Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming apparatus

1. An electrophotographic photoreceptor, comprising:

a conductive support; and, provided thereon, at least an undercoat layer and a photosensitive layer,

wherein the undercoat layer comprises a binder resin and

wherein the binder resin comprises a polyamide resin having a degree of elastic deformation, as determined on the basis of the following measuring method, of 56.0% or higher:

[Measuring method] The polyamide resin is molded into a film having a thickness of 10 μm or larger, and examined with a Vickers indenter in an atmosphere having a temperature of 25° C. and a relative humidity of 50% under the conditions of a maximum indentation load of 5 mN, a load-increasing period of 10 seconds and a load-removing period of 10 seconds to obtain a maximum indentation depth, and the value at the maximum indentation depth is taken as the degree of elastic deformation.

2. The electrophotographic photoreceptor according to claim 1 , wherein the polyamide resin comprises a polyether structure.

3. The electrophotographic photoreceptor according to claim 1 , wherein the content of the polyamide resin is 25 parts by mass or higher per 100 parts by mass of the binder resin.

4. The electrophotographic photoreceptor according to claim 1 , wherein the photosensitive layer contains a polyarylate resin.

5. An electrophotographic photoreceptor cartridge, comprising:

the electrophotographic photoreceptor according to claim 1 ; and

at least one part selected from the group consisting of a charging part for charging the electrophotographic photoreceptor, an exposure part for exposing the charged electrophotographic photoreceptor to form an electrostatic latent image, a development part for developing the electrostatic latent image formed on the electrophotographic photoreceptor, and a cleaning part for cleaning the surface of the electrophotographic photoreceptor.

6. An image forming apparatus, comprising:

the electrophotographic photoreceptor according to claim 1 ;

a charging part for charging the electrophotographic photoreceptor;

an exposure part for exposing the charged electrophotographic photoreceptor to form an electrostatic latent image;

a development part for developing the electrostatic latent image formed on the electrophotographic photoreceptor; and

a cleaning part for cleaning the surface of the electrophotographic photoreceptor.

7. An electrophotographic photoreceptor comprising:

a conductive support; and, provided thereon, at least an undercoat layer and a photosensitive layer, which have been laminated in this order from the conductive-support side,

wherein the undercoat layer comprises a polyamide resin comprising:

at least one of a linear dicarboxylic acid component and a branched dicarboxylic acid component;

at least one of a lactam component and an aminocarboxylic acid component; and

polytetramethylene ether glycol as a polyether component.

8. The electrophotographic photoreceptor according to claim 7 , wherein the polyamide resin is a block copolymerized polyamide resin comprising: a polyamide block which comprises the at least one of a linear dicarboxylic acid component and branched dicarboxylic acid component and the at least one of a lactam component and aminocarboxylic acid component; and a polyether block which comprises the polyether component.

9. The electrophotographic photoreceptor according to claim 8 , wherein the block copolymerized polyamide resin has formula [1]:

-[HS-SS] n -  [1]

HS represents a hard segment, which is a polymer unit comprising at least one kind of polyamide block that comprises at least one of a lactam component and an aminocarboxylic acid component and at least one of a linear dicarboxylic acid component and a branched dicarboxylic acid component; and

SS represents a soft segment, which is a polymer unit comprising a polyether block that comprises at least one kind of polyether component.

10. The electrophotographic photoreceptor according to claim 9 , wherein the HS and SS in the block copolymerized polyamide resin represented by formula [1] are bonded to each other by an ester bond.

11. The electrophotographic photoreceptor according to claim 8 , wherein the polyether block includes polytetramethylene ether glycol or polypropylene ether glycol.

12. The electrophotographic photoreceptor according to claim 8 , wherein the content of the polyether block in the undercoat layer is 4% by mass or higher.

13. The electrophotographic photoreceptor according to claim 8 , wherein the polyamide block is obtained by polymerizing at least one of a lactam having a single structure and an aminocarboxylic acid having a single structure.

14. The electrophotographic photoreceptor according to claim 8 , wherein the block copolymerized polyamide resin contains no dimer acid component.

15. The electrophotographic photoreceptor according to claim 8 , wherein the block copolymerized polyamide resin contains no diamine component.

16. An electrophotographic photoreceptor comprising:

a conductive support; and, provided thereon, at least an undercoat layer and a photosensitive layer, which have been laminated in this order from the conductive-support side,

wherein the undercoat layer comprises a polyamide resin comprising:

at least one of a linear dicarboxylic acid component and a branched dicarboxylic acid component;

at least one of a lactam component and an aminocarboxylic acid component; and

a polyether component, and

wherein the polyamide resin has an ester bond.

17. The electrophotographic photoreceptor according to claim 16 , wherein the polyamide resin is a block copolymerized polyamide resin comprising: a polyamide block which comprises the at least one of a linear dicarboxylic acid component and branched dicarboxylic acid component and the at least one of a lactam component and aminocarboxylic acid component; and a polyether block which comprises the polyether component.

18. The electrophotographic photoreceptor according to claim 17 , wherein the block copolymerized polyamide resin has formula [1]:

-[HS-SS] n -  [1]

wherein:

HS represents a hard segment, which is a polymer unit comprising at least one kind of polyamide block that comprises at least one of a lactam component and an aminocarboxylic acid component and at least one of a linear dicarboxylic acid component and a branched dicarboxylic acid component; and

SS represents a soft segment, which is a polymer unit comprising a polyether block that comprises at least one kind of polyether component.

19. The electrophotographic photoreceptor according to claim 18 , wherein the HS and SS in the block copolymerized polyamide resin represented by formula [1] are bonded to each other by an ester bond.

20. The electrophotographic photoreceptor according to claim 17 , wherein the polyether block includes polytetramethylene ether glycol or polypropylene ether glycol.

21. The electrophotographic photoreceptor according to claim 17 , wherein the content of the polyether block in the undercoat layer is 4% by mass or higher.

22. The electrophotographic photoreceptor according to claim 17 , wherein the polyamide block is obtained by polymerizing at least one of a lactam having a single structure and an aminocarboxylic acid having a single structure.

23. The electrophotographic photoreceptor according to claim 17 , wherein the block copolymerized polyamide resin contains no dimer acid component.

24. The electrophotographic photoreceptor according to claim 17 , wherein the block copolymerized polyamide resin contains no diamine component.