Electrophotographic photosensitive member, process cartridge, and image forming apparatus

An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer of a single layer, wherein

• the photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, an additive, and a binder resin,
• an optical response time is at least 0.05 milliseconds and no greater than 0.85 milliseconds,
• the optical response time is a time from irradiation to decay, the irradiation being a time of a start of irradiation of a surface of the photosensitive layer charged to +800 V with pulse light having a wavelength of 780 nm, the decay being a time when a surface potential of the photosensitive layer decays from +800 V to +400 V,
• an optical intensity of the pulse light is set so that the surface potential of the photosensitive layer becomes+200 V from +800 V when 400 milliseconds elapse after the irradiation of the surface of the photosensitive layer charged to +800 V with the pulse light,
• the additive includes a compound represented by a general formula (1), and
• a mass mHTM of the hole transport material, a mass mETM of the electron transport material, and a mass mR of the binder resin satisfy a relational expression (A) shown below:
• [(mHTM+mETM)/mR]>1.30 (A),
• where in the general formula (1),
• R1 represents a halogen atom or an alkyl group having a carbon number of at least 1 and no greater than 6 and substituted by a halogen atom,
• R2 represents an alkyl group having a carbon number of at least 1 and no greater than 10, an aralkyl group having a carbon number of at least 7 and no greater than 20, or an aryl group having a carbon number of at least 6 and no greater than 22,
• n and m each represent, independently of each other, an integer of at least 0 and no greater than 4,
• when n represents an integer of at least 2 and no greater than 4, plural chemical groups R1 may be the same as or different from one another, and
• when m represents an integer of at least 2 and no greater than 4, plural chemical groups R2 may be the same as or different from one another.