-
- (a) a charge transport material having the formula
-
- where Y1 and Y2 comprise, independently, an aromatic group;
- X1 and X2 are each a linking group;
- W1 and W2 are each a —(CH2)n— group or a —(CH2)n-1—C(═O)— group, where n is an integer between 1 and 10;
- Ar1 and Ar2 comprise each a divalent aromatic group;
- Q1 and Q2 are each O, S, or NR;
- Z1 and Z2 comprise, independently, a bond, a vinyl group, a —CR1═N—NR2— group, or a —CR3═N—N═CR4— group; and
- R, R1, R2, R3, and R4 comprise, independently, H, an alkyl group, an alkenyl group, an alkynyl group, an acyl group, a heterocyclic group, or an aromatic group; and
- (b) a charge generating compound.
Corresponding electrophotographic apparatuses and imaging methods are described.
Tokarski, Zbigniew (Woodbury, MN, US)
Daskeviciene, Maryte (Jonava, LT)
Gaidelis, Valentas (Vilnius, LT)
Getautis, Vytautas (Kaunas, LT)
Montrimas, Edmundas (Vilnius, LT)
Stanisauskaite, Albina (Kaunas, LT)
Plaque It!
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| JP2001166519 | June, 2001 | ELECTROPHOTOGRAPHIC PHOTORECEPTOR, PROCESS CARTRIDGE AND ELECTROPHOTOGRAPHIC DEVICE |
1. An organophotoreceptor comprising an electrically conductive substrate and a photoconductive element on the electrically conductive substrate, the photoconductive element comprising: (a) a charge transport material having the formula
2. An organophotoreceptor according to claim 1 wherein Y1 and Y2 comprise, each independently, an aryl group selected from the group consisting of a phenyl group, a naphthyl group, a bis[(N,N-disubstituted)-amino]aryl group, a julolidinyl group, an (N-substituted)arylamine group, and an (N,N-disubstituted)arylamine group.
3. An organophotoreceptor according to claim 2 wherein the aryl group further comprises at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
4. An organophotoreceptor according to claim 1 wherein Y1 and Y2 comprise, each independently, an aromatic heterocyclic group selected from the group consisting of a furanyl group, a thiophenyl group, a pyrrolyl group, an indolyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridinyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, a tetrazinyl group, a petazinyl group, a quinolinyl group, an isoquinolinyl group, a cinnolinyl group, a phthalazinyl group, a quinazolinyl group, a quinoxalinyl group, a naphthyridinyl group, an acridinyl group, a phenanthridinyl group, a phenanthrolinyl group, an anthyridinyl group, a purinyl group, a pteridinyl group, an alloxazinyl group, a phenazinyl group, a phenothiazinyl group, a phenoxazinyl group, a phenoxathiinyl group, a dibenzo(1,4)dioxinyl group, a thianthrenyl group, a bicarbazolyl group, and a 1,6-di(10H-10-phenothiazinyl)hexyl group.
5. An organophotoreceptor according to claim 1 wherein X1 and X2 are, each independently, a —(CH2)m— group, where m is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NRa group, a CRb group, a CRcRd group, a SiReRf group, a BRg group, or a P(═O)Rh group, where Ra, Rb, Rc, Rd, Re, Rf, Rg, and Rh are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group.
6. An organophotoreceptor according to claim 5 wherein X1 and X2 are, each independently, a —CH2— group, a —OCH2— group, or a —Ar—OCH2— group; Y1 and Y2 comprise, each independently, an aryl group or an aromatic heterocyclic group; and W1 and W2 are, each independently, a bond, a —CH2— group, a —(CH2)(n-1)—C(═O)— group, or a —CH2CH2— group, where n is an integer between 2 and 6 and Ar comprises an aromatic group.
7. An organophotoreceptor according to claim 6 wherein Z1 and Z2 comprise, each independently, a —CR2═N—NR2— group where R1 is H and R2 comprises an aromatic group.
8. An organophotoreceptor according to claim 6 wherein and Z1 and Z2 comprise, each independently, a bond.
9. An organophotoreceptor according to claim 6 wherein Z1 and Z2 comprise, each independently, a —CR3═N—N═CR4— group; and X1 and X2 are, each independently, a —Ar—OCH2— group, where Ar comprises an aromatic group and R3 and R4 comprise, each independently, H, an alkyl group, an aromatic group, or a heterocyclic group.
10. An organophotoreceptor according to claim 6 wherein the aryl group or the aromatic heterocyclic group is selected from the group consisting of the following formulae:
11. An organophotoreceptor according to claim 10 wherein the aryl group or the aromatic heterocyclic group further comprises at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
12. An organophotoreceptor according to claim 1 wherein Ar1 and Ar2 are, each independently, selected from the group consisting of the following formulae:
13. An organophotoreceptor according to claim 12 wherein the bridging group is a —(CH2)p— group, where p is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NRi group, a CRj group, a CRkRl group, a SiRmRn group, a BRo group, or a P(═O)Rp group, where Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group.
14. An organophotoreceptor according to claim 1 wherein the photoconductive element further comprises a second charge transport material.
15. An organophotoreceptor according to claim 14 wherein the second charge transport material comprises an electron transport compound.
16. An organophotoreceptor according to claim 1 wherein the photoconductive element further comprises a binder.
17. An electrophotographic imaging apparatus comprising: (a) a light imaging component; and (b) an organophotoreceptor oriented to receive light from the light imaging component, the organophotoreceptor comprising an electrically conductive substrate and a photoconductive element on the electrically conductive substrate, the photoconductive element comprising: (i) a charge transport material having the formula
18. An electrophotographic imaging apparatus according to claim 17 wherein Y1 and Y2 comprise, each independently, an aryl group selected from the group consisting of a phenyl group, a naphthyl group, a bis[(N,N-disubstituted)amino]aryl group, a julolidinyl group, an (N-substituted)arylamine group, and an (N,N-disubstituted)arylamine group.
19. An electrophotographic imaging apparatus according to claim 18 wherein the aryl group further comprises at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
20. An electrophotographic imaging apparatus according to claim 17 wherein Y1 and Y2 comprise, each independently, an aromatic heterocyclic group selected from the group consisting of a furanyl group, a thiophenyl group, a pyrrolyl group, an indolyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridinyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, a tetrazinyl group, a petazinyl group, a quinolinyl group, an isoquinolinyl group, a cinnolinyl group, a phthalazinyl group, a quinazolinyl group, a quinoxalinyl group, a naphthyridinyl group, an acridinyl group, a phenanthridinyl group, a phenanthrolinyl group, an anthyridinyl group, a purinyl group, a pteridinyl group, an alloxazinyl group, a phenazinyl group, a phenothiazinyl group, a phenoxazinyl group, a phenoxathiinyl group, a dibenzo(1,4)dioxinyl group, a thianthrenyl group, a bicarbazolyl group, and a 1,6-di(10H-10-phenothiazinyl)hexyl group.
21. An electrophotographic imaging apparatus according to claim 17 wherein X1 and X2 are, each independently, a —(CH2)m— group, where m is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NRa group, a CRb group, a CRcRd group, a SiReRf, a BRg group, or a P(═O)Rh group, where Ra, Rb, Rc, Rd, Re, Rf, Rg, and Rh are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group.
22. An electrophotographic imaging apparatus according to claim 21 wherein X1 and X2 are, each independently, a —CH2— group, a —OCH2— group, or a —Ar—OCH2— group; Y1 and Y2 comprise, each independently, an aryl group or an aromatic heterocyclic group; and W1 and W2 are, each independently, a bond, a —CH2— group, a —CH2CH2— group, or a —(CH2)(n-1)—C(═O)— group, where n is an integer between 2 and 6 and Ar comprises an aromatic group.
23. An electrophotographic imaging apparatus according to claim 22 wherein Z1 and Z2 comprise, each independently, a —CR1═N—NR2— group where R1 is H and R2 comprises an aromatic group.
24. An electrophotographic imaging apparatus according to claim 22 wherein and Z1 and Z2 comprise, each independently, a bond.
25. An electrophotographic imaging apparatus according to claim 22 wherein Z1 and Z2 comprise, each independently, a —CR3═N—N═CR4— group; and X1 and X2 are, each independently, a —Ar—OCH2— group, where Ar comprises an aromatic group and R3 and R4 comprise, each independently, H, an alkyl group, an aromatic group, or a heterocyclic group.
