NOVELTY - The cylindrical part comprises aluminum, where an average area of crystal particles of an outer circumferential surface is smaller than an average area of crystal particles of an inner circumferential surface. The ratio of the average area of the crystal particles of the outer circumferential surface to the average area of the crystal particles of the inner circumferential surface is 24-38%. The average area of the crystal particles of the outer circumferential surface is 0.9-1.25 mu m2. The average area of the crystal particles of the inner circumferential surface is 2.76-4.54 mu m2.    USE - The cylindrical part is useful in an electrophotographic photoreceptor and a process cartridge of an image forming apparatus (all claimed) i.e. laser printer, where the cylindrical part is useful as a conductive support and in conductive rolls, fixing rolls, cleaning sponges roll, cleaning brushes roll, cosmetic product cases and battery cases.    ADVANTAGE - The crystal particles of the high hardness outer circumferential surface are smaller than crystal particles of the low hardness inner circumferential surface, so that that elastic deformation with respect to a relatively weak impact is suppressed due to the small crystal particle structure of the outer circumferential surface.    DETAILED DESCRIPTION - The cylindrical part comprises aluminum, where an average area of crystal particles of an outer circumferential surface is smaller than an average area of crystal particles of an inner circumferential surface. The ratio of the average area of the crystal particles of the outer circumferential surface to the average area of the crystal particles of the inner circumferential surface is 24-38%. The average area of the crystal particles of the outer circumferential surface is 0.9-1.25 mu m2. The average area of the crystal particles of the inner circumferential surface is 2.76-4.54 mu m2. The average area of the crystal particles is reduced in a thickness direction from the inner circumferential surface to the outer circumferential surface. The cylindrical part contains 99.6 wt.% of aluminum and has a thickness of 0.4-0.6 mm. An INDEPENDENT CLAIM is included for an image forming apparatus.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic partial cross-sectional view of an electrophotographic photoreceptor.    Undercoat layer (1)    Charge generation layer (2)    Charge transport layer (3)    Photosensitive layer (5)    Electrophotographic photoreceptor. (7A)