Electrophotographic photoreceptor and image forming apparatus including the same

A photoreceptor comprising an undercoat layer between a conductive support and a photosensitive layer, wherein

• the undercoat layer contains at least titanium oxide microparticles coated with anhydrous silicon dioxide and a first binder resin,
• the photosensitive layer is a monolayered photosensitive layer containing at least a charge generation material and a charge transport material or a multilayered photosensitive layer formed of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material stacked in this order or in an inverse order, and
• the charge generation material contains a crystal type oxotitanylphthalocyanine having peaks in an X-ray diffraction spectrum with Cu—Kα characteristic X-rays (0.15418 nm) at Bragg angles (2θ±0.2°) of 7.3°, 9.4°, 9.6°, 11.6°, 13.3°, 17.9°, 24.1° and 27.2°, in which a peak bundle formed by overlapping the peaks at 9.4° and 9.6° is a largest peak, and the peak at 27.2° is a second largest peak;
• and an X-type metal-free phthalocyanine having peaks in the X-ray diffraction spectrum at Bragg angles (2θ±0.2°) of 7.5°, 9.1°, 16.7°, 17.3° and 22.3°;
• wherein the X-type metal-free phthalocyanine is contained in the photosensitive layer in a proportion of 10% by weight to 70% by weight with respect to the crystal type oxotitanylphthalocyanine;
• and
• wherein the titanium oxide microparticles have anhydrous silicon dioxide in a proportion of 10% by weight to 33% by weight.