26. An electrophotographic imaging apparatus according to claim 22 wherein the aryl group or the aromatic heterocyclic group is selected from the group consisting of the following formulae:
27. An electrophotographic imaging apparatus according to claim 26 wherein the aryl group or the aromatic heterocyclic group further comprises at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
28. An electrophotographic imaging apparatus according to claim 17 wherein Ar1 and Ar2 are, each independently, selected from the group consisting of the following formulae:
29. An electrophotographic imaging apparatus according to claim 28 wherein the bridging group is a —(CH2)p— group, where p is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NRi group, a CRj group, a CRkRl group, a SiRmRn group, a BRo group, or a P(═O)Rp group, where Ri, j, Rk, Rl, Rm, Rn, Ro, and Rp are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group.
30. An electrophotographic imaging apparatus according to claim 17 wherein the photoconductive element further comprises a second charge transport material.
31. An electrophotographic imaging apparatus according to claim 30 wherein second charge transport material comprises an electron transport compound.
32. An electrophotographic imaging apparatus according to claim 17 further comprising a toner dispenser.
33. An electrophotographic imaging process comprising; (a) applying an electrical charge to a surface of an organophotoreceptor comprising an electrically conductive substrate and a photoconductive element on the electrically conductive substrate, the photoconductive element comprising (i) a charge transport material having the formula
34. An electrophotographic imaging process according to claim 33 wherein Y1 and Y2 comprise, each independently, an aryl group selected from the group consisting of a phenyl group, a naphthyl group, a bis[(N,N-disubstituted)amino]aryl group, a julolidinyl group, an (N-substituted)arylamine group, and an (N,N-disubstituted)arylamine group.
35. An electrophotographic imaging process according to claim 34 wherein the aryl group further comprises at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
36. An electrophotographic imaging process according to claim 33 wherein Y1 and Y2 comprise, each independently, an aromatic heterocyclic group selected from the group consisting of a furanyl group, a thiophenyl group, a pyrrolyl group, an indolyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridinyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, a tetrazinyl group, a petazinyl group, a quinolinyl group, an isoquinolinyl group, a cinnolinyl group, a phthalazinyl group, a quinazolinyl group, a quinoxalinyl group, a naphthyridinyl group, an acridinyl group, a phenanthridinyl group, a phenanthrolinyl group, an anthyridinyl group, a purinyl group, a pteridinyl group, an alloxazinyl group, a phenazinyl group, a phenothiazinyl group, a phenoxazinyl group, a phenoxathiinyl group, a dibenzo(1,4)dioxinyl group, a thianthrenyl group, a bicarbazolyl group, and a 1,6-di(10H-10-phenothiazinyl)hexyl group.
37. An electrophotographic imaging process according to claim 33 wherein X1 and X2 are, each independently, a —(CH2)m— group, where m is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NRa group, a CRb group, a CRcRd group, a SiReRf group, a BRg group, or a P(═O)Rh group, where Ra, Rb, Rc, Rd, Re, Rf, Rg, and Rh are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group.
38. An electrophotographic imaging process according to claim 37 wherein X1 and X2 are, each independently, a —CH2— group, a —OCH2— group, or a —Ar—OCH2— group; Y1 and Y2 comprise, each independently, an aryl group or an aromatic heterocyclic group; and W1 and W2 are, each independently, a bond, a —CH2— group, a —CH2CH2— group, or a —(CH2)(n-1)—C(═O)— group, where n is an integer between 2 and 6 and Ar comprises an aromatic group.
39. An electrophotographic imaging process according to claim 38 wherein Z1 and Z2 comprise, each independently, a —CR1═N—NR2— group where R1 is H and R2 comprises an aromatic group.
40. An electrophotographic imaging process according to claim 38 wherein and Z1 and Z2 comprise, each independently, a bond.
41. An electrophotographic imaging process according to claim 38 wherein Z1 and Z2 comprise, each independently, a —CR3═N—N═CR4— group; and X1 and X2 are, each independently, a —Ar—OCH2— group, where Ar comprises an aromatic group and R3 and R4 comprise, each independently, H, an alkyl group, an aromatic group, or a heterocyclic group.
42. An electrophotographic imaging process according to claim 38 wherein the aryl group or the aromatic heterocyclic group is selected from the group consisting of the following formulae:
43. An electrophotographic imaging process according to claim 42 wherein the aryl group or the aromatic heterocyclic group further comprises at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
44. An electrophotographic imaging process according to claim 33 wherein Ar1 and Ar2 are, each independently, selected from the group consisting of the following formulae:
45. An electrophotographic imaging process according to claim 44 wherein the bridging group is a —(CH2)p— group, where p is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NRa group, a CRb group, a CRcRd group, or a SiReRf where Ra, Rb, Rc, Rd, Re, and Rf are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, such as a vinyl group, an allyl group, and a 2-phenylethenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group.
46. An electrophotographic imaging process according to claim 33 wherein the photoconductive element further comprises a second charge transport material.
47. An electrophotographic imaging process according to claim 46 wherein the second charge transport material comprises an electron transport compound.
48. An electrophotographic imaging process according to claim 33 wherein the photoconductive element further comprises a binder.
49. An electrophotographic imaging process according to claim 33 wherein the toner comprises colorant particles.
50. A charge transport material having the formula
51. A charge transport material according to claim 50 wherein Y1 and Y2 comprise, each independently, an aryl group selected from the group consisting of a phenyl group, a naphthyl group, a bis[(N,N-disubstituted)amino]aryl group, a julolidinyl group, an (N-substituted)arylamine group, and an (N,N-disubstituted)arylamine group.
52. A charge transport material according to claim 51 wherein the aryl group further comprises at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
53. A charge transport material according to claim 50 wherein Y1 and Y2 comprise, each independently, an aromatic heterocyclic group selected from the group consisting of a furanyl group, a thiophenyl group, a pyrrolyl group, an indolyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridinyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, a tetrazinyl group, a petazinyl group, a quinolinyl group, an isoquinolinyl group, a cinnolinyl group, a phthalazinyl group, a quinazolinyl group, a quinoxalinyl group, a naphthyridinyl group, an acridinyl group, a phenanthridinyl group, a phenanthrolinyl group, an anthyridinyl group, a purinyl group, a pteridinyl group, an alloxazinyl group, a phenazinyl group, a phenothiazinyl group, a phenoxazinyl group, a phenoxathiinyl group, a dibenzo(1,4)dioxinyl group, a thianthrenyl group, a bicarbazolyl group, and a 1,6-di(10H-10-phenothiazinyl)hexyl group.
54. A charge transport material according to claim 50 wherein X1 and X2 are, each independently, a —(CH2)m— group, where m is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NRa group, a CRb group, a CRcRd group, a SiReRf group, a BRg group, or a P(═O)Rh group, where Ra, Rb, Rc, Rd, Re, Rf, Rg, and Rh are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group.
55. A charge transport material according to claim 54 wherein X1 and X2 are, each independently, a —CH2— group, a —OCH2— group, or a —Ar—OCH2— group; Y1 and Y2 comprise, each independently, an aryl group or an aromatic heterocyclic group; and W1 and W2 are, each independently, a bond, a —CH2— group, a —CH2CH2— group, or a —(CH2)(n-1)—C(═O)— group, where n is an integer between 2 and 6 and Ar comprises an aromatic group.
56. A charge transport material according to claim 55 wherein Z1 and Z2 comprise, each independently, a —CR1═N—NR2— group where R1 is H and R2 comprises an aromatic group.
57. A charge transport material according to claim 55 wherein and Z1 and Z2 comprise, each independently, a bond.
58. A charge transport material according to claim 55 wherein Z1 and Z2 comprise, each independently, a —CR3═N—N═CR4— group; and X1 and X2 are, each independently, a —Ar—OCH2— group, where Ar comprises an aromatic group and R3 and R4 comprise, each independently, H, an alkyl group, an aromatic group, or a heterocyclic group.
59. A charge transport material according to claim 55 wherein the aryl group or the aromatic heterocyclic group is selected from the group consisting of the following formulae:
60. A charge transport material according to claim 59 wherein the aryl group or the aromatic heterocyclic group further comprises at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
61. A charge transport material according to claim 50 wherein Ar1 and Ar2 are, each independently, selected from the group consisting of the following formulae:
62. A charge transport material according to claim 61 wherein the bridging group is a —(CH2)p— group, where p is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NRi group, a CRj group, a CRkRl group, a SiRmRn group, a BRo group, or a P(═O)Rp group, where Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rp are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group.
