Abstract: A fixing apparatus includes a mold (holding member) formed by injection molding to hold a coil so that the coil maintains a predetermined positional relation with respect to a heating roller, and capable of holding a temperature sensor which detects a temperature of the heating roller and a thermostat which detects an abnormal temperature of the heating roller in predetermined positions facing the heating roller.

Abstract: A fixing device includes a heat roller having a degaussing alloy material, an induction heating member for exciting the heat roller, an inverter circuit for giving power at a predetermined frequency to the induction heating member, and a control unit, and when driving at a first drive frequency and fixing small size sheets by continuous passing, a local temperature rise occurs at an end part of the heat roller, and the end part approaches the Curie temperature, and when impedance of the inverter circuit reduces and an excessive current flows in the circuit, the fixing device drives at a higher second drive frequency, thereby increases a resistance of the heat roller by an epidermal effect of magnetic flux, increases an apparent resistance of the inverter circuit, makes it possible to use a flowing current within a normal range, heating a central part of the heat roller, and continues the fixing.

Abstract: In a coil unit according to this invention in which an electromagnetic induction coil and a magnetic core are sealed by a coil mold, an insulating board that secures insulation between the electromagnetic induction coil and the magnetic core and that can adjust the distance between them is provided between the electromagnetic induction coil and the magnetic core.

Abstract: A fixing device of this invention enables variable control of power to be supplied to a heat roller side or a press roller side in accordance with the temperature of the heat roller and the press roller while each mode is carried out. A secondary battery is used in addition to a commercial power source, thus enabling supply of power to the heat roller side or the press roller side. The secondary battery is used when necessary, thus increasing the power supply. In a copy mode, the temperature of the heat roller and the press roller is controlled in detail. In a non-copy state, the power supply to the fixing device is stopped.

Abstract: A fixing apparatus includes a heating roller which provides heat to a developer-holding medium holding a developer image, a pressurizing roller which is in contact with the heating roller, a heating device having a plurality of heating members which heat the heating roller, a first thermoelectric converting section having a plurality of thermoelectric converting elements, each of which has a heat-absorbing surface and a cooling surface and generates electromotive force by difference in temperature between the heat-absorbing surface and the cooling surface, and formed along a curved surface of the heating roller, in which the heat-absorbing surface is disposed with a predetermined space from an outer circumferential surface of the heating roller, an auxiliary power supply charged with electric power generated by the first thermoelectric converting section, and a switching section which switches the apparatus between a first state in which electric power is supplied from utility power to the heating members and

Abstract: An induction heating device of the invention is made to have a two-layer structure in which at an end of a magnetic core of an induction current generating coil, a litz wire of outside three turns is stacked on a litz wire of inside three turns. The width of a joint portion between plural induction current generating coils is made narrow, and a mutual induction current generated at the joint portion is reduced. Further, the whole length of the litz wire is shortened without changing the length of the magnetic core of the inductor current generating coil.

Abstract: A fixing apparatus according to one aspect of the present invention includes a non-contact temperature detecting element 81 allocated in non-contact with a heat roller, the sensing element detecting a temperature of the heat roller. The non-contact temperature sensing section 81 includes a thermopile P which detects a target temperature Pt of a heat roller 2, a temperature element CPU 100 which estimates an ambient temperature at the periphery of the thermopile P and computes an estimated ambient temperature SQt, and a thermister Q which detects an ambient temperature Qt at the periphery of the thermopile and outputs the ambient temperature Qt at an output voltage of a predetermined rate with respect to a total output voltage value corresponding to the estimated ambient temperature SQt.

Abstract: A fixing device of this invention enables variable control of power to be supplied to a heat roller side or a press roller side in accordance with the temperature of the heat roller and the press roller while each mode is carried out. The heating range of a first induction heating coil on the heat roller side and the heating range of a first halogen lamp heater on the press roller side are set differently. In a copy mode, the temperature of the heat roller and the press roller is controlled in detail, and also controlled in accordance with the size of a sheet paper. In a copy standby mode, only the power required for maintaining a set temperature is supplied.

Abstract: A fixing apparatus according to an embodiment of the invention comprises a heating roller for providing heat to a developer holding medium holding a developer image, a pressurizing roller which comes in contact with the heating roller, a heater having heating members for heating the heating roller, a non-contact temperature detector which includes a non-contact temperature detection element for detecting a first temperature of the heating roller in an area between a position heated by the heater and a position to contact the pressurizing roller with heating the heater, from detection positions in the longitudinal direction of the heating roller, and a detection range adjustment member which is placed between the non-contact temperature detection element and the heating roller, and has openings to set a detection range wider for far detection positions, compared with a range for near detection positions.

