An electrophotographic photosensitive member includes: a support; an undercoat layer; a charge generation layer; and a charge transport layer, wherein the undercoat layer contains a polyamide resin and a titanium oxide fine particle, and on the surface of the undercoat layer, an arithmetic mean roughness Ra and an average length Rsm of a roughness curve element both according to JIS B0601:2001 satisfy Ra≤50 nm and 0.1≤Ra/Rsm≤0.5; and the charge generation layer contains a hydroxygallium phthalocyanine pigment, wherein the hydroxygallium phthalocyanine pigment includes crystal particles having a crystal form exhibiting peaks at 7.4°±0.3° and 28.2°±0.3° at Bragg angles 2θ in a spectrum of X-ray diffraction using a CuKα, ray; and in a size distribution of the crystal particles, which is measured using small-angle X-ray scattering, a peak exists in a range of 20 to 50 nm, and the peak has a half-value width of 50 nm or smaller.

An electrophotographic photosensitive member includes: a support; an undercoat layer; a charge generation layer; and a charge transport layer, wherein the undercoat layer contains a polyamide resin and a titanium oxide fine particle, and on the surface of the undercoat layer, an arithmetic mean roughness Ra and an average length Rsm of a roughness curve element both according to JIS B0601:2001 satisfy Ra≤50 nm and 0.1≤Ra/Rsm≤0.5; and the charge generation layer contains a hydroxygallium phthalocyanine pigment, wherein the hydroxygallium phthalocyanine pigment includes crystal particles having a crystal form exhibiting peaks at 7.4°±0.3° and 28.2°±0.3° at Bragg angles 2θ in a spectrum of X-ray diffraction using a CuKα, ray; and in a size distribution of the crystal particles, which is measured using small-angle X-ray scattering, a peak exists in a range of 20 to 50 nm, and the peak has a half-value width of 50 nm or smaller.

An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.00×10.sup.12 Ω.Math.cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.

An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.00×10.sup.12 Ω.Math.cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.

An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.0010.sup.12 .Math.cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.

An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.0010.sup.12 .Math.cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.

An electrophotographic photosensitive member includes: a support; an undercoat layer; a charge generation layer; and a charge transport layer, wherein the undercoat layer contains a polyamide resin and a titanium oxide fine particle, and on the surface of the undercoat layer, an arithmetic mean roughness Ra and an average length Rsm of a roughness curve element both according to JIS B0601:2001 satisfy Ra50 nm and 0.1Ra/Rsm0.5; and the charge generation layer contains a hydroxygallium phthalocyanine pigment, wherein the hydroxygallium phthalocyanine pigment includes crystal particles having a crystal form exhibiting peaks at 7.40.3 and 28.20.3 at Bragg angles 2 in a spectrum of X-ray diffraction using a CuK, ray; and in a size distribution of the crystal particles, which is measured using small-angle X-ray scattering, a peak exists in a range of 20 to 50 nm, and the peak has a half-value width of 50 nm or smaller.

An electrophotographic photosensitive member includes: a support; an undercoat layer; a charge generation layer; and a charge transport layer, wherein the undercoat layer contains a polyamide resin and a titanium oxide fine particle, and on the surface of the undercoat layer, an arithmetic mean roughness Ra and an average length Rsm of a roughness curve element both according to JIS B0601:2001 satisfy Ra50 nm and 0.1Ra/Rsm0.5; and the charge generation layer contains a hydroxygallium phthalocyanine pigment, wherein the hydroxygallium phthalocyanine pigment includes crystal particles having a crystal form exhibiting peaks at 7.40.3 and 28.20.3 at Bragg angles 2 in a spectrum of X-ray diffraction using a CuK, ray; and in a size distribution of the crystal particles, which is measured using small-angle X-ray scattering, a peak exists in a range of 20 to 50 nm, and the peak has a half-value width of 50 nm or smaller.