Abstract: An electrophotographic photoconductor, including a substrate of a cylindrical shape, an organic photosensitive layer formed on an outer peripheral surface of the substrate, and a two-dimensional code provided on the outer peripheral surface of the substrate between the substrate and the organic photosensitive layer, at at least one axial end of the substrate. The two-dimensional code encodes identification information, and is formed outside an image formation region of the electrophotographic photoconductor. The two-dimensional code includes a first part and a second part satisfying 15??L1?20, wherein ?L1 is a difference between an L-value of the first part and that of the second part in a Lab color space. The outer peripheral surface of the substrate and the organic photosensitive layer satisfy ?L2?60, wherein ?L2 is a difference between an L-value of the outer peripheral surface of the substrate and an L-value of the organic photosensitive layer in the Lab color space.

Abstract: An electrophotographic photoreceptor of a negatively-chargeable laminate-type includes a conductive substrate; a charge generation layer provided on the conductive substrate and including a charge generating material; and a charge transport layer provided on the charge generation layer and containing, as a binder resin, a copolymerized polycarbonate resin having a repeating unit represented by Formula (1); as a hole transporting substance, a compound having a structure represented by Formula (2); as an electron transporting substance, a compound having a structure represented by Formula (3), and, as an antioxidant, a compound represented by Structural Formula (4), where a mass ratio H/(B+H) represents a ratio of mass (H) of the hole transporting substance with respect to a sum of mass (B) of the binder resin and the mass (H) of the hole transporting substance, and satisfies Formula (5), 0.20 by mass?H/(B+H)?0.

Abstract: An electrophotographic photoreceptor of a negatively-chargeable laminate-type includes a conductive substrate; a charge generation layer provided on the conductive substrate and including a charge generating material; and a charge transport layer provided on the charge generation layer and containing, as a binder resin, a copolymerized polycarbonate resin having a repeating unit represented by Formula (1); as a hole transporting substance, a compound having a structure represented by Formula (2); as an electron transporting substance, a compound having a structure represented by Formula (3), and, as an antioxidant, a compound represented by Structural Formula (4), where a mass ratio H/(B+H) represents a ratio of mass (H) of the hole transporting substance with respect to a sum of mass (B) of the binder resin and the mass (H) of the hole transporting substance, and satisfies Formula (5), 20% by mass?H/(B+H)?35% by mass.

Abstract: In a negatively-chargeable laminate-type electrophotographic photoreceptor, a charge generation layer and another charge transport layer are arranged on a conductive substrate directly or via an intermediate layer. The charge transport layer contains at least a hole-transporting substance, an electron-transporting substance and a binder resin; the mass ratio (RPN) [% by mass] between mass (P) of the hole-transporting substance and mass (N) of the electron-transporting substance is represented by the following equation (1), and satisfies the following equation (2): RPN=(N/(P+N))×100??(1) 1?RPN?40??(2); and when a voltage of +6 kV is applied to the photoreceptor for 5 seconds via a resin sheet having a thickness of 50 ?m and a surface resistivity of 2×107 ?/cm2, the surface potential difference (?Vo) and half-tone potential difference (?Vh) between before and after the voltage application are both 15 V or less.

Abstract: In a negatively-chargeable laminate-type electrophotographic photoreceptor, a charge generation layer and another charge transport layer are arranged on a conductive substrate directly or via an intermediate layer. The charge transport layer contains at least a hole-transporting substance, an electron-transporting substance and a binder resin; the mass ratio (RPN) [% by mass] between mass (P) of the hole-transporting substance and mass (N) of the electron-transporting substance is represented by the following equation (1), and satisfies the following equation (2): RPN=(N/(P+N))×100??(1) 1?RPN?40??(2); and when a voltage of +6 kV is applied to the photoreceptor for 5 seconds via a resin sheet having a thickness of 50 ?m and a surface resistivity of 2×107 ?/cm2, the surface potential difference (?Vo) and half-tone potential difference (?Vh) between before and after the voltage application are both 15 V or less.