Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus

A process cartridge, comprising:

• an electrophotographic photosensitive member;
• and
• at least one unit selected from the group consisting of a charging unit, a developing 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;
• the electrophotographic photosensitive member comprising an electroconductive support, a photosensitive layer and a protection layer;
• the protection layer comprising an electroconductive particle, the electroconductive particle having a surface comprising a titanium oxide containing a niobium atom;
• an atomic concentration ratio of the niobium atom to the titanium atom in the titanium oxide being 0.04 to 0.20, and a niobium atom/titanium atom concentration ratio at an inside portion that is 5% of a maximum diameter of the particle from the surface of the particle being at least 2.0 times as high as a niobium atom/titanium atom concentration ratio at a center of the maximum particle diameter in energy-dispersive X-ray spectroscopy (EDS analysis) with a scanning transmission electron microscope (STEM);
• and
• the electroconductive particle being surface-treated with a compound having a silicon atom, wherein
• a content ratio of the electroconductive particle in the protection layer is 5 to less than 40 vol % with respect to a total volume of the protection layer, and
• 0<d(Ti)≤2.0,
• 0<d(Si)≤8.0, and
• 0.01≤d(Ti)/d(Si)≤1.0
• when at a surface of the protection layer, a total of a relative concentration d(C) of a carbon atom, a relative concentration d(O) of an oxygen atom, a relative concentration d(Ti) of the titanium atom, a relative concentration d(Nb) of the niobium atom, and a relative concentration d(Si) of the silicon atom is defined as 100.0 atomic %, as determined by X-ray photoelectron spectroscopy.

An electrophotographic apparatus, comprising:

• an electrophotographic photosensitive member;
• a charging unit;
• an exposing unit;
• a developing unit;
• and
• a transfer unit,
• the electrophotographic photosensitive member comprising an electroconductive support, a photosensitive layer and a protection layer;
• the protection layer comprising an electroconductive particle, the electroconductive particle having a surface comprising a titanium oxide containing a niobium atom;
• an atomic concentration ratio of the niobium atom to the titanium atom in the titanium oxide being 0.04 to 0.20, and a niobium atom/titanium atom concentration ratio at an inside portion that is 5% of a maximum diameter of the particle from the surface of the particle being at least 2.0 times as high as a niobium atom/titanium atom concentration ratio at a center of the maximum particle diameter in energy-dispersive X-ray spectroscopy (EDS analysis) with a scanning transmission electron microscope (STEM);
• and
• the electroconductive particle being surface-treated with a compound having a silicon atom, wherein
• a content ratio of the electroconductive particle in the protection layer is 5 to less than 40 vol % with respect to a total volume of the protection layer, and
• 0<d(Ti)≤2.0,
• 0<d(Si)≤8.0, and
• 0.01≤d(Ti)/d(Si)≤1.0
• when at a surface of the protection layer, a total of a relative concentration d(C) of a carbon atom, a relative concentration d(O) of an oxygen atom, a relative concentration d(Ti) of the titanium atom, a relative concentration d(Nb) of the niobium atom, and a relative concentration d(Si) of the silicon atom is defined as 100.0 atomic %, as determined by X-ray photoelectron spectroscopy.