# US 5,707,767 A · Mechanically robust electrophotographic imaging member free of interference fringes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,707,767 A - Document ID: US5707767A - Status: Granted - Kind: A - Application number: 08/752,017 - Filed: 1996-11-19 - Granted: 1998-01-13 - Earliest claimed: 1996-11-19 - Assignees: Xerox Corporation - Inventors: Robert C. U. Yu - Web page: https://patentgrep.com/patent/US5707767A ## CPC - G03G 5/144: {comprising inorganic material} - G03G 5/043: Photoconductive layers characterised by having two or more layers or characterised by their composite structure - G03G 5/0436: {combining organic and inorganic layers} - G03G 5/047: characterised by the charge-generation layers or charge transport layers {(G03G5/0433 and G03G5/0436 take precedence)} - G03G 5/05: Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers - G03G 5/14704: {comprising inorganic material} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An electrophotographic imaging member having including a supporting substrate having an electrically conductive surface, a hole blocking layer, an optional adhesive layer, a charge generating layer, a charge transport layer, an optional anticurl back coating, a ground strip layer and an optional overcoating layer, at least one of the charge transport layer, anticurl back coating, ground strip layer and overcoating layer comprising a silica particle clusters homogeneously distributed in a film forming matrix. ## Claims ### Claim 1 An electrophotographic imaging member comprising a supporting substrate having an electrically conductive surface, a hole blocking layer, an optional adhesive layer, a charge generating layer, a charge transport layer, an optional anticurl back coating, a ground strip layer and an optional overcoating layer, at least one of said charge transport layer, anticurl back coating, ground strip layer and overcoating layer comprising silica particle clusters homogeneously dispersed in a film forming matrix, said silica particle clusters consisting essentially of spherically shaped amorphous primary silicon dioxide particles permanently bonded or fused to each other. ### Claim 2 (depends on 1) An electrophotographic imaging member according to claim 1 wherein said at least one of said charge transport layer, anticurl back coating, ground strip layer and overcoating layer comprises between about 0.1 and about 30 weight percent of said silica particle clusters based on the total dried weight of said layer of coating. ### Claim 3 (depends on 1) An electrophotographic imaging member according to claim 1 wherein said dispersed silica particle clusters have an average cluster diameter substantially less than the thickness of the layer or coating containing said clusters. ### Claim 4 (depends on 1) An electrophotographic imaging member according to claim 1 wherein said silica particle clusters having an average cluster diameter size distribution of between about 0.105 micrometers and about 2 micrometers. ### Claim 5 (depends on 1) An electrophotographic imaging member according to claim 1 wherein said overcoating layer comprises from about 0.1 percent by eight to about 10 percent by weight of said dispersed silica clusters, based on the total dried weight of said overcoating layer. ### Claim 6 (depends on 4) An electrophotographic imaging member according to claim 4 wherein said overcoating layer comprises between about 0.5 percent by weight and about 6 percent by weight of said silica clusters dispersion, based on the total weight of said overcoating layer. ### Claim 7 (depends on 1) An electrophotographic imaging member according to claim 1 wherein said anticurl back coating comprises from about 0.1 percent by weight to about 30 percent by weight of said dispersed silica clusters, based on the total dried weight of said anticurl back coating. ### Claim 8 (depends on 1) An electrophotographic imaging member according to claim 1 wherein said ground strip layer comprises from about 1 percent by weight to about 20 percent by weight of said dispersed silica clusters, based on the total dried weight of said ground strip layer. ### Claim 9 (depends on 1) An electrophotographic imaging member according to claim 1 wherein said silica clusters have a hardness of about 5.2 Mohs, a refractive index of about 1.46 and a density of about 2.2 grams/cubic centimeter. ### Claim 10 (depends on 9) An electrophotographic imaging member according to claim 9 wherein said silica clusters consists of pyrogenic or fumed silica. ### Claim 11 (depends on 9) An electrophotographic imaging member according to claim 9 wherein said silica clusters consists of precipitated silica. ### Claim 12 (depends on 1) An electrophotographic imaging member according to claim 1 wherein said silica clusters is silica gel. ### Claim 13 An electrophotographic imaging member comprising a charge transport layer comprising a thermoplastic film forming binder matrix, charge transport molecules and a homogeneous dispersion of silica particle clusters in said film forming binder matrix, said silica particle clusters consisting essentially of spherically shaped amorphous primary silicon dioxide particles permanently bonded or fused to each other. ### Claim 14 (depends on 13) An electrophotographic imaging member according to claim 13 wherein said charge transport molecules comprise a charge transporting aryl amine compound. ### Claim 15 (depends on 14) An electrophotographic imaging member according to claim 14 wherein said dispersed silica particle clusters have an average cluster diameter less than the thickness of said charge transport layer. ### Claim 16 (depends on 15) An electrophotographic imaging member according to claim 15 wherein said charge transport layer comprises from about 0.1 percent by weight to about 10 percent by weight of said silica based on the total dried weight of said charge transport layer. ### Claim 17 (depends on 13) An electrophotographic imaging member according to claim 13 wherein said silica particle clusters having an average cluster diameter size distribution between about 0.105 micrometer and about 2 micrometers. ### Claim 18 (depends on 13) An electrophotographic imaging member according to claim 13 wherein said dispersed silica particle clusters are synthetic amorphous silicon dioxide particle aggregate consisting essentially of between about 110 and about 750,000 spherically shaped primary amorphous silicon dioxide particles having a particle diameter of from about 70 angstroms to about 600 angstroms permanently bonded or fused to each other. ### Claim 19 (depends on 18) An electrophotographic imaging member according to claim 18 wherein said dispersed silica particle clusters have a hardness of about 5.2 Mohs, a refractive index of about 1.46 and a density of about 2.2 grams/cubic centimeter. ### Claim 20 (depends on 19) The electrophotographic imaging member of claim 19 wherein surfaces of said dispersed silica particle clusters are treated with a bifunctional silane coupling agent.