Patent ID: 7561816
Filing Date: 2009-07-14
Classification: G03G

Abstract:
1. An image heating apparatus comprising: a rotatable heat-producing medium that produces heat by action of magnetic flux; a magnetic flux generator positioned proximate to a portion of a first peripheral surface of said heat-producing medium and generates magnetic flux that acts upon said heat-producing medium; a magnetic flux adjuster that is rotatably positioned on a second peripheral surface of said heat-producing medium, opposite the first peripheral surface, that has a paper passage area magnetic flux adjustment unit that causes a magnitude of magnetic flux acting upon a paper passage area of said heat-producing medium to vary depending upon whether the paper passage area magnetic flux adjustment unit is positioned close to and facing the magnetic flux generator or is positioned far from the magnetic flux generator, and a paper non-passage area magnetic flux adjustment unit that has a different rotational phase from said paper passage area magnetic flux adjustment unit and that causes a magnitude of magnetic flux acting upon a paper non-passage area of said heat-producing medium to vary depending upon whether the paper non-passage area magnetic flux adjustment unit is positioned close to and facing the magnetic flux generator or is positioned far from the magnetic flux generator, and that rotates during a fixing operation for each sheet of recording paper and periodically changes the magnitude of magnetic flux acting upon said heat producing medium at different timings between the paper passage area and the paper non-passage area; and a synchronization controller that periodically controls, for each sheet of recording paper, a timing of magnetic flux generation by said magnetic flux generator in synchronization with rotational phases of the magnetic flux adjustment units of said magnetic flux adjuster, wherein a calorific value distribution across a width of the heat-producing medium is adjusted by changing the timing of magnetic flux generation that is periodically controlled by the synchronization controller and by changing a spatial distribution of the magnetic flux acting upon the heat-producing medium.