Electrophotographic photoconductor, and image forming process, image forming apparatus and process cartridge for an image forming apparatus using the same
Disclosed is an electrophotographic photoconductor including at least a photoconductive layer on a conductive substrate, wherein the surface layer of the photoconductive layer contains at least a surface crosslinked layer formed by curing a tri- or more-functional radical polymerizable monomer without having a charge transporting structure and a mono-functional radical polymerizable compound having a charge transporting structure and the surface crosslinked layer has a surface roughness Rz of 1.3 μm or less.
1. An electrophotographic photoconductor, comprising:
an electroconductive substrate; and
a photoconductive layer on or above the electroconductive substrate, the photoconductive layer comprising:
a cross-linked surface layer which comprises:
a cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure; and
a cured mono-functional radical polymerizable compound having a charge transporting structure,
wherein the cross-linked surface layer has an elastic displacement rate τe of 35% or more and a standard deviation of the elastic displacement rate τe of 2% or less; and
the cured mono-functional radical polymerizable compound having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group, a methacryloyloxy group and a vinyl group.
2. An electrophotographic photoconductor according to claim 1 , wherein the cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group and a methacryloyloxy group.
3. An electrophotographic photoconductor according to claim 1 , wherein the cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure has a ratio (molecular weight/number of functional group) of molecular weight to the number of functional group of 250 or less.
4. An electrophotographic photoconductor according to claim 1 , wherein the charge transporting structure of the cured mono-functional radical polymerizable compound having a charge transporting structure is a triarylamine structure.
5. An electrophotographic photoconductor according to claim 1 , wherein the cured mono-functional radical polymerizable compound having a charge transporting structure is represented by one of the formulae (1) and (2):
wherein, R 1 represents a hydrogen atom or a methyl group;
Ar 1 and Ar 2 represent a substituted or unsubstituted arylene group, which may be identical or different;
Ar 3 and Ar 4 represent a substituted or unsubstituted aryl group, which may be identical or different;
X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, a oxygen atom, a sulfur atom or a vinylene group;
Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group or an alkyleneoxycarbonyl group; and
“m” and “n” represent an integer of 0 to 3.
6. An electrophotographic photoconductor according to claim 1 , wherein the cured mono-functional radical polymerizable compound having a charge transporting structure is represented by the following formula (3):
wherein, “o,” “p” and “q” each represent an integer of 0 or 1;
Ra represents a hydrogen atom or a methyl group;
Rb and Rc represent an alkyl group having 1 to 6 carbon atoms, wherein each of Rb and Rc may be different when there are two or more Rb and Rc, respectively;
“s” and “t” represent an integer of 0 to 3; and
Za represents a single bond, a methylene group, an ethylene group,
7. An electrophotographic photoconductor according to claim 1 , wherein the cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure is 30% to 70% by weight, based on the total amount of the cross-linked surface layer.
8. An electrophotographic photoconductor according to claim 1 , wherein the cured mono-functional radical polymerizable compound having a charge transporting structure is 30% to 70% by weight, based on the total amount of the cross-linked surface layer.
9. An electrophotographic photoconductor according to claim 1 , wherein the photoconductive layer comprises:
a charge generation layer;
a charge transport layer; and
the cross-linked surface layer laminated on or above the electroconductive substrate in this order.
10. An electrophotographic photoconductor according to claim 9 , wherein the charge transport layer comprises a polymer charge transport material.
11. An electrophotographic photoconductor according to claim 10 , wherein the polymer charge transport material is a polycarbonate having a triarylamine structure in the main chain or side chain thereof.
12. An electrophotographic photoconductor according to claim 1 , wherein the cross-linked surface layer is cured by one of heating and light irradiation.
13. An electrophotographic photoconductor according to claim 9 , wherein the cross-linked surface layer has a thickness of from 1 μm to 10 μm.
14. An electrophotographic photoconductor according to claim 9 , wherein the thickness is from 2 μm to 8 μm.
15. An electrophotographic photoconductor according to claim 9 , wherein the cross-linked surface layer is insoluble in an organic solvent.
