Abstract: A heating apparatus which can increase the temperature of a heating element to a target temperature in a short time and ensures temperature uniformity of the heating element. In the heating apparatus, when the specific resistance of a material of a heat generating layer of a heating roller is ? (???cm), the average thickness of the heat generating layer is 5? (?m) or more but not more than 15? (?m), and the thickness error is 1.2? (?m) or less. For instance, when the heat generating layer is copper having a specific resistance of 1.7 (???cm), the average thickness of the heat generating layer is 8-25 (?m), and the thickness error is 2 (?m) or less. Thus, the heating roller having a short heat increasing time and excellent temperature uniformity is provided.

Abstract: A fixing device for reducing, without fail, the heating output without using a control circuit if an excessive temperature rise of a rotary heating member is predicted, even if the control circuit fails or runs away. In the fixing device, heating of a fixing belt for heat-fixing an unfixed image on a recording medium is controlled by a body-side processor. When the fixing belt stops or rotates at a rotational speed equal to or below a threshold, an oscillation stop circuit stops the oscillation of an inverter circuit to stop the heating, independently of the processor. To check the operation of a rotation detection circuit for detecting the rotating state of the fixing belt (fixing roller) and the oscillation stop circuit, self-diagnosis is utilized to ascertain that the fixing belt is not heated by giving a heating instruction when the condition of not heating the fixing belt is satisfied is performed when the power is turned on or is performed regularly during standby.

Abstract: A heating apparatus which can increase the temperature of a heating element to a target temperature in a short time and ensures temperature uniformity of the heating element. In the heating apparatus, when the specific resistance of a material of a heat generating layer (212) of a heating roller (210) is ? (??cm), the average thickness of the heat generating layer (212) is 5? (?m) or more but not more than 15? (?m) and the thickness error is 1.2? (?m) or less. For instance, in the case of forming the heat generating layer (212) by using cupper having a specific resistance of 1.7 (??cm), the average thickness of the heat generating layer (212) is 8-25 (?m) and the thickness error is 2 (?m) or less. Thus, the heating roller (210) having a short heat increasing time and excellent temperature uniformity is provided.

Abstract: A fixing unit is provided with a fixing belt that heats recording paper that bears and moves a toner image, an exciting coil that generates magnetic flux in the fixing belt and causes the fixing belt to produce heat by electromagnetic induction, and a heat production adjustment section that adjusts the calorific value distribution of the fixing belt by adjusting the magnetic flux acting upon the fixing belt.

Abstract: A fixing device enabling the temperature of a heating element to be uniformly and stably maintained even if the heating element is eccentrically moved or vibrated. An opposed core (233) is so formed that a small diameter opposed core (2332) is fixedly inserted onto the center part of a core shaft (2331) and large diameter opposed cores (2333) are fixedly inserted onto both end parts of the core shaft (2331) so that the cross sectional area thereof at both ends in the lateral direction (both ends in the longitudinal direction) is larger than the cross sectional area thereof at the center part in the lateral direction. A fixing belt (210) is formed of a non-magnetic material and disposed between a core (232) and the opposed core (233).

Abstract: A heat generating roller, fixing equipment and an image forming apparatus in which warm-up time is shortened while preventing excessive temperature rise and good fixing performance is realized by preventing offset. The heat generating roller is formed principally by laying a high permeability conductive layer and a nonmagnetic conductive layer in layer. When a voltage is applied from a power supply to an exciting coil and an alternating current flow, magnetic flux is generated around the exciting coil and a magnetic field is formed. Magnetic coupling of a system including the heat generating roller and the exciting coil is advantageous at a low temperature and heat generation of the heat generating roller is accelerated. When the Curie point is exceeded, skin depth increases and skin resistance decreases, which suppresses generation of Joules heat and reduces heat generation of the heat generating roller.

Abstract: There is provided a fixing apparatus capable of reducing the warm-up time, improving the heating efficiency, and suppressing the temperature increase out of the sheet width by using a magnetic adjuster. In this apparatus, the Currie temperature Tc of the magnetic adjuster material heated by electromagnetic induction is set to 220 degrees C. or below and the fixation setting temperature of a heating member corresponding to the portion where a recording material passes during continuous sheet feed is set lower than a value than the temperature at which the relative magnetic permeability of the magnetic adjuster material begins to decrease. Thus, it is possible to obtain a large difference between the heating portion and the non-heating portion, to surely prevent excessive temperature increase of the portion out of the recording material width, to reduce the warm-up time, and improve the heating efficiency.

