Electrophotographic photoconductor, image forming apparatus, and process cartridge

1. An electrophotographic photoconductor, comprising:

a conductive support;

an undercoat layer; and

a photoconductive layer;

wherein:

the undercoat layer and the photoconductive layer are provided over the conductive support in the order of recited;

the undercoat layer comprises metal oxide particles, a binder, and a salicylic acid derivative;

the metal oxide particles comprise zinc oxide particles doped with a Group XIII element;

a compacted powder of the metal oxide particles at a volume filling ratio of 50 vol % has a volume resistivity of 1×10 5 Ω·cm or higher but 1×10 8 Ω·cm or lower;

the undercoat layer has a volume resistivity of 0.001×10 6 Ω·cm or higher but 0.02×10 6 Ω·cm or lower at a field intensity of 5×10 6 V/m;

the undercoat layer has a thickness of 2 micrometers or greater but 20 micrometers or less; and

the salicylic acid derivative is a salicylic acid derivative according to formula (1):

 where X 1 and X 2 represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, a hydroxyl group, a carboxyl group, or a carbonyl group, and X 1 and X 2 may be same or different.

2. The electrophotographic photoconductor according to claim 1 , wherein one or both of X 1 and X 2 in the salicylic acid derivative according to formula (1) is/are a hydrogen atom, an alkyl group that comprises 4 or more carbon atoms, an alkoxy group that comprises 4 or more carbon atoms, or an aralkyl group that comprises 4 or more carbon atoms.

3. The electrophotographic photoconductor according to claim 1 , wherein a compacted powder of the metal oxide particles at a volume filling ratio of 50 vol % has a volume resistivity of 1×10 6 Ω·cm or higher but 1×10 8 Ω·cm or lower.

4. The electrophotographic photoconductor according to claim 1 , wherein the undercoat layer has a volume resistivity of 0.005×10 6 Ω·cm or higher but 0.015×10 6 Ω·cm or lower at a field intensity of 5×10 6 V/m.

5. The electrophotographic photoconductor according to claim 1 , wherein the metal oxide particles comprise zinc oxide particles doped with aluminum.

6. The electrophotographic photoconductor according to claim 1 , wherein the metal oxide particles comprise zinc oxide particles doped with gallium.

7. An image forming apparatus comprising:

an electrophotographic photoconductor;

a charging unit configured to charge a surface of the electrophotographic photoconductor;

an exposing unit configured to expose the charged surface of the electrophotographic photoconductor to light to form an electrostatic latent image;

a developing unit configured to develop the electrostatic latent image with a toner to form a visible image; and

a transfer unit configured to transfer the visible image onto a recording medium,

wherein the electrophotographic photoconductor is the electrophotographic photoconductor according to claim 1 .

8. An image forming apparatus comprising a process cartridge that comprises:

an electrophotographic photoconductor; and

at least one unit selected from the group consisting of a charging unit configured to charge a surface of the electrophotographic photoconductor, an exposing unit configured to expose the charged surface of the electrophotographic photoconductor to light to form an electrostatic latent image, a developing unit configured to develop the electrostatic latent image with a toner to form a visible image, a transfer unit configured to transfer the visible image onto a recording medium, and a cleaning unit configured to remove the toner remaining on the surface of the electrophotographic photoconductor after a transfer process,

wherein the process cartridge is mountable on and demountable from the image forming apparatus, and

wherein the electrophotographic photoconductor is the electrophotographic photoconductor according to claim 1 .

9. A process cartridge comprising:

an electrophotographic photoconductor; and

at least one unit selected from the group consisting of a charging unit configured to charge a surface of the electrophotographic photoconductor, an exposing unit configured to expose the charged surface of the electrophotographic photoconductor to light to form an electrostatic latent image, a developing unit configured to develop the electrostatic latent image with a toner to form a visible image, a transfer unit configured to transfer the visible image onto a recording medium, and a cleaning unit configured to remove the toner remaining on the surface of the electrophotographic photoconductor after a transfer process,

wherein the electrophotographic photoconductor is the electrophotographic photoconductor according to claim 1 .

