Abstract: A warm-up operation control section performs warm-up operation of a fixing-side rotation unit and a pressure-side rotation unit from start-up until the temperature of the fixing-side rotation unit exceeds a first specified value based on an output of a heating-side thermistor in forming a monochrome image. In forming a color image, the warm-up operation control section performs warm-up operation of the fixing-side rotation unit and the pressure-side rotation unit from start-up until the temperature of the pressure-side rotation unit exceeds a second specified value based on an output of a pressure-side thermistor. Time required for the temperature of the fixing-side rotation unit to exceed the first specified value is set shorter than time required for temperature of the pressure-side rotation unit to exceed the second specified value.

Abstract: A warm-up operation control section performs warm-up operation of a fixing-side rotation unit and a pressure-side rotation unit for a first period of time from start-up in the case of a monochrome mode set by a setting section. In the case of a color mode, the warm-up operation control section performs warm-up operation of the fixing-side rotation unit and the pressure-side rotation unit for a second period of time which is longer than the first period of time from start-up.

Abstract: An image forming apparatus is provided with a feed interval control section that sets feed intervals of the recording materials, for a defined period from immediately after completion of the warm-up operation for a fixing-side rotor and the pressure-side rotor determined by a warm-up completion determination section, to be longer than feed intervals of the recording materials posterior to the defined period in a high-humidity and low-temperature state. Thereby, the image forming apparatus prevents elongation of a warm-up time while achieving both reduction of the back curl and maintenance of fixability in the high-humidity and low-temperature state.

Abstract: A belt type fixing device of the invention comprises a fixing belt, a heating panel, a pressure member, and a pressure roller. The heating panel has a curved outer surface in sliding contact with the inner surface of the fixing belt and a curved inner surface on which a resistance heating band element is formed. The resistance heating band element is formed in a zigzag pattern with a plurality of stripes perpendicular to the direction in which the fixing belt moves. The pressure member gives tension to the fixing belt in cooperation with the heating panel and has an elastic body in sliding contact with the inner surface of the fixing belt. The pressure roller rotating in a predetermined direction applies pressure to toner carrying recording paper led into a nip formed by the pressure roller and the pressure member.

Abstract: A belt-type fixing device for an image forming apparatus is capable of raising a temperature to a level suitable for a fixing process in a short period of time with high heating efficiency. A fixing belt is entrained in spanning relation between a heating plate providing a heat generator on the inner surface of the semi-cylindrical plate and a pressing pad disposed at a distance from the heating plate. A pressing roller is disposed at a position opposing the pressing pad. The fixing belt is revolved by rotating the pressing roller. A recording medium having a toner adhered thereto is caused to pass through a nip portion of the fixing belt and the pressing roller.

Abstract: A belt tape fixing device of the invention comprises a fixing belt, a heating panel, a pressure member, and a pressure roller. The heating panel has a curved outer surface in sliding contact with the inner surface of the fixing belt and a curved inner surface on which a resistance heating band element is formed. The resistance heating band element is formed in a zigzag pattern with a plurality of stripes perpendicular to the direction in which the fixing belt moves. The pressure member gives tension to the fixing belt in cooperation with the heating panel and has an elastic body in sliding contact with the inner surface of the fixing belt. The pressure roller rotating in a predetermined direction applies pressure to toner carrying recording paper led into a nip formed by the pressure roller and the pressure member.

Abstract: A belt-type fixing device for an image forming apparatus is capable of raising a temperature to a level suitable for a fixing process in a short period of time with high heating efficiency. A fixing belt is entrained in spanning relation between a heating plate providing a heat generator on the inner surface of the semi-cylindrical plate and a pressing pad disposed at a distance from the heating plate. A pressing roller is disposed at a position opposing the pressing pad. The fixing belt is revolved by rotating the pressing roller. A recording medium having a toner adhered thereto is caused to pass through a nip portion of the fixing belt and the pressing roller.

Abstract: A metal sheet showing either voltage characteristics, impedance or calorific characteristics close to the case where low frequency is applied even when a high frequency alternating current voltage is applied. This metal sheet presents a good movement of displacement and less starting points of cracking, because of its good crystallinity (good mobility of conductive electrons). Therefore, it is hardly destroyed under the repeated deformation. In short, it presents a high fatigue resistance against repetitive deformation. Therefore, this metal sheet is suited for a fixing belt and a fixing apparatus. The evaluation of fatigue resistance using this can be realized by comparing voltage characteristics, impedance, or calorific characteristics when high and low frequency alternating current voltages are applied to a test piece.

Abstract: In a receiver-integrated condenser, a super-cooling portion for cooling liquid refrigerant from a receiving unit is disposed between first and second condensing portions in a core portion in a vertical direction. Therefore, in an engine-idling, even when high-temperature air having passed through the receiver-integrated condenser is introduced again toward an upstream air side of the receiver-integrated condenser through a lower side of the receiver-integrated condenser, the high-temperature air is not introduced toward the arrangement position of said super-cooling portion, because the super-cooling portion is positioned at an upper side from the second condensing portion. Thus, super-cooling performance of refrigerant in the super-cooling portion of the core portion is prevented from being decreased even in the engine idling.

Abstract: A metal sheet showing either voltage characteristics, impedance or calorific characteristics close to the case where low frequency is applied even when a high frequency alternating current voltage is applied. This metal sheet presents a good movement of displacement and less starting points of cracking, because of its good crystallinity (good mobility of conductive electrons). Therefore, it is hardly destroyed under the repeated deformation. In short, it presents a high fatigue resistance against repetitive deformation. Therefore, this metal sheet is suited for a fixing belt and a fixing apparatus. The evaluation of fatigue resistance using this can be realized by comparing voltage characteristics, impedance, or calorific characteristics when high and low frequency alternating current voltages are applied to a test piece.

Abstract: A fixing belt is applied to a fixing apparatus of an electronic photography type printer. The fixing belt consists of a belt base and an elastic layer having a thickness of 200 .mu.m or more formed on the belt base. The elastic layer consists of first, second and third elastic layers arranged in that order from the base side, and is deformable to conform to the surface shape of a recording paper so that all unfixed toner held on the recording paper can be pressed. The second elastic layer is a barrier layer for preventing releasing agent from permeating and the belt from swelling to suppress the thickening of the elastic layer as a whole and maintain the belt thickness within a range that does not cause any image noises.

Abstract: A heating device comprises an endless rotary member, a resistance heating member, a current receiver member provided at the endless rotary member and a current supply member being in contact with the current receiver member.In a form, the current supply member is made of a sintered material containing copper and carbon, and a content of the copper in the sintered material is in a range from 55% to 80% by weight.In another form, a contact surface of the current receiver member is formed of a material harder than the current supply member. The contact surface of the current receiver member and the contact surface of the current supply member have surface roughnesses satisfying a relationship of (surface roughness of the current receiver member).ltoreq.(surface roughness of the current supply member). The surface roughness Ra of the current receiver member is in a range from 0.3 .mu.m to 5.5 .mu.m. The surface roughness Ra of the current supply member is equal to or smaller than 5.5 .mu.m.

Abstract: A heating device comprises an endless rotary member having a peripheral surface to be moved rotatively, a resistance heating member arranged at the peripheral surface of the rotary member and generating a heat when supplied with an electric current, a current receiver member arranged in a space inside the rotary member and electrically connected to the resistance heating member, and a current supply member being in contact with the current receiver member and to be electrically connected to a power source.A heating rotary member for the heating device comprising the endless rotary member, the resistance heating member, and the current receiver member.

Abstract: An induction heating fixing device is disclosed which is provided with a conducting sleeve, a coil for causing the sleeve to generate an induced current, and a high-frequency power source for feeding a high-frequency wave to the coil. This fixing device detects the switching cycle of the high-frequency power source and the electric power injected into the sleeve and, based on the detected switching cycle and the detected electric power, controls the amount of electric current to be fed from the high-frequency power source to the coil.

Abstract: In a fixing apparatus having a flexible metal fixing sleeve provided around a holder, which holds a coil inside, and heated by induction current of the coil, and a pressure roller that pinches the fixing sleeve between it and the holder by pressing on the holder, the following relation is satisfied:(F1+F2)/F3.gtoreq.1.7where symbols F1, F2 and F3 represent respectively during recording paper feeding: a drive force transmitted from the pressure roller to the fixing sleeve via recording paper in the region where the recording paper passes through; a drive force transmitted from the pressure roller directly to the fixing sleeve in the region where the recording paper does not pass through; and a friction resistance force generated between the inner surface of the fixing sleeve and the outer surface of the holder.

Abstract: A fixing apparatus for controlling an oil transfer apparatus to maintain a releasing agent holding layer such that it is not always saturated with the releasing agent. This makes it a compact, cost-effective unit with a long service life and provides a uniform, stable oil coating that eliminates image noise problems. In order to use a constant and minimum necessary amount of releasing agent, a releasing agent supply nozzle is incorporated with multiple protrusive or retrusive droplet growth assisting members at or near multiple releasing agent discharge ports. The supply nozzle used for supplying the oil has multiple discharge holes having approximately equal opening cross-sectional areas and an equalizing member which equalizes the amount of oil discharged from each discharge hole. The outer diameter D1 of the oil supply roller, the outer diameter D2 of the metal core and the distance P of adjacent through-holes formed on the periphery of the metal core satisfy a relation, 0.6<D1.multidot.(D1-D2)/(D2.

Abstract: A fixing apparatus that supports an endless belt by rollers, forms a nipping area with a pressuring roller contacting outside periphery of the belt, and fixes unfixed images on sheets that are transported into the nipping area, the fixing apparatus characterized in that transportation of the sheets into the nipping area is prohibited until the minimum belt temperature detected by a temperature sensor reaches a fixing approval temperature.

Abstract: This invention is related to a power supply unit used in an image forming apparatus having a induction heat fusing device. In the power supply unit, each of a first and a second rectifying circuits rectifies AC voltage from a power supply to generate DC voltage. An inverter circuit generates a high frequency voltage to be applied to a coil of the induction heat fusing device by switching the DC voltage from the first rectifying circuit. A switching circuit switches the DC voltage from said second rectifying circuit and generates AC voltage. A transformer receives the AC voltage from the switching circuit and outputs a transformed voltage to be apply to a component of the image forming apparatus. The inverter, second rectifying circuit and switching circuit are connected to a common ground line.

Abstract: An induction heating fixing apparatus is disclosed which in characterized by comprising an object to be heated formed of an electroconductive material, a coil for effecting induction heating on the object to be heated, an inverter circuit for effecting the flow of a high frequency to the coil, a thermistor for detecting the temperature of the object to be heated, a control circuit electrically insulated from the inverter circuit and adapted to control the inverter circuit based on the temperature detected by the thermistor so as to keep the object to be heated at a temperature in a prescribed range, and an insulating switch for transmitting the control signal from the control circuit in an electrically insulated state to the inverter circuit.

Abstract: A fixing device for heating and fixing an unfixed image to a record member, including: a heating roller having a core roller and a layer of a resistance heating material formed on an outer or inner peripheral surface of the core roller; a pair of carriers rotatably carrying the heating roller; a pair of ring-shaped current receiver members each located between the carrier and a center of the heating roller, a pair of current supply members being in contact with the current receiver members; and insulating members made of an electrical insulation material, each being in contact with an outer end of the current receiver member and extending toward the carrier, wherein a distance L3 from the inner end of the carrier to the outer end of the current receiver member is 1 mm or more, a sum (L1+L2) of a width L1 of the insulating member and a height L2 of the insulating member from the core roller is 2.5 mm or more, and the distance L3 and the width L1 satisfy a relationship of L3.gtoreq.L1.