Silanol containing photoconductors

Abstract

A photoconductor containing an optional supporting substrate, a silanol containing photogenerating layer, and at least one charge transport layer.

Description

EXAMPLE I

An imaging member was prepared by repeating the process of Comparative Example 1 except that the photogenerating layer was prepared by introducing 0.45 grams of the known polycarbonate LUPILON™ 200 (PCZ-200) or POLYCARBONATE Z™, weight average molecular weight of 20,000, available from Mitsubishi Gas Chemical Corporation, and 50 milliliters of tetrahydrofuran into a 4 ounce glass bottle. To this solution were added 2.4 grams of hydroxygallium phthalocyanine (Type V), 0.06 grams of the silanol phenyl-POSS trisilanol (SO1458™, available from Hybrid Plastics, Fountain Valley, Calif.) and 300 grams of ⅛ inch (3.2 millimeters) diameter stainless steel shot. This mixture was then placed on a ball mill for 8 hours. Subsequently, 2.25 grams of PCZ-200 were dissolved in 46.1 grams of tetrahydrofuran, and added to the hydroxygallium phthalocyanine dispersion. This slurry was then placed on a shaker for 10 minutes. The resulting dispersion was, thereafter, applied to the above adhesive interface with a Bird applicator to form a photogenerating layer having a wet thickness of 0.25 mil. A strip about 10 millimeters wide along one edge of the substrate web bearing the blocking layer, and the adhesive layer was deliberately left uncoated by any of the photogenerating layer material to facilitate adequate electrical contact by the ground strip layer that was applied later. The photogenerating layer was dried at 120° C. for 1 minute in a forced air oven to form a dry photogenerating layer having a thickness of 0.4 micrometers.

EXAMPLE II

An imaging member was prepared by repeating the process of Comparative Example 1 except that to the photogenerating layer dispersion of Comparative Example 1 were added 0.06 grams of the phenyl-POSS trisilanol (SO1458™, available from Hybrid Plastics, Fountain Valley, Calif.).

Electrical Property Testing

The above prepared three photoreceptor devices were tested in a scanner set to obtain photoinduced discharge cycles, sequenced at one charge-erase cycle followed by one charge-expose-erase cycle, wherein the light intensity was incrementally increased with cycling to produce a series of photoinduced discharge characteristic curves from which the photosensitivity and surface potentials at various exposure intensities were measured. Additional electrical characteristics were obtained by a series of charge-erase cycles with incrementing surface potential to generate several voltage versus charge density curves. The scanner was equipped with a scorotron set to a constant voltage charging at various surface potentials. The devices were tested at surface potentials of 500 with the exposure light intensity incrementally increased by means of regulating a series of neutral density filters; and the exposure light source is a 780 nanometer light emitting diode. The xerographic simulation is completed in an environmentally controlled light tight chamber at ambient conditions (40 percent relative humidity and 22° C.). The devices were also cycled to 10,000 cycles electrically with charge-discharge-erase. Six photoinduced discharge characteristic (PIDC) curves were generated, one for each of the above prepared photoconductors at both cycle=0 and cycle=10,000. The results are summarized in Table 1.

	TABLE 1
	V (3.5 ergs/cm2 (V)
	Cycle = 0	Cycle = 10,000
	Comparative Example 1	70	120
	Example I	22	25
	Example II	24	28

In embodiments, there is disclosed a number of improved characteristics for the above silanol containing photoconductive members as determined by the generation of known PIDC curves, such as the minimization or prevention of V_r cycle up by the physical doping of the silanol into the photogenerating layer. More specifically, in Table 1, V (3.5 ergs/cm²) represents the surface potential of the devices when exposure is 3.5 ergs/cm² and volt, and this is used to characterize the PIDC. Incorporation of the silanol into photogenerating layer reduces V (3.5 ergs/cm²), and prevents the photoconductor cycle up with extended cycling.

An in-house field-induced dark decay (FIDD) test implied that the CDS (charge deficient spots, which adversely affects image resolution) counts of the photoconductor of Example I were significantly lower than the photoconductor of Comparative Example 1, which in turn indicated better dispersion quality of the photogenerating pigment, and excellent hydrophobic treatments on the surfaces of the photogenerating pigments enabled by the incorporation of the hydrophobic silanol into the photogenerating layer which should result in lower CDS.

The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others. Unless specifically recited in a claim, steps or components of claims should not be implied or imported from the specification or any other claims as to any particular order, number, position, size, shape, angle, color, or material.

Claims

1. An imaging member comprising an optional supporting substrate, a photogenerating layer containing a silanol, and at least one charge transport layer comprised of at least one charge transport component.

