Electrophotographic photosensitive body

1. An electrophotographic photoreceptor comprising:

an electroconductive substrate; and

a photosensitive layer provided on the electroconductive substrate;

wherein

the photosensitive layer comprises an organic pigment and

a polyester resin containing the repeating unit represented by the following formula 5:

wherein

a ratio of a/(a+b) is greater than 0.7,

A is a compound having a structure represented by the following formula (A)

wherein

each of Ra 1 and Ra 2 independently represents a hydrogen atom or a monovalent substituent which may have a substituent, and

each of n and m is independently an integer from 0 to 4,

F is a compound having a structure represented by the following formula (F):

wherein X 2 represents one selected from the group consisting of a single bond and a bivalent group, and

said bivalent group is one selected from the group consisting of a sulfur atom, an oxygen atom, a sulfonyl group, a cycloalkylene group, and —CR 19 R 20 —,

each of R 7 and R 8 independently represents one selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, a halogen group, and an alkoxy group, and

each of k and l independently represents an integer from 1 to 4, wherein

each of R 19 and R 20 independently represents one selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, a halogen and an alkoxy group,

G is a compound having a structure represented by the following formula (G.):

wherein X 3 represents a bivalent group.

2. The electrophotographic photoreceptor according to claim 1 , wherein the organic pigment is at least one selected from the group consisting of a phthalocyanine pigment, an azo pigment, a quinacridone pigment, an indigo pigment, a perylene pigment, a polycyclic quinone pigment, an anthraquinone pigment and a benzimidazole pigment.

3. The electrophotographic photoreceptor according to claim 2 , wherein the organic pigment is a phthalocyanine or an azo pigment.

4. The electrophotographic photoreceptor according to claim 1 , wherein F in formula 5 is a compound having a structure represented by any one of the following formulae (B) to (E):

wherein each of R 1 and R 2 independently represents one selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, a halogen group, and an alkoxy group,

wherein

each of R 3 and R 4 independently represents one selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, a halogen group, and an alkoxy group,

wherein X 1 represents one selected from the group consisting of a single bond and a bivalent group,

wherein

each of R 5 and R 6 independently represents one selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, a halogen group, and an alkoxy group.

5. The electrophotographic photoreceptor according to claim 1 , wherein

A in the formula 5 is a diphenyl ether dicarboxylic acid.

6. The electrophotographic photoreceptor according to claim 1 , wherein

A in the formula 5 is selected from the group consisting of diphenyl ether 2,2′-dicarboxylic acid, diphenyl ether 2,4′-dicarboxylic acid, and diphenyl ether 4,4′-dicarboxylic acid.

7. The electrophotographic photoreceptor according to claim 1 , wherein

A in the formula 5 is diphenyl ether 4,4′-dicarboxylic acid.

8. The electrophotographic photoreceptor according to claim 1 , wherein

G in formula 5 is an aromatic dicarboxylic acid.

9. The electrophotographic photoreceptor according to claim 1 , wherein

G in formula 5 is selected from the group consisting of isophthalic acid and terephthalic acid.

10. The electrophotographic photoreceptor according to claim 1 , wherein

the photosensitive layer further comprises a compound represented by the following general formula 6

wherein,

each of Ar 1 to Ar 6 independently represents one selected from the group consisting of an arylene group which may have a substituent, and a bivalent heterocyclic group which may have a substituent;

each of m 1 and m 2 independently represents 0 or 1;

Q represents one selected from the group consisting of a direct bond and a bivalent residue;

each of R 9 to R 16 independently represents one selected from the group consisting of a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, and a heterocyclic group which may a substituent; each of n 1 to n 4 represents independently an integer from 0 to 4; and

Ar 1 to Ar 6 may bond with each other to form a cyclic structure.

11. The electrophotographic photoreceptor according to claim 1 , wherein

the polyester resin has a viscosity-average molecular weight (Mv) of 10,000 to 300,000.

12. A photoreceptor cartridge to be attached to an image forming device, the photoreceptor cartridge comprising:

the electrophotographic photoreceptor as set forth in claim 1 ; and

at least one device selected from the group consisting of a charging device for charging the electrophotographic photoreceptor at a predetermined potential, a developing device for supplying toner on a surface of the electrophotographic photoreceptor, and a cleaning device for scraping off and collecting residual toner adhered on the surface of the electrophotographic photoreceptor.

13. An image forming device comprising:

the electrophotographic photoreceptor as set forth in claim 1 ;

a charging device for charging the electrophotographic photoreceptor;

an exposing device for forming an electrostatic latent image on a photosensitive surface of the electrophotographic photoreceptor;

a developing device for supplying toner on a surface of the electrophotographic photoreceptor;

a transporting device for transferring a toner image formed on the electrophotographic photoreceptor onto a sheet of recording paper; and

a fixing device for fixing the toner image transferred onto the recording paper.