Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming apparatus

1. An electrophotographic photoreceptor comprising a conductive support and a photosensitive layer provided thereon, wherein the electrophotographic photoreceptor comprises an outermost layer which contains a charge transport substance represented by the following formula (1) and a compound represented by the following formula (5):

wherein Ar 1 to Ar 5 each independently represent an aryl group which may have a substituent, Ar 6 to Ar 9 each is a 1,4-phenylene group which may have a substituent, and m and n each independently represent an integer of 1 to 3;

wherein R 9 to R 11 each independently represent an alkyl group, A represents a cyclohexane ring or benzene ring, X represents a single bond, —CH 2 —, or —CH 2 OCO—, and i to k each independently represent an integer of 0 to 3.

2. The electrophotographic photoreceptor according to claim 1 , wherein the photosensitive layer includes, as a binder resin, a polycarbonate resin which has a structural unit represented by the following formula (7):

3. The electrophotographic photoreceptor according to claim 1 , wherein the photosensitive layer includes, as a binder resin, a polyester resin represented by the following formula (6):

wherein Ar 10 to Ar 13 each independently represent an arylene group which may have a substituent, X represents a single bond, an oxygen atom, a sulfur atom, or an alkylene group, s represents an integer of 0 to 2, and Y represents a single bond, an oxygen atom, a sulfur atom, or an alkylene group.

4. The electrophotographic photoreceptor according to claim 1 , wherein the outermost layer contains the compound represented by formula (5) in an amount of 1 to 20 parts by mass per 100 parts by mass of a binder resin of the outermost layer.

5. The electrophotographic photoreceptor according to claim 1 , wherein the compound represented by formula (5) is any of compounds represented by the following formulae (2), (3), and (4):

wherein R 1 to R 3 each independently represent an alkyl group, and a, b, and c each independently represent an integer of 0 to 3;

wherein R 4 and R 5 each independently represent an alkyl group, and d and e each independently represent an integer of 0 to 3;

wherein R 6 to R 8 each independently represent an alkyl group, and f, g, and h each independently represent an integer of 0 to 3.

6. The electrophotographic photoreceptor according to claim 1 , wherein in formula (1), Ar 1 to Ar 5 each independently represent a phenyl group which may have an alkyl group or alkoxy group, Ar 6 to Ar 9 each independently represent a 1,4-phenylene group which may have a substituent, and m and n are 1.

7. An electrophotographic photoreceptor cartridge comprising: the electrophotographic photoreceptor according to claim 1 ; and at least one selected from the group consisting of a charging device for charging the electrophotographic photoreceptor, an exposure device for exposing the charged electrophotographic photoreceptor to form an electrostatic latent image, and a developing device for developing the electrostatic latent image formed on the electrophotographic photoreceptor.

8. An image forming apparatus comprising: the electrophotographic photoreceptor according to claim 1 ; a charging device for charging the electrophotographic photoreceptor; an exposure device for exposing the charged electrophotographic photoreceptor to form an electrostatic latent image; and a developing device for developing the electrostatic latent image formed on the electrophotographic photoreceptor.