16. An electrophotographic photoconductor, comprising:
an electroconductive substrate;
a charge generation layer;
a charge transport layer; and
a cross-linked surface layer, the layers sequentially laminated on the electroconductive substrate,
wherein the cross-linked surface layer comprises:
a cross-linked and cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure; and
a cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure,
wherein the cross-linked surface layer has thickness of from 1 μm to 10 μm; and
the cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group, a methacryloyloxy group and a vinyl group.
17. An electrophotographic photoconductor according to claim 16 , wherein the thickness is from 2 μm to 8 μm.
18. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked surface layer is insoluble in an organic solvent.
19. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked and cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group and a methacryloyloxy group.
20. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked and cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure has a ratio (molecular weight/number of functional group) of molecular weight to the number of functional group of 250 or less.
21. An electrophotographic photoconductor according to claim 16 , wherein the charge transporting structure of the cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure is a triarylamine structure.
22. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure is represented by one of the formulae (1) and (2):
wherein, R 1 represents a hydrogen atom or a methyl group;
Ar 1 and Ar 2 represent a substituted or unsubstituted arylene group, which may be identical or different;
Ar 3 and Ar 4 represent a substituted or unsubstituted aryl group, which may be identical or different;
X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, a oxygen atom, a sulfur atom or a vinylene group;
Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group or an alkyleneoxycarbonyl group; and
“m” and “n” represent an integer of 0 to 3.
23. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure is represented by the following formula (3):
wherein, “o,” “p” and “q” each represent an integer of 0 or 1;
Ra represents a hydrogen atom or a methyl group;
Rb and Rc represent an alkyl group having 1 to 6 carbon atoms, wherein each of Rb and Rc may be different when there are two or more Rb and Rc, respectively;
“s” and “t” represent an integer of 0 to 3; and
Za represents a single bond, a methylene group, an ethylene group,
24. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked and cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure is 30% to 70% by weight, based on the total amount of the cross-linked surface layer.
25. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure is 30% to 70% by weight, based on the total amount of the cross-linked surface layer.
26. An electrophotographic photoconductor according to claim 16 , wherein the charge transport layer comprises a polymer charge transport material.
27. An electrophotographic photoconductor according to claim 26 , wherein the polymer charge transport material is a polycarbonate having a triarylamine structure in the main chain or side chain thereof.
28. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked surface layer is cured by one of heating and light irradiation.
29. An electrophotographic photoconductor according to claim 16 , wherein the cross-linked surface layer has an elastic displacement rate τe of 35% or more and a standard deviation of the elastic displacement rate τe of 2% or less.
30. A process for forming an image, comprising:
charging an electrophotographic photoconductor;
exposing the electrophotographic photoconductor which is charged to a recording light so as to form an electrostatic latent image;
developing the electrostatic latent image by a developing agent so as to visualize the electrostatic latent image and form a toner image; and
transferring the toner image formed by developing onto a transfer material,
wherein the electrophotographic photoconductor comprises: an electroconductive substrate; and
a photoconductive layer on or above the electroconductive substrate, the photoconductive layer comprising:
a cross-linked surface layer which comprises:
a cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure; and
a cured mono-functional radical polymerizable compound having a charge transporting structure,
wherein the cross-linked surface layer has an elastic displacement rate τe of 35% or more and a standard deviation of the elastic displacement rate τe of 2% or less; and
the cured mono-functional radical polymerizable compound having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group, a methacryloyloxy group and a vinyl group.
31. A process for forming an image, comprising:
charging an electrophotographic photoconductor;
exposing the electrophotographic photoconductor which is charged to a recording
light so as to form an electrostatic latent image;
developing the electrostatic latent image by a developing agent so as to visualize the electrostatic latent image and form a toner image; and
transferring the toner image formed by developing onto a transfer material,
wherein the electrophotographic photoconductor comprises:
an electroconductive substrate;
a charge generation layer;
a charge transport layer; and
a cross-linked surface layer, the layers sequentially laminated on the electroconductive substrate,
wherein the cross-linked surface layer comprises:
a cross-linked and cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure; and
a cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure,
wherein the cross-linked surface layer has thickness of from 1 μm to 10 μm; and
the cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group, a methacryloyloxy group and a vinyl group.
