Electrophotographic member with surface layer comprising tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and fixing device, and electrophotographic image forming apparatus including electrophotographic member

An electrophotographic member comprising a base layer, an elastic layer on an outer peripheral surface of the base layer, and a surface layer on an outer peripheral surface of the elastic layer, wherein

• the surface layer comprises a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer,
• a plurality of crystals of the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer having different circle-equivalent diameters is exposed on an outer surface of the surface layer,
• at least a part of an outer surface of the electrophotographic member is composed of a surface of the crystals and is roughened by the crystals,
• when a rectangular region having a length of 5 mm in a direction along a circumferential direction of the electrophotographic member and a length of 10 mm in a longitudinal direction perpendicular to the circumferential direction is arranged on the outer surface of the electrophotographic member so that a center of the rectangular region in the longitudinal direction coincides with a center of the electrophotographic member in the longitudinal direction, the rectangular region is divided into 200 observation regions by squares with sides of 500 μm, and an arithmetic-mean height Sa of each observation region is determined,
• in a frequency distribution of the observation regions in which the arithmetic-mean height Sa is taken as a class and a class width is 0.05 μm,
• where the number of the observation regions comprised in an observation region group X1 belonging to a class where the arithmetic-mean height Sa is 0.10 to 0.40 μm is denoted by x1, x1 satisfies 160≤x1≤200, and
• where the number of the observation regions comprised in an observation region group X2 belonging to a class where the arithmetic-mean height Sa is 0.10 to 0.20 μm is denoted by x2, and
• the number of the observation regions comprised in an observation region group X3 belonging to a class where the arithmetic-mean height Sa is 0.25 to 0.40 μm is denoted by x3, x1 and x2 satisfy a following formula (1), and x1 and x3 satisfy a following formula (2):
• 0.25
• ·
• x
• ⁢
• 1
• ≤
• x
• ⁢
• 2
• ≤
• 0.75
• ·
• x
• ⁢
• 1
• (
• 1
• )
• 0.25
• ·
• x
• ⁢
• 1
• ≤
• x
• ⁢
• 3
• ≤
• 0.75
• ·
• x
• 1.
• (
• 2
• )