Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus

A process cartridge comprising:

• an electrophotographic photosensitive member including a surface layer containing a binder resin and metal oxide particles;
• and
• at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit, and a cleaning unit,
• the process cartridge integrally supporting the electrophotographic photosensitive member and the at least one unit, and being detachably attachable onto a main body of an electrophotographic apparatus,
• wherein an average primary particle diameter of the metal oxide particles measured from a cross-section of the surface layer is 20 to 70 nm, and
• wherein a content ratio of the metal oxide particles in the surface layer measured from the cross-section of the surface layer is 30 to 75 vol % with respect to a total volume of the surface layer.

An electrophotographic apparatus comprising:

• an electrophotographic photosensitive member including a surface layer containing a binder resin and metal oxide particles;
• and
• a charging unit, an exposing unit, a developing unit, and a transfer unit,
• wherein an average primary particle diameter of the metal oxide particles measured from a cross-section of the surface layer is 20 to 70 nm, and
• wherein a content ratio of the metal oxide particles in the surface layer measured from the cross-section of the surface layer is 30 to 75 vol % with respect to a total volume of the surface layer.