Fixing device and image forming apparatus incorporating same

A fixing device for fixing a toner image on a recording medium, comprising:

• a flexible endless belt-shaped fixing member to rotate in a predetermined direction of rotation, foamed into a loop;
• a heating member provided inside the loop formed by the fixing member and facing an inner circumferential surface of the fixing member to heat the fixing member;
• a nip formation member provided inside the loop formed by the fixing member and supported by the heating member, with a central convex portion of increased thickness provided at a center of the nip formation member in an axial direction of the fixing member and protruding toward the heating member;
• and
• a pressing member pressed against the nip formation member via the fixing member to form a fixing nip between the fixing member and the pressing member through which the recording medium bearing the toner image passes,
• the heating member having a tapered shape corresponding to the convex portion of the nip formation member, in which the heating member is tapered from lateral ends of increased diameter toward a center of reduced diameter of the heating member in the axial direction of the fixing member.