FIELD OF THE INVENTION
This invention relates to organophotoreceptors suitable for use in electrophotography and, more specifically, to organophotoreceptors including a charge transport material having two aromatic groups bonded together through linking groups and a central disulfane (—S—S—) linkage. The method of making the charge transport material is also described.
BACKGROUND OF THE INVENTION
In electrophotography, an organophotoreceptor in the form of a plate, disk, sheet, belt, drum, or the like having an electrically insulating photoconductive element on an electrically conductive substrate is imaged by first uniformly electrostatically charging the surface of the photoconductive layer, and then exposing the charged surface to a pattern of light. The light exposure selectively dissipates the charge in the illuminated areas where light strikes the surface, thereby forming a pattern of charged and uncharged areas, referred to as a latent image. A liquid or solid toner is then provided in the vicinity of the latent image and toner droplets or particles deposit in the vicinity of either the charged or uncharged areas to create a toned image on the surface of the photoconductive layer. The resulting toned image can be transferred to a suitable ultimate or intermediate receiving surface, such as paper, or the photoconductive layer can operate as an ultimate receptor for the image. The imaging process can be repeated many times to complete a single image, for example, by overlaying images of distinct color components or effect shadow images, such as overlaying images of distinct colors to form a full color final image, and/or to reproduce additional images.
Both single layer and multilayer photoconductive elements have been used. In single layer embodiments, a charge transport material and charge generating material are combined with a polymeric binder and then deposited on the electrically conductive substrate. In multilayer embodiments, the charge transport material and charge generating material are present in the element in separate layers, each of which can optionally be combined with a polymeric binder, deposited on the electrically conductive substrate. Two arrangements are possible for a two-layer photoconductive element. In one two-layer arrangement (the “dual layer” arrangement), the charge-generating layer is deposited on the electrically conductive substrate and the charge transport layer is deposited on top of the charge generating layer. In an alternate two-layer arrangement (the “inverted dual layer” arrangement), the order of the charge transport layer and charge generating layer is reversed.
In both the single and multilayer photoconductive elements, the purpose of the charge generating material is to generate charge carriers (i.e., holes and/or electrons) upon exposure to light. The purpose of the charge transport material is to accept at least one type of these charge carriers and transport them through the charge transport layer in order to facilitate discharge of a surface charge on the photoconductive element. The charge transport material can be a charge transport compound, an electron transport compound, or a combination of both. When a charge transport compound is used, the charge transport compound accepts the hole carriers and transports them through the layer with the charge transport compound. When an electron transport compound is used, the electron transport compound accepts the electron carriers and transports them through the layer with the electron transport compound.
SUMMARY OF THE INVENTION
This invention provides organophotoreceptors having good electrostatic properties such as high V acc and low V dis .
In a first aspect, an organophotoreceptor comprises an electrically conductive substrate and a photoconductive element on the electrically conductive substrate, the photoconductive element comprising:
(a) a charge transport material having the formula:
where Y 1 and Y 2 comprise, each independently, an aromatic group;
X 1 and X 2 are, each independently, a linking group, such as a —(CH 2 ) m — group, where m is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NR a group, a CR b group, a CR c R d group, a SiR e R f group, a BR g group, or a P(═O)R h group, where R a , R b , R c , R d , R e , R f , R g , and R h are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, such as a vinyl group, an allyl group, and a 2-phenylethenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group, such as cycloalkyl groups, heterocyclic groups, or a benzo group;
W 1 and W 2 are, each independently, a —(CH 2 ) n — group or a —(CH 2 ) n-1 —C(═O)— group, where n is an integer between 1 and 10, inclusive;
Ar 1 and Ar 2 comprise, each independently, a divalent aromatic group;
Q 1 and Q 2 are, each independently, O, S, or NR;
Z 1 and Z 2 comprise, each independently, a bond, a vinyl group, a —CR 1 ═N—NR 2 — group, or a —CR 3 ═N—N═CR 4 — group; and
R, R 1 , R 2 , R 3 , and R 4 comprise, each independently, H, an alkyl group, an alkenyl group, an alkynyl group, an acyl group, a heterocyclic group, or an aromatic group; and
(b) a charge generating compound.
The organophotoreceptor may be provided, for example, in the form of a plate, a flexible belt, a flexible disk, a sheet, a rigid drum, or a sheet around a rigid or compliant drum. In one embodiment, the organophotoreceptor includes: (a) a photoconductive element comprising the charge transport material, the charge generating compound, a second charge transport material, and a polymeric binder; and (b) the electrically conductive substrate.
In a second aspect, the invention features an electrophotographic imaging apparatus that comprises (a) a light imaging component; and (b) the above-described organophotoreceptor oriented to receive light from the light imaging component. The apparatus can further comprise a toner dispenser, such as a liquid toner dispenser. The method of electrophotographic imaging with photoreceptors containing the above noted charge transport materials is also described.
In a third aspect, the invention features an electrophotographic imaging process that includes (a) applying an electrical charge to a surface of the above-described organophotoreceptor; (b) imagewise exposing the surface of the organophotoreceptor to radiation to dissipate charge in selected areas and thereby form a pattern of at least relatively charged and uncharged areas on the surface; (c) contacting the surface with a toner, such as a liquid toner that includes a dispersion of colorant particles in an organic liquid, to create a toned image; and (d) transferring the toned image to a substrate.
In a fourth aspect, the invention features a charge transport material having Formula (I) above.
In a fifth aspect, the invention features a method of preparing a charge transport material comprising the step of
(a) forming at least one aromatic thiol compound by reacting an aromatic dithiol compound with a reactive-ring compound having the following formula:
where Y 1 comprises an aromatic group;
X 1 is a linking group, such as a —(CH 2 ) m — group, where m is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NR a group, a CR b group, a CR c R d group, a SiR e R f , a BR g group, or a P(═O)R h group, where R a , R b , R c , R d , R e , R f , R g , and R h are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, such as a vinyl group, an allyl group, and a 2-phenylethenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group, such as cycloalkyl groups, heterocyclic groups, or a benzo group;
W 1 is a —(CH 2 ) n — group or a —(CH 2 ) n-1 —(═O)— group, where n is an integer between 1 and 10, inclusive;
Q 1 is O, S, or NR;
Z 1 , comprises a bond, a vinyl group, a —CR 1 ═N—NR 2 — group, or a —CR 3 ═N—N═CR 4 — group; and
R, R 1 , R 2 , R 3 , and R 4 comprise, each independently, H, an alkyl group, an alkenyl group, an alkynyl group, an acyl group, an aromatic group, or a heterocyclic group; and
(b) dimerizing or coupling the at least one aromatic thiol compound by heating the aromatic thiol compound in dimethyl sulfoxide.
The invention provides suitable charge transport materials for organophotoreceptors featuring a combination of good mechanical and electrostatic properties. These photoreceptors can be used successfully with toners, such as liquid toners, to produce high quality images. The high quality of the imaging system can be maintained after repeated cycling.
Other features and advantages of the invention will be apparent from the following description of the particular embodiments thereof, and from the claims.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
An organophotoreceptor as described herein has an electrically conductive substrate and a photoconductive element including a charge generating compound and a charge transport material having two aromatic groups, Y 1 and Y 2 , bonded together through a bridging group including a central disulfane (—S—S—) linkage. These charge transport materials have desirable properties as evidenced by their performance in organophotoreceptors for electrophotography. In particular, the charge transport materials of this invention have high charge carrier mobilities and good compatibility with various binder materials, and possess excellent electrophotographic properties. The organophotoreceptors according to this invention generally have a high photosensitivity, a low residual potential, and a high stability with respect to cycle testing, crystallization, and organophotoreceptor bending and stretching. The organophotoreceptors are particularly useful in laser printers and the like as well as fax machines, photocopiers, scanners and other electronic devices based on electrophotography. The use of these charge transport materials is described in more detail below in the context of laser printer use, although their application in other devices operating by electrophotography can be generalized from the discussion below.