32. An apparatus for forming an image, comprising:
an electrophotographic photoconductor;
a charger to charge the electrophotographic photoconductor;
an exposer to expose the electrophotographic photoconductor charged by the charger to a recording light to form an electrostatic latent image;
a developing unit to supply a developing agent to the electrostatic latent image to visualize the electrostatic latent image and form a toner image; and
a transferring unit to transfer the toner image formed by the developing unit on a transfer material,
wherein the electrophotographic photoconductor comprises:
an electroconductive substrate; and
a photoconductive layer on or above the electroconductive substrate, the photoconductive layer comprising:
a cross-linked surface layer which comprises:
a cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure; and
a cured mono-functional radical polymerizable compound having a charge transporting structure,
wherein the cross-linked surface layer has an elastic displacement rate τe of 35% or more and a standard deviation of the elastic displacement rate τe of 2% or less; and
the cured mono-functional radical polymerizable compound having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group, a methacryloyloxy group and a vinyl group.
33. An apparatus for forming an image, comprising:
an electrophotographic photoconductor;
a charger to charge the electrophotographic photoconductor;
an exposer to expose the electrophotographic photoconductor charged by the charger to a recording light to form an electrostatic latent image;
a developing unit to supply a developing agent to the electrostatic latent image to visualize the electrostatic latent image and form a toner image; and
a transferring unit to transfer the toner image formed by the developing unit on a transfer material,
wherein the electrophoto graphic photo conductor comprises:
an electroconductive substrate;
a charge generation layer;
a charge transport layer; and
a cross-linked surface layer, the layers sequentially laminated on the electroconductive substrate,
wherein the cross-linked surface layer comprises:
a cross-linked and cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure; and
a cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure,
wherein the cross-linked surface layer has thickness of from 1 μm to 10 μm; and
the cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group, a methacryloyloxy group and a vinyl group.
34. A process cartridge for an image forming apparatus, comprising:
an electrophotographic photoconductor; and
at least one selected from the group consisting of:
a charger to charge the electrophotographic photoconductor;
a developing unit to supply a developing agent to an electrostatic latent image formed by exposure on the electrophotographic photoconductor to visualize the electrostatic latent image and form a toner image;
a transferring unit to transfer the toner image formed by the developing unit on a transfer material;
a cleaning unit to remove toner remaining on the electrophotographic photoconductor after transferring; and
a discharging unit to remove the latent image on the photoconductor after transferring so as to form a monolithic structure,
wherein the process cartridge is adapted to be attached to and detached from a main body of the image forming apparatus, and
the electrophotographic photoconductor comprises:
an electroconductive substrate; and
a photoconductive layer on or above the electroconductive substrate, the photoconductive layer comprising:
a cross-linked surface layer which comprises:
a cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure; and
a cured mono-functional radical polymerizable compound having a charge transporting structure,
wherein the cross-linked surface layer has an elastic displacement rate τe of 35% or more and a standard deviation of the elastic displacement rate τe of 2% or less; and
the cured mono-functional radical polymerizable compound having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group, a methacryloyloxy group and a vinyl group.
35. A process cartridge for an image forming apparatus, comprising:
an electrophotographic photoconductor; and
at least one selected from the group consisting of:
a charger to charge the electrophotographic photoconductor;
a developing unit to supply a developing agent to an electrostatic latent image formed by exposure on the electrophotographic photoconductor to visualize the electrostatic latent image and form a toner image;
a transferring unit to transfer the toner image formed by the developing unit on a transfer material;
a cleaning unit to remove toner remaining on the electrophotographic photoconductor after transferring; and
a discharging unit to remove the latent image on the photoconductor after transferring so as to form a monolithic structure,
wherein the process cartridge is adapted to be attached to and detached from a main body of the image forming apparatus, and
the electrophotographic photoconductor comprises:
an electroconductive substrate;
a charge generation layer;
a charge transport layer; and
a cross-linked surface layer, the layers sequentially laminated on the electroconductive substrate,
wherein the cross-linked surface layer comprises:
a cross-linked and cured tri- or more-functional radical polymerizable monomer without having a charge transporting structure; and
a cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure,
wherein the cross-linked surface layer has thickness of from 1 μm to 10 μm; and
the cross-linked and cured mono-functional radical polymerizable compound having a charge transporting structure has a functional group selected from the group consisting of an acryloyloxy group, a methacryloyloxy group and a vinyl group.