Abstract: A fixing apparatus of an image forming apparatus of the present invention, in arrival timing of a temperature falling area of a heat roller passing a nip at opposite position ? of an induction heating coil from temperature detection position ? by an infrared temperature sensor around the heat roller, according to detection results by the infrared temperature sensor, controls an output value of the induction heating coil under control of an inverter circuit, heats and returns the heat roller in real time to a fixable temperature, and realizes energy conversation. At the time of arrival at the nip, the heat controller is always set to a fixed fixable temperature, thus in a fixed image, a high image quality free of ripple marks can be obtained.

Abstract: A fixing apparatus of the present invention includes a heating roller 2 that is a cylindrical member having a center axis, a pressurizing roller 3 that exerts pressure on the heating roller 2, and a temperature detecting element 6 that detects the temperature of the heating roller 2. The outer peripheral surface of the heating roller 2 is induction heated on the basis of the temperature information detected by the temperature detecting element 6. The fixing apparatus thus utilizes induction heating. The present invention is characterized in that the temperature detecting element 6 is placed in an area located vertically below the center axis of the heating member 2 and vertically below the outer peripheral surface of the heating member. The temperature detecting element 6 is thus provided at a position where it is unlikely to suffer thermal convection from the heating roller 2.

Abstract: In the present invention, a front-side focal distance L2 is changed without changing a rear-side focal distance L1 so as to bring an MTF value D2 and brightness fluctuation D3 into an MTF balance range, so that collapse of color balance can be improved, and life of optical members such as a light source can be extended.

Abstract: When the three U-, V-, W-phase arms of a DC/DC converter are turned on, they are alternately turned on by gate drive signals. When the U-, V-, W-phase arms are alternately turned on, an upper arm switching device of the U-phase arm, for example, is turned on, and thereafter a lower arm switching device of the U-phase arm is turned on. Thereafter, an upper arm switching device of the V-phase arm which is next to the U-phase arm is turned on, and thereafter a lower arm switching device of the V-phase arm is turned on. The upper and lower arm switching devices are thus turned on in a rotation switching process.

Abstract: A fixing apparatus according to an embodiment of the invention includes 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: 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: A fixing apparatus of an image forming apparatus of the present invention, in arrival timing of a temperature falling area of a heat roller passing a nip at opposite position ? of an induction heating coil from temperature detection position ? by an infrared temperature sensor around the heat roller, according to detection results by the infrared temperature sensor, controls an output value of the induction heating coil under control of an inverter circuit, heats and returns the heat roller in real time to a fixable temperature, and realizes energy conversation. At the time of arrival at the nip, the heat controller is always set to a fixed fixable temperature, thus in a fixed image, a high image quality free of ripple marks can be obtained.

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: 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 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: 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: 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: 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. 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: 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: 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.