To produce high quality images, particularly after multiple cycles, it is desirable for the charge transport materials to form a homogeneous solution with the polymeric binder and remain approximately homogeneously distributed through the organophotoreceptor material during the cycling of the material. In addition, it is desirable to increase the amount of charge that the charge transport material can accept (indicated by a parameter known as the acceptance voltage or “V acc ”), and to reduce retention of that charge upon discharge (indicated by a parameter known as the discharge voltage or “V dis ”).
The charge transport materials can be classified as a charge transport compound or an electron transport compound. There are many charge transport compounds and electron transport compounds known in the art for electrophotography. Non-limiting examples of charge transport compounds include, for example, pyrazoline derivatives, fluorene derivatives, oxadiazole derivatives, stilbene derivatives, enamine derivatives, enamine stilbene derivatives, hydrazone derivatives, carbazole hydrazone derivatives, (N,N-disubstituted)arylamines such as triaryl amines, polyvinyl carbazole, polyvinyl pyrene, polyacenaphthylene, and the charge transport compounds described in U.S. Pat. Nos. 6,689,523, 6,670,085, and 6,696,209, and U.S. patent application Ser. Nos. 10/431,135, 10/431,138, 10/699,364, 10/663,278, 10/699,581, 10/449,554, 10/748,496, 10/789,094, 10/644,547, 10/749,174, 10/749,171, 10/749,418, 10/699,039, 10/695,581, 10/692,389, 10/634,164, 10/663,970, 10/749,164, 10/772,068, 10/749,178, 10/758,869, 10/695,044, 10/772,069, 10/789,184, 10/789,077, 10/775,429, 10/775,429, 10/670,483, 10/671,255, 10/663,971, 10/760,039. All the above patents and patent applications are incorporated herein by reference.
Non-limiting examples of electron transport compounds include, for example, bromoaniline, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-indeno[1,2-b]thiophene-4-one, and 1,3,7-trinitrodibenzo thiophene-5,5-dioxide, (2,3-diphenyl-1-indenylidene)malononitrile, 4H-thiopyran-1,1-dioxide and its derivatives such as 4-dicyanomethylene-2,6-diphenyl-4H-thiopyran-1,1-dioxide, 4-dicyanomethylene-2,6-di-m-tolyl-4H-thiopyran-1,1-dioxide, and unsymmetrically substituted 2,6-diaryl-4H-thiopyran-1,1-dioxide such as 4H-1,1-dioxo-2-(p-isopropylphenyl)-6-phenyl-4-(dicyanomethyl idene)thiopyran and 4H-1,1-dioxo-2-(p-isopropylphenyl)-6-(2-thienyl)-4-(dicyanom ethylidene)thiopyran, derivatives of phospha-2,5-cyclohexadiene, alkoxycarbonyl-9-fluorenylidene)malononitrile derivatives such as (4-n-butoxycarbonyl-9-fluorenylidene)malononitrile, (4-phenethoxycarbonyl-9-fluorenylidene)malononitrile, (4-carbitoxy-9-fluorenylidene)malononitrile, and diethyl(4-n-butoxycarbonyl-2,7-dinitro-9-fluorenylidene)malo nate, anthraquinodimethane derivatives such as 11,11,12,12-tetracyano-2-alkylanthraquinodimethane and 11,11-dicyano-12,12-bis(ethoxycarbonyl)anthraquinodimethane, anthrone derivatives such as 1-chloro-10-[bis(ethoxycarbonyl)methylene]anthrone, 1,8-dichloro-10-[bis(ethoxycarbonyl)methylene]anthrone, 1,8-dihydroxy-10-[bis(ethoxycarbonyl)methylene]anthrone, and 1-cyano-10-[bis(ethoxycarbonyl)methylene)anthrone, 7-nitro-2-aza-9-fluroenylidene-malononitrile, diphenoquinone derivatives, benzoquinone derivatives, naphtoquinone derivatives, quinine derivatives, tetracyanoethylenecyanoethylene, 2,4,8-trinitro thioxantone, dinitrobenzene derivatives, dinitroanthracene derivatives, dinitroacridine derivatives, nitroanthraquinone derivatives, dinitroanthraquinone derivatives, succinic anhydride, maleic anhydride, dibromo maleic anhydride, pyrene derivatives, carbazole derivatives, hydrazone derivatives, N,N-dialkylaniline derivatives, diphenylamine derivatives, triphenylamine derivatives, triphenylmethane derivatives, tetracyano quinodimethane, 2,4,5,7-tetranitro-9-fluorenone, 2,4,7-trinitro-9-dicyanomethylene fluorenone, 2,4,5,7-tetranitroxanthone derivatives, 2,4,8-trinitrothioxanthone derivatives, 1,4,5,8-naphthalene bis-dicarboximide derivatives as described in U.S. Pat. Nos. 5,232,800, 4,468,444, and 4,442,193 and phenylazoquinolide derivatives as described in U.S. Pat. No. 6,472,514. In some embodiments of interest, the electron transport compound comprises an (alkoxycarbonyl-9-fluorenylidene)malononitrile derivative, such as (4-n-butoxycarbonyl-9-fluorenylidene)malononitrile, and 1,4,5,8-naphthalene bis-dicarboximide derivatives.
Although there are many charge transport materials available, there is a need for other charge transport materials to meet the various requirements of particular electrophotography applications.
In electrophotography applications, a charge-generating compound within an organophotoreceptor absorbs light to form electron-hole pairs. These electrons and holes can be transported over an appropriate time frame under a large electric field to discharge locally a surface charge that is generating the field. The discharge of the field at a particular location results in a surface charge pattern that essentially matches the pattern drawn with the light. This charge pattern then can be used to guide toner deposition. The charge transport materials described herein are especially effective at transporting charge, and in particular holes from the electron-hole pairs formed by the charge generating compound. In some embodiments, a specific electron transport compound or charge transport compound can also be used along with the charge transport material of this invention.
The layer or layers of materials containing the charge generating compound and the charge transport materials are within an organophotoreceptor. To print a two dimensional image using the organophotoreceptor, the organophotoreceptor has a two dimensional surface for forming at least a portion of the image. The imaging process then continues by cycling the organophotoreceptor to complete the formation of the entire image and/or for the processing of subsequent images.
The organophotoreceptor may be provided in the form of a plate, a flexible belt, a disk, a rigid drum, a sheet around a rigid or compliant drum, or the like. The charge transport material can be in the same layer as the charge generating compound and/or in a different layer from the charge generating compound. Additional layers can be used also, as described further below.
In some embodiments, the organophotoreceptor material comprises, for example: (a) a charge transport layer comprising the charge transport material and a polymeric binder; (b) a charge generating layer comprising the charge generating compound and a polymeric binder; and (c) the electrically conductive substrate. The charge transport layer may be intermediate between the charge generating layer and the electrically conductive substrate. Alternatively, the charge generating layer may be intermediate between the charge transport layer and the electrically conductive substrate. In further embodiments, the organophotoreceptor material has a single layer with both a charge transport material and a charge generating compound within a polymeric binder.
The organophotoreceptors can be incorporated into an electrophotographic imaging apparatus, such as laser printers. In these devices, an image is formed from physical embodiments and converted to a light image that is scanned onto the organophotoreceptor to form a surface latent image. The surface latent image can be used to attract toner onto the surface of the organophotoreceptor, in which the toner image is the same or the negative of the light image projected onto the organophotoreceptor. The toner can be a liquid toner or a dry toner. The toner is subsequently transferred, from the surface of the organophotoreceptor, to a receiving surface, such as a sheet of paper. After the transfer of the toner, the surface is discharged, and the material is ready to cycle again. The imaging apparatus can further comprise, for example, a plurality of support rollers for transporting a paper receiving medium and/or for movement of the photoreceptor, a light imaging component with suitable optics to form the light image, a light source, such as a laser, a toner source and delivery system and an appropriate control system.
An electrophotographic imaging process generally can comprise (a) applying an electrical charge to a surface of the above-described organophotoreceptor; (b) imagewise exposing the surface of the organophotoreceptor to radiation to dissipate charge in selected areas and thereby form a pattern of charged and uncharged areas on the surface; (c) exposing the surface with a toner, such as a liquid toner that includes a dispersion of colorant particles in an organic liquid to create a toner image, to attract toner to the charged or discharged regions of the organophotoreceptor; and (d) transferring the toner image to a substrate.
