Photoconductive imaging members

1. A photoconductive imaging member comprised of a supporting substrate, an optional blocking layer, a photogenerating layer, and a charge transport layer, and wherein said charge transport layer is comprised of a polycarbonate given by the formula

wherein R 1 is selected from the group consisting of hydrogen, alkyl of from about 1 to about 15 carbon atoms, a halogenated alkyl of from about 1 to about 15 carbon atoms, optionally further containing one or more heteroatoms selected from the group consisting of nitrogen oxygen, sulfur, silicon, and phosphorus, and an aryl or substituted aryl of from about 6 to about 30 carbon atoms; R 2 represents a divalent linkage of an alkylene with from about 1 to about 15 carbon atoms; Ar 3 and Ar 4 each independently represent aryl groups of from about 6 to about 30 carbon atoms; R 3 and R 4 are independently selected from the group consisting of hydrogen, alkyl of from about 1 to about 15 carbon atoms, aryl or substituted aryl of from about 6 to about 30 carbon atoms; L represents a divalent linkage, and wherein x and y represent the mole fractions of the repeating segments, and wherein x is from about 0.01 to about 1, and y is from about 0 to about 0.99.

2. A photoconductive imaging member in accordance with claim 1 wherein said alkyl R 1 is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, and hexyl.

3. A photoconductive imaging member in accordance with claim 1 wherein said halogenated alkyl for R 1 is fluoroalkyl, perfluoroalkyl, and chloroalkyl, and wherein said alkyl has from 1 to about 15 carbon atoms.

4. A photoconductive imaging member in accordance with claim 1 wherein R 2 is selected from the group consisting of dimethylene, trimethylene, and tetramethylene.

5. A photoconductive imaging member in accordance with claim 1 wherein each of Ar 3 and Ar 4 are arylene containing from about 6 to about 30 carbon atoms.

6. A photoconductive imaging member in accordance with claim 5 wherein said arylene is selected from the group consisting of

and wherein said arylene group optionally contains a substituent selected from the group consisting of hydrogen, halogen, alkyl of from 1 to about 15 carbons, halogenated alkyl of 1 to about 15 carbon atoms, or alkyl containing one or more heteroatoms of nitrogen, oxygen, sulfur, silicon, or phosphorus.

7. A photoconductive imaging member in accordance with claim 1 wherein R 3 and R 4 each are independently selected from the group consisting of an alkyl of from about 1 to about 15 carbon atoms, an aryl of from about 6 to about 20 carbon atoms, and a halogenated alkyl of from about 1 to about 15 carbon atoms.

8. A photoconductive imaging member in accordance with claim 7 wherein said alkyl is selected from the group consisting of methyl, ethyl, propyl, trifluoromethyl, 3,3,3-trifluoropropyl, and phenyl.

9. A photoconductive imaging member in accordance with claim 1 wherein R 3 and R 4 form a combined structure of cyclobutylidene, cyclopentylidene, cyclohexylidene, cycloheptylidene, and cyclooctylidene.

10. A photoconductive imaging member in accordance with claim 1 wherein said polycarbonate possesses a weight average molecular weight, M w , of from about 2,000 to about 600,000.

11. A photoconductive imaging member in accordance with claim 1 wherein said polycarbonate is crosslinked and comprises an adduct formed from the reaction of a diisocyanate and a polymer of Formula (II)

wherein R 1 is selected from the group consisting of hydrogen, said alkyl, said halogenated alkyl, and an aryl or substituted aryl of from about 6 to about 30 carbon atoms; R 2 represents a divalent linkage; Ar 3 and Ar 4 each independently represent aromatic groups of from about 6 to about 30 carbon atoms; R 3 and R 4 are independently selected from the group consisting of hydrogen, said alkyl, and said aryl; and wherein x and y represent the mole fractions of the repeating segments, the sum of x+y being equal to 1, and wherein x is from about 0.03 to about 1. and y is from about 0.03 to about 0.99.

12. A photoconductive imaging member in accordance with claim 11 wherein said crosslinked polycarbonate comprises an adduct formed by the reaction of a diisocyanate and a polymer comprised of

wherein x and y are the mole fractions of the repeating units, the sum of x+y being equal to 1, and said polycarbonate possesses a weight average molecular weight of from about 2,000 to about 500,000.

13. A photoconductive imaging member in accordance with claim 11 wherein said alkyl for R 1 is selected from a group consisting of methyl, ethyl, propyl, butyl, pentyl, and hexyl; wherein said halogenated alkyl for R 1 is fluoroalkyl, perfluoroalkyl, and chloroalkyl, and wherein said alkyl contains from 1 to about 15 carbons; and wherein R 2 is a divalent linkage of alkylene with from 1 to about 15 carbons selected from the group consisting of dimethylene, trimethylene, and tetramethylene.

14. A photoconductive imaging member in accordance with claim 11 wherein each of Ar 3 and Ar 4 are arylene containing from about 6 to about 24 carbon atoms.

15. A photoconductive imaging member in accordance with claim 14 wherein arylene is selected from the group consisting of

16. A photoconductive imaging member in accordance with claim 11 wherein R 3 and R 4 each are independently selected from the group consisting of an alkyl of from about 1 to about 15 carbon atom, an aryl of from about 6 to about 30 carbon atoms, and a halogenated alkyl of from about 1 to about 15 carbon atoms.

17. A photoconductive imaging member in accordance with claim 16 wherein said alkyl is selected from the group consisting of methyl, ethyl, propyl, trifluoromethyl, and 3,3,3-trifluoropropyl.

18. A photoconductive imaging member in accordance with claim 1 wherein said charge transport layer contains