstract: In a fixing apparatus, an internal temperature detection device is arranged within a heat generation region and detects temperature of a fixing device. An external temperature detection device is arranged at the outside of the heat generation region and detects temperature of the fixing device. Heat generation in the heat generating device is stopped when temperature reaches a prescribed first high temperature detection limit and a temperature rising amount in a prescribed time period after the first high temperature detection limit is reached exceeds a prescribed threshold.

Abstract: A fixing device configured to fix a toner image on a moving printing medium includes: a fixing heat generator that generates heat by electromagnetic induction; a fixing medium that rotates and is heated while being carried by the heating medium; and a pressing member that presses a back surface of the printing medium coming into contact with the fixing medium, the fixing heat generator including a center coil and a pair of side coils provided at a center portion and both side portions thereof along a direction perpendicular to the direction of movement of the printing medium for heating the fixing medium by induction heating, the pressing member including a center heater and a side heater that heat a center portion and both side portions thereof in a direction perpendicular to the direction of movement of the printing medium integrated therein.

Abstract: To enhance the fixing quality of a fixing device to continuously fix sheets of a plurality of sizes, a carbon nanotube sheet 75, in which a plurality of carbon nanotubes are arranged such that the longitudinal directions thereof are oriented in the same direction, is provided on the surface of a heating roller 70 so that the carbon nanotube sheet ranges from the position a predetermined distance inside and the position a predetermined distance outside of the position through which each of the both edges of a sheet P2 with smaller width dimension than a sheet P1 of the largest width dimension to be fixed passes.

Abstract: In a fixing apparatus of an image forming apparatus, a heating member melts and fixes the unfixed toner. A heat controller controls temperatures of opposite end portion areas and a middle portion area of a surface of the heating member in a width direction perpendicular to a conveyance direction on an individual area basis. A pressure member is pressed against and contact with the heating member to form a fixing part therebetween. The heat controller controls the temperatures of the surface of the heating member so that the temperature of at least one of the opposite end portion areas of the surface of the heating member is higher than the temperature of the middle portion area of the surface of the heating member.

Abstract: The heat fixing apparatus includes a fixing heater and a pressure roller. The fixing heater has a plurality of resistance-type heat generation layers which are different in heat distribution in the longitudinal direction perpendicular to the direction of conveying a recording material. The recording material P is heated when passed through a fixing nip portion formed between the fixing heater and the pressure roller. The pressurization conditions between the fixing heater and the pressure roller can be changed. The heat fixing apparatus includes a fixing member which adjusts the lengthwise heat distribution of the fixing heater by changing the applied current proportion of the plurality of resistance-type heat generation layers according to the pressurization conditions between the fixing heater and the pressure roller.

Abstract: A controlled fuser assembly for a reproduction apparatus. The fuser assembly includes a fuser member for fusing a marking particle image to a receiver member and a cooling system for controlling the temperature of the fuser system. Optional external heater rollers have a heat transfer surface adapted to be selectively engaged with the fuser member, and a device for heating said heat transfer surfaces. A mechanism is provided for controlling the heat transfer with the fuser member to selectively change the amount of heat transferred from the fuser.

Abstract: An asymmetrical printer includes a housing (101) and a first fuser member (121) rotationally supported in the housing. The first fuser member has a first fuser member end (210) and a second fuser member end (220). The first fuser member fuses an image on a media sheet traveling in a media sheet 112 travel direction (115). A fuser nip (126) has a fuser nip width dimension (128) parallel to the media sheet travel direction and having a fuser nip length (116) from the first fuser member end to the second fuser member end. The fuser nip length is perpendicular to the media sheet travel direction. The fuser nip width dimension is asymmetrical along the fuser nip length. A second fuser member (122) is rotationally supported in the housing and coupled to the first fuser member at the fuser nip. The second fuser member fuses the image on the media sheet.

Abstract: An image forming apparatus includes a generator, image forming unit, fixing unit, fixing temperature setting unit, and heating control unit. The generator generates image drawing data including text and/or photo, page by page, from image data. The image forming unit forms a latent image based on image drawing data, and develops and transfers developed image onto a recording medium. The fixing unit includes a fixing device having a plurality of heaters, and a surface of the fixing device is segmented into a plurality of heating areas each corresponding to one of the plurality of heaters. The fixing temperature setting unit sets a control-target fixing temperature at each heating area by associating text and/or photo in image drawing data with each heating area. The heating control unit controls current supply to each heater to heat each heating area to the set control-target fixing temperature.

Abstract: A fixing device includes a fixing roller, a pressure roller and a soaking roller. Temperature of the soaking roller, which contacts with the pressure roller, is measured by a temperature measurement section. This makes it possible to precisely estimate the temperature distribution of the fixing roller and the pressure roller including a non-paper feed area of paper sheets. Based on the temperature of the soaking roller, fixing operation is controlled by a fixing operation control section. Thereby, optimal control can be implemented to suppress the temperature rise in the non-paper feed area according to the estimated temperature distribution of the fixing roller and the pressure roller.

