Electrophotographic photoconductor, image forming apparatus, image forming method, and process cartridge

• US 20070059619A1
• Filed: 09/12/2006
• Published: 03/15/2007
• Est. Priority Date: 09/13/2005
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Sasaki, Michitaka, Kawamura, Shinichi, Yanagawa, Yoshiki, Kurimoto, Eiji, Niimi, Tatsuya, Shimoyama, Keisuke, Orito, Takeshi
• Granted Patent: US 7,871,747 B2
• Time in Patent Office: Days
• US Class Current: 430/58.700
• CPC Class Codes: G03G 5/0651 containing four relevant rings
• CPC Class Codes: G03G 5/0696 Phthalocyanines
• CPC Class Codes: G03G 5/072 comprising pending monoamine groups
• CPC Class Codes: G03G 5/0732 comprising pending alkenylarylamine
• CPC Class Codes: G03G 5/074 comprising pending diamine
• CPC Class Codes: G03G 5/0745 comprising pending hydrazone
• CPC Class Codes: G03G 5/144 comprising inorganic material
• CPC Class Codes: G03G 5/14704 comprising inorganic material
• CPC Class Codes: G03G 5/14734 Polymers comprising at least one carboxyl radical, e.g. polyacrylic acid, polycrotonic acid, polymaleic acid; Derivatives thereof, e.g. their esters, salts, anhydrides, nitriles, amides
• CPC Class Codes: G03G 5/14786 Macromolecular compounds characterised by specific side-chain substituents or end groups
• CPC Class Codes: G03G 5/14791 Macromolecular compounds characterised by their structure, e.g. block polymers, reticulated polymers, or by their chemical properties, e.g. by molecular weight or acidity

Abstract

To provide an electrophotographic photoconductor that has a layer containing a compound represented by the following general formula (1), and an image forming apparatus using the electrophotographic photoconductor.

• • where R¹ and R² independently represent any one of a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group, and R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ independently represent any one of a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group

Claims

1. An electrophotographic photoconductor, comprising:

a layer comprising a compound represented by the following general formula (1).

where R¹ and R² independently represent any one of a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group, and R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ independently represent any one of a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group

2. The electrophotographic photoconductor according to claim 1, comprising:

a support;

an under layer; and

a photosensitive layer, the under layer and the photosensitive layer being disposed on or over the support,

wherein the photosensitive layer comprises a compound represented by the general formula (1), and

wherein the under layer is composed of a charge blocking layer and a moire preventing layer.

3. The electrophotographic photoconductor according to claim 2, wherein the charge blocking layer comprises an insulating material, and the thickness of the charge blocking layer is 0.1 μ

m to 4.0 μ

m.

4. The electrophotographic photoconductor according to claim 3, wherein the insulating material is a polyamide.

5. The electrophotographic photoconductor according to claim 4, wherein the polyamide is N-methoxymethylated nylon.

6. The electrophotographic photoconductor according to claim 2, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray.

7. The electrophotographic photoconductor according to claim 2, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is a titanyl phthalocyanine crystal which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

, main peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.3° and

9.4° and

at 26.3°

in its X-ray diffraction spectrum for CuKα

X-ray.

8. The electrophotographic photoconductor according to claim 7, wherein the average particle diameter of the titanyl phthalocyanine is 0.25 μ

m or less.

9. The electrophotographic photoconductor according to claim 1, comprising:

a support;

a photosensitive layer; and

a surface protective layer, the photosensitive layer and the surface protective layer being disposed on or over the support,

wherein the photosensitive layer comprises a compound represented by the general formula (1), and

wherein the surface protective layer comprises a cured material obtained by curing a radically polymerizable compound that bears three or more functional groups and has no charge transporting structure and a radically polymerizable compound that bears one functional group and has a charge transporting structure.

10. The electrophotographic photoconductor according to claim 9, wherein the radically polymerizable compound that bears one functional group and has a charge transporting structure is at least one selected from compounds represented by the following general formula (i) and compounds represented by the following general formula (ii)

11. The electrophotographic photoconductor according to claim 9, wherein the radically polymerizable compound that bears one functional group and has a charge transporting structure is at least one selected from compounds represented by the following general formula (iii).

12. The electrophotographic photoconductor according to claim 9, wherein the cured material contained in the surface protective layer is a material cured by irradiation with light or by application of heat.

13. The electrophotographic photoconductor according to claim 9, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray.