As described herein, an organophotoreceptor comprises a charge transport material having the formula:
where Y 1 and Y 2 comprise, each independently, an aromatic group;
X 1 and X 2 are, each independently, a linking group, such as a —(CH 2 ) m — group, where m is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NR a group, a CR b group, a CR c R d group, a SiR e R f group, a BR g group, or a P(═O)R h group, where R a , R b , R c , R d , R e , R f , R g , and R h are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, such as a vinyl group, an allyl group, and a 2-phenylethenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group, such as cycloalkyl groups, heterocyclic groups, or a benzo group;
W 1 and W 2 are, each independently, a —(CH 2 ) n — group or a —(CH 2 ) n-1 —C(═O)— group, where n is an integer between 1 and 10, inclusive;
Ar 1 and Ar 2 comprise, each independently, a divalent aromatic group;
Q 1 and Q 2 are, each independently, O, S, or NR;
Z 1 and Z 2 comprise, each independently, a bond, a vinyl group, a —CR 1 ═N—NR 2 — group, or a —CR 3 ═N—N═CR 4 — group; and
R, R 1 , R 2 , R 3 , and R 4 comprise, each independently, H, an alkyl group, an alkenyl group, an alkynyl group, an acyl group, a heterocyclic group, or an aromatic group.
A heterocyclic group includes any monocyclic or polycyclic (e.g., bicyclic, tricyclic, etc.) ring compound having at least a heteroatom (e.g., O, S, N, P, B, Si, etc.) in the ring.
An aromatic group can be any conjugated ring system containing 4n+2 pi-electrons. There are many criteria available for determining aromaticity. A widely employed criterion for the quantitative assessment of aromaticity is the resonance energy. Specifically, an aromatic group has a resonance energy. In some embodiments, the resonance energy of the aromatic group is at least 10 KJ/mol. In further embodiments, the resonance energy of the aromatic group is greater than 0.1 KJ/mol. Aromatic groups may be classified as an aromatic heterocyclic group which contains at least a heteroatom in the 4n+2 pi-electron ring, or as an aryl group which does not contain a heteroatom in the 4n+2 pi-electron ring. The aromatic group may comprise a combination of aromatic heterocyclic group and aryl group. Nonetheless, either the aromatic heterocyclic or the aryl group may have at least one heteroatom in a substituent attached to the 4n+2 pi-electron ring. Furthermore, either the aromatic heterocyclic or the aryl group may comprise a monocyclic or polycyclic (such as bicyclic, tricyclic, etc.) ring.
Non-limiting examples of the aromatic heterocyclic group are furanyl, thiophenyl, pyrrolyl, indolyl, carbazolyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, tetrazinyl, petazinyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, acridinyl, phenanthridinyl, phenanthrolinyl, anthyridinyl, purinyl, pteridinyl, alloxazinyl, phenazinyl, phenothiazinyl, phenoxazinyl, phenoxathiinyl, dibenzo(1,4)dioxinyl, thianthrenyl, and a combination thereof. The aromatic heterocyclic group may also include any combination of the above aromatic heterocyclic groups bonded together either by a bond (as in bicarbazolyl) or by a linking group (as in 1,6 di(10H-10-phenothiazinyl)hexane). The linking group may include an aliphatic group, an aromatic group, a heterocyclic group, or a combination thereof. Furthermore, the linking group may comprise at least one heteroatom such as O, S, Si, and N.
Non-limiting examples of the aryl group are phenyl, naphthyl, benzyl, or tolanyl group, sexiphenylene, phenanthrenyl, anthracenyl, coronenyl, and tolanylphenyl. The aryl group may also include any combination of the above aryl groups bonded together either by a bond (as in biphenyl group) or by a linking group (as in stilbenyl, diphenyl sulfone, an arylamine group). The linking group may include an aliphatic group, an aromatic group, a heterocyclic group, or a combination thereof. Furthermore, the linking group may comprise at least one heteroatom such as O, S, Si, and N.
Substitution is liberally allowed on the chemical groups to affect various physical effects on the properties of the compounds, such as mobility, sensitivity, solubility, stability, and the like, as is known generally in the art. In the description of chemical substituents, there are certain practices common to the art that are reflected in the use of language. The term group indicates that the generically recited chemical entity (e.g., alkyl group, alkenyl group, alkynyl group, phenyl group, aromatic group, heterocyclic group, arylamine group, julolidine group, carbazole group, (N,N-disubstituted)arylamine group, etc.) may have any substituent thereon which is consistent with the bond structure of that group. For example, where the term ‘alkyl group’ or ‘alkenyl group’ is used, that term would not only include unsubstituted linear, branched and cyclic alkyl group or alkenyl group, such as methyl, ethyl, ethenyl or vinyl, isopropyl, tert-butyl, cyclohexyl, cyclohexenyl, dodecyl and the like, but also substituents having heteroatom(s), such as 3-ethoxylpropyl, 4-(N,N-diethylamino)butyl, 3-hydroxypentyl, 2-thiolhexyl, 1,2,3-tribromoopropyl, and the like, and aromatic group, such as phenyl, naphthyl, carbazolyl, pyrrole, and the like. However, as is consistent with such nomenclature, no substitution would be included within the term that would alter the fundamental bond structure of the underlying group. For example, where a phenyl group is recited, substitution such as 2- or 4-aminophenyl, 2- or 4-(N,N-disubstituted)aminophenyl, 2,4-dihydroxyphenyl, 2,4,6-trithiophenyl, 2,4,6-trimethoxyphenyl and the like would be acceptable within the terminology, while substitution of 1,1,2,2,3,3-hexamethylphenyl would not be acceptable as that substitution would require the ring bond structure of the phenyl group to be altered to a non-aromatic form. Where the term moiety is used, such as alkyl moiety or phenyl moiety, that terminology indicates that the chemical material is not substituted. Where the term alkyl moiety is used, that term represents only an unsubstituted alkyl hydrocarbon group, whether branched, straight chain, or cyclic.
Organophotoreceptors
The organophotoreceptor may be, for example, in the form of a plate, a sheet, a flexible belt, a disk, a rigid drum, or a sheet around a rigid or compliant drum, with flexible belts and rigid drums generally being used in commercial embodiments. The organophotoreceptor may comprise, for example, an electrically conductive substrate and on the electrically conductive substrate a photoconductive element in the form of one or more layers. The photoconductive element can comprise both a charge transport material and a charge generating compound in a polymeric binder, which may or may not be in the same layer, as well as a second charge transport material such as a charge transport compound or an electron transport compound in some embodiments. For example, the charge transport material and the charge generating compound can be in a single layer. In other embodiments, however, the photoconductive element comprises a bilayer construction featuring a charge generating layer and a separate charge transport layer. The charge generating layer may be located intermediate between the electrically conductive substrate and the charge transport layer. Alternatively, the photoconductive element may have a structure in which the charge transport layer is intermediate between the electrically conductive substrate and the charge generating layer.
The electrically conductive substrate may be flexible, for example in the form of a flexible web or a belt, or inflexible, for example in the form of a drum. A drum can have a hollow cylindrical structure that provides for attachment of the drum to a drive that rotates the drum during the imaging process. Typically, a flexible electrically conductive substrate comprises an electrically insulating substrate and a thin layer of electrically conductive material onto which the photoconductive material is applied.
The electrically insulating substrate may be paper or a film forming polymer such as polyester (e.g., polyethylene terephthalate or polyethylene naphthalate), polyimide, polysulfone, polypropylene, nylon, polyester, polycarbonate, polyvinyl resin, polyvinyl fluoride, polystyrene and the like. Specific examples of polymers for supporting substrates included, for example, polyethersulfone (STABAR™ S-100, available from ICI), polyvinyl fluoride (TEDLAR®, available from E.I. DuPont de Nemours & Company), polybisphenol-A polycarbonate (MAKROFOL™, available from Mobay Chemical Company) and amorphous polyethylene terephthalate (MELINAR™, available from ICI Americas, Inc.). The electrically conductive materials may be graphite, dispersed carbon black, iodine, conductive polymers such as polypyrroles and CALGON® conductive polymer 261 (commercially available from Calgon Corporation, Inc., Pittsburgh, Pa.), metals such as aluminum, titanium, chromium, brass, gold, copper, palladium, nickel, or stainless steel, or metal oxide such as tin oxide or indium oxide. In embodiments of particular interest, the electrically conductive material is aluminum. Generally, the photoconductor substrate has a thickness adequate to provide the required mechanical stability. For example, flexible web substrates generally have a thickness from about 0.01 to about 1 mm, while drum substrates generally have a thickness from about 0.5 mm to about 2 mm.