10. An electrophotographic photoconductor, comprising:

a conductive support;

an undercoat layer; and

a photoconductive layer;

wherein:

the undercoat layer and the photoconductive layer are provided over the conductive support in the order of recited;

the undercoat layer comprises metal oxide particles, a binder, and a salicylic acid derivative;

the metal oxide particles have an average primary particle diameter of 50 nm or greater but 200 nm or less;

a compacted powder of the metal oxide particles at a volume filling ratio of 50 vol % has a volume resistivity of 1×10 5 Ω·cm or higher but 1×10 8 Ω·cm or lower;

the undercoat layer has a volume resistivity of 0.001×10 6 Ω·cm or higher but 0.02×10 6 Ω·cm or lower at a field intensity of 5×10 6 V/m;

the undercoat layer has a thickness of 2 micrometers or greater but 20 micrometers or less; and

the salicylic acid derivative is a salicylic acid derivative according to formula (1):

 where X 1 and X 2 represent a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group, an aryl group, a hydroxyl group, a carboxyl group, or a carbonyl group, and X 1 and X 2 may be same or different.

11. The electrophotographic photoconductor according to claim 10 , wherein the metal oxide particles comprise zinc oxide particles.

12. The electrophotographic photoconductor according to claim 10 , wherein the metal oxide particles comprise zinc oxide particles doped with a Group XIII element.

13. The electrophotographic photoconductor according to claim 10 , wherein a compacted powder of the metal oxide particles at a volume filling ratio of 50 vol % has a volume resistivity of 1×10 6 Ω·cm or higher but 1×10 8 Ω·cm or lower.

14. The electrophotographic photoconductor according to claim 10 , wherein the undercoat layer has a volume resistivity of 0.005×10 6 Ω·cm or higher but 0.015×10 6 Ω·cm or lower at a field intensity of 5×10 6 V/m.

15. The electrophotographic photoconductor according to claim 10 , wherein the metal oxide particles comprise zinc oxide particles doped with aluminum.

16. The electrophotographic photoconductor according to claim 10 , wherein the metal oxide particles comprise zinc oxide particles doped with gallium.

17. An image forming apparatus comprising:

an electrophotographic photoconductor;

a charging unit configured to charge a surface of the electrophotographic photoconductor;

an exposing unit configured to expose the charged surface of the electrophotographic photoconductor to light to form an electrostatic latent image;

a developing unit configured to develop the electrostatic latent image with a toner to form a visible image; and

a transfer unit configured to transfer the visible image onto a recording medium,

wherein the electrophotographic photoconductor is the electrophotographic photoconductor according to claim 10 .

18. An image forming apparatus comprising

a process cartridge that comprises:

an electrophotographic photoconductor; and

at least one unit selected from the group consisting of a charging unit configured to charge a surface of the electrophotographic photoconductor, an exposing unit configured to expose the charged surface of the electrophotographic photoconductor to light to form an electrostatic latent image, a developing unit configured to develop the electrostatic latent image with a toner to form a visible image, a transfer unit configured to transfer the visible image onto a recording medium, and a cleaning unit configured to remove the toner remaining on the surface of the electrophotographic photoconductor after a transfer process,

wherein the process cartridge is mountable on and demountable from the image forming apparatus, and

wherein the electrophotographic photoconductor is the electrophotographic photoconductor according to claim 10 .

19. A process cartridge comprising:

an electrophotographic photoconductor; and

at least one unit selected from the group consisting of a charging unit configured to charge a surface of the electrophotographic photoconductor, an exposing unit configured to expose the charged surface of the electrophotographic photoconductor to light to form an electrostatic latent image, a developing unit configured to develop the electrostatic latent image with a toner to form a visible image, a transfer unit configured to transfer the visible image onto a recording medium, and a cleaning unit configured to remove the toner remaining on the surface of the electrophotographic photoconductor after a transfer process,

wherein the electrophotographic photoconductor is the electrophotographic photoconductor according to claim 10 .