Patent ID: 8472854

Claim:
A fixing device that fixes an unfixed image formed on a recording sheet to the recording sheet by applying heat and pressure to the unfixed image when the recording sheet passes through a fixing nip, the fixing device comprising: a first belt and a second belt in pressing contact with each other so as to form the fixing nip, the first belt being rotatably suspended on a pair of first rollers including a first upstream roller and a first downstream roller, and the second belt being rotatably suspended on a pair of second rollers including a second upstream roller and a second downstream roller; the first and second belts have a stiffness such that, prior to configuring the first belt and the second belt in pressing contact with each other, (a) two portions of the first belt that oppose each other across a first axis passing through a center of each of the first rollers project away from each other in a manner that the two portions are arc-shaped, and (b) two portions of the second belt that oppose each other across a second axis passing through a center of each of the second rollers project away from each other in a manner that the two portions of the second belt are arc-shaped; one of the two portions of the first belt and one of the two portions of the second belt form the fixing nip when the first belt and the second belt are configured in pressing contact with each other; and wherein a length of the fixing nip is greater than or equal to a distance separating the center of the first upstream roller and the center of the first downstream roller.