The charge generating compound is a material that is capable of absorbing light to generate charge carriers (such as a dye or pigment). Non-limiting examples of suitable charge generating compounds include, for example, metal-free phthalocyanines (e.g., ELA 8034 metal-free phthalocyanine available from H.W. Sands, Inc. or Sanyo Color Works, Ltd., CGM-X01), metal phthalocyanines such as titanium phthalocyanine, copper phthalocyanine, oxytitanium phthalocyanine (also referred to as titanyl oxyphthalocyanine, and including any crystalline phase or mixtures of crystalline phases that can act as a charge generating compound), hydroxygallium phthalocyanine, squarylium dyes and pigments, hydroxy-substituted squarylium pigments, perylimides, polynuclear quinones available from Allied Chemical Corporation under the trade name INDOFAST™ Double Scarlet, INDOFAST™ Violet Lake B, INDOFAST™ Brilliant Scarlet and INDOFAST™ Orange, quinacridones available from DuPont under the trade name MONASTRAL™ Red, MONASTRAL™ Violet and MONASTRAL™ Red Y, naphthalene 1,4,5,8-tetracarboxylic acid derived pigments including the perinones, tetrabenzoporphyrins and tetranaphthaloporphyrins, indigo- and thioindigo dyes, benzothioxanthene-derivatives, perylene 3,4,9,10-tetracarboxylic acid derived pigments, polyazo-pigments including bisazo-, trisazo- and tetrakisazo-pigments, polymethine dyes, dyes containing quinazoline groups, tertiary amines, amorphous selenium, selenium alloys such as selenium-tellurium, selenium-tellurium-arsenic and selenium-arsenic, cadmium sulphoselenide, cadmium selenide, cadmium sulphide, and mixtures thereof. For some embodiments, the charge generating compound comprises oxytitanium phthalocyanine (e.g., any phase thereof), hydroxygallium phthalocyanine or a combination thereof.
The photoconductive layer of this invention may optionally contain a second charge transport material which may be a charge transport compound, an electron transport compound, or a combination of both. Generally, any charge transport compound or electron transport compound known in the art can be used as the second charge transport material.
An electron transport compound and a UV light stabilizer can have a synergistic relationship for providing desired electron flow within the photoconductor. The presence of the UV light stabilizers alters the electron transport properties of the electron transport compounds to improve the electron transporting properties of the composite. UV light stabilizers can be ultraviolet light absorbers or ultraviolet light inhibitors that trap free radicals.
UV light absorbers can absorb ultraviolet radiation and dissipate it as heat. UV light inhibitors are thought to trap free radicals generated by the ultraviolet light and after trapping of the free radicals, subsequently to regenerate active stabilizer moieties with energy dissipation. In view of the synergistic relationship of the UV stabilizers with electron transport compounds, the particular advantages of the UV stabilizers may not be their UV stabilizing abilities, although the UV stabilizing ability may be further advantageous in reducing degradation of the organophotoreceptor over time. The improved synergistic performance of organophotoreceptors with layers comprising both an electron transport compound and a UV stabilizer are described further in copending U.S. patent application Ser. No. 10/425,333 filed on Apr. 28, 2003 to Zhu, entitled “Organophotoreceptor With A Light Stabilizer,” incorporated herein by reference.
Non-limiting examples of suitable light stabilizer include, for example, hindered trialkylamines such as Tinuvin 144 and Tinuvin 292 (from Ciba Specialty Chemicals, Terrytown, N.Y.), hindered alkoxydialkylamines such as Tinuvin 123 (from Ciba Specialty Chemicals), benzotriazoles such as Tinuvan 328, Tinuvin 900 and Tinuvin 928 (from Ciba Specialty Chemicals), benzophenones such as Sanduvor 3041 (from Clariant Corp., Charlotte, N.C.), nickel compounds such as Arbestab (from Robinson Brothers Ltd, West Midlands, Great Britain), salicylates, cyanocinnamates, benzylidene malonates, benzoates, oxanilides such as Sanduvor VSU (from Clariant Corp., Charlotte, N.C.), triazines such as Cyagard UV-1164 (from Cytec Industries Inc., N.J.), polymeric sterically hindered amines such as Luchem (from Atochem North America, Buffalo, N.Y.). In some embodiments, the light stabilizer is selected from the group consisting of hindered trialkylamines having the following formula:
where R 1 , R 2 , R 3 , R 4 , R 6 , R 7 , R 8 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 are, each independently, hydrogen, alkyl group, or ester, or ether group; and R 5 , R 9 , and R 14 are, each independently, alkyl group; and X is a linking group selected from the group consisting of —O—CO—(CH 2 ) m —CO—O— where m is between 2 to 20.
The binder generally is capable of dispersing or dissolving the charge transport material (in the case of the charge transport layer or a single layer construction), the charge generating compound (in the case of the charge generating layer or a single layer construction) and/or an electron transport compound for appropriate embodiments. Examples of suitable binders for both the charge generating layer and charge transport layer generally include, for example, poly(styrene-co-butadiene), poly(styrene-co-acrylonitrile), modified acrylic polymers, poly(vinyl acetate), styrene-alkyd resins, soya-alkyl resins, poly(vinylchloride), poly(vinylidene chloride), polyacrylonitrile, polycarbonates, poly(acrylic acid), polyacrylates, polymethacrylates, styrene polymers, poly(vinyl butyral), alkyd resins, polyamides, polyurethanes, polyesters, polysulfones, polyethers, polyketones, phenoxy resins, epoxy resins, silicone resins, polysiloxanes, poly(hydroxyether) resins, polyhydroxystyrene resins, novolak, poly(phenylglycidyl ether-co-dicyclopentadiene), copolymers of monomers used in the above-mentioned polymers, and combinations thereof. Specific suitable binders include, for example, polyvinyl butyral, polycarbonate, and polyester. Non-limiting examples of polyvinyl butyral include BX-1 and BX-5 from Sekisui Chemical Co. Ltd., Japan. Non-limiting examples of suitable polycarbonate include polycarbonate A which is derived from bisphenol-A (e.g. Iupilon-A from Mitsubishi Engineering Plastics, or Lexan 145 from General Electric); polycarbonate Z which is derived from cyclohexylidene bisphenol (e.g. Iupilon-Z from Mitsubishi Engineering Plastics Corp, White Plain, N.Y.); and polycarbonate C which is derived from methylbisphenol A (from Mitsubishi Chemical Corporation). Non-limiting examples of suitable polyester binders include ortho-polyethylene terephthalate (e.g. OPET TR-4 from Kanebo Ltd., Yamaguchi, Japan).
Suitable optional additives for any one or more of the layers include, for example, antioxidants, coupling agents, dispersing agents, curing agents, surfactants, and combinations thereof.
The photoconductive element overall typically has a thickness from about 10 microns to about 45 microns. In the dual layer embodiments having a separate charge generating layer and a separate charge transport layer, charge generation layer generally has a thickness form about 0.5 microns to about 2 microns, and the charge transport layer has a thickness from about 5 microns to about 35 microns. In embodiments in which the charge transport material and the charge generating compound are in the same layer, the layer with the charge generating compound and the charge transport composition generally has a thickness from about 7 microns to about 30 microns. In embodiments with a distinct electron transport layer, the electron transport layer has an average thickness from about 0.5 microns to about 10 microns and in further embodiments from about 1 micron to about 3 microns. In general, an electron transport overcoat layer can increase mechanical abrasion resistance, increases resistance to carrier liquid and atmospheric moisture, and decreases degradation of the photoreceptor by corona gases. A person of ordinary skill in the art will recognize that additional ranges of thickness within the explicit ranges above are contemplated and are within the present disclosure.
