Process cartridge

A process cartridge that is detachable from a main body of an electrophotographic image forming apparatus, the process cartridge comprising:

• an electrophotographic photosensitive member;
• a toner;
• and
• a developing unit;
• the electrophotographic photosensitive member comprising an electroconductive support, a photosensitive layer formed on the electroconductive support, and a surface protective layer formed on the surface of the electrophotographic photosensitive member;
• the surface protective layer containing electroconductive titanium oxide particles each containing a niobium atom;
• the developing unit being configured to accommodate the toner, and to supply the toner to a surface of the electrophotographic photosensitive member;
• and
• the toner comprising toner particles and an external additive A, external additive A having (i) a long diameter of 100 to 3,000 nm, (ii) an aspect ratio of 5.0 or more, and (iii) a specific resistance of 1×105 to 1×108 Ω·cm or less, wherein
• a ratio of a number of the toner particle having the external additive A on surface thereof to a number of the toner particle is 30 number % or more when observed by using a scanning electron microscope,
• in each of the electroconductive titanium oxide particles, a concentration ratio calculated as niobium atom concentration/titanium atom concentration at an inside portion at 5% of a maximum diameter of a measurement particle from a surface of the particle is 2.0 or more times as high as a concentration ratio calculated as niobium atom concentration/titanium atom concentration at a central portion of the particle,
• a content of the electroconductive titanium oxide particles in the surface protective layer is 5 to 70 vol %, and
• the surface protective layer has a volume resistivity of 1.0×109 to 1.0×1014 Ω·cm.