Abstract: 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.

Abstract: An image heating apparatus and heat generating rotary member for use in the image heating apparatus has a fixing roller including a magnetic metal layer and a non-magnetic metal layer, and the non-magnetic metal layer is provided on the outer side of the magnetic metal layer and is thinner than the magnetic metal layer.

Abstract: The present invention provides an image heating device in a simple configuration capable of reliably positioning a member to be heated and an exciting coil and reliably preventing vibration transmission from the exciting coil to the member to be heated.

Abstract: A PDA includes a printed-circuit board on which at least one printed antenna pair having two chip-like printed antennas, which receive linearly polarized signals and are disposed along axes orthogonal to each other, is mounted. In each of the printed antennas, an open end is formed of at least two antenna conductors separated from each other. Besides, in the printed-circuit board, a ground required by one or plural other modules is disposed so as to surround a surrounding area of at least three sides of four sides forming a rectangular section in each of the printed antennas, and each of the printed antennas is disposed and mounted so that a remaining one side faces an edge portion of the printed-circuit board. While the PDA can receive circularly polarized signals very effectively, the degree of freedom in layout is greatly expanded and miniaturization can be realized.

Abstract: An image heating device includes a heat generating member that heats a body to be heated that is allowed to travel while carrying an image, an excitation unit that is provided close to the heat generating member and generates magnetic flux so as to cause the heat generating member to generate heat by electromagnetic induction, and a heat generation suppressing unit that suppresses an amount of heat generated in the heat generating member by regulating magnetic flux generated by the excitation unit. The heat generation suppressing unit suppresses heat generation of the heat generating member in a region corresponding to a region including at least a center portion of the body to be heated in a width direction. Thus, an amount of heat generated in the width direction can be regulated using a simple configuration at a reduced cost. Further, when the heat generation suppressing unit is operated, diffusion of magnetic flux into a wide area can be prevented.

Abstract: 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).

Abstract: A chip-like printed antenna in which an open end is formed by at least two antenna conductors separated from each other is mounted on a printed-circuit board. A ground required by one or plural other modules is disposed and mounted on the printed-circuit board so as to surround a remaining area of a surrounding area of the printed antenna except a partial area as indicated by oblique line parts. By this, in the printed-circuit board, a radiation electric field does not come to have a dipole mode, but is formed into a balloon shape and is radiated in one direction as indicated by a broken line.

Abstract: A temperature determining device is composed of a temperature detecting unit that detects a temperature of a determination object member based on an intensity of infrared rays from the object member, a unit for determining a temperature for correction that determines a temperature of an opposing member opposed to the object member or a temperature of a member whose temperature changes in correlation to a change in the temperature of the opposing member, and a calculating unit that corrects the detected temperature obtained by the temperature detecting unit using the temperature as the temperature for correction obtained by the unit for determining a temperature for correction. Thus, stable temperature determination can be performed accurately without being influenced by infrared rays from around a determination object member.

Abstract: An image heating device with a small thermal capacity that can be heated rapidly. The image heating device includes a fixing belt (20) having a heat resistance; a rotatable heat-generating roller (21), which is at least partially conductive and arranged in contact with an inner peripheral surface of the fixing belt (20); a fixing roller (22), the fixing roller and the heat-generating roller (21) movably suspending the fixing belt (20) therebetween; and a magnetization means (24) for heating the heat-generating roller (21) through magnetization, which is arranged outside the heat-generating roller (21). In this image heating device, the magnetization means (24) heats the heat-generating roller (21) through magnetization after a rotating operation of the heat-generating roller (21) is started.

Abstract: 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).

Abstract: An image heating device with a small thermal capacity that can be heated rapidly. The image heating device includes a fixing belt (20) having a heat resistance; a rotatable heat-generating roller (21), which is at least partially conductive and arranged in contact with an inner peripheral surface of the fixing belt (20); a fixing roller (22), the fixing roller and the heat-generating roller (21) movably suspending the fixing belt (20) therebetween; and a magnetization means (24) for heating the heat-generating roller (21) through magnetization, which is arranged outside the heat-generating roller (21). In this image heating device, the magnetization means (24) heats the heat-generating roller (21) through magnetization after a rotating operation of the heat-generating roller (21) is started.

Abstract: In a fixing unit 230, a medium introducing port 250 is provided near a gripping part 230a of a housing 230, and a sheet material 90 to be subjected to a fixing process is guided to the medium introducing port. A shutter 260 is provided slanted at a given angle with respect to a gripping surface 240 of the gripping part 230a of the fixing unit 230 such that the shutter has a fulcrum at a part thereof, which is closer to the gripping part 230a of the fixing unit 230, at the medium introducing port 250, and the shutter 260 is turnable to a position to close the medium introducing port 250 while resisting the urging forces of the twisted springs 270.

Abstract: A short ring is provided outside a support frame. In the short ring, eddy current is generated in such a direction as to cancel apart of a magnetic flux developed from the exciting coil when it is fed with current, which the part of the magnetic flux leaks to outside. When the eddy current is generated, a magnetic field is developed in such a direction as to cancel the magnetic field by the leaking flux, as taught by Fleming's law. The result is that unnecessary radiation by the leaking flux is prevented, and hence noise generation in other members or devices is suppressed.

Abstract: A fixing device is formed by using a heat generating roller having magnetism and electric conductive characteristics and a magnetizing coil opposed to the outer peripheral of the heat generating roller and generating heat on the heat generating roller by an electromagnetic induction. The magnetizing coil is formed in such a manner that 60 copper wires whose surfaces are insulated and have the outside diameter of 0.2 mm are bundled to form a bundle of wires and the bundle of wires is drawn in the direction of rotation axis of the heat generating roller and wound in the direction of a circumference of the heat generating roller. Further, the magnetizing coil is disposed so that the bundles of wires mutually come into close contact along the circumference of the heat generating roller to cover the upper half of the heat generating roller.

Abstract: 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).

Abstract: An image heating device having a predetermined amount of heat generation with a small electric current. The device has a heat-generating roller having magnetism and conductivity, and an exciting coil opposed to the peripheral face of the heat-generating roller and adapted for allowing the heat-generating roller to generate heat with electromagnetic induction. The exciting coil is composed of a bundle of copper wires extended in the direction of the rotation axis of the heat generating roller. The wires are circumferentially wound along the circumferential direction of the heat-generating roller. The bundled wires are arranged in close contact with each other in the circumferential direction of the heat-generating roller so as to cover the upper half of the heat-generating roller.

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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).