摘要:
An excitation coil is arranged so as to be opposed to a rotatable heat generating roller of a conductive material, and on a rear side of the excitation coil, a core of a magnetic material is provided. The core is composed of a central core that is formed continuously in a rotation axis direction of the heat generating roller, and a plurality of U-shaped cores arranged at a distance from each other in that direction. A high-frequency current is applied to the excitation coil so that the heat generating roller 1 generates heat by electromagnetic induction. An additional coil is wound around the U-shaped core. Both ends of the additional coil are connected to a switching unit. When the switching unit is brought to a connected state, under an induction current generated in the additional coil, a magnetic flux in a direction in which a magnetic flux of the excitation coil is cancelled out is generated, so that heat generation of the heat generating roller can be suppressed. The switching unit is switched over according to a width of a paper sheet to be passed and a temperature distribution in the rotation axis direction. Thus, a uniform temperature distribution of the heat generating roller in the rotation axis direction can be maintained.
摘要:
The present invention relates to an image forming apparatus that enables the occurrence of print defects due to a first print start time delay to be eliminated without using a temperature sensor that has a small thermal time constant. When the temperature of a fixing belt serving as an image heating body is greater than or equal to a predetermined temperature following the elapse of a fixed time after an image forming operation is started, recording paper is transported to a nip area (fixing area) of a fixing apparatus before the temperature detected by a temperature sensor reaches a predetermined image fixing temperature, and an image forming operation is started immediately.
摘要:
An image heating device is operational to estimate a temperature of a pressure roller so as to determine a set temperature for a roller belt in a subsequent image heating period.
摘要:
An image heating device having a predetermined amount of heat generation with a small electric current. The device includes a heat-generating roller (1) having magnetism and conductivity, an exciting coil (5) opposed to the peripheral face of the heat-generating roller (1) and adapted for allowing the heat-generating roller (1) to generate heat with electromagnetic induction. The exciting coil (5) is composed of a bundle of 60 copper wires of a 0.2 mm diameter are extended in the direction of the rotation axis of the heat-generating roller (1) and they are circumferentially wound along the circumferential direction of the heat-generating roller (1). The bundled wires are arranged in close contact with each other in the circumferential direction of the heat-generating roller (1) so as to cover the upper half of the heat-generating roller (1).
摘要:
An image heating device is provided with reduced cost, by which a difference in glossiness among printed images on recording media is eliminated, and the wrapping of a belt and the like at a high temperature is prevented. In the image heating device, a controller estimates a temperature of a pressure roller according to at least one of a temperature of a belt detected by a temperature sensor and a variation with time in the detected temperature from completion of the heating after application of an electric power to the magnetization coil by an exciting circuit is stopped and the heating of the belt by the heating roller is stopped, so as to determine a set temperature for the belt in a subsequent image heating period.
摘要:
An image heating device having a predetermined amount of heat generation with a small electric current. The device comprises a heat-generating roller (1) having magnetism and conductivity, an exciting coil (5) opposed to the peripheral face of the heat-generating roller (1) and adapted for allowing the heat-generating roller (1) to generate heat with electromagnetic induction. The exciting coil (5) is composed of a bundle of 60 copper wires of a 0.2 mm diameter are extended in the direction of the rotation axis of the heat-generating roller (1) and they are circumferentially wound along the circumferential direction of the heat-generating roller (1). The bundled wires are arranged in close contact with each other in the circumferential direction of the heat-generating roller (1) so as to cover the upper half of the heat-generating roller (1).
摘要:
The present invention relates to an image forming apparatus that enables the occurrence of print defects due to a first print start time delay to be eliminated without using a temperature sensor that has a small thermal time constant. When the temperature of a fixing belt serving as an image heating body is greater than or equal to a predetermined temperature following the elapse of a fixed time after an image forming operation is started, recording paper is transported to a nip area (fixing area) of a fixing apparatus before the temperature detected by a temperature sensor reaches a predetermined image fixing temperature, and an image forming operation is started immediately.
摘要:
An image heating device is provided with reduced cost, by which a difference in glossiness among printed images on recording media is eliminated, and the wrapping of a belt and the like at a high temperature is prevented. In the image heating device, controlling means estimates a temperature of a pressure roller according to at least one of a temperature of a belt detected by a temperature sensor and a variation with time in the detected temperature from completion of the heating after application of an electric power to the magnetization coil by an exciting circuit is stopped and the heating of the belt by the heating roller is stopped, so as to determine a set temperature for the belt in a subsequent image heating period.
摘要:
An image heating device having a predetermined amount of heat generation with a small electric current. The device includes a heat-generating roller (1) having magnetism and conductivity, an exciting coil (5) opposed to the peripheral face of the heat-generating roller (1) and adapted for allowing the heat-generating roller (1) to generate heat with electromagnetic induction. The exciting coil (5) is composed of a bundle of 60 copper wires of a 0.2 mm diameter are extended in the direction of the rotation axis of the heat-generating roller (1) and they are circumferentially wound along the circumferential direction of the heat-generating roller (1). The bundled wires are arranged in close contact with each other in the circumferential direction of the heat-generating roller (1) so as to cover the upper half of the heat-generating roller (1).
摘要:
A fixing device as an image heating device is provided, by which a difference in glossiness is not caused in a recording medium in the axial direction of a pressure roller. When a print request is issued during the end-processing sequence, an electric power applied to a magnetization coil via an exciting circuit is dropped to 0 by controlling means during the start-processing sequence, and after an appropriate interval, the heating with full power is restarted by the controlling means. By so doing, the decrease in temperature at both ends of a fixing belt and a heat-generating roller in the axial direction can be compensated.