Electrophotographic photoreceptor, electrophotographic apparatus comprising the same, and package of electrophotographic photoreceptor

A negatively-chargeable laminate-type electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are arranged in the order mentioned on a conductive substrate directly or via an intermediate layer, wherein:

• said charge transport layer comprises at least a hole-transporting substance, an electron-transporting substance and a binder resin;
• the mass ratio (RPN) [% by mass] between the mass (P) of said hole-transporting substance and the mass (N) of said electron-transporting substance, which mass ratio is represented by the following equation (1), 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 said electrophotographic photoreceptor for 5 seconds via a resin sheet having a thickness of 50 μm and a surface resistivity of 2×107 Ω/cm2, the surface potential difference (ΔVo) and half-tone potential difference (ΔVh) between before and after application of said voltage are both 15 V or less.