Abstract: A shield plate that has a plate portion stretching in a width direction of exciting coils is positioned so that end portions of the shield plate oppose the exciting coils. The present invention prevents elongated warm-up time and reduces a dramatic temperature drop when printing on thick paper in a low temperature environment.

Abstract: In a fixing apparatus using an induction heating type of heating apparatus, there are provided an excitation apparatus that generates magnetic flux, an opposed core located opposite the excitation apparatus, a fixing belt that is induction-heated by the aforementioned magnetic flux, and magnetism masking elements that block magnetic paths corresponding to paper non-passage areas of fixing belt between the excitation apparatus and the opposed core. By blocking magnetic paths between the excitation apparatus and the opposed core by the magnetism masking elements, magnetic flux that induction-heats the fixing belt is effectively masked, and an excessive rise in temperature of paper non-passage areas of fixing belt is prevented.

Abstract: An image heating apparatus is provided that enables the entire width of a heat-producing medium to be heated uniformly and an excessive rise in temperature to be prevented, without making the configuration complex. In a fixing unit 19 in which this apparatus is applied, a fixing belt 112 is an annular member that has an inner peripheral surface and an outer peripheral surface, and produces heat through the action of magnetic flux. An exciting coil 120 is located in proximity to the outer peripheral surface of fixing belt 112, and generates magnetic flux that acts upon fixing belt 112. A suppression member 650 is located in proximity to inner peripheral surface of fixing belt 112, and reduces, of the magnetic flux generated by exciting coil 120, magnetic flux that acts upon a paper non-passage area of fixing belt 112.

Abstract: A fixing apparatus that enables the calorific value of a heat-producing rotating element to be stabilized and the heat production efficiency of that heat-producing rotating element to be improved. A fixing apparatus (200) is equipped with a heat-producing sleeve (210), an induction heating apparatus (230), a magnetic field absorption member (233) that absorbs a magnetic field generated by the induction heating apparatus (230), and a fixing roller (240) and pressure roller (250) that grip and rotate the heat-producing sleeve (210). The magnetic field absorption member (233) is located in an area opposite an exciting coil (231) with the heat-producing sleeve (210) between, and absorbs a magnetic field generated by the induction heating apparatus (230). The heat-producing sleeve (210) is composed of a nonmagnetic metallic material of thickness in the range from 10 ?m to 500 ?m and specific resistance of 80×10?6 ?cm or less.

Abstract: A heat generating roller, fixing equipment and an image forming apparatus in which warm-up time is shortened while preventing excessive temperature rise and good fixing performance is realized by preventing occurrence of offset. In the heat generating roller, fixing equipment and image forming apparatus, the heat generating roller is formed principally by laying a high permeability conductive layer and a nonmagnetic conductive layer in layer. When a voltage is applied from a power supply (not shown) to an exciting coil and an AC current flow through it, magnetic flux is generated around the exciting coil and a magnetic field is formed. Since the heat generating roller has the high permeability conductive layer and the nonmagnetic conductive layer laid in layer, magnetic coupling of a system consisting of the heat generating roller and the exciting coil is good at the time of low temperature and heat generation of the heat generating roller is accelerated.

Abstract: A fixing device for infallibly reduce the heating output without using a control circuit if an excessive temperature rise of a rotary heating member is predicted even if the control circuit fails or runs away. In the fixing device (200), heating of a fixing belt (230) for heat-fixing an unfixed image on a recording medium is controlled by a body-side processor (401). When the fixing belt (230) stops or rotates at a rotational speed of a threshold or less, an oscillation stop circuit (307) stops the oscillation of an inverter circuit (305) to stop the heating independently of the processor (401).

Abstract: A shield plate that has a plate portion stretching in a width direction of exciting coils is positioned so that end portions of the shield plate oppose the exciting coils. The present invention prevents elongated warm-up time and reduces a dramatic temperature drop when printing on thick paper in a low temperature environment.

