Electrophotographic photoconductor, process cartridge and image forming apparatus

1. An electrophotographic photoconductor comprising:

a substrate;

a charge generating layer; and

a charge transporting layer,

the charge generating layer and the charge transporting layer being disposed over the substrate,

wherein the charge transporting layer contains a charge transporting material represented by General Formula (I) below, an additive represented by General Formula (II) below and a binder resin prepared by mixing a polycarbonate resin represented by General Formula (III) below with a polycarbonate copolymer resin represented by a combination of Structural Formulae (A), (B) and (C) below:

where R 1 , R 2 and R 3 each independently denote any one of a hydrogen atom, a halogen atom, an alkyl group which may contain a substituent, and an alkoxy group which may contain a substituent,

where R 4 and R 5 each denote a tertiary butyl group, and R 6 and R7 each independently denote one of an alkyl group which may contain a substituent, and an aryl group which may contain a substituent, and

where n denotes the number of times the repeat unit is repeated such that the one of the polycarbonate resins has a viscosity average molecular weight of 20,000 to 50,000.

2. The electrophotographic photoconductor according to claim 1 , wherein the additive represented by General Formula (II) has a maximum absorption wavelength in the range of 300 nm to 370 nm and does not have an absorption wavelength in the range of 730 nm to 800 nm.

3. The electrophotographic photoconductor according to claim 1 , wherein the charge transporting material represented by General Formula (I) comprises the compound represented by Structural Formula (Ia) below:

4. The electrophotographic photoconductor according to claim 1 , wherein the charge transporting material represented by General Formula (I) comprises the compound represented by Structural Formula (Ib) below:

5. The electrophotographic photoconductor according to claim 1 , wherein the charge transporting material represented by General Formula (I) comprises the compound represented by Structural Formula (Ie) below:

6. The electrophotographic photoconductor according to claim 1 , wherein the charge transporting material represented by General Formula (I) comprises the compound represented by Structural Formula (Id) below:

7. The electrophotographic photoconductor according to claim 1 , wherein the charge transporting material represented by General Formula (I) comprises the compound represented by Structural Formula (Ie) below:

8. The electrophotographic photoconductor according to claim 1 , wherein the additive represented by General Formula (II) comprises the compound represented by Structural Formula (IIa) below:

where t-Bu denotes a tertiary butyl group, and Me denotes a methyl group.

9. The electrophotographic photoconductor according to claim 1 , wherein the additive represented by General Formula (II) comprises the compound represented by Structural Formula (IIb) below:

where t-Bu denotes a tertiary butyl group, and Me denotes a methyl group.

10. The electrophotographic photoconductor according to claim 1 , wherein the additive represented by General Formula (II) comprises the compound represented by Structural Formula (IIc) below:

where t-Bu denotes a tertiary butyl group, and n-Pr denotes an n-propyl group.

11. The electrophotographic photoconductor according to claim 1 , wherein the additive represented by General Formula (II) comprises the compound represented by Structural Formula (IId) below:

where t-Bu denotes a tertiary butyl group, and Me denotes a methyl group.

12. The electrophotographic photoconductor according to claim 1 , wherein the additive represented by General Formula (II) comprises the compound represented by Structural Formula (IIe) below:

where t-Bu denotes a tertiary butyl group.

13. The electrophotographic photoconductor according to claim 1 , wherein the additive represented by General Formula (II) comprises the compound represented by Structural Formula (IIf) below:

where t-Bu denotes a tertiary butyl group.

14. The electrophotographic photoconductor according to claim 1 , wherein the charge transporting layer further contains a benzotriazole-based ultraviolet absorber.

15. The electrophotographic photoconductor according to claim 1 , wherein the charge transporting layer further contains a phenolic antioxidant.

16. A process cartridge detachably mountable to a main body of an image forming apparatus, comprising:

an electrophotographic photoconductor; and

a developing unit configured to develop a latent electrostatic image, formed on the electrophotographic photoconductor, with a toner so as to form a visible image,

wherein the electrophotographic photoconductor comprises a substrate, a charge generating layer and a charge transporting layer, the charge generating layer and the charge transporting layer being disposed over the substrate, and

wherein the charge transporting layer contains a charge transporting material represented by General Formula (I) below, an additive represented by General Formula (II) below and a binder resin prepared by mixing a polycarbonate resin represented by General Formula (III) below with a polycarbonate copolymer resin represented by a combination of Structural Formulae (A), (B) and (C) below:

where R 1 , R 2 and R 3 each independently denote anyone of a hydrogen atom, a halogen atom, an alkyl group which may contain a substituent, and an alkoxy group which may contain a substituent,

where R 4 and R 5 each denote a tertiary butyl group, and R 6 and R 7 each independently denote one of an alkyl group which may contain a substituent, and an aryl group which may contain a substituent, and

where n denotes the number of times the repeat unit is repeated such that the one of the of carbonate resins has a viscosity average molecular weight of 20,000 to 50,000.

17. An image forming apparatus comprising:

an electrophotographic photoconductor;

a latent electrostatic image forming unit configured to form a latent electrostatic image on the electrophotographic photoconductor;

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

a transfer unit configured to transfer the visible image onto recording medium; and

a fixing unit configured to fix the visible image transferred onto the recording medium,

wherein the electrophotographic photoconductor comprises a substrate, a charge generating layer and a charge transporting layer, the charge generating layer and the charge transporting layer being disposed over the substrate, and

wherein the charge transporting layer contains a charge transporting material represented by General Formula (I) below, an additive represented by General Formula (II) below and a binder resin prepared by mixing a polycarbonate resin represented by General Formula below with a polycarbonate copolymer resin represented by a combination of Structural Formulae (A), (B) and (C) below:

where R 1 , R 2 and R 3 each independently denote anyone of a hydrogen atom, a halogen atom, an alkyl group which may contain a substituent, and an alkoxy group which may contain a substituent,

where R 4 and R 5 each denote a tertiary butyl group, and R 6 and R 7 each independently denote one of an alkyl group which may contain a substituent, and an aryl group which may contain a substituent,

where n denotes the number of times the repeat unit is repeated such that the one of the polycarbonate resins has a viscosity average molecular weight of 20,000 to 50,000.