Polyphenyl ether phosphate containing photoconductors

Abstract

An imaging member containing an optional supporting substrate, a photogenerating layer, and at least one charge transport layer of at least one charge transport component, at least one polyphenyl ether of the formula

Description

COMPARATIVE EXAMPLE 1

An imaging member was prepared by providing a 0.02 micrometer thick titanium layer coated (the coater device) on a biaxially oriented polyethylene naphthalate substrate (KALEDEX™ 2000) having a thickness of 3.5 mils, and applying thereon, with a gravure applicator, a solution containing 50 grams of 3-amino-propyltriethoxysilane, 41.2 grams of water, 15 grams of acetic acid, 684.8 grams of denatured alcohol, and 200 grams of heptane. This layer was then dried for about 5 minutes at 135° C. in the forced air dryer of the coater. The resulting blocking layer had a dry thickness of 500 Angstroms. An adhesive layer was then prepared by applying a wet coating over the blocking layer, using a gravure applicator, and which adhesive contains 0.2 percent by weight based on the total weight of the solution of copolyester adhesive (ARDEL D100™ available from Toyota Hsutsu Inc.) in a 60:30:10 volume ratio mixture of tetrahydrofuran/monochlorobenzene/methylene chloride. The adhesive layer was then dried for about 5 minutes at 135° C. in the forced air dryer of the coater. The resulting adhesive layer had a dry thickness of 200 Angstroms.

A photogenerating layer dispersion 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) 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 charge generation layer was dried at 135° C. for 5 minutes in a forced air oven to form a dry photogenerating layer having a thickness of 0.4 micrometer.

The resulting imaging member web was then overcoated with a two-layer charge transport layer. Specifically, the photogenerating layer was overcoated with a charge transport layer (the bottom layer) in contact with the photogenerating layer. The bottom layer of the charge transport layer was prepared by introducing into an amber glass bottle in a weight ratio of 1:1 N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine, and MAKROLON 5705®, a known polycarbonate resin having a molecular weight average of from about 50,000 to 100,000, commercially available from Farbenfabriken Bayer A.G. The resulting mixture was then dissolved in methylene chloride to form a solution containing 15 percent by weight solids. This solution was applied on the photogenerating layer to form the bottom layer coating that upon drying (120° C. for 1 minute) had a thickness of 14.5 microns. During this coating process, the humidity was equal to or less than 15 percent.

The bottom layer of the charge transport layer was then overcoated with a top layer. The charge transport layer solution of the top layer was prepared as described above for the bottom layer. This solution was applied on the bottom layer of the charge transport layer to form a coating that upon drying (120° C. for 1 minute) had a thickness of 14.5 microns. During this coating process the humidity was equal to or less than 15 percent.

EXAMPLE I

An imaging member is prepared by repeating the process of Comparative Example 1 except that (1) the top layer of the charge transport layer is prepared by introducing into an amber glass bottle in a weight ratio of 1:1:0.2:0.1 N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine, MAKROLON 5705®, a polycarbonate resin having a weight average molecular weight of from about 50,000 to about 100,000, commercially available from Farbenfabriken Bayer A.G, the polyphenyl ether SANTOVAC OS-124™, commercially available from Santovac Fluids LLC, and which consists of five benzene rings linked by ether bonds with a pour point of 40° F. and a flash point of 550° F., and the antioxidant IRGANOX 1010™, tetrakis methylene(3,5-di-tert-butyl-4-hydroxy hydrocinnamate), commercially available from Ciba Specialty Chemical. The resulting mixture is dissolved in methylene chloride to form a solution containing 15 percent by weight solids. (2) Also, to the photogenerating layer dispersion of Comparative Example 1 are added 0.72 grams of zinc dialkyldithiophosphate (ZDDP ELCO-103™, wherein alkyl is a mixture of primary and secondary propyl, butyl and pentyl), commercially available from Elco Corporation.