2. A photoconductor comprising an optional substrate, a photogenerating layer comprised of a photogenerating component and a silanol, and at least one charge transport layer comprised of at least one charge transport component, and wherein said silanol is selected from the group comprised of the following formulas/structures

3. A photoconductor in accordance with claim 2 wherein R and R′ are phenyl, methyl, vinyl, allyl, isobutyl, isooctyl, cyclopentyl, cyclohexyl, cyclohexenyl-3-ethyl, epoxycyclohexyl-4-ethyl, fluorinated alkyl, methacrylolpropyl, or norbornenylethyl.

4. A photoconductor in accordance with claim 2 wherein said silanol is selected from the group comprised of at least one of isobutyl-polyhedral oligomeric silsesquioxane cyclohexenyldimethylsilyldisilanol, cyclopentyl-polyhedral oligomeric silsesquioxane dimethylphenyldisilanol, cyclohexyl-polyhedral oligomeric silsesquioxane dimethylvinyidisilanol, cyclopentyl-polyhedral oligomeric silsesquioxane dimethylvinyldisilanol, isobutyl-polyhedral oligomeric silsesquioxane dimethylvinyldisilanol, cyclopentyl-polyhedral oligomeric silsesquioxane disilanol, isobutyl-polyhedral oligomeric silsesquioxane disilanol, isobutyl-polyhedral oligomeric silsesquioxane epoxycyclohexyldisilanol, cyclopentyl-polyhedral oligomeric silsesquioxane fluoro(3)disilanol, cyclopentyl-polyhedral oligomeric silsesquioxane fluoro(13)disilanol, isobutyl-polyhedral oligomeric silsesquioxane fluoro(13)disilanol, cyclohexyl-polyhedral oligomeric silsesquioxane methacryldisilanol, cyclopentyl-polyhedral oligomeric silsesquioxane methacryldisilanol, isobutyl-polyhedral oligomeric silsesquioxane methacryldisilanol, cyclohexyl-polyhedral oligomeric silsesquioxane monosilanol, cyclopentyl-polyhedral oligomeric silsesquioxane monosilanol, isobutyl-polyhedral oligomeric silsesquioxane monosilanol, cyclohexyl-polyhedral oligomeric silsesquioxane norbornenylethyldisilanol, cyclopentyl-polyhedral oligomeric silsesquioxane norbornenylethyldisilanol, isobutyl-polyhedral oligomeric silsesquioxane norbornenylethyldisilanol, cyclohexyl-polyhedral oligomeric silsesquioxane TMS disilanol, isobutyl-polyhedral oligomeric silsesquioxane TMS disilanol, cyclohexyl-polyhedral oligomeric silsesquioxane trisilanol, cyclopentyl-polyhedral oligomeric silsesquioxane trisilanol, isobutyl-polyhedral oligomeric silsesquioxane trisilanol, isooctyl-polyhedral oligomeric silsesquioxane trisilanol, and phenyl-polyhedral oligomeric silsesquioxane trisilanol.

5. A photoconductor in accordance with claim 2 wherein said silanol is selected from the group comprised of at least one of dimethyl(thien-2-yl)silanol, tris(isopropoxy)silanol, tris(tert-butoxy)silanol, tris(tert-pentoxy)silanol, tris(o-tolyl)silanol, tris(1-naphthyl)silanol, tris(2,4,6-trimethylphenyl)silanol, tris(2-methoxyphenyl)silanol, tris(4-(dimethylamino)phenyl)silanol, and tris(4-biphenylyl)silanol, tris(trimethylsilyl)silanol, dicyclohexyltetrasilanol.

6. A photoconductor in accordance with claim 2 wherein said charge transport component is comprised of aryl amine molecules, and which aryl amines are of the formula

7. A photoconductor in accordance with claim 6 wherein said alkyl and said alkoxy each contains from about 1 to about 12 carbon atoms, and said aryl contains from about 6 to about 36 carbon atoms, and said substrate is present.

8. A photoconductor in accordance with claim 6 wherein said aryl amine is N,N′-diphenyl-N,N-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine, and said substrate is present.

9. A photoconductor in accordance with claim 2 wherein said charge transport component is comprised of aryl amine molecules, and which aryl amines are of the formula

10. A photoconductor in accordance with claim 9 wherein alkyl and alkoxy each contains from about 1 to about 12 carbon atoms, and aryl contains from about 6 to about 36 carbon atoms, and said substrate is present.

