Patent ID: 8811871

Claim:
A fixing device comprising: an endless-shaped fixing belt for conveying a recording medium; a heating roller for heating the fixing belt; a fixing roller having an elastic layer formed on an outer peripheral surface thereof; and a pressing roller which pressure-contacts with the fixing roller through the fixing belt, wherein the recording medium passes through a nip portion where the pressing roller and the fixing roller pressure-contact with each other while rotating, so as to fix an unfixed toner image on the recording medium, and a detachment angle formed by a tangent line of the fixing roller and a conveying direction of the recording medium is kept at 23 degrees or more at an exit point of the nip portion relative to the conveying direction of the recording medium, wherein the pressing roller includes: a heating portion in an inside thereof; and an elastic layer, and wherein a setting temperature of the pressing roller is increased step by step in accordance with the number of the recording medium, and a thickness of the elastic layer of the pressing roller ranges from 0.5 mm to 1.5 mm.