Patent ID: 8195076

Claim:
A fixing device to fix a toner image on a sheet of recording media, comprising: a flexible endless belt that rotates in a predetermined direction, an inner circumferential surface of which includes a fluorine-containing surface layer; a rotary member that contacts an outer circumferential surface of the belt; a fixed member fixed inside the belt to press against the rotary member via the belt, forming a nip portion therebetween thorough which the sheet is transported; the fixed member, a surface of which includes a fluorine-containing surface layer that slidingly contacts the inner circumferential surface of the belt; a lubricant, applied between the fluorine-containing surface layer of the fixed member and the inner circumferential surface of the belt; and a heat source to heat at least one of the belt and the rotary member, wherein one of the fluorine-containing surface layers covering the inner circumferential surface of the belt and the fixed member is porous, at least one of the fluorine-containing surface layers covering the inner circumferential surface of the belt and the fixed member has a surface energy greater than a surface tension of the lubricant, and the fluorine-containing surface layer of the belt and the fluorine-containing surface layer of the fixed member that slidingly contact each other satisfy the relationship Va<Vb, wherein Va and Vb respectively represent a wear speed of the surface layer of the belt and a wear speed of the surface layer of the fixed member.