Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, image-forming apparatus, and triarylamine compound

1. A compound represented by the formula (1):

wherein Ar 1 represents an aryl group having an alkoxy group, an aryloxy group, or an aralkyloxy group as a substituent, Ar 2 to Ar 5 each independently represent an aryl group which may have a substituent, Ar 6 to Ar 9 each independently represent a 1,4-phenylene group which may have a substituent; R 1 to R 4 each independently represent a hydrogen atom or an alkyl group; m and n each independently represent an integer of 1 or more and 3 or less; in the case where m or n is 2 or more, plurally existing R 1 s to R 4 s each may be the same or different from each other.

2. The compound according to claim 1 , wherein, in the above formula (1), Ar 1 is a phenyl group having an alkoxy group having 8 or less carbon atoms, Ar 2 to Ar 5 each independently are a phenyl group which may have an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as a substituent, Ar 6 to Ar 9 each independently are a 1,4-phenylene group which may have an alkyl group having 1 to 6 carbon atoms, R 1 to R 4 are a hydrogen atom, and m and n are both 1.

3. The compound according to claim 2 , wherein, in the above formula (1), Ar 2 to Ar 5 each independently are a phenyl group which may have an alkyl group having 1 to 6 carbon atoms and Ar 6 to Ar 9 are a 1,4-phenylene group.

4. An electrophotographic photoreceptor comprising an electroconductive support and at least a photosensitive layer formed on the support, wherein the photosensitive layer contains a charge transport substance represented by the following formula (1):

wherein Ar 1 represents an aryl group having an alkoxy group, an aryloxy group, or an aralkyloxy group as a substituent, Ar 2 to Ar 5 each independently represent an aryl group which may have a substituent, Ar 6 to Ar 9 each independently represent a 1,4-phenylene group which may have a substituent; R 1 to R 4 each independently represent a hydrogen atom or an alkyl group; m and n each independently represent an integer of 1 or more and 3 or less; in the case where m or n is 2 or more, plurally existing R 1 s to R 4 s each may be the same or different from each other.

5. The electrophotographic photoreceptor according to claim 1 , wherein the photosensitive layer contains oxytitanium phthalocyanine of crystal form which shows a diffraction peak at Bragg angles (2θ±0.2°) of at least 24.1° and 27.2° in a powder X-ray diffraction spectrum with a CuKα characteristic X-ray.

6. The electrophotographic photoreceptor according to claim 1 , wherein the photosensitive layer further contains at least either one of a polyarylate resin and a polycarbonate resin.

7. The electrophotographic photoreceptor according to claim 1 , wherein the photosensitive layer comprises a charge transport layer and a charge generation layer and the charge transport layer contains a charge transport substance represented by the above formula (1) and at least either one of a polyarylate resin having a structural unit represented by the formula (α) and a polycarbonate resin having a structural unit represented by the formula (β):

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; v represents an integer of 0 or more and 2 or less; and Y represents a single bond, an oxygen atom, a sulfur atom, or an alkylene group,

wherein R 7 and R 8 each independently represent a hydrogen atom, an aryl group, or an alkyl group having 1 to 10 carbon atoms and the R 7 and R 8 groups may be combined to form a ring; R 9 and R 10 each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms and j and k each independently represent an integer of 0 to 4; W represents a single bond, an oxygen atom, or —CR 11 R 12 — and the R 11 and R 12 groups each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group; t and u each independently represent a numeral of 0 to 100; provided that the units represented by t and u have different structures and there is no case of t=u=0.

8. An electrophotographic photoreceptor cartridge comprising: the electrophotographic photoreceptor according to claim 4 ; and at least one device selected from the group consisting of a charging device which charges the electrophotographic photoreceptor, an exposure device which exposes the charged electrophotographic photoreceptor to form an electrostatic latent image, and a developing device which develops the electrostatic latent image formed on the electrophotographic photoreceptor.

9. An image-forming apparatus comprising: the electrophotographic photoreceptor according to claim 1 ; a charging device which charges the electrophotographic photoreceptor; an exposure device which exposes the charged electrophotographic photoreceptor to form an electrostatic latent image; and a developing device which develops the electrostatic latent image formed on the electrophotographic photoreceptor.