Generally, for the organophotoreceptors described herein, the charge generation compound is in an amount from about 0.5 to about 25 weight percent, in further embodiments in an amount from about 1 to about 15 weight percent, and in other embodiments in an amount from about 2 to about 10 weight percent, based on the weight of the photoconductive layer. The charge transport material is in an amount from about 10 to about 80 weight percent, based on the weight of the photoconductive layer, in further embodiments in an amount from about 35 to about 60 weight percent, and in other embodiments from about 45 to about 55 weight percent, based on the weight of the photoconductive layer. The optional second charge transport material, when present, can be in an amount of at least about 2 weight percent, in other embodiments from about 2.5 to about 25 weight percent, based on the weight of the photoconductive layer, and in further embodiments in an amount from about 4 to about 20 weight percent, based on the weight of the photoconductive layer. The binder is in an amount from about 15 to about 80 weight percent, based on the weight of the photoconductive layer, and in further embodiments in an amount from about 20 to about 75 weight percent, based on the weight of the photoconductive layer. A person of ordinary skill in the art will recognize that additional ranges within the explicit ranges of compositions are contemplated and are within the present disclosure.
For the dual layer embodiments with a separate charge generating layer and a charge transport layer, the charge generation layer generally comprises a binder in an amount from about 10 to about 90 weight percent, in further embodiments from about 15 to about 80 weight percent and in some embodiments in an amount from about 20 to about 75 weight percent, based on the weight of the charge generation layer. The optional charge transport material in the charge generating layer, if present, generally can be in an amount of at least about 2.5 weight percent, in further embodiments from about 4 to about 30 weight percent and in other embodiments in an amount from about 10 to about 25 weight percent, based on the weight of the charge generating layer. The charge transport layer generally comprises a binder in an amount from about 20 weight percent to about 70 weight percent and in further embodiments in an amount from about 30 weight percent to about 50 weight percent. A person of ordinary skill in the art will recognize that additional ranges of binder concentrations for the dual layer embodiments within the explicit ranges above are contemplated and are within the present disclosure.
For the embodiments with a single layer having a charge generating compound and a charge transport material, the photoconductive layer generally comprises a binder, a charge transport material, and a charge generation compound. The charge generation compound can be in an amount from about 0.05 to about 25 weight percent and in further embodiment in an amount from about 2 to about 15 weight percent, based on the weight of the photoconductive layer. The charge transport material can be in an amount from about 10 to about 80 weight percent, in other embodiments from about 25 to about 65 weight percent, in additional embodiments from about 30 to about 60 weight percent and in further embodiments in an amount from about 35 to about 55 weight percent, based on the weight of the photoconductive layer, with the remainder of the photoconductive layer comprising the binder, and optionally additives, such as any conventional additives. A single layer with a charge transport composition and a charge generating compound generally comprises a binder in an amount from about 10 weight percent to about 75 weight percent, in other embodiments from about 20 weight percent to about 60 weight percent, and in further embodiments from about 25 weight percent to about 50 weight percent. Optionally, the layer with the charge generating compound and the charge transport material may comprise a second charge transport material. The optional second charge transport material, if present, generally can be in an amount of at least about 2.5 weight percent, in further embodiments from about 4 to about 30 weight percent and in other embodiments in an amount from about 10 to about 25 weight percent, based on the weight of the photoconductive layer. A person of ordinary skill in the art will recognize that additional composition ranges within the explicit compositions ranges for the layers above are contemplated and are within the present disclosure.
In general, any layer with an electron transport layer can advantageously further include a UV light stabilizer. In particular, the electron transport layer generally can comprise an electron transport compound, a binder, and an optional UV light stabilizer. An overcoat layer comprising an electron transport compound is described further in copending U.S. patent application Ser. No. 10/396,536 to Zhu et al. entitled, “Organophotoreceptor With An Electron Transport Layer,” incorporated herein by reference. For example, an electron transport compound as described above may be used in the release layer of the photoconductors described herein. The electron transport compound in an electron transport layer can be in an amount from about 10 to about 50 weight percent, and in other embodiments in an amount from about 20 to about 40 weight percent, based on the weight of the electron transport layer. A person of ordinary skill in the art will recognize that additional ranges of compositions within the explicit ranges are contemplated and are within the present disclosure.
The UV light stabilizer, if present, in any one or more appropriate layers of the photoconductor generally is in an amount from about 0.5 to about 25 weight percent and in some embodiments in an amount from about 1 to about 10 weight percent, based on the weight of the particular layer. A person of ordinary skill in the art will recognize that additional ranges of compositions within the explicit ranges are contemplated and are within the present disclosure.
For example, the photoconductive layer may be formed by dispersing or dissolving the components, such as one or more of a charge generating compound, the charge transport material of this invention, a second charge transport material such as a charge transport compound or an electron transport compound, a UV light stabilizer, and a polymeric binder in organic solvent, coating the dispersion and/or solution on the respective underlying layer and drying the coating. In particular, the components can be dispersed by high shear homogenization, ball-milling, attritor milling, high energy bead (sand) milling or other size reduction processes or mixing means known in the art for effecting particle size reduction in forming a dispersion.
The photoreceptor may optionally have one or more additional layers as well. An additional layer can be, for example, a sub-layer or an overcoat layer, such as a barrier layer, a release layer, a protective layer, or an adhesive layer. A release layer or a protective layer may form the uppermost layer of the photoconductor element. A barrier layer may be sandwiched between the release layer and the photoconductive element or used to overcoat the photoconductive element. The barrier layer provides protection from abrasion to the underlayers. An adhesive layer locates and improves the adhesion between a photoconductive element, a barrier layer and a release layer, or any combination thereof. A sub-layer is a charge blocking layer and locates between the electrically conductive substrate and the photoconductive element. The sub-layer may also improve the adhesion between the electrically conductive substrate and the photoconductive element.
Suitable barrier layers include, for example, coatings such as crosslinkable siloxanol-colloidal silica coating and hydroxylated silsesquioxane-colloidal silica coating, and organic binders such as poly(vinyl alcohol), methyl vinyl ether/maleic anhydride copolymer, casein, poly(vinyl pyrrolidone), poly(acrylic acid), gelatin, starch, polyurethanes, polyimides, polyesters, polyamides, poly(vinyl acetate), poly(vinyl chloride), poly(vinylidene chloride), polycarbonates, poly(vinyl butyral), poly(vinyl acetoacetal), poly(vinyl formal), polyacrylonitrile, poly(methyl methacrylate), polyacrylates, poly(vinyl carbazoles), copolymers of monomers used in the above-mentioned polymers, vinyl chloride/vinyl acetate/vinyl alcohol terpolymers, vinyl chloride/vinyl acetate/maleic acid terpolymers, ethylene/vinyl acetate copolymers, vinyl chloride/vinylidene chloride copolymers, cellulose polymers, and mixtures thereof. The above barrier layer polymers optionally may contain small inorganic particles such as fumed silica, silica, titania, alumina, zirconia, or a combination thereof. Barrier layers are described further in U.S. Pat. No. 6,001,522 to Woo et al., entitled “Barrier Layer For Photoconductor Elements Comprising An Organic Polymer And Silica,” incorporated herein by reference. The release layer topcoat may comprise any release layer composition known in the art. In some embodiments, the release layer is a fluorinated polymer, siloxane polymer, fluorosilicone polymer, silane, polyethylene, polypropylene, polyacrylate, or a combination thereof. The release layers can comprise crosslinked polymers.
The release layer may comprise, for example, any release layer composition known in the art. In some embodiments, the release layer comprises a fluorinated polymer, siloxane polymer, fluorosilicone polymer, polysilane, polyethylene, polypropylene, polyacrylate, poly(methyl methacrylate-co-methacrylic acid), urethane resins, urethane-epoxy resins, acrylated-urethane resins, urethane-acrylic resins, or a combination thereof. In further embodiments, the release layers comprise crosslinked polymers.
The protective layer can protect the organophotoreceptor from chemical and mechanical degradation. The protective layer may comprise any protective layer composition known in the art. In some embodiments, the protective layer is a fluorinated polymer, siloxane polymer, fluorosilicone polymer, polysilane, polyethylene, polypropylene, polyacrylate, poly(methyl methacrylate-co-methacrylic acid), urethane resins, urethane-epoxy resins, acrylated-urethane resins, urethane-acrylic resins, or a combination thereof. In some embodiments of particular interest, the release layers are crosslinked polymers.
An overcoat layer may comprise an electron transport compound as described further in copending U.S. patent application Ser. No. 10/396,536, filed on Mar. 25, 2003 to Zhu et al. entitled, “Organoreceptor With An Electron Transport Layer,” incorporated herein by reference. For example, an electron transport compound, as described above, may be used in the release layer of this invention. The electron transport compound in the overcoat layer can be in an amount from about 2 to about 50 weight percent, and in other embodiments in an amount from about 10 to about 40 weight percent, based on the weight of the release layer. A person of ordinary skill in the art will recognize that additional ranges of composition within the explicit ranges are contemplated and are within the present disclosure.