14. The electrophotographic photoconductor according to claim 13, wherein the titanyl phthalocyanine has peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.3° and

9.4° and

at 26.3°

in its X-ray diffraction spectrum for CuKα

X-ray.

15. The electrophotographic photoconductor according to claim 14, wherein the average particle diameter of the titanyl phthalocyanine is 0.25 μ

m or less.

16. The electrophotographic photoconductor according to claim 1, comprising:

a support;

an under layer; and

a photosensitive layer, the under layer and the photosensitive layer being disposed on or over the support,

wherein the photosensitive layer comprises a compound represented by the general formula (1), and

wherein the under layer is composed of a conductive layer and a barrier layer.

17. The electrophotographic photoconductor according to claim 16, wherein the barrier layer comprises an insulating material, and the thickness of the barrier layer is 0.1 μ

m to 4.0 μ

m.

18. The electrophotographic photoconductor according to claim 17, wherein the insulating material is a polyamide.

19. The electrophotographic photoconductor according to claim 18, wherein the polyamide is N-methoxymethylated nylon.

20. The electrophotographic photoconductor according to claim 16, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray.

21. The electrophotographic photoconductor according to claim 16, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is a titanyl phthalocyanine crystal which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

, main peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.3° and

9.4° and

at 26.3°

in its X-ray diffraction spectrum for CuKα

X-ray.

22. The electrophotographic photoconductor according to claim 21, wherein the average particle diameter of the titanyl phthalocyanine is 0.25 μ

m or less.

23. The electrophotographic photoconductor according to claim 1, comprising:

a support;

an under layer; and

a photosensitive layer, the under layer and the photosensitive layer being disposed on or over the support,

wherein the photosensitive layer comprises a compound represented by the general formula (1), and

wherein the support is a support whose surface has been subjected to anodizing treatment for forming an anodized film thereon.

24. The electrophotographic photoconductor according to claim 23, wherein the anodized film is made of anodized aluminum.

25. The electrophotographic photoconductor according to claim 24, wherein the anodized aluminum is one which has been subjected to pore-filling treatment after the anodizing treatment.

26. The electrophotographic photoconductor according to claim 24, wherein the thickness of the anodized aluminum is 1 μ

m to 15 μ

m.

27. The electrophotographic photoconductor according to claim 23, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray.

28. The electrophotographic photoconductor according to claim 23, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is a titanyl phthalocyanine crystal which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

, main peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.3° and

9.4° and

at 26.3°

in its X-ray diffraction spectrum for CuKα

X-ray.

29. The electrophotographic photoconductor according to claim 28, wherein the average particle diameter of the titanyl phthalocyanine is 0.25 μ

m or less.

30. The electrophotographic photoconductor according to claim 1, comprising:

a support;

an under layer; and

a photosensitive layer, the under layer and the photosensitive layer being disposed on or over the support,

wherein the photosensitive layer comprises a compound represented by the general formula (1), and

wherein the under layer comprises two different metal oxides (T1) and (T2) with different average particle diameters and satisfies the condition 0.2<

(D2/D1)≦

0.5 (where D1 is the average particle diameter of the metal oxide (T1) having an average particle diameter larger than that of the other metal oxide (T2), and D2 is the average particle diameter of the metal oxide (T2)).

31. The electrophotographic photoconductor according to claim 30, wherein the average diameter (D2) of the metal oxide (T2) is 0.05 μ

m to 0.2 μ

m.

32. The electrophotographic. photoconductor according to claim 30, wherein the proportion of the metal oxide (T2) in the metal oxides (T1) and (T2) on a mass basis satisfies the condition 0.2≦

T2/(T1+T2)≦

0.8.

33. The electrophotographic photoconductor according to claim 30, wherein each of the metal oxides (T1) and (T2) is titanium oxide.

34. The electrophotographic photoconductor according to claim 30, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray.

35. The electrophotographic photoconductor according to claim 30, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is a titanyl phthalocyanine crystal which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

, main peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.3° and

9.4° and

at 26.3°

in its X-ray diffraction spectrum for CuKα

X-ray.

36. The electrophotographic photoconductor according to claim 35, wherein the average particle diameter of the titanyl phthalocyanine is 0.25 μ

m or less.

