# US 8,541,151 B2 · Imaging members having a novel slippery overcoat layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,151 B2 - Document ID: US8541151B2 - Status: Granted - Kind: B2 - Application number: 12/763,126 - Filed: 2010-04-19 - Published: 2011-10-20 - Granted: 2013-09-24 - Earliest claimed: 2010-04-19 - Assignees: Xerox Corporation - Applicants: Robert C. U. Yu - Inventors: Robert C. U. Yu - Web page: https://patentgrep.com/patent/US8541151B2 ## CPC - G03G 5/14791: {Macromolecular compounds characterised by their structure, e.g. block polymers, reticulated polymers, or by their chemical properties, e.g. by molecular weight or acidity} - G03G 5/047: characterised by the charge-generation layers or charge transport layers {(G03G5/0433 and G03G5/0436 take precedence)} - G03G 5/14704: {comprising inorganic material} - G03G 5/14708: {comprising organic material} - G03G 5/14756: {Polycarbonates} - G03G 5/14773: {Polycondensates comprising silicon atoms in the main chain} - G03G 5/14795: {Macromolecular compounds characterised by their physical properties} - G03G 15/754: {relating to band, e.g. tensioning (G03G15/757 takes precedence)} - G03G 2215/00957: Compositions - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract The presently disclosed embodiments relate in general to electrophotographic imaging members which include a protective overcoat layer comprising specific low surface energy polycarbonates of excellent optical clarity and having a slippery and adhesive surface to impact toner image transfer efficiency to receiving papers and effect contact friction reduction by which imaging members abrasion/wear resistance is enhanced. The present embodiments also disclose a process for making and using these members. ## Claims ### Claim 1 An imaging member comprising: a substrate; a charge generating layer disposed on the substrate; at least one charge transport layer disposed on the charge generating layer; and an overcoat layer disposed on the charge transport layer, wherein the overcoat layer comprises a low surface energy polycarbonate being an A-B di-block copolymer comprising two segmental blocks, the first segment block (A) being wherein x polydimethyl siloxane (PDMS) repeat units is from about 10 to about 40 and y is from about 1 to about 15, and the second segment block (B) being selected from the group consisting of wherein z is from about 50 to about 400; wherein the overcoat layer has a thickness of from about 2 to about 4 micrometers; and further wherein the overcoat layer comprises a charge transport compound in an amount of from 1 to 5 percent by weight based on the total weight of the overcoat layer. ### Claim 2 (depends on 1) The imaging member of claim 1, wherein the substrate is a flexible belt or a rigid drum. ### Claim 3 (depends on 1) The imaging member of claim 1, wherein the low surface energy polycarbonate is wherein x is from about 10 to about 40, y is from about 1 to about 15, and z is from about 50 to about 400. ### Claim 4 (depends on 1) The imaging member of claim 1, wherein x is about 26 and the overcoat layer exhibits optical clarity. ### Claim 5 (depends on 1) The imaging member of claim 1, wherein the overcoat layer comprises a polymer blend of the low surface energy polycarbonate and a bisphenol A polycarbonate of poly(4,4′-isopropylidene diphenyl carbonate) having a weight average molecular weight of from about 20,000 to about 130,000 and a molecular structure: wherein n indicates the degree of polymerization and is from about 79 to about 512. ### Claim 6 (depends on 5) The imaging member of claim 5, wherein a ratio of the low surface energy polycarbonate to the bisphenol polycarbonate is from about 10:90 to about 90:10 by weight based on the total weight of the overcoat layer. ### Claim 7 (depends on 1) The imaging member of claim 1, wherein the overcoat layer comprises a polymer blend of the low surface energy polycarbonate and a bisphenol Z polycarbonate of poly(4,4′-diphenyl-1,1′-cyclohexane carbonate) having a weight average molecular weight of from about 20,000 to about 200,000 and a molecular structure: wherein n indicates the degree of polymerization and is from about 68 to about 680. ### Claim 8 (depends on 7) The imaging member of claim 7, wherein a ratio of the low surface energy polycarbonate to the bisphenol polycarbonate is from about 10:90 to about 90:10 by weight based on the total weight of the overcoat layer. ### Claim 9 (depends on 1) The imaging member of claim 1, wherein the low surface energy polycarbonate polymer comprises from about 2 to about 10 weight percent of PDMS repeat units in block (A) segments based on the molecular weight of the low surface energy polycarbonate. ### Claim 10 (depends on 1) The imaging member of claim 1, wherein the low surface energy polycarbonate exhibits little or no light scattering effect to render optical clarity. ### Claim 11 (depends on 1) The imaging member of claim 1, wherein the overcoat layer further comprises organic fillers, inorganic fillers, or a hybrid of organic/inorganic fillers in an amount of from about 2 to about 10 weight percent based on the total weight of the overcoat layer. ### Claim 12 (depends on 11) The imaging member of claim 11, wherein the inorganic fillers are selected from the group consisting of silica, metal oxides, metal carbonate, metal silicates, and mixtures thereof, and the organic fillers are selected from the group consisting of polytetrafluoroethylene (PTFE), stearates, fluorocarbon (PTFE) polymers, waxy polyethylene, fatty amides, and mixtures thereof. ### Claim 13 (depends on 11) The imaging member of claim 11, wherein the overcoat layer further comprises a hybrid inorganic/organic Polyhedral Oligomeric Silsesquioxane (POSS) nano-particle dispersion. ### Claim 14 (depends on 1) The imaging member of claim 1, wherein a surface energy of the charge transport layer is about 22 dynes/cm. ### Claim 15 (depends on 1) The imaging member of claim 1, wherein a 180° tape peel-off strength from the surface of the charge transport layer is about 16 gms/cm. ### Claim 16 An imaging member comprising: a substrate; a charge generating layer disposed on the substrate; at least one charge transport layer disposed on the charge generating layer; and an overcoat layer disposed on the charge transport layer, wherein the overcoat layer comprises a polymer blend of a low surface energy polycarbonate being an A-B di-block copolymer comprising two segmental blocks, the first segment block (A) being wherein x is from about 10 to about 40 and y is from about 1 to about 15, and the second segment block (B) being selected from the group consisting of wherein z is from about 50 to about 400, and a bisphenol polycarbonate being selected from the group consisting of a bisphenol A polycarbonate of poly(4,4′-isopropylidene diphenyl carbonate) having a weight average molecular weight of from about 20,000 to about 130,000 and a molecular structure: wherein n indicates the degree of polymerization and is from about 79 to about 512 and a bisphenol Z polycarbonate of poly(4,4′-diphenyl-1,1′-cyclohexane carbonate) having a weight average molecular weight is from about 20,000 to about 200,000 and a molecular structure: wherein n indicates the degree of polymerization and is from about 68 to about 680; wherein the overcoat layer has a thickness of from about 2 to about 4 micrometers; and further wherein the overcoat layer comprises a charge transport compound in an amount of from 1 to 5 percent by weight based on the total weight of the overcoat layer. ### Claim 17 (depends on 16) The imaging member of claim 16, wherein a ratio of the low surface energy polycarbonate to the bisphenol polycarbonate is from about 10:90 to 90:10 by weight based on the total weight of the overcoat layer. ### Claim 18 An image forming apparatus for forming images on a recording medium comprising: a) an imaging member having a charge retentive-surface for receiving an electrostatic latent image thereon, wherein the flexible imaging member comprises a substrate, a charge generating layer disposed on the substrate, at least one charge transport layer disposed on the charge generating layer, and an overcoat layer disposed on the charge transport layer, wherein the overcoat layer comprises a low surface energy polycarbonate being an A-B di-block copolymer comprising two segmental blocks, the first segment block (A) being wherein x is from about 10 to about 40 and y is from about 1 to about 15, and the second segment block (B) being selected from the group consisting of wherein z is from about 50 to about 400; wherein the overcoat layer has a thickness of from about 2 to about 4 micrometers; and further wherein the overcoat layer comprises a charge transport compound in an amount of from 1 to 5 percent by weight based on the total weight of the overcoat layer; b) a development component for applying a developer material to the charge-retentive surface to develop the electrostatic latent image to form a developed image on the charge-retentive surface; c) a transfer component for transferring the developed image from the charge-retentive surface to a copy substrate; and d) a fusing component for fusing the developed image to the copy substrate.