# US 8,785,100 B2 · Two-component developer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,100 B2 - Document ID: US8785100B2 - Status: Granted - Kind: B2 - Application number: 13/727,980 - Filed: 2012-12-27 - Published: 2013-07-25 - Granted: 2014-07-22 - Earliest claimed: 2012-01-20 - Assignees: Konica Minolta Business Technologies, Inc. - Applicants: Hitomi Motani; Tomoko Mine; Tomomi Oshiba - Inventors: Hitomi Motani; Tomoko Mine; Tomomi Oshiba - Web page: https://patentgrep.com/patent/US8785100B2 ## CPC - G03G 9/08: with toner particles - G03G 9/108: {Ferrite carrier, e.g. magnetite} - G03G 9/1085: {with non-ferrous metal oxide, e.g. MgO-Fe2O3} - G03G 9/10882: {Binder is obtained by reactions only involving carbon-carbon unsaturated bonds} - G03G 9/10884: {Binder is obtained other than by reactions only involving carbon-carbon unsaturated bonds} - G03G 9/113: having coatings applied thereto - G03G 9/1133: {obtained by reactions only involving carbon-to-carbon unsaturated bonds} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract The present invention relates to a two-component developer which comprises a toner, and a carrier having a surface of a core material particle coated with a resin having a unit of general formula (1). The present invention provides a two-component developer which has enhanced environmental stability of carrier charging performance. ## Claims ### Claim 1 A two-component developer comprising a toner, and a carrier having a surface of a core material particle coated with a resin, wherein the resin is a vinyl polymer having a unit of the following general formula (1): wherein R1 represents an optionally substituted cycloalkyl group of 3 to 10 carbon atoms; R2 represents a hydrogen atom or a methyl group; R3 and R4 each represent a hydrogen atom; R5 and R6 each independently represent a hydrogen atom or an alkyl group; and n is an integer of 0 or greater. ### Claim 2 (depends on 1) The two-component developer according to claim 1, wherein the vinyl polymer is a homopolymer of the unit of the general formula (1). ### Claim 3 (depends on 1) The two-component developer according to claim 1, wherein R1 represents a cyclohexyl group or a cyclohexyl group substituted with at least one of an alkyl group of 1 to 4 carbon atoms or an alkoxy group of 1 to 5 carbon atoms. ### Claim 4 (depends on 3) The two-component developer according to claim 3, wherein R1 represents a cyclohexyl group or a cyclohexyl group substituted with an alkyl group of 1 to 4 carbon atoms. ### Claim 5 (depends on 1) The two-component developer according to claim 1, wherein the unit of the general formula (1) is a partial structure of the vinyl polymer formed from at least one vinyl polymerizable monomer selected from the group consisting of 1-cyclopropyl-2-methyl-2-propen-1-one, 1-cyclobutyl-2-methyl-2-propen-1-one, 1-cyclopentyl-2-methyl-2-propen-1-one, 1-cyclohexyl-2-methyl-2-propen-1-one, 1-cycloheptyl-2-methyl-2-propen-1-one, 1-adamantyl-2-methyl-2-propen-1-one, 1-cyclohexyl-3-methyl-3-buten-1-one, and 2-methyl-1-(2-methylcyclohexyl)-2-propen-1-one. ### Claim 6 (depends on 5) The two-component developer according to claim 5, wherein the unit of the general formula (1) is a partial structure of the vinyl polymer formed from 1-cyclohexyl-2-methyl-2-propen-1-one. ### Claim 7 (depends on 1) The two-component developer according to claim 1, wherein the resin is a copolymer having the unit of the general formula (1) and a unit of the following general formula (2): wherein R7 represents an alkyl group or a cycloalkyl group. ### Claim 8 (depends on 7) The two-component developer according to claim 7, wherein a weight ratio of the unit of the general formula (1) and the unit of the general formula (2) used at the time of forming the copolymer resin is 10/90 to 90/10. ### Claim 9 (depends on 8) The two-component developer according to claim 8, wherein the weight ratio of the unit of the general formula (1) and the unit of the general formula (2) used at the time of forming the copolymer resin is 50/50 to 80/20. ### Claim 10 (depends on 1) The two-component developer according to claim 1, wherein an amount of the resin is in the range of 1.0 to 4.5% by weight, relative to an amount of the core material particle. ### Claim 11 (depends on 10) The two-component developer according to claim 10, wherein an amount of the resin is in the range of 3 to 3.5% by weight, relative to an amount of the core material particle. ### Claim 12 (depends on 1) The two-component developer according to claim 1, wherein a weight average molecular weight of the resin is 200,000 to 800,000. ### Claim 13 (depends on 1) The two-component developer according to claim 1, wherein the core material particle is formed of light metal ferrite. ### Claim 14 (depends on 1) The two-component developer according to claim 1, wherein the toner contains a styrene-acrylic copolymer resin or a polyester-based resin. ### Claim 15 (depends on 1) The two-component developer according to claim 1, wherein the toner is mixed in an amount of 2 to 15 parts by weight relative to 100 parts by weight of the carrier. ### Claim 16 A two-component developer comprising a toner, and a carrier having a surface of a core material particle coated with a resin, wherein the resin is a vinyl polymer having a unit of the following general formula (1): wherein R1 represents an optionally substituted phenyl group; R2 represents a hydrogen atom or a methyl group; R3 and R4 each represent a hydrogen atom; R5 and R6 each independently represent a hydrogen atom or an alkyl group; and n is an integer of 0