Abstract: A canceling exciting coil is supported by a coil supporting member of electrically insulating material fitted to an arch core. A canceling current Ic of opposite phase to a main current I flowing in the magnetic field generation circuit of the exciting coil by means of an exciting circuit is made to flow in a canceling magnetic field generation circuit provided with a canceling exciting coil, and generates canceling flux Mc. The idle component of the AC voltage generated in the canceling exciting coil is minimized by changing the number of turns n, coil inner area, and winding distribution of the canceling exciting coil, and adjusting canceling current Ic.

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 electromagnetic induction exothermic roller (21) having, in the order from the surface, at least a release layer, induction exothermic layer (22), an elastic layer (23), and a core (24). Exothermic roller (21) is pressed by a press member (31) to form a nip portion (34) and heat up a heating subject material (11) passing through the nip portion (34). The induction exothermic layer (22) has a layer prepared by dispersing an electrically conductive filler in the base material consisting of a heat resistant resin or heat resistant rubber. For this reason, the induction exothermic layer (22) can easily deform, so that a nip portion (34) having a large width (W) can be formed. Further, the durability of the induction exothermic layer (22) against repeated bending is improved.

Abstract: An electromagnetic induced heating roller (21) comprises a core member (24), an elastic layer (23), induction heating layer (22), 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 (24) is interposed between the induction heating layer (22) and the core member (24). Out of an alternating magnetic field from a magnetic field generating means, a leakage flux having penetrated through the induction heating layer (22) is trapped by the magnetic shield layer. As a result, most of the impressed alternating magnetic flux is consumed for heating the heating layer (22), resulting in an improvement in the heating efficiency. A trouble is prevented which is generated by heating the bearing of the core member (24).

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: 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: 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: 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 &OHgr;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.

Abstract: An ultrasonic vibration tool is made of a block of substantially rectangular parallelepiped form, and has its one end face formed as an output end face, and has its other end face opposite the output end face formed as an input end face. An ultrasonic oscillator is connected to the input end face for transmitting a longitudinal standing wave to the output end face. Peripheries of the input and output end faces of the block constitute mass portions. Between the mass portions are formed slits at a pitch less than a half of an oscillation wavelength, whereby a plurality of elastic portions are obtained. The mass portion on the input end face side has a protrusion having a height equal to or less than a quarter of the oscillation wavelength, thereby obtaining a mass distribution. Hence, a uniform amplitude distribution is achieved in the output end face.

Abstract: Device and method for fixing an image in which a vibrator, which generates ultrasonic waves by applying a voltage, and a horn connected thereto are arranged opposite a pressure roller with an endless belt passing between the horn and the pressure roller. Recording paper is carried between the belt and the pressure roller so that an image surface thereof is brought into contact with a rubber layer on the endless belt. Ultrasonic vibration is transmitted to the image surface of the traveling recording paper via the belt, thereby directly heating and melting toner so that the image is fixed on the recording paper.

Abstract: A vibrator for generating ultrasonic waves by applying a voltage, and a horn connected thereto are disposed as opposed to a pressure roller via an endless belt. Recording paper is carried between the belt and the pressure roller so that an image surface thereof is brought into close contact with a rubber layer on the endless belt. Ultrasonic vibration is transmitted to the image surface of the traveling recording paper via the belt, thereby directly heating and melting toner so that the image is fixed.

Abstract: A clutch cover assembly 3 having a disk-shaped clutch cover 4, an annular pressure plate 5, a cone spring 6, and a diaphragm spring 7. The pressure plate 5 is disposed in the clutch cover 4 and has a pressing surface 5a. The cone spring 6 is disposed on the opposite side of the pressure plate 5 in the clutch cover 4, and has its radial inner end supported on the clutch cover and its radial outer end biasing the pressure plate 5. Within the clutch cover, a hardened support member coupled to the cover is provided to engage at least one inner portion of the cone spring 6 in order to minimize wear associated with engagement with the spring 6 as it moves in response to movement of the pressure plate 5. The hardened support member is provided in the present invention is a number of forms. In one embodiment the hardened support member is integrally formed with the clutch cover 4.