Generally, adhesive layers comprise a film forming polymer, such as polyester, polyvinylbutyral, polyvinylpyrrolidone, polyurethane, poly(methyl methacrylate), poly(hydroxy amino ether) and the like. Barrier and adhesive layers are described further in U.S. Pat. No. 6,180,305 to Ackley et al., entitled “Organic Photoreceptors for Liquid Electrophotography,” incorporated herein by reference.
Sub-layers can comprise, for example, polyvinylbutyral, organosilanes, hydrolyzable silanes, epoxy resins, polyesters, polyamides, polyurethanes, cellulosics and the like. In some embodiments, the sub-layer has a dry thickness between about 20 Angstroms and about 20,000 Angstroms. Sublayers containing metal oxide conductive particles can be between about 1 and about 25 microns thick. A person of ordinary skill in the art will recognize that additional ranges of compositions and thickness within the explicit ranges are contemplated and are within the present disclosure.
The charge transport materials as described herein, and photoreceptors including these compounds, are suitable for use in an imaging process with either dry or liquid toner development. For example, any dry toners and liquid toners known in the art may be used in the process and the apparatus of this invention. Liquid toner development can be desirable because it offers the advantages of providing higher resolution images and requiring lower energy for image fixing compared to dry toners. Examples of suitable liquid toners are known in the art. Liquid toners generally comprise toner particles dispersed in a carrier liquid. The toner particles can comprise a colorant/pigment, a resin binder, and/or a charge director. In some embodiments of liquid toner, a resin to pigment ratio can be from 1:1 to 10:1, and in other embodiments, from 4:1 to 8:1. Liquid toners are described further in Published U.S. Patent Applications 2002/0128349, entitled “Liquid Inks Comprising A Stable Organosol,” and 2002/0086916, entitled “Liquid Inks Comprising Treated Colorant Particles,” and U.S. Pat. No. 6,649,316, entitled “Phase Change Developer For Liquid Electrophotography,” all three of which are incorporated herein by reference.
Charge Transport Material
As described herein, an organophotoreceptor comprises a charge transport material having the formula
where Y 1 and Y 2 comprise, each independently, an aromatic group;
X 1 and X 2 are, each independently, a linking group, such as a —(CH 2 ) m — group, where m is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NR a group, a CR b group, a CR c R d group, a SiR e R f group, a BR g group, or a P(═O)R h group, where R a , R b , R c , R d , R e , R f , R g , and Rh are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, such as a vinyl group, an allyl group, and a 2-phenylethenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group, such as cycloalkyl groups, heterocyclic groups, or a benzo group;
W 1 and W 2 are, each independently, a —(CH 2 ) n — group or a —(CH 2 ) n-1 —C(═O)— group, where n is an integer between 1 and 10, inclusive;
Ar 1 and Ar 2 comprise, each independently, a divalent aromatic group;
Q 1 and Q 2 are, each independently, O, S, or NR;
Z 1 and Z 2 comprise, each independently, a bond, a vinyl group, a —CR 1 ═N—NR 2 — group, or a —CR 3 ═N—N═CR 4 — group; and
R, R 1 , R 2 , R 3 , and R 4 comprise, each independently, H, an alkyl group, an alkenyl group, an alkynyl group, an acyl group, a heterocyclic group, or an aromatic group.
In some embodiments, Ar 1 and Ar 2 comprise, each independently, a divalent aromatic heterocyclic group, or a divalent aryl group. Non-limiting examples of suitable aromatic groups include the following formulae:
where Q 3 is a bond, O, S, C═O, SO 2 , C(═O)O, an NR b group, or a CR c R d group; R a , R b , R c , and R d are, each independently, H, an alkyl group, an alkenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group; and X 3 , X 4 , X 5 , X 6 , X 7 , X 8 , X 9 , X 10 , X 11 , and X 12 are, each independently, a bond or a bridging group, such as a —(CH 2 ) p — group, where p is an integer between 1 and 10, inclusive, and one or more of the methylene groups is optionally replaced by O, S, N, C, B, Si, P, C═O, O═S═O, a heterocyclic group, an aromatic group, an NR i group, a CR j group, a CR k R l group, a SiR m R n group, a BR o group, or a P(═O)R p group, where R i , R j , R k , R l , R m , R n , R o , and R p are, each independently, a bond, H, a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, such as a vinyl group, an allyl group, and a 2-phenylethenyl group, an alkynyl group, a heterocyclic group, an aromatic group, or a part of a ring group, such as cycloalkyl groups, heterocyclic groups, or a benzo group.
With respect to Formula (I), substitution is liberally allowed, especially on W 1 , W 2 , X 1 , X 2 , Y 1 , Y 2 , Z 1 , and Z 2 . Variation of the substituents, such as an aromatic group, an alkyl group, a heterocyclic group, and a ring group such as a benzo group, on W 1 , W 2 , X 1 , X 2 , Y 1 , Y 2 , Z 1 , and Z 2 can result in various physical effects on the properties of the compounds, such as mobility, solubility, compatibility, stability, spectral absorbance, dispersibility, and the like, including, for example, substitutions known in the art to effect particular modifications.
The charge transport material of Formula (I) may be symmetrical or unsymmetrical. Thus, for example, X 1 and X 2 may be the same or different. Similarly, Y 1 and Y 2 may be the same or different; Z 1 and Z 2 may be the same or different W 1 and W 2 may be the same or different; Q 1 and Q 2 may be the same or different; or Ar 1 and Ar 2 may be the same or different. In addition, Formula (I) for the charge transport material is intended to cover isomers.
The organophotoreceptors as described herein may comprise an improved charge transport material of Formula (I) where Y 1 and Y 2 comprise, each independently, an aryl group, such as a phenyl group, a naphthyl group, a bis[(N,N-disubstituted)amino]aryl group, a julolidinyl group, an (N-substituted)arylamine group, and an (N,N-disubstituted)arylamine group, or an aromatic heterocyclic group, such as a furanyl group, a thiophenyl group, a pyrrolyl group, an indolyl group, a carbazolyl group, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a pyridinyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, a triazinyl group, a tetrazinyl group, a petazinyl group, a quinolinyl group, an isoquinolinyl group, a cinnolinyl group, a phthalazinyl group, a quinazolinyl group, a quinoxalinyl group, a naphthyridinyl group, an acridinyl group, a phenanthridinyl group, a phenanthrolinyl group, an anthyridinyl group, a purinyl group, a pteridinyl group, an alloxazinyl group, a phenazinyl group, a phenothiazinyl group, a phenoxazinyl group, a phenoxathiinyl group, a dibenzo(1,4)dioxinyl group, a thianthrenyl group, a bicarbazolyl group, and a 1,6-di(10H-10-phenothiazinyl)hexyl group. The aryl group or the aromatic heterocyclic group may include at least a substituent selected from the group consisting of a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
In some embodiments of interest, Y 1 and Y 2 , each independently, is selected from the group consisting of the following formulae:
where R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 19 , R 20 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , and R 27 comprise, each independently, H, an alkyl group, an alkenyl group, an alkynyl group, an acyl group, an aromatic group, or a heterocyclic group. The above Y 1 and Y 2 groups may further include at least a substituent, such as a hydroxyl group, a thiol group, a carboxyl group, an amino group, a halogen, an alkyl group, an acyl group, an alkoxy group, an alkylsulfanyl group, an alkenyl group, such as a vinyl group, an allyl group, and a 2-phenylethenyl group, an alkynyl group, an ester group, an amido group, a nitro group, a cyano group, a sulfonate group, a phosphate, phosphonate, a heterocyclic group, an aromatic group, an (N,N-disubstituted)hydrazone group, an enamine group, an azine group, an epoxy group, a thiiranyl group, and an aziridinyl group.
In other embodiments of interest, X 1 and X 2 are, each independently, a —CH 2 — group, a —OCH 2 — group, or a —Ar—OCH 2 — group; and W 1 and W 2 are, each independently, a bond, a —CH 2 — group, a —CH 2 CH 2 — group, or a —(CH 2 ) n-1 —C(═O)— group, where n is an integer between 2 and 6 and Ar comprises an aromatic group. Z 1 and Z 2 may comprise, each independently, a bon