Abstract: In an induction heat fixing device of the invention, a metal conductive layer of a heat roller is supported by a foamed rubber (sponge). A sheet paper is curled in a direction of separating from the heat roller by a nip shape between the heat roller and a press roller. The press roller is formed to be longer than the heat roller to such a degree that even if the heat roller laterally shifts, an edge of the press roller does not come in contact with the heat roller.

Abstract: A fixing device of this invention enables variable control of power to be supplied to a heat roller side or a press roller side in accordance with the temperature of the heat roller and the press roller while each mode is carried out. In a copy mode, the temperature of the heat roller and the press roller is finely controlled. In a copy standby mode, only the power required for maintaining a set temperature is supplied.

Abstract: The fixing device of the image forming apparatus of the present invention has a cleaning pad arranged on the upper frame which supports a heat roller. An infrared temperature sensor is supported by a supporting mechanism that is capable of supporting the infrared temperature sensor at the temperature detecting position and the evacuating position. When the right and left frames are attached/removed to/from the main body of the apparatus at the time of maintenance, the infrared temperature sensor is moved to the evacuating position and pressed against the cleaning pad and then, the right and left frames are moved by sliding to the main body of the apparatus. The cleaning pad is also slid and moved jointly with the slide moving of the right and left frames, and the infrared temperature sensor contacts the cleaning pad and dirt on the infrared temperature sensor is removed.

Abstract: An image forming apparatus according to the present invention includes a heating roller 2 fixed at a predetermined position, a pressurizing roller 3 press-fitted to the heating roller 2 by a pressurizing mechanism 4 to be movable, and a hardness change detecting mechanism 310 which becomes electrically conductive when the pressurizing roller 3 moves due to thermal expansion of the heating roller 2, and which detects a hardness change of the heating roller 2.

Abstract: In an induction heating fixing device according to the invention, a first induction heating coil that generates an induced current across the total length of a heat roller is provided on the outer circumference of the heat roller having a metal conductive layer. A second induction heating coil that generates an induced current at a central part of the heat roller is provided, which crosses the first induction heating coil and is arranged on the outer side than the first induction heating coil. With the first induction heating coil, the heat roller is heated across the total length without generating any uneven temperature. On-off control of the first induction heating coil and the second induction heating coil is carried out, and the temperature distribution in the longitudinal direction of the heat roller is kept constant irrespective of the size of a sheet paper P.

Abstract: An induction heating coil of an induction heating device of the invention is formed such that a first coil width of an active coil section parallel to a longitudinal direction of a heat roller and a second coil width of an end coil section in a direction parallel to a rotating direction of the heat roller are different. When the induction heating coil is divided into plural coils, portions having weak magnetic fields in joint portions of the induction heating coils, at both ends of the induction heating coils, or the like are narrowed.

Abstract: A fixing device of the invention detects a temperature of plural positions of a heat roller by a multiple non-contact temperature sensor at the same time and controls the temperature of plural heat source members The non-contact temperature sensor and a contact temperature sensor detect the temperature of the same position. According to the detection result, maintenance is performed or a temperature conversion table is corrected, the non-contact temperature sensor is maintained with high precision, and the heat roller is controlled the temperature with high precision.

Abstract: A fixing apparatus includes a mold (holding member) formed by injection molding to hold a coil so that the coil maintains a predetermined positional relation with respect to a heating roller, and capable of holding a temperature sensor which detects a temperature of the heating roller and a thermostat which detects an abnormal temperature of the heating roller in predetermined positions facing the heating roller.

Abstract: In a fixing device of an image forming apparatus of the present invention, inner surfaces of upper and lower frames for respectively supporting a heat roller and a pressure roller are formed as a mirror surface. Between the heat roller and an infrared temperature sensor, an infrared transmission filter for cutting infrared rays beyond a wave length zone equivalent to a heatable area of the heat roller is installed. Detection results of a surface temperature of the heat roller by the infrared temperature sensor are prevented from exceeding the error tolerance due to infrared rays radiated from other than the heat roller. Temperature control for the heat roller is improved and a fixed image of high image quality is obtained.

Abstract: In an aspect of this invention, a fixing device includes a heating member including a first area and a second area formed of conductive members (e.g., aluminum and iron) having different magnetic permeability ratios, and an induction heating unit which generates a magnetic field from a coil to induction-heat this heating member, and the fixing device changes a frequency of a high-frequency current to be supplied to the coil to thereby control a heating area of the heating member.

Abstract: In a fixing device for an image forming apparatus of the invention, circumferences of both side parts of an elastic layer are made larger than a circumference of a central part, and the expansion of a foamed rubber layer is absorbed by space between the elastic layer and a metal conductive layer. Thereby, the hardness of a heat roller at the time of fixing is made nearly uniform across the entire length in the shaft direction. The contact area of a core member and the elastic layer in the both side parts of the heat roller is made larger, and the stress per unit area generated in the elastic layer due to contact with the pressure roller is reduced.