# US 7,078,139 B2 · Electrophotographic photoreceptor for wet development > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,078,139 B2 - Document ID: US7078139B2 - Status: Granted - Kind: B2 - Application number: 10/680,421 - Filed: 2003-10-08 - Published: 2004-07-15 - Granted: 2006-07-18 - Earliest claimed: 2002-10-09 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Saburo Yokota; Hwan-koo Lee; Kyung-yoi Yon - Web page: https://patentgrep.com/patent/US7078139B2 ## CPC - G03G 5/0609: {containing oxygen} - G03G 5/047: characterised by the charge-generation layers or charge transport layers {(G03G5/0433 and G03G5/0436 take precedence)} - G03G 5/051: {Organic non-macromolecular compounds} - G03G 5/056: {Polyesters} - G03G 5/0564: {Polycarbonates} - G03G 5/06: characterised by the photoconductive material being organic - G03G 5/0605: {Carbocyclic compounds} - G03G 5/0607: {containing at least one non-six-membered ring} - G03G 5/06147: {alkenylarylamine} - G03G 5/06149: {enamine} - G03G 5/0616: {Hydrazines; Hydrazones} - G03G 5/0672: {containing two or more methine or polymethine groups} - G03G 5/14795: {Macromolecular compounds characterised by their physical properties} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An electrophotographic photoreceptor for wet development including an electrically conductive substrate, and an organic photosensitive layer formed on the electrically conductive substrate, wherein a surface layer of the organic photosensitive layer includes at least a binder resin comprising a polymer compound and a charge transport material comprising a low molecule compound, the surface layer having an oxygen gas permeation coefficient of 5×10−13 cm3 (STP)*cm/s*cm2*cmHg or less. The electrophotographic photoreceptor has high durability for liquid developer used in a wet development technique and can produce good image characteristics. ## Claims ### Claim 1 An electrophotographic photoreceptor for wet development comprising: an electrically conductive substrate; and an organic photosensitive layer formed on the electrically conductive substrate, wherein a surface layer of the organic photosensitive layer includes at least a binder resin comprising a polymer compound and a charge transport material comprising a low molecule compound, the surface layer having an oxygen gas permeation coefficient of 5×10−13 cm3(STP)*cm/s*cm2*cmHg or less. ### Claim 2 (depends on 1) The electrophotographic photoreceptor of claim 1, wherein the binder resin is formed of a polymer compound having a biphenylfluroene unit represented by Formula 1 in a main chain: wherein at least one hydrogen atom of the benzene rings is substitutable by an arbitrary substituent selected from the group consisting of a halogen atom, a C1˜C20 alkyl group and a C5˜C8 cycloalkyl group. ### Claim 3 (depends on 1) The electrophotographic photoreceptor of claim 1, wherein the charge transport material includes a hole transport material represented by Formula 2: wherein R1 through R5 are independently one selected from the group consisting of a hydrogen atom, a C1˜C30 substituted or unsubstituted alkyl group, a C6˜C30 substituted or unsubstituted aryl group, a C1˜C30 substituted or unsubstituted alkoxy group, and a C8˜C30 substituted or unsubstituted styrile group, and at least one hydrogen atom in the benzene rings is substitutable by an arbitrary substituent. ### Claim 4 (depends on 1) The electrophotographic photoreceptor of claim 1, wherein the charge transport material includes an electron transport material represented by Formula 3: wherein A and B are independently one selected from the group consisting of a hydrogen atom, a halogen atom, a C2˜C30 substituted or unsubstituted alkoxycarbonyl group and a C2˜C30 substituted or unsubstituted alkylaminocarbonyl group, and at least one hydrogen atom in the benzene rings is substitutable by a halogen atom. ### Claim 5 (depends on 1) The electrophotographic photoreceptor of claim 1, wherein a proportion of the binder resin in the surface layer is preferably 60˜90% by weight. ### Claim 6 (depends on 2) The electrophotographic photoreceptor of claim 2, wherein the polymer compound is represented by Formula 4, 5, 6 or 7: wherein k, l, m, n and p are independently an integer between about 10 and about 1000. ### Claim 7 (depends on 1) The electrophotographic photoreceptor of claim 1, wherein the electrophotographic photoreceptor further comprises an intermediate layer for enhancing bonding strength of the organic photosensitive layer to the electrically conductive substrate. ### Claim 8 (depends on 1) The electrophotographic photoreceptor of claim 1, wherein the electrophotographic photoreceptor further comprises an intermediate layer for preventing charge injection from the electrically conductive substrate, between the electrically conductive substrate and the photosensitive layer. ### Claim 9 An electrophotographic imaging apparatus comprising: a developing unit utilizing liquid developer, wherein the liquid developer is able to directly contact the surface of an electrophotographic photoreceptor comprising an organic photosensitive layer formed on an electrically conductive substrate, wherein a surface layer of the organic photosensitive layer includes at least a binder resin comprising a polymer compound and a charge transport material comprising a low molecule compound, the surface layer having an oxygen gas permeation coefficient of 5×10−13 cm3(STP)*cm/s*cm2*cmHg or less. ### Claim 10 (depends on 9) The electrophotographic imaging apparatus of claim 9, wherein the binder resin is formed of a polymer compound having a biphenylfluorene unit represented