Abstract: The present invention includes individually (independently) a drive control section for driving/controlling an induction heating device of a fixing device and a main-body control section for entirely controlling an electronic copying machine. The start-up processing for the induction heating device is started prior to start-up processing for parts of the main body of the electronic copying machine other than the induction heating device.

Abstract: The present invention provides a fixing device and a digital photocopier which can shorten the time from an instruction of starting image formation to end of fixing. The fixing device is provided in a cylinder made of metal and having a small thickness, and includes a magnetic excitation coil. When the power source is turned on, all the electric power defined by subtracting an electric power amount consumed by components other than the fixing device is supplied to the magnetic excitation coil to perform heating. As the structural components of the photocopier and auxiliary devices added to the photocopier operate, the electric power defined by subtracting, from the maximum input electric power, the electric power consumed by the structural components of the photocopier and the auxiliary devices is supplied to perform heating. In this manner, the heat roller of the fixing device is heated, in a short time, to a temperature which enables fixing, so that the time required for first copying can be shortened.

Abstract: An electrophotographic fixing device allowing a flow of an AC current through an electromagnetic induction coil arranged close to a heating roller having a metal layer formed of a conductor and allowing the heat generation of the heating roller to heat a to-be-fixed member, in which the fixing device comprises a circuit board for outputting the AC current from an output terminal and passing the current through the electromagnetic induction coil, a conductive plate metal having one end side fixed by a fastening screw to the output terminal of the circuit board, a male-side connection terminal provided on the other end of the plate metal, and a female-side connection terminal provided at an end of a leader line of the electromagnetic induction coil and detachably connected to a male-side connection terminal.

Abstract: A fixing device comprising an endless heating member which is adapted to be contacted with a fixable member to thereby enable an image on the fixable member to be thermally fixed, an electromagnetic inductive coil member disposed close to the endless heating member and inductively heating the endless heating member, and an AC power supply circuit supplying an AC current to the electromagnetic inductive coil member. The coil member is constructed such that in a state where the coil member is positioned in the fixing device, a ratio between an inductance L of the coil member and a load resistance R of the coil member meets a condition of L/R<50×10−6 (H/&OHgr;).

Abstract: The present invention is a fixing device for use in an electrophotographic apparatus arranged in a structure in which a high-frequency current is flowed through an induction coil provided close to an endless member having a metal layer made of a conductive material and the endless member is caused to generate heat to heat a material to be fixed. This fixing device is characterized in that, when a start-up operation is started by electrically conducting the induction coil, the endless member is rotated after the metal layer reaches a temperature higher than a final setting temperature, and for a predetermined time from starting rotation of the endless member, a high-frequency current having a size corresponding to a control value of a temperature lower than the final setting temperature and higher than a target temperature is supplied to the coil.

Abstract: A fixing device for an electrophotography system, which is capable of efficiently and uniformly heating an object to be heated, which has a coil capable of being easily produced and which is capable of being stably fixing a fixed material, is provided by preventing the distance between the going and returning portions of a certain turn of the coil from being too close to each other, by preventing the diameter of the coil from changing when the coil is wound, by providing a uniform gap between the coil and the inside surface of the heating roller over the whole length, by preventing the fixing performed by the heating roller to be affected by the turning ON/OFF of a power supply, by preventing noises from being generated from the coil ejecting portion, and by devising the procedure for efficiently winding the coil.

Abstract: When a voltage abnormality error signal from a drive control section is at a low level, a control section determines a normal state. When the voltage abnormality error signal has arisen to a high level, the control section does not immediately determine an abnormal state and instead measures a time in which the voltage abnormality error signal is at the high level. If the measured time does not exceed a predetermined error timer value (limit value) T, the control section ignores this abnormal state as a temporary voltage abnormality. If the time in which the voltage abnormality error signal is at the high level exceeds the error timer value T, the control section determines a serviceman call error (SC) as the occurrence of voltage abnormality.

Abstract: A high-frequency current is supplied from a high-frequency generating circuit to a coil of a heat roller, and a high-frequency magnetic field is generated from the coil. The high-frequency magnetic field causes an eddy current to be generated in the heat roller, and a developer image on a recording medium is fixed by self-generation of heat of the heating roller based on an eddy-current loss. Electric wires between the high-frequency generating circuit and the coil are electrically shielded by a shield member.

Abstract: A fixing device includes a heat roller which is adapted to be moved at the same velocity as the transferring speed of a paper with an image thereon and is adapted to be contacted with the paper to thereby enable the image on the paper to be thermally fixed, and an induction heating mechanism for performing an induction heating of the heat roller. The induction heating mechanism includes a coil, and a supporter for supporting the coil, and the supporter has a frame structure which is partitioned into a plurality of sections which are partitioned in a direction perpendicular to the transferring direction of the paper.

Abstract: An electrophotography fixing device has a heating roller and an induction heating device. In order to improve heat resistance, heat radiating performance and insulation performance and in order to appropriately uniformly heat the heating roller, in the induction heating device, induction heating coils wound onto a core are fixed by varnish mixed with mica, and the outside surfaces thereof are fixed by a heat resistant bundling band or a molded body of a heat resistant material, or coated with a heat resistant, insulating and thermal conductive sheet. Alternatively, the same sheets as the above described sheet are provided between the core and the coils and between the layers of the coils. In addition, the core is formed with a hole extending in axial directions or holes extending in directions perpendicular to the axial directions. Moreover, the coils are doubly insulated.

