Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus

1. An electrophotographic photosensitive member, comprising:

an undercoat layer, a photosensitive layer and a surface layer on or above an electro-conductive support in this order;

the undercoat layer containing metal oxide particles and at least one binder resin selected from the group consisting of a urethane resin, a polyamide resin and a melamine-alkyd resin;

the surface layer containing a charge transporting substance, fluororesin particles, and at least one binder resin selected from the group consisting of a polycarbonate resin and a polyarylate resin, a surface of the undercoat layer having an arithmetic average roughness Ra of 0.15 μm or less, wherein

0.70≤(a)−(b)≤1.00 and 0.20≤(c)−(d) where (a) is a refractive index of the metal oxide particles, (b) is a refractive index of the binder resin contained in the undercoat layer, (c) is a refractive index (c) of the binder resin contained in the surface layer and (d) is a refractive index of the fluororesin particles, and

5.0≤e/f≤15.0 where in an any region including at least a part of each of the surface layer and the undercoat layer of a cut surface obtained by cutting the electrophotographic photosensitive member vertically from the surface layer toward the undercoat layer, when e (%) is a ratio of a cross-sectional area of the metal oxide particles contained in the undercoat layer to a cross-sectional area of the undercoat layer, and f (%) is a ratio of a cross-sectional area of the fluororesin particles contained in the surface layer to a cross-sectional area of the surface layer.

2. The electrophotographic photosensitive member according to claim 1 , wherein a content of the metal oxide particles is 100 to 500% by mass relative to the binder resin contained in the undercoat layer.

3. The electrophotographic photosensitive member according to claim 1 , wherein a content of the fluororesin particles is 3.0 to 20.0% by mass relative to a total mass of the surface layer.

4. The electrophotographic photosensitive member according to claim 1 , wherein a number average primary particle diameter of the metal oxide particles is 10 to 100 nm.

5. The electrophotographic photosensitive member according to claim 1 , wherein the metal oxide particles are strontium titanate or anatase type titanium oxide.

6. A process cartridge which integrally supports an electrophotographic photosensitive member and at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit, and a cleaning unit, and is detachably attachable to a main body of an electrophotographic apparatus,

the electrophotographic photosensitive member comprising an undercoat layer, a photosensitive layer and a surface layer on or above an electro-conductive support in this order;

the undercoat layer containing metal oxide particles and at least one binder resin selected from the group consisting of a urethane resin, a polyamide resin and a melamine-alkyd resin;

the surface layer containing a charge transporting substance, fluororesin particles, and at least one binder resin selected from the group consisting of a polycarbonate resin and a polyarylate resin, a surface of the undercoat layer having an arithmetic average roughness Ra of 0.15 μm or less, wherein

0.70≤(a)−(b)≤1.00 and 0.20≤(c)−(d) where (a) is a refractive index of the metal oxide particles, (b) is a refractive index of the binder resin contained in the undercoat layer, (c) is a refractive index (c) of the binder resin contained in the surface layer and (d) is a refractive index of the fluororesin particles, and

5.0≤e/f≤15.0 where in an any region including at least a part of each of the surface layer and the undercoat layer of a cut surface obtained by cutting the electrophotographic photosensitive member vertically from the surface layer toward the undercoat layer, when e (%) is a ratio of a cross-sectional area of the metal oxide particles contained in the undercoat layer to a cross-sectional area of the undercoat layer, and f (%) is a ratio of a cross-sectional area of the fluororesin particles contained in the surface layer to a cross-sectional area of the surface layer.

7. 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 undercoat layer, a photosensitive layer and a surface layer on or above an electro-conductive support in this order;

the undercoat layer containing metal oxide particles and at least one binder resin selected from the group consisting of a urethane resin, a polyamide resin and a melamine-alkyd resin;

the surface layer containing a charge transporting substance, fluororesin particles, and at least one binder resin selected from the group consisting of a polycarbonate resin and a polyarylate resin, a surface of the undercoat layer having an arithmetic average roughness Ra of 0.15 μm or less, wherein

0.70≤(a)−(b)≤1.00 and 0.20≤(c)−(d) where (a) is a refractive index of the metal oxide particles, (b) is a refractive index of the binder resin contained in the undercoat layer, (c) is a refractive index (c) of the binder resin contained in the surface layer and (d) is a refractive index of the fluororesin particles, and

5.0≤e/f≤15.0 where in an any region including at least a part of each of the surface layer and the undercoat layer of a cut surface obtained by cutting the electrophotographic photosensitive member vertically from the surface layer toward the undercoat layer, when e (%) is a ratio of a cross-sectional area of the metal oxide particles contained in the undercoat layer to a cross-sectional area of the undercoat layer, and f (%) is a ratio of a cross-sectional area of the fluororesin particles contained in the surface layer to a cross-sectional area of the surface layer.