37. The electrophotographic photoconductor according to claim 1, comprising:

a support;

an intermediate layer; and

a photosensitive layer, the intermediate layer and the photosensitive layer being disposed on or over the support,

wherein the intermediate layer comprises a compound represented by the general formula (1).

38. The electrophotographic photoconductor according to claim 37, wherein the intermediate layer comprises two different metal oxides (T1) and (T2) with different average particle diameters and satisfies the condition 0.2<

(D2/D1)≦

0.5 (where D1 is the average particle diameter of the metal oxide (T1) having an average particle diameter larger than that of the other metal oxide (T2), and D2 is the average particle diameter of the metal oxide (T2)).

39. The electrophotographic photoconductor according to claim 37, wherein the average diameter (D2) of the metal oxide (T2) is 0.05 μ

m to 0.2 μ

m.

40. The electrophotographic photoconductor according to claim 37, wherein the proportion of the metal oxide (T2) in the metal oxides (T1) and (T2) on a mass basis satisfies the condition 0.2≦

T2/(T1+T2)≦

0.8.

41. The electrophotographic photoconductor according to claim 38, wherein the intermediate layer is composed of a charge blocking layer and a moire preventing layer.

42. The electrophotographic photoconductor according to claim 41, wherein the charge blocking layer comprises an insulating material, and the thickness of the charge blocking layer is 0.1 μ

m to 4.0 μ

m.

43. The electrophotographic photoconductor according to claim 42, wherein the insulating material is a polyamide.

44. The electrophotographic photoconductor according to claim 43, wherein the polyamide is N-methoxymethylated nylon.

45. The electrophotographic photoconductor according to claim 37, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray.

46. The electrophotographic photoconductor according to claim 37, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is a titanyl phthalocyanine crystal which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

, main peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.3° and

9.4° and

at 26.3°

in its X-ray diffraction spectrum for CuKα

X-ray.

47. The electrophotographic photoconductor according to claim 46, wherein the average particle diameter of the titanyl phthalocyanine is 0.25 μ

m or less.

48. The electrophotographic photoconductor according to claim 1, comprising:

a support;

an under layer; and

a photosensitive layer, the under layer and the photosensitive layer being disposed on or over the support,

wherein the photosensitive layer comprises a compound represented by the general formula (1), and

wherein the under layer comprises an organic metal compound and a silane coupling agent.

49. The electrophotographic photoconductor according to claim 48, wherein the under layer comprises a binder resin.

50. The electrophotographic photoconductor according to claim 48, wherein the organic metal compound is one of an organic zirconium compound and an organic titanium compound.

51. The electrophotographic photoconductor according to claim 48, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray.

52. The electrophotographic photoconductor according to claim 51, wherein the titanyl phthalocyanine has peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.3° and

9.4° and

at 26.3°

in its X-ray diffraction spectrum for CuKα

X-ray.

53. The electrophotographic photoconductor according to claim 52, wherein the average particle diameter of the titanyl phthalocyanine is 0.25 μ

m or less.

54. The electrophotographic photoconductor according to claim 1, comprising:

a support;

a photosensitive layer; and

a surface protective layer, the photosensitive layer and the surface protective layer being disposed on or over the support,

wherein the photosensitive layer comprises a compound represented by the general formula (1), and

wherein the surface protective layer comprises at least one of a diamond like carbon and an amorphous carbon, both containing hydrogen.

55. The electrophotographic photoconductor according to claim 1, comprising:

a support;

an intermediate layer;

a photosensitive layer; and

a surface protective layer, the intermediate layer, the photosensitive layer and the surface protective layer being disposed on or over the support,

wherein the intermediate layer comprises a compound represented by the general formula (1), and

wherein the surface protective layer comprises at least one of a diamond like carbon and an amorphous carbon, both containing hydrogen.

56. The electrophotographic photoconductor according to claim 54, wherein the surface protective layer comprises at least one element selected from the group consisting of nitrogen, fluorine, phosphorus, chlorine, and bromine.

57. The electrophotographic photoconductor according to claim 54, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray.

58. The electrophotographic photoconductor according to claim 54, wherein the photosensitive layer comprises a charge generating substance, and the charge generating substance is a titanyl phthalocyanine crystal which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

, main peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.3° and

9.4° and

at 26.3°

in its X-ray diffraction spectrum for CuKα

X-ray.

59. The electrophotographic photoconductor according to claim 58, wherein the average particle diameter of the titanyl phthalocyanine is 0.25 μ

m or less.