Abstract: An electrophotography fixing device has a heating roller and an induction heating device. In order to improve heat resistance, heat radiating performance and insulation performance and in order to appropriately uniformly heat the heating roller, in the induction heating device, induction heating coils wound onto a core are fixed by varnish mixed with mica, and the outside surfaces thereof are fixed by a heat resistant bundling band or a molded body of a heat resistant material, or coated with a heat resistant, insulating and thermal conductive sheet. Alternatively, the same sheets as the above described sheet are provided between the core and the coils and between the layers of the coils. In addition, the core is formed with a hole extending in axial directions or holes extending in directions perpendicular to the axial directions. Moreover, the coils are doubly insulated.

Abstract: A fixing device for an electrophotography system, which is capable of efficiently and uniformly heating an object to be heated, which has a coil capable of being easily produced and which is capable of being stably fixing a fixed material, is provided by preventing the distance between the going and returning portions of a certain turn of the coil from being too close to each other, by preventing the diameter of the coil from changing when the coil is wound, by providing a uniform gap between the coil and the inside surface of the heating roller over the whole length, by preventing the fixing performed by the heating roller to be affected by the turning ON/OFF of a power supply, by preventing noises from being generated from the coil ejecting portion, and by devising the procedure for efficiently winding the coil.

Abstract: A fixing device includes a conductive and magnetic hollow roller, a metallic layer made of high thermal conductive material formed on the outer surface of the hollow roller, and a magnetic field generating coil provided in the hollow roller to generate eddy current on the hollow roller. A power source applies high-frequency current to the magnetic field generating coil and a pressure roller contacts the hollow roller in a specified nipping width. Also provided is a fixing device with a second hollow roller fitted to the outer surface of a first hollow roller, a coil provided in the first hollow roller, a current source for selectively applying current of at least two frequencies, and a third roller contacting the second roller in a specified nipping width.

Abstract: A fixing device includes a heating belt made of a conductive material, a pair of belt stretching rollers on which the heating belt is wound, and a pressure roller pressed against the heating belt via a specified nipping portion. A magnetic field generating unit is arranged opposed to the back of the heating belt at a portion equivalent to the nipping portion of the heating belt via an air layer for generating eddy current on the surface of the heating belt, and a power source applies high-frequency current to the magnetic field generating unit.

Abstract: A fixing device of the present invention includes a first roller that is made of a conductive material, and is rotated and driven; a second roller that is in contact with the first roller in the pressed state; and an induction heating unit that is arranged at the first roller side and concentrates the induction heating to the nip portion of the first roller and change a developer image formed on a fixing medium to a fixed imaged. This induction heating unit of the fixing device is made of a high permeable material, has a core that is open at the surface opposite to the first roller and a coil wound round the core and generates magnetic flux on the core when high frequency current is supplied to the core and has a high projecting portion so that a part of the core closes the first roller.

Abstract: A fixing device is provided, which can maintain good fixing properties, irrespective of the kind of a material on which a developer image is to be fixed and a temperature condition of a pressure roller. In a rotary contact region between a heat supply medium and the pressure roller, pressure and heat are applied to the material, thereby fixing the developer image on the material. The heat supply medium includes a metallic body for induction heating, which is provided with a magnetic field to produce an eddy current. The heat supply medium contains a magnetic field generating unit. The magnetic field generating unit includes a core provided with a coil. The core is situated near the metallic body of the heat supply medium such that a distance between a position closest to the metallic body and an end portion of the core is less than a distance between magnetic force line guiding portions provided on the core.

Abstract: A fixing device of the present invention includes a first roller that is made of a conductive material, and is rotated and driven; a second roller that is in contact with the first roller in the pressed state; and an induction heating unit that is arranged at the first roller side and concentrates the induction heating to the nip portion of the first roller and change a developer image formed on a fixing medium to a fixed imaged. This induction heating unit of the fixing device is made of a high permeable material, has a core that is open at the surface opposite to the first roller and a coil wound round the core and generates magnetic flux on the core when high frequency current is supplied to the core and has a high projecting portion so that a part of the core closes the first roller.

Abstract: A fixing device includes a conductive and magnetic hollow roller, a metallic layer made of high thermal conductive material formed on the outer surface of the hollow roller, and a magnetic field generating coil provided in the hollow roller to generate eddy current on the hollow roller. A power source applies high-frequency current to the magnetic field generating coil and a pressure roller contacts the hollow roller in a specified nipping width. Also provided is a fixing device with a second hollow roller fitted to the outer surface of a first hollow roller, a coil provided in the first hollow roller, a current source for selectively applying current of at least two frequencies, and a third roller contacting the second roller in a specified nipping width.

Abstract: A color copying machine includes a plurality of image forming sections having rotatable photoconductive drums, respectively. One of the drums, which is used for forming images in black, is rotated by a first drum drive motor, and the other drums are rotated by a second drum drive motor. A plurality of transfer devices are arranged to oppose the image carriers, respectively. A paper sheet is sequentially moved to positions opposing the drums and clamped between the drums and transfer rollers so as to transfer images on the drum to the paper sheet. When a image formation is performed by using the image forming section for black, the first drive motor is operated and the second motor is stopped. The transfer rollers opposing the drums for other than black are moved to positions wherein these transfer rollers are away from the corresponding drums.