EXAMPLE II

An imaging member is prepared by repeating the process of Comparative Example 1 except that (1) the top layer of the charge transport layer is prepared by introducing into an amber glass bottle in a weight ratio of 1:1:0.2 N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine, MAKROLON 5705®, a polycarbonate resin having a molecular weight of from about 50,000 to about 100,000, commercially available from Farbenfabriken Bayer A.G, and SANTOVAC OS-124™, commercially available from Santovac Fluids LLC. The resulting mixture is dissolved in methylene chloride to form a solution containing 15 percent by weight solids. (2) Also, to the photogenerating layer dispersion of Comparative Example 1 is added 0.24 grams of the above zinc dialkyldithiophosphate (ZDDP ELCO-103™) commercially available from Elco Corporation.

EXAMPLE III

An imaging member is prepared by repeating the process of Comparative Example 1 except that (1) the top layer of the charge transport layer is prepared by introducing into an amber glass bottle in a weight ratio of 1:1:0.4:0.1 N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine, MAKROLON 5705®, a polycarbonate resin having a molecular weight of from about 50,000 to about 100,000, commercially available from Farbenfabriken Bayer A.G, SANTOVAC OS-124™, commercially available from Santovac Fluids LLC, and IRGANOX 101O™, commercially available from Ciba Specialty Chemical. The resulting mixture is dissolved in methylene chloride to form a solution containing 15 percent by weight solids. (2) Further, to the photogenerating layer dispersion of Comparative Example 1 are added 0.72 grams of the above zinc dialkyldithiophosphates (ZDDP ELCO-103™), commercially available from Elco Corporation.

EXAMPLE IV

An imaging member is prepared by repeating the process of Comparative Example 1 except that (1) the top layer of the charge transport layer is prepared by introducing into an amber glass bottle in a weight ratio of 1:1:0.4 N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine, MAKROLON 5705®, a polycarbonate resin having a weight average molecular weight of from about 50,000 to about 100,000, commercially available from Farbenfabriken Bayer A.G, and SANTOVAC OS-124™, commercially available from Santovac Fluids LLC. The resulting mixture is dissolved in methylene chloride to form a solution containing 15 percent by weight solids. (2) Additionally, to the photogenerating layer dispersion of Comparative Example 1 are added 0.24 grams of the above zinc dialkyldithiophosphate (ZDDP ELCO-103™) commercially available from Elco Corporation.

Electrical Property Testing:

The above prepared five photoreceptor devices are 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 is incrementally increased with cycling to produce a series of photoinduced discharge characteristic (PIDC) curves from which the photosensitivity and surface potentials at various exposure intensities are measured. Additional electrical characteristics are obtained by a series of charge-erase cycles with incrementing surface potential to generate several voltage versus charge density curves. The scanner is equipped with a scorotron set to a constant voltage charging at various surface potentials. The devices are tested at surface potentials of 500 with the exposure light intensity incrementally increased by means of regulating a series of neutral density filters; 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.). Five photoinduced discharge characteristic (PIDC) curves are generated, which -curves show that incorporation of the polyphenyl ether into the charge transport layer, and the presence of the thiophosphate in the photogenerating layer significantly improves PIDC including higher photosensitivity and lower V_r. Further, there is almost no residual potential cycle up with long cycling for the photoconductor members with the ether and thiophosphate as compared to the Comparative Example 1 imaging member with no ether and no thiophosphate.

Scratch Resistance Testing:

R_q, which represents the surface roughness, can be considered the root mean square roughness as the standard metric for the scratch resistance assessment with a scratch resistance of grade 1 representing poor scratch resistance and a scratch resistance of grade 5 representing excellent scratch resistance as measured by a surface profile meter. More specifically, the scratch resistance is grade 1 when the R_q measurement is greater than 0.3 microns; grade 2 for R_q between 0.2 and 0.3 microns; grade 3 for R_q between 0.15 and 0.2 microns; grade 4 for R_q between 0.1 and 0.15 microns; and grade 5 being the best or excellent scratch resistance when R_q is less than 0.1 microns.

The above prepared five photoconductive belts are cut into strips of 1 inch in width by 12 inches in length, and are flexed in a tri-roller flexing system. Each belt is under a 1.1 lb/inch tension, and each roller is ⅛ inch in diameter. A polyurethane “spots blade” is placed in contact with each belt at an angle between 5 and 15 degrees. Carrier beads of about 100 micrometers in size diameter are attached to the spots blade by the aid of double tape. These beads strike the surface of each of the belts as the photoconductor rotates in contact with the spots blade for 200 simulated imaging cycles. The surface morphology of each scratched area is then analyzed.