60. An image forming apparatus, comprising:

an electrophotographic photoconductor,

wherein the electrophotographic photoconductor includes a layer comprising a compound represented by the following general formula (1)

where R¹ and R² independently represent any one of a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group, and R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ independently represent any one of a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group

61. The image forming apparatus according to claim 60, wherein the image forming apparatus is a full color image forming apparatus in which a plurality of image forming element is provided,

wherein each of the image forming elements comprises:

an electrophotographic photoconductor which includes a layer comprising a compound represented by the general formula (1);

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

an exposure unit configured to selectively expose the electrophotographic photoconductor to form a latent electrostatic image thereon; and

a developing unit configured to develop the latent electrostatic image using a toner.

62. An image forming apparatus, comprising:

an electrophotographic photoconductor;

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

an exposure unit configured to selectively expose the electrophotographic photoconductor to form a latent electrostatic image thereon; and

a developing unit configured to develop the latent electrostatic image using a toner,

wherein the electrophotographic photoconductor comprises a support and a photosensitive layer disposed on or over the support,

wherein the photosensitive layer comprises a compound represented by the following general formula (1) and titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray (wavelength=1.542 angstrom), and

wherein the image forming apparatus is operated under the condition that the time from charging to development is 300 msec or less

where R¹ and R² independently represent any one of a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group, and R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ independently represent any one of a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group

63. The image forming apparatus according to claim 62, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2)

64. The image forming apparatus according to claim 62, wherein the titanyl phthalocyanine has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

, main peaks at Bragg angles 2θ

(±

0.2°

) of 9.4°

, 9.6° and

24.0°

, a peak at the smallest Bragg angle 2θ

(±

0.2°

) of 7.3°

, and no peaks between 7.30 and 9.4°

in its X-ray diffraction spectrum for CuKα

X-ray (wavelength=1.542 angstrom).

65. The image forming apparatus according to claim 62, wherein the photosensitive layer comprises a charge transporting substance, and

wherein the charge transporting substance comprises a hole transporting substance and an electron transporting substance.

66. The image forming apparatus according to claim 65, wherein the hole transporting substance is represented by the following structural formula.

67. The image forming apparatus according to claim 62, wherein a charging process is carried out by positively charging the electrophotographic photoconductor.

68. The image forming apparatus according to claim 62, wherein the image forming apparatus comprises a plurality of the electrophotographic photoconductors, and monochrome toner images developed on the electrophotographic photoconductors are sequentially combined with one another to form a color image.

69. The image forming apparatus according to claim 62, wherein the charging unit uses AC superposition current for the charging of the electrophotographic photoconductor.

70. The image forming apparatus according to claim 62, wherein the charging unit is in contact with or in the vicinity of the electrophotographic photoconductor.

71. The image forming apparatus according to claim 62, further comprising:

an intermediate transferring unit configured to transfer a toner image that has been developed on the electrophotographic photoconductor to an intermediate transferring medium and transfer the toner image on the intermediate transferring medium to a recording medium,

wherein toner images of different colors are sequentially combined with one another on the intermediate transferring medium to form a color image, and the color image thus combined is then transferred to the recording medium at a time.

72. An image forming method, comprising:

equally charging a surface of an electrophotographic photoconductor which includes a layer comprising a compound represented by the general formula (1);

selectively exposing the electrophotographic photoconductor to form a latent electrostatic image thereon; and

developing the latent electrostatic image using a toner,

wherein the electrophotographic photoconductor comprises a support and a photosensitive layer disposed on or over the support, and

wherein the photosensitive layer comprises a compound represented by the following general formula (1) and titanyl phthalocyanine which has a maximum peak at least at a Bragg angle 2θ

(±

0.2°

) of 27.2°

in its X-ray diffraction spectrum for CuKα

X-ray (wavelength=1.542 angstrom)

where R¹ and R² independently represent any one of a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group, and R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ independently represent any one of a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group

73. A process cartridge, comprising:

an electrophotographic photoconductor which includes a layer comprising a compound represented by the general formula (1); and

at least one unit selected from the group consisting of a charging unit, a developing unit, a transferring unit, and a cleaning unit,

wherein the process cartridge can be detachably attached to an image forming apparatus

where R¹ and R² independently represent any one of a hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group, and R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹ and R¹⁰ independently represent any one of a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group and substituted or unsubstituted aralkyl group