Fixing device and image forming apparatus having the same, and fixing method

摘要

A fixing device includes: an endless fixing belt configured to convey a sheet-like medium on which a toner image is to be fixed; heating and fixing rollers configured to have said fixing belt wound thereon; a pressing roller configured to be disposed opposite to said fixing roller via said fixing belt; and wherein said fixing device further comprises first to third heaters provided respectively in said heating, pressure and fixing rollers; first to third voltage applying devices configured to apply voltages respectively to said first to third heaters; and a nip portion configured to perform the fixing only by pressure contact between said fixing and pressing rollers via said fixing belt.