Incorporation of the above polyphenyl ether into the charge transport layer in combination with the incorporation of the above thiophosphate into the photogenerating layer improved scratch resistance by from about 30 to about 50 percent.

For example, after the scratch resistance test, the comparative imaging member with no ether and no thiophosphate had an R_q value of 0.3 microns; the imaging members with the above polyphenyl ether and thiophosphate had an R_q value of from 0.15 to 0.2 microns depending on the type and loading of the polyphenyl ether and thiophosphate. Thus, a scratch resistance improvement of from about 30 percent to about 50 percent was realized with incorporation of the polyphenyl ether into the charge transport layer and incorporation of the above thiophosphate into the photogenerating layer.

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, and at least one charge transport layer comprised of at least one charge transport component, at least one polyphenyl ether of the formula

2. An imaging member in accordance with claim 1 wherein said polyphenyl ether comprises n+1 benzene rings linked by ether bonds.

3. An imaging member in accordance with claim 1 wherein said polyphenyl ether is selected from the group consisting of m-diphenoxybenzene, bis(m-phenoxyphenyl)ether, m-phenoxyphenyl p-phenoxyphenyl ether, m-phenoxyphenyl o-phenoxyphenyl ether, bis(p-phenoxyphenyl)ether, p-phenoxyphenyl o-phenoxyphenyl ether, bis(o-phenoxyphenyl ether, bis(phenoxyphenyl)ether isomer mixture, m-phenoxyphenoxy m-biphenyl, m-bis(m-phenoxyphenoxy)benzene, 1-(m-phenoxyphenoxy)-3-(p-phenoxyphenoxy)benzene, p-bis(m-phenoxyphenoxy)benzene, 1-(m-phenoxyphenoxy)-4-(p-phenoxyphenoxy)benzene, m-bis(p-phenoxyphenoxy)benzene, p-bis(p-phenoxyphenoxy)benzene, o-bis(m-phenoxyphenoxy)benzene, m-bis(o-phenoxyphenoxy)benzene, p-bis(o-phenoxyphenoxy)benzene, o-bis(o-phenoxyphenoxy)benzene, bis(phenoxyphenoxy)benzene isomer mixture, bis(phenoxyphenoxyphenyl)ether isomer mixture, and optionally mixtures thereof.

4. An imaging member in accordance with claim 1 wherein said n is a number of from 1 to about 9.

5. An imaging member in accordance with claim 1 wherein said n is a number of from 3 to about 8.

6. An imaging member in accordance with claim 1 wherein said n is a number of from 3 to about 7, and said at least one is from 1 to about 4.

7. An imaging member in accordance with claim 1 wherein said charge transport component is comprised of aryl amine molecules, and which aryl amines are of the formula

8. An imaging member in accordance with claim 7 wherein alkyl contains from about 1 to about 10 carbon atoms.

9. An imaging member in accordance with claim 7 wherein said aryl amine is N,N′-diphenyl-N,N-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine.

10. An imaging member in accordance with claim 1 wherein said charge transport component is comprised of aryl amine molecules, and which aryl amines are of the formula

11. An imaging member in accordance with claim 10 wherein each alkoxy and alkyl contains from about 1 to about 10 carbon atoms; aryl contains from about 6 to about 36 carbon atoms; and halogen is chloride, bromide, fluoride, or iodide; and optionally wherein said alkoxy, alkyl, and aryl are comprised of mixtures thereof.

12. An imaging member in accordance with claim 10 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.

13. An imaging member in accordance with claim 1 further including a hole blocking layer, and an adhesive layer wherein at least one of said charge transport layers includes an antioxidant.

14. An imaging member in accordance with claim 1 wherein said at least one charge transport contains an antioxidant optionally comprised of a hindered phenol or a hindered amine.

15. An imaging member in accordance with claim 1 wherein said at least one charge transport layer is from 1 to about 7 layers.

16. An imaging member in accordance with claim 1 wherein said at least one charge transport layer is from 1 to about 3 layers.

17. An imaging member in accordance with claim 1 wherein said at least one charge transport layer is comprised of a top charge transport layer and a bottom charge transport layer.