Abstract: A fixing unit for fixing a toner image onto a sheet passing between a first element and a second element pressed against the first element includes a looped coil surface formed with a coil so that the coil surface generates a magnetic field for induction-heating the first element, the coil surface including an inner edge defining an opening region; an upright wall disposed inside the opening region, an opening being formed in the upright wall; a center core disposed along the opening region, the center core including a conductive shaft and a magnetic tube configured to at least partially cover the conductive shaft; and a nonconductive cap inserted into the opening, the nonconductive cap partially covering the conductive shaft to electrically insulate the coil from the conductive shaft.

Abstract: A fuser includes an endless heat generating part including a conductive layer, an induced current generating part to heat the conductive layer by electromagnetic induction, and a magnetic shunt metal member that is located at a side opposite to the induced current generating part across the heat generating part, forms a first gap between the magnetic shunt metal member and the heat generating part in a first paper passing region of the heat generating part, and forms a second gap, which is different from the first gap in size, between the magnetic shunt metal member and the heat generating part in a second paper passing region different from the first paper passing region.

Abstract: A fixing device includes an induction heater constructed of an exciting coil, a first pair of degaussing coils, and a second pair of degaussing coils. A controller turns off the exciting coil while the controller turns on one of the first pair of degaussing coils and the second pair of degaussing coils and at the same time turns off the other one of the first pair of degaussing coils and the second pair of degaussing coils, and then turns on the exciting coil for an extra time period corresponding to reserved power not supplied to the exciting coil while the exciting coil is turned off.

Abstract: In a fixing device, when sheets of small width size are continuously passed and temperature rises in both side parts, a temperature control unit stops print control of an auxiliary lamp. When the temperature rise in both side parts continues after that, a drive control unit shifts the fixing device to a wait mode and pre-runs the fixing device. Moreover, in a low-temperature environment, when temperature rises in both side parts when sheets Ps of small width size are continuously passed, the temperature control unit switches temperature control of the fixing device to three-stage control.

Abstract: A fixing apparatus of the invention includes a heating roller, a fixing roller, a fixing belt that is wound around the heating roller and the fixing roller and circulates between the heating roller and the fixing roller, a pressing roller to press the fixing roller through the fixing belt, a first heater that is included in the heating roller and mainly heats a center part of the heating roller, a second heater that is included in the heating roller and mainly heats a peripheral part of the heating roller, and a temperature control unit to control a temperature of the heating roller by an on/off control of the first heater and the second heater, and the temperature control unit performs the on/off control in which when one of the first heater and the second heater is turned on, the other is turned off.

Abstract: A portion 421 on each inner surface of both end sections 42c, 42d of an exciting coil 42, which is positioned on an outermost side in a width direction of a fixing roller 1, is positioned within an edge of a maximum paper feed area Z in the width direction of the fixing roller 1. A heat pipe 3 extends to farther outside of the maximum paper feed area Z in the width direction of the fixing roller 1.

Abstract: A fixing device includes a heat applying system having an exciting coil that creates a magnetic flux for generating induction heat in a heat generation layer provided in a fixing roller. Plural demagnetizing coils are stacked in plural layers partially overlying the exciting coil to cancel the magnetic flux at one end of the fixing roller. The plural demagnetizing coils partially overlap each other.

Abstract: A planar heat generating element includes an insulating layer and a resistance heat generator formed on one surface in a thickness direction of the insulating layer, for generating heat under a passage of electric current therethrough, the resistance heat generator constituting a plane of certain configuration as a whole and forming a heat generating pattern. The resistance heat generator includes a plurality of linear portions formed on one surface of the insulating layer that extend transversely with respect to a longitudinal direction of the insulating layer, the linear portions being arranged side by side substantially in parallel to each other; and a low-volume resistivity portion formed on the one surface so as to extend in the longitudinal direction of the insulating layer, and connecting the adjacent linear portions at their extending direction-wise ends to form a single line composed of the adjacent linear portions and the low-volume resistivity portion.

Abstract: In an image forming apparatus having a fixing rotor (22) that is driven to rotate and fixes an image by heating a recording paper while conveying the paper pressurized against the rotor, an excitation coil (24) that is provided extending in an axial direction along the fixing rotor (22) and causes induction heating by applying an alternating magnetic field to the fixing rotor (22), and a demagnetizing coil (25) that is provided superposed on an end of the excitation coil (24) and is able to partially diminish a magnetic flux generated by the excitation coil (24), by making the shape of the portion that belongs to the demagnetizing coil (25) and overlaps the excitation coil (24) has an asymmetrical shape have no axis of symmetry in the direction in which the recording paper is conveyed, a trouble due to overheating and defective fixing due to a shortage in the generation of heat can be reduced even when a plurality of kinds of recording papers of slightly different sizes are used.

Abstract: A fixing apparatus includes a heating element with an NTC characteristic in which an electric resistance value decreases as a temperature increases, which extends (i) in a direction parallel to a recording paper and (ii) in a width direction perpendicular to a carrying direction of the recording paper, and which has a longer length, in the width direction, than a width of the recording paper. The fixing apparatus further includes electrode sections provided in close proximity to both ends of the heating element in the width direction), the electrode sections being connected to the heating element, so that a current flows in the heating element in a direction substantially perpendicular to the carrying direction of the recording paper. This makes it possible to restrain excessive increase in temperature at the both ends of the heating element and to obtain a uniform temperature distribution.