11. A photoconductor in accordance with claim 9 wherein said aryl amine is selected from the group consisting of N,N′-bis(4-butylphenyl)-N,N′-di-p-tolyl-[p-terphenyl]-4,4″-diamine, N,N′-bis(4-butylphenyl)-N,N′-di-m-tolyl-[p-terphenyl]-4,4″-diamine, N,N′-bis(4-butylphenyl)-N,N′-di-o-tolyl-[p-terphenyl]-4,4″-diamine, N,N′-bis(4-butylphenyl)-N,N′-bis-(4-isopropylphenyl)-[p-terphenyl]-4,4″-diamine, N,N′-bis(4-butylphenyl)- N,N′-bis-(2-ethyl-6-methylphenyl)-[p-terphenyl]-4,4″-diamine, N,N′-bis(4-butylphenyl)-N,N′-bis-(2,5-dimethylphenyl)-[p-terphenyl]-4,4″-diamine, N,N′-diphenyl-N,N′-bis(3-chlorophenyl)-[p-terphenyl]-4,4″-diamine, and optionally mixtures thereof.

12. A photoconductor in accordance with claim 2 wherein said silanol is present in an amount of from about 0.1 to about 40 weight percent; at least one charge transport layer is comprised of from 2 to about 4 transport layers, wherein the charge transport layers contain hole transport molecules and a resin binder; and wherein said photogenerating layer contains said silanol, a photogenerating pigment and a resin binder; and further wherein said photogenerating layer is situated between said substrate and said charge transport, and said substrate is present.

13. A photoconductor in accordance with claim 2 further including in at least one of said charge transport layers an antioxidant optionally comprised of hindered phenolics and hindered amines.

14. A photoconductor in accordance with claim 2 wherein said photogenerating component is comprised of a photogenerating pigment or photogenerating pigments.

15. A photoconductor in accordance with claim 14 wherein said photogenerating pigment is comprised of at least one of a metal phthalocyanine, a metal free phthalocyanine, a titanyl phthalocyanine, a halogallium phthalocyanine, a perylene, or mixtures thereof.

16. A photoconductor in accordance with claim 14 wherein said photogenerating pigment is comprised of a titanyl phthalocyanine.

17. A photoconductor in accordance with claim 14 wherein said photogenerating pigment is comprised of chlorogallium phthalocyanine.

18. A photoconductor in accordance with claim 14 wherein said photogenerating pigment is comprised of hydroxygallium phthalocyanine.

19. A photoconductor in accordance with claim 2 wherein said photogenerating layer is coated from a photogenerating dispersion that is prepared by adding said silanol into a dispersion of a photogenerating component and a polymeric resin, or by ball milling a mixture of said silanol, a photogenerating component, and a polymeric resin, and said substrate is present.

20. A photoconductor in accordance with claim 2 further including a hole blocking layer, and an adhesive layer.

21. A photoconductor in accordance with claim 2 wherein said photoconductor is a flexible belt, and wherein the weight average molecular weight Mw of said silanols is from about 700 to about 2,000.

22. A photoconductor in accordance with claim 2 wherein said at least one charge transport layer is from 1 to about 7 layers, and said substrate is present.

23. A photoconductor in accordance with claim 2 wherein said at least one charge transport layer is from 1 to about 3 layers.

24. A photoconductor in accordance with claim 2 wherein said at least one charge transport layer is comprised of a top charge transport layer and a bottom charge transport layer, and wherein said top layer is in contact with said bottom layer, and said bottom layer is in contact with said photogenerating layer.

25. A photoconductor in accordance with claim 24 wherein said top layer is comprised of said charge transport component, a resin binder, and an optional antioxidant; and said bottom layer is comprised of a charge transport component, a resin binder and an optional antioxidant.

26. A photoconductor in accordance with claim 2 wherein said silanol is present in an amount of from about 0.1 to about 40 weight percent.

27. A photoconductor in accordance with claim 2 wherein said silanol is present in an amount of from about 1 to about 30 weight percent

28. A photoconductor comprised in sequence of a supporting substrate, a photogenerating layer comprised of at least one photogenerating pigment, and a silanol, and thereover at least one charge transport layer comprised of at least one charge transport component, and wherein said silanol is selected from the group comprised of the following formulas/structures

29. A photoconductor in accordance with claim 28 wherein said silanol is present in an amount of from 1 to about 20 weight percent.

30. A photoconductor in accordance with claim 28 wherein at least one of said charge transport layers contains a resin binder; said photogenerating layer is situated between said at least one charge transport and said substrate, and which layer contains a resin binder; said silanol is present in an amount of from about 1 to about 20 weight percent; and wherein said at least one is from 1 to about 4.

31. A photoconductor in accordance with claim 28 wherein said silanol is a hydrophobic silanol, said suitable hydrocarbon is alkyl, alkoxy, or aryl wherein said silanol is present in an amount of from about 0.05 to about 30 weight percent; and wherein said at least one is from 1 to about 3.

32. A photoconductor in accordance with claim 28 wherein said silanol is phenyl-polyhedral oligomeric silsesquioxane trisilanol.