Electrophotographic photoreceptor including a conductive substrate, an organic photosensitive layer on an outer peripheral surface of the conductive substrate, and an inorganic protective layer on an outer peripheral surface of the organic photosensitive layer, the inorganic protective layer containing gallium and oxygen. A volume resistivity of an inner region of the inorganic protective layer, the inner region extending 0.2 m or about 0.2 m from an inner peripheral surface of the inorganic protective layer in a thickness direction, and a volume resistivity of an outer region of the inorganic protective layer, the outer region extending 0.2 m or about 0.2 m from an outer peripheral surface of the inorganic protective layer in the thickness direction, are both 6.010.sup.7 .Math.cm or more and 4.010.sup.8 .Math.cm or less or about 6.010.sup.7 .Math.cm or more and about 4.010.sup.8 .Math.cm or less.

Electrophotographic photoreceptor including a conductive substrate, an organic photosensitive layer on an outer peripheral surface of the conductive substrate, and an inorganic protective layer on an outer peripheral surface of the organic photosensitive layer, the inorganic protective layer containing gallium and oxygen. A volume resistivity of an inner region of the inorganic protective layer, the inner region extending 0.2 m or about 0.2 m from an inner peripheral surface of the inorganic protective layer in a thickness direction, and a volume resistivity of an outer region of the inorganic protective layer, the outer region extending 0.2 m or about 0.2 m from an outer peripheral surface of the inorganic protective layer in the thickness direction, are both 6.010.sup.7 .Math.cm or more and 4.010.sup.8 .Math.cm or less or about 6.010.sup.7 .Math.cm or more and about 4.010.sup.8 .Math.cm or less.

An electrophotographic photosensitive member with suppressed potential variation even in the case that a protective layer including a cured material of a composition having a polymerizable functional group is used is provided. An electrophotographic photosensitive member including a support, a charge generation layer, a charge transport layer containing a charge transporting material, and a protective layer, in the order presented, wherein the charge transport layer contains a polycarbonate resin having a structure selected from a group A and a structure selected from a group B, and the protective layer includes a cured material of a composition containing a compound having at least a functional group selected from chain-polymerizable functional groups and sequential polymerizable functional groups.

An electrophotographic photosensitive member includes a photosensitive layer. The photosensitive layer contains a charge generating material, a hole transport material, and a binder resin. The binder resin contains a polyarylate resin represented by general formula (1). In general formula (1), r and s each represent an integer of at least 0 and no greater than 49 and t and u represents an integer of at least 1 and no greater than 50. Furthermore, r+s+t+u=100 and r+t=s+u. X and Y each represent, independently of one another, a divalent group represented by chemical formula (1-1), (1-2), (1-3), or (1-4).

##STR00001##

An electrophotographic photoreceptor comprising at least a photosensitive layer on a conductive substrate, wherein the photosensitive layer is a laminate having a charge transport layer and a charge generation layer, the charge transport layer contains four or more types of compounds each having a maximum absorption wavelength falling within a wavelength range of from 300 nm to 600 nm in a tetrahydrofuran solution at 25? C., and maximum absorption wavelengths falling within the wavelength range of at least four types of the compounds of said four or more types of the compounds are separated from each other by 10 nm or more.

In a negatively-chargeable laminate-type electrophotographic photoreceptor, a charge generation layer and another charge transport layer are arranged on a conductive substrate directly or via an intermediate layer. The charge transport layer contains at least a hole-transporting substance, an electron-transporting substance and a binder resin; the mass ratio (R.sub.PN) [% by mass] between mass (P) of the hole-transporting substance and mass (N) of the electron-transporting substance is represented by the following equation (1), and satisfies the following equation (2):
R.sub.PN=(N/(P+N))100(1)
1R.sub.PN40(2); and
when a voltage of +6 kV is applied to the photoreceptor for 5 seconds via a resin sheet having a thickness of 50 m and a surface resistivity of 210.sup.7 /cm.sup.2, the surface potential difference (Vo) and half-tone potential difference (Vh) between before and after the voltage application are both 15 V or less.

A compound has a structure represented by the following formula (C1):

##STR00001## wherein R.sub.a1, R.sub.a2, R.sub.a3, R.sub.a41, R.sub.a42, R.sub.a43, R.sub.a44, R.sub.a45, R.sub.a5, R.sub.a6, R.sub.a7, R.sub.a8, R.sub.a9, R.sub.a10, and R.sub.a11 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an aralkyl group, an aryl group, a cyano group, a halogen atom, or a group obtained by combining two or more of the above groups, and a combination of R.sub.a1 and R.sub.a2, R.sub.a41 and R.sub.a42, R.sub.a42 and R.sub.a43, R.sub.a43 and R.sub.a44, R.sub.a44 and R.sub.a45, R.sub.a5 and R.sub.a6, R.sub.a8 and R.sub.a9, or R.sub.a10 and R.sub.a11 each independently may form a ring.

An electrophotographic photoreceptor for use in an image forming apparatus having a proximity charge-type charging unit includes a conductive support and at least photosensitive layer and surface layer laminated in order on the conductive support, wherein the surface layer includes (A) a charge transport material, (B) a cured product of a composition containing a polymerizable compound and inorganic fine particles, and (C) organic fine particles, and the inorganic fine particles contain a metal oxide, has a surface treated with a surface treatment agent having a reactive organic group, and has a volume resistivity of 1.21011.Math.cm or more.

An electrophotographic photoreceptor includes a conductive substrate, an organic photosensitive layer on the conductive substrate, and an inorganic protective layer on the organic photosensitive layer. A layer that constitutes a surface of the organic photosensitive layer contains a charge transport material, a binder resin, silica particles, and a silicone compound.

In a negatively-chargeable laminate-type electrophotographic photoreceptor, a charge generation layer and another charge transport layer are arranged on a conductive substrate directly or via an intermediate layer. The charge transport layer contains at least a hole-transporting substance, an electron-transporting substance and a binder resin; the mass ratio (R.sub.PN) [% by mass] between mass (P) of the hole-transporting substance and mass (N) of the electron-transporting substance is represented by the following equation (1), and satisfies the following equation (2):

R.sub.PN=(N/(P+N))100(1)

1R.sub.PN40(2); and

when a voltage of +6 kV is applied to the photoreceptor for 5 seconds via a resin sheet having a thickness of 50 m and a surface resistivity of 210.sup.7 /cm.sup.2, the surface potential difference (Vo) and half-tone potential difference (Vh) between before and after the voltage application are both 15 V or less.