An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer having a single-layer structure. The photosensitive layer contains a charge generating material, an electron transport material, a polycarbonate resin, and a hole transport material. The electron transport material includes a compound having a halogen atom and represented by general formula (1), (2), (3), (4), or (5). The hole transport material includes a compound represented by general formula (20), (21), (22), (23), (24), (25), (26), or (27). A charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer is at least +6.5 C/g. A Vickers hardness of the photosensitive layer at 45 C. is at least 17.0 HV.

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The photoconductor includes a conductive support, a photosensitive layer, and a protective layer. The protective layer is a polymer of a radical-polymerizable composition containing a perfluoropolyether compound including a radical-polymerizable functional group, a radical-polymerizable monomer including a radical-polymerizable functional group, and an inorganic fine particle including a radical-polymerizable functional group. The radical-polymerizable functional group of the perfluoropolyether compound is different from the radical-polymerizable functional group of the radical-polymerizable monomer and identical to the radical-polymerizable functional group of the inorganic fine particle.

An electrophotographic photoreceptor includes at least a photosensitive layer and a protective layer sequentially layered on a conductive support, wherein the protective layer contains a cured product of a curable composition containing p-type semiconductor fine particles, an n-type organic semiconductor, and a polymerizable 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.

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.

An electrophotographic photoreceptor includes a conductive substrate, an undercoat layer provided on the conductive substrate and containing a binder resin and an electron transport material represented by General Formula (P), and a photosensitive layer provided on the undercoat layer,

##STR00001## in General Formula (P), R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an alkoxycarbonyl group, or a halogen atom.

A single-layer photosensitive layer included in an electrophotographic photosensitive member contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin includes a polyarylate resin. The polyarylate resin includes repeating units represented by formulas (1), (2), (3), and (4). ##STR00001## The percentage of the number of repeats of the repeating unit represented by formula (3) relative to a total of the number of repeats of the repeating unit represented by formula (1) and the number of repeats of the repeating unit represented by formula (3) is greater than 0% and less than 20%.

The present disclosure relates to a compound having one or more polymerizable functional groups.

An electrophotographic photoreceptor includes a conductive support; and an undercoat layer and a photosensitive layer stacked on the conductive support, in which the undercoat layer contains crystalline electron transport compound particles. In X-ray diffraction measurement performed on the undercoat layer in a thickness direction, a maximum intensity peak has a half-width of 5 or less, and a maximum value Nmax among orientation indices N expressed by equation (1) below is 1 or more and 3 or less: $\begin{array}{cc}\mathrm{Orientation}\mathrm{index}=\frac{\frac{I_1}{.Math.I_1}}{\frac{I_2}{.Math.I_2}}& \left(1\right)\end{array}$ where I.sub.1 represents a relative integral intensity of each of peaks in the X-ray diffraction measurement performed on the undercoat layer in the thickness direction, and I.sub.2 represents a relative integral intensity of each of peaks in X-ray diffraction measurement performed on the undercoat layer processed into a powder form having a volume-average particle diameter of 5m or less.

An electrophotographic photoreceptor includes a conductive substrate, a first undercoat layer that is provided on the conductive substrate, a second undercoat layer that is provided on the first undercoat layer, and a photosensitive layer that is provided on the second undercoat layer, in which the first undercoat layer contains at least one electron transport material selected from the group consisting of a compound represented by Formula (1), a compound represented Formula (2), and a compound represented by Formula (3), and a binder resin, and a content of silica particles in the first undercoat layer is 0% by mass or 5% by mass or less, and the second undercoat layer contains at least one electron transport material selected from the group consisting of the compound represented by Formula (1), the compound represented Formula (2), and the compound represented by Formula (3), silica particles, and a binder resin, and a content of the silica particles in the second undercoat layer is larger than the content of the silica particles in the first undercoat layer.

##STR00001##

In Formula (1), R.sup.11, R.sup.12, R.sup.13, R.sup.14, R.sup.15, R.sup.16, R.sup.17, and R.sup.18 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group, or a halogen atom, R.sup.11 and R.sup.12, R.sup.12 and R.sup.13, or R.sup.13 and R.sup.14 may be each independently linked to each other to form a ring, and R.sup.15 and R.sup.16, R.sup.16 and R.sup.17, or R.sup.17 and R.sup.18 may be each independently linked to each other to form a ring.

In Formula (2), R.sup.21, R.sup.22, R.sup.23, R.sup.24, R.sup.25, R.sup.26, R.sup.27, and R.sup.28 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkoxycarbonylalkyl group, an aryloxycarbonylalkyl group, or a halogen atom, R.sup.21 and R.sup.22, R.sup.22 and R.sup.23, or R.sup.23 and R.sup.24 may be each independently linked to each other to form a ring, and R.sup.25 and R.sup.26, R.sup.26 and R.sup.27, or R.sup.27 and R.sup.28 may be each independently linked to each other to form a ring.

In Formula (3), R.sup.31, R.sup.32, R.sup.33, R.sup.34, R.sup.35, R.sup.36, R.sup.37, and R.sup.38 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, an alkoxycarbonyl group, or a halogen atom.