Abstract: An induction heating cooker includes a surface, a heating coil for inductionally-heating a load pan, an inverter for supplying a high-frequency current to the heating coil, an infrared detector which detects infrared radiation emitted from the load pan and is located under a top plate, a first temperature detector for detecting a temperature of the load pan based on an output of the infrared detector, a heating controller for controlling a power output from the inverter, a thermo-sensitive element for receiving heat from the top plate, and a second temperature detector for detecting a temperature of the load pan based on an output of the first thermo-sensitive element. This induction heating cooker detects a temperature change of the load pan accurately by detecting an infrared radiation from the load pan, and detects the temperature of the load pan by the heat conduction from the pan even if ambient light enters.

Abstract: The present invention offers an induction heating apparatus in which the infrared sensor performs stable temperature detection without undergoing the influence of leakage magnetic flux from the induction heating means.

Abstract: An induction heating cooker includes a surface, a heating coil for inductionally-heating a load pan, an inverter for supplying a high-frequency current to the heating coil, an infrared detector which detects infrared radiation emitted from the load pan and is located under a top plate, a first temperature detector for detecting a temperature of the load pan based on an output of the infrared detector, a heating controller for controlling a power output from the inverter, a thermo-sensitive element for receiving heat from the top plate, and a second temperature detector for detecting a temperature of the load pan based on an output of the first thermo-sensitive element. This induction heating cooker detects a temperature change of the load pan accurately by detecting an infrared radiation from the load pan, and detects the temperature of the load pan by the heat conduction from the pan even if ambient light enters.

Abstract: An induction heating cooker includes an infrared sensor for sensing an infrared intensity from a load pot, a waveguide for guiding infrared radiation from the load pot to the infrared sensor, a first magnetism-proofing unit and a second magnetism-proofing unit for reducing magnetic fluxes leaking from a heating coil. Placement of the waveguide at a position lower than an upper surface of the second magnetism-proofing unit reduces self-heating of the waveguide due to magnetic flux supplied from the heating coil. As a result, a temperature rise of the infrared sensor due to radiation heat from the waveguide can be reduced, and an accuracy of sensing a temperature by the infrared sensor can be improved.

Abstract: The present invention offers an induction heating apparatus in which the infrared sensor performs stable temperature detection without undergoing the influence of leakage magnetic flux from the induction heating means.

Abstract: A heating roller device which incorporates a metal roller having a curier temperature adjusted to an appropriate level and enabling a self-temperature-controllability and which has a structure that the metal roller is induction-heated by an induction heating section. A method of manufacturing the foregoing metal roller according to the present invention has a step of joining a pipe, which is made of temperature-sensitive magnetic metal, and the composition of which has been adjusted so as to have a predetermined curier temperature, and metal having a resistivity lower than that of the temperature-sensitive magnetic metal to each other by a drawing work in such a manner as to prevent formation of any gap. Thus, an induction heating pipe exhibiting an excellent heating characteristic is manufactured.

Abstract: An image heating device comprises a cylindrical heating roller with a Curie temperature of 210.degree. C., a magnetization coil for magnetizing the heating roller with an alternating magnetic field, which is arranged inside the heating roller, and a nip portion for heating a recording material that carries a toner image with heat from the heating roller, while the recording material is being conveyed along said nip portion. The ratio between the amount of heat generated in said heat-generating member at Curie temperature or higher to the amount of heat generated at room temperature in said heat-generating member is not more than 1/2. With this configuration, the heating roller can regulate its own temperature to stabilize at a temperature that is suitable for fixing, and the problems of partial overheating or underheating, unstable heat generation, or damage of the device can be eliminated.

Abstract: An image heating device comprises a cylindrical heating roller with a Curie temperature of 210° C., a magnetization coil for magnetizing the heating roller with an alternating magnetic field, which is arranged inside the heating roller, and a nip portion for heating a recording material that carriers a toner image with heat from the heating roller, while the recording material is being conveyed along said nip portion. The ratio between the amount of heat generated in said heat-generating member at Curie temperature or higher to the amount of heat generated at room temperature in said heat-generating member is not more than ½. With this configuration, the heating roller can regulate its own temperature to stabilize at a temperature that is suitable for fixing, and the problems of partial overheating or underheating, unstable heat generation, or damage of the device can be eliminated.