Patent Application
20070292789
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.
An imaging member was prepared by repeating the process of Comparative Example 1 except that the top charge transport layer was 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 weight average molecular weight of from about 50,000 to about 100,000, commercially available from Farbenfabriken Bayer A.G, and the polyphenyl ether SANTOVAC OS-124™, which comprises five benzene rings linked by ether bonds with a pour point of 40° F. and a flash point of 550° F., commercially available from Santovac Fluids LLC. The resulting mixture was dissolved in methylene chloride to form a solution containing 15 percent by weight of solids.
An imaging member was prepared by repeating the process of Comparative Example 1 except that the top charge transport layer was 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 was dissolved in methylene chloride to form a solution containing 15 percent by weight of solids.
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 (PIDC) 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; the exposure light source was a 780 nanometer light emitting diode. The xerographic simulation was completed in an environmentally controlled light tight chamber at ambient conditions (40 percent relative humidity and 22° C.). Three photoinduced discharge characteristic (PIDC) curves were generated, one for each of the above prepared photoconductors. Incorporation of the polyphenyl ether into the charge transport layer did not adversely affect the electrical properties of the imaging members such as photosensitivity and dark decay. However, there was a slight increase in residual potential when the polyphenyl ether was present as compared to the comparative photoconductor, which contained no polyphenyl ether.
Rq, 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 Rq measurement is greater than 0.3 microns; grade 2 for Rq between 0.2 and 0.3 microns; grade 3 for Rq between 0.15 and 0.2 microns; grade 4 for Rq between 0.1 and 0.15 microns; and grade 5 being the best or excellent scratch resistance when Rq is less than 0.1 microns.
The above prepared three 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 charge transport layer improved scratch resistance by from about 30 percent to about 50 percent.
For example, after the scratch resistance test, the comparative imaging member with no ether had an Rq value of 0.3 microns; and the imaging members with the polyphenyl ether had an Rq value of from 0.15 to 0.2 microns depending on the type and loading of the polyphenyl ether. 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.
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.
U.S. application No. (not yet assigned) (Attorney Docket No. 20060179-US-NP), filed concurrently herewith, on Ether Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060491-US-NP), filed concurrently herewith, on Ether Phosphate Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060490-US-NP), filed concurrently herewith, on Ether Phosphate Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060489-US-NP), filed concurrently herewith, on Polyphenyl Ether Phosphate Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060488-US-NP), filed concurrently herewith, on Polyphenyl Ether Phosphate Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060181 -US-NP), filed concurrently herewith, on Polyphenyl Thioether Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060487-US-NP), filed concurrently herewith, on Polyphenyl Thioether Phosphate Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060486-US-NP), filed concurrently herewith, on Polyphenyl Thioether Phosphate Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060137-US-NP), filed concurrently herewith, on Thiophosphate Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060110-US-NP), filed concurrently herewith, on Thiophosphate Containing Photoconductors, by Jin Wu et al. U.S. application No. (not yet assigned) (Attorney Docket No. 20060146-US-NP), filed concurrently herewith, on Thiophosphate Containing Photoconductors, by Jin Wu et al. The following patents and copending commonly assigned patent applications are recited: U.S. ptent application Ser. No. 11/126,664, filed May 11, 2005, (Attorney Docket 20050144-US-NP) entitled Photoconductive Members; U.S. patent application Ser. No. 11/193,242, filed Jul. 28, 2005, (Attorney Docket 20050226-US-NP) entitled Polytetrafluoroethylene-doped Photoreceptor Layer Having Polyol Ester Lubricants; U.S. patent application Ser. No. 11/193,541, filed Jul. 28, 2005, (Attorney Docket 20050226Q-US-NP) entitled Photoreceptor Layer Having Solid and Liquid Lubricants; U.S. patent application Ser. No. 11/193,672, filed Jul. 28, 2005, (Attorney Docket 20050226Q1-US-NP) entitled Photoreceptor Layer having Polyphenyl Ether Lubricant; U.S. patent application Ser. No. 11/193,241, filed Jul. 28, 2005, (Attorney Docket 20050226Q2-US-NP) entitled Photoreceptor Layer Having Dialkyldithiophosphate Lubricant; U.S. patent application Ser. No. 11/193,129, filed Jul. 28, 2005, (Attorney Docket 20050626-US-NP) entitled Photoreceptor Layer having Phosphate-based Lubricant; and U.S. patent application Ser. No. 11/193,754, filed Jul. 28, 2005, (Attorney Docket 20050626Q-US-NP) entitled “Photoreceptor Layer having Antioxidant Lubricant Additives.” The disclosures of each of these applications are totally incorporated herein by reference in their entireties. There is illustrated in U.S. Pat. No. 7,037,631, the disclosure of which is totally incorporated herein by reference, a photoconductive imaging member comprised of a supporting substrate, a hole blocking layer thereover, a crosslinked photogenerating layer and a charge transport layer, and wherein the photogenerating layer is comprised of a photogenerating component and a vinyl chloride, allyl glycidyl ether, hydroxy containing polymer. There is illustrated in U.S. Pat. No. 6,913,863, the disclosure of which is totally incorporated herein by reference, a photoconductive imaging member comprised of a hole blocking layer, a photogenerating layer, and a charge transport layer, and wherein the hole blocking layer is comprised of a metal oxide; and a mixture of a phenolic compound and a phenolic resin wherein the phenolic compound contains at least two phenolic groups. A number of the components and amounts thereof of the above copending applications and patents, such as the supporting substrates, resin binders, photogenerating layer components, antioxidants, charge transport components, ethers, thiophosphates, hole blocking layer components, adhesive layers, and the like may be selected for the members of the present disclosure in embodiments thereof.
