Fixing device

摘要

In a fixing device, a core material of a fixing rotating member has a largest-diameter portion between a central portion and each end portion within a region where a recording material of the largest size passes, and the diameter of the core material is gradually reduced from the largest-diameter portion toward the inside and the outside. The outer shape of the fixing rotating member conforms to the shape of the core material. According to this configuration, it is possible to prevent corrugation and curl of the recording material, and to provide excellent mountability of the recording material.