18. An imaging member in accordance with claim 17 wherein said top layer is comprised of at least one charge transport component, a resin binder, an antioxidant, and said polyphenyl ether, and said bottom layer is comprised of at least one charge transport component, a resin binder, and an optional antioxidant, and wherein said bottom layer is situated between said photogenerating layer and said top charge transport layer; or wherein said top layer is comprised of at least one charge transport component, a resin binder, and an optional antioxidant, and said bottom layer is comprised of at least one charge transport component, a resin binder, an antioxidant, and said polyphenyl ether, and wherein said bottom layer is situated between said photogenerating layer and said top charge transport layer.

19. An imaging member in accordance with claim 17 wherein said top layer is comprised of charge transport components, a resin binder, an optional antioxidant, and said polyphenyl ether, and said bottom layer is comprised of charge transport components, a resin binder, an optional antioxidant, and said polyphenyl ether, and wherein said bottom layer is situated between said photogenerating layer and said top charge transport layer.

20. An imaging member in accordance with claim 1 wherein said phosphate is a zinc alkylthiophosphate.

21. An imaging member in accordance with claim 1 wherein said photogenerating layer is comprised of a photogenerating component, a polymeric resin, and said thiophosphate.

22. An imaging member in accordance with claim 1 wherein said photogenerating layer is coated from a photogenerating dispersion prepared by adding said thiophosphate into a ball-milled dispersion of said photogenerating component and a polymeric resin, or by ball milling said thiophosphate, a photogenerating component, and a polymeric resin.

23. An imaging member in accordance with claim 21 wherein said photogenerating component is comprised of a photogenerating pigment comprised of at least one of a metal phthalocyanine, a metal free phthalocyanine, titanyl phthalocyanine, a halogallium phthalocyanine, a perylene, or mixtures thereof.

24. An imaging member in accordance with claim 21 wherein said photogenerating component is comprised of chlorogallium phthalocyanine; or wherein said photogenerating pigment is comprised of hydroxygallium phthalocyanine.

25. An imaging member in accordance with claim 1 wherein said thiophosphate is metal free or metal containing thiophosphate, and wherein said metal is selected from a group consisting of zinc, molybdenum, lead, antimony, and optionally mixtures thereof.

26. An imaging member in accordance with claim 1 wherein said thiophosphate is of the formulas/structure:

27. An imaging member in accordance with claim 26 wherein R1, R2, R3, R4, R5 and R6 each independently represents alkyl containing from 1 to about 20 carbon atoms; cycloalkyl containing from about 6 to about 26 carbon atoms; aryl, alkylaryl or arylalkyl, containing from about 6 to about 50 carbon atoms.

28. An imaging member in accordance with claim 26 wherein said thiophosphate is a zinc dialkyldithiophosphate, and wherein said alkyl is a straight chain or branched alkyl with from about 2 to about 18 carbon atoms.

29. An imaging member in accordance with claim 1 wherein said polyphenyl ether is present in an amount of from about 0.1 to about 30 weight percent, and said thiophosphate is present in an amount of from about 0.01 to about 40 weight percent.

30. An imaging member in accordance with claim 1 wherein said polyphenyl ether is present in an amount of from about 6 to about 20 weight percent, and said thiophosphate is present in an amount of from about 1 to about 30, or from about 5 to about 20 weight percent.

31. A flexible photoconductive member comprising in sequence of a substrate, a photogenerating layer, and at least one charge transport layer comprised of at least one charge transport component, at least one polyphenyl ether of the formula

32. An imaging member in accordance with claim 1 wherein said thiophosphate is molybdenum di(2-ethylhexyl)dithiophosphate, zinc diethyldithiophosphate, or antimony diamyldithiophosphate.

33. A photoconductor comprised of a substrate, at least one hole transport layer comprising hole transport molecules, resin binder, and a polyphenyl ether of the formula

34. A photoconductor in accordance with claim 33 wherein said at least one is from 1 to about 5; said R1, R2 and R3-comprise mixtures thereof; and said n is a number of from 1 to about 10.

35. An imaging member in accordance with claim 1 wherein each R represents a suitable hydrocarbon.