Patent ID: 8867975
Filing Date: 2014-10-21
Classification: G03G

Abstract:
1. A fixing unit comprising: a heating rotor, a pressure rotor that is disposed facing the heating rotor and that forms a fixing nip with the heating rotor, an induction coil disposed along an outer surface at a predetermined distance from the outer surface of the heating rotor to thereby generate a magnetic flux to heat the heating rotor, and a magnetic core portion including a bypass core portion and a magnetic flux shielding member, wherein a Curie point of the bypass core portion is higher than the temperature of the bypass core portion when the temperature of the heating rotor has reached a fixing temperature for fixing of the transfer material, and lower than the temperature of the bypass core portion when the temperature of the heating rotor has reached a heat-resistant temperature, and wherein the magnetic flux shielding member is configured about the periphery of the bypass core portion in close proximity or abutment with the bypass core portion; wherein the magnetic core portion includes a first core portion separated from the outer peripheral surface of the heating rotor by a predetermined distance without sandwiching the induction coil therebetween, and facing the outer surface of the heating rotor, and a second core portion facing the outer surface of the heating rotor and sandwiching the induction coil with the heating rotor, and wherein the first core portion is disposed more in proximity to the heating rotor than the second core portion, and wherein the magnetic flux shielding member is disposed in an inner portion of the first core portion.