by Formula 1 in a main chain: wherein at least one hydrogen atom of the benzene rings is substitutable by an arbitrary substituent selected from the group consisting of a halogen atom, a C1˜C20 alky I group and a C5˜C8 cycloalkyl group. ### Claim 11 (depends on 9) The electrophotographic imaging apparatus of claim 9, wherein the charge transport material includes a hole transport material represented by Formula 2: wherein R1 through R5 are independently one selected from the group consisting of a hydrogen atom, a C1˜C30 substituted or unsubstituted alkyl group, a C6˜C30 substituted or unsubstituted aryl group, a C1˜C30 substituted or unsubstituted alkoxy group, and a C8˜C30 substituted or unsubstituted styrile group, and at least one hydrogen atom in the benzene rings is substitutable by an arbitrary substituent. ### Claim 12 (depends on 9) The electrophotographic imaging apparatus of claim 9, wherein the charge transport material includes an electron transport material represented by Formula 3: wherein A and B are independently selected from the group consisting of a hydrogen atom, a halogen atom, a C2˜C30 substituted or unsubstituted alkoxycarbonyl group and a C2˜C30 substituted or unsubstituted alkylaminocarbonyl group, and at least one hydrogen atom in the benzene rings is substitutable by a halogen atom. ### Claim 13 (depends on 9) The electrophotographic imaging apparatus of claim 9, wherein a proportion of the binder resin in the surface layer is preferably 60˜90% by weight. ### Claim 14 (depends on 9) The electrophotographic imaging apparatus of claim 9, wherein the polymer compound is represented by Formula 4, 5, 6 or 7: wherein k, l, m, n and p are independently an integer between about 10 and about 1000. ### Claim 15 (depends on 9) The electrophotographic imaging apparatus of claim 9, wherein the electrophotographic photoreceptor further comprises an intermediate layer for enhancing bonding strength of the organic photosensitive layer to the electrically conductive substrate. ### Claim 16 (depends on 9) The electrophotographic imaging apparatus of claim 9, wherein the electrophotographic photoreceptor further comprises an intermediate layer for preventing charge injection from the electrically conductive substrate, between the electrically conductive substrate and the photosensitive layer. ### Claim 17 An electrophotographic cartridge, comprising: an electrophotographic photoreceptor comprising an organic photosensitive layer formed on an electrically conductive substrate, wherein a surface layer of the organic photosensitive layer includes at least a binder resin comprising a polymer compound and a charge transport material comprising a low molecule compound, the surface layer having an oxygen gas permeation coefficient of 5×10−13 cm3(STP)*cm/s*cm2*cmHg or less; a charging device that charges the electrophotographic photoreceptor; a developing device which develops an electrostatic latent image formed on the electrophotographic photoreceptor; and a cleaning device which cleans a surface of the electrophotographic photoreceptor; wherein the electrophotographic cartridge is attachable to or detachable from an image forming apparatus. ### Claim 18 (depends on 17) The electrophotographic cartridge of claim 17, wherein the binder resin is formed of a polymer compound having a biphenylfluorene unit represented by Formula 1 in a main chain: wherein at least one hydrogen atom of the benzene rings is substitutable by an arbitrary substituent selected from the group consisting of a halogen atom, a C1˜C20 alky I group and a C5˜C8 cycloalkyl group. ### Claim 19 (depends on 17) The electrophotographic cartridge of claim 17, wherein the charge transport material includes a hole transport material represented by Formula 2: wherein R1 through R5 are independently one selected from the group consisting of a hydrogen atom, a C1˜C30 substituted or unsubstituted alkyl group, a C6˜C30 substituted or unsubstituted aryl group, a C1˜C30 substituted or unsubstituted alkoxy group, and a C8˜C30 substituted or unsubstituted styrile group, and at least one hydrogen atom in the benzene rings is substitutable by an arbitrary substituent. ### Claim 20 (depends on 17) The electrophotographic cartridge of claim 17, wherein the charge transport material includes an electron transport material represented by Formula 3: wherein A and B are independently selected from the group consisting of a hydrogen atom, a halogen atom, a C2˜C30 substituted or unsubstituted alkoxycarbonyl group and a C2˜C30 substituted or unsubstituted alkylaminocarbonyl group, and at least one hydrogen atom in the benzene rings is substitutable by a halogen atom. ### Claim 21 (depends on 17) The electrophotographic cartridge of claim 17, wherein a proportion of the binder resin in the surface layer is preferably 60˜90% by weight. ### Claim 22 (depends on 17) The electrophotographic cartridge of claim 17 wherein the polymer compound is represented by Formula 4, 5, 6 or 7: wherein k, l, m, n and p are independently an integer between about 10 and about 1000. ### Claim 23 (depends on 17) The electrophotographic cartridge of claim 17, wherein the electrophotographic photoreceptor further comprises an intermediate layer for enhancing bonding strength of the organic photosensitive layer to the electrically conductive substrate. ### Claim 24 (depends on 17) The electrophotographic cartridge of claim 17, wherein the electrophotographic photoreceptor further comprises an intermediate layer for preventing charge injection from the electrically conductive substrate, between the electrically conductive substrate and the photosensitive layer.