Patent ID: 7835679
Filing Date: 2010-11-16
Classification: G03G

Abstract:
1. A heating device comprising: a magnetic field generating unit that generates a magnetic field; and a heating/rotating unit disposed so as to oppose the magnetic field generating unit, and having n (n≧2) metal layers which satisfy the following conditions (a), (b), (c) and include at least a heat generating layer, which is electromagnetically induced by the magnetic field to generate heat, and a supporting layer which supports the heat generating layer, wherein the magnetic field generating unit includes a first magnetic core and a second magnetic core such that the first magnetic core is arranged inside the heating/rotating unit and the second magnetic core is arranged outside the heating/rotating unit: (a) a total thickness t of the metal layers is greater than or equal to 30 μm and less than or equal to 200 μm; (b) the following formula (1) and formula (2) are satisfied: where δ is a surface skin depth of metal, surface skin depths δ (c) the following formula (3) is satisfied: where R is expressed as a ratio of specific resistance value to thickness as R=ρ/t, R 1 =ρ 1 /t 1 , R 2 =ρ 2 /t 2 , R 3 =ρ 3 /t 3 , and Rn=ρn/tn, wherein the metal layers include a protective layer which protects the heat generating layer, and wherein the supporting layer and the protective layer are formed of a metal which is different than the heat generating layer, and all of the metal layers are non-magnetic metals and used as non-magnetic materials.