Abstract: A fixing apparatus that enables the calorific value of a heat-producing rotating element to be stabilized and the heat production efficiency of that heat-producing rotating element to be improved. A fixing apparatus (200) is equipped with a heat-producing sleeve (210), an induction heating apparatus (230), a magnetic field absorption member (233) that absorbs a magnetic field generated by the induction heating apparatus (230), and a fixing roller (240) and pressure roller (250) that grip and rotate the heat-producing sleeve (210). The magnetic field absorption member (233) is located in an area opposite an exciting coil (231) with the heat-producing sleeve (210) between, and absorbs a magnetic field generated by the induction heating apparatus (230). The heat-producing sleeve (210) is composed of a nonmagnetic metallic material of thickness in the range from 10 ?m to 500 ?m and specific resistance of 80×10?6 ?cm or less.

Abstract: An electromagnetic induced heating roller comprises a core member, an elastic layer, induction heating layer, and a mold release layer in this order from inside to outside. Further, a magnetic shield layer for preventing a magnetic flux from penetrating into the core member is interposed between the induction heating layer and the core member. The production of an alternating magnetic field from a magnetic field generating device, a leakage flux having penetrated through the induction heating layer is trapped by the magnetic shield layer. As a result, most of the impressed alternating magnetic flux is consumed for heating the heating layer, resulting in an improvement in the heating efficiency. A trouble is prevented which is generated by heating the bearing of the core member.

Abstract: In a fixing apparatus using an induction heating type of heating apparatus, there are provided an excitation apparatus that generates magnetic flux, an opposed core located opposite the excitation apparatus, a fixing belt that is induction-heated by the aforementioned magnetic flux, and magnetism masking elements that block magnetic paths corresponding to paper non-passage areas of fixing belt between the excitation apparatus and the opposed core. By blocking magnetic paths between the excitation apparatus and the opposed core by the magnetism masking elements, magnetic flux that induction-heats the fixing belt is effectively masked, and an excessive rise in temperature of paper non-passage areas of fixing belt is prevented.

Abstract: A heating roller (21) includes a heat generating layer (22) that generates heat by electromagnetic induction, a heat insulating layer (23), and a supporting layer (24), which are provided inwardly in this order. The supporting layer (24) is formed of a material having a specific resistance of 1×10?5 ?m or higher. Therefore, even when the heat generating layer (22) has a thickness smaller than a skin depth, i.e. a thickness defined by a flow of an induction current, so that magnetic flux penetrates the heat generating layer (22) and even reaches the supporting layer (24), heat generation of the supporting layer (24) under an eddy current can be suppressed. Thus, the heat generating layer (22) can be decreased in thermal capacity, and heat generation of the supporting layer (24) is suppressed, so that only the heat generating layer (22) can be heated efficiently. As a result, a warm-up time can be reduced. Further, breakage by heat of, for example, bearings supporting the heating roller (21) can be prevented.

Abstract: An image heating device according to an embodiment of the present invention includes a heat generator that has an outer surface and that generates heat by induction heating and a heater positioned close to the outer surface of the heat generator, the heater being configured to heat the heat generator by induction heating. A positioner is located close to an end of the heater, the positioner being configured to position the heater with respect to the heat generator. A vibration absorber is attached to the positioner and is configured, in one embodiment, to viscoelasticly absorb vibration of the heater produced by a vibration caused by an electromagnetic repulsive force acting between the heat generator and the heater when the heater heats the heat generator by induction heating.

Abstract: An image heating apparatus is provided that enables the entire width of a heat-producing medium to be heated uniformly and an excessive rise in temperature to be prevented, without making the configuration complex. In a fixing unit 19 in which this apparatus is applied, a fixing belt 112 is an annular member that has an inner peripheral surface and an outer peripheral surface, and produces heat through the action of magnetic flux. An exciting coil 120 is located in proximity to the outer peripheral surface of fixing belt 112, and generates magnetic flux that acts upon fixing belt 112. A suppression member 650 is located in proximity to inner peripheral surface of fixing belt 112, and reduces, of the magnetic flux generated by exciting coil 120, magnetic flux that acts upon a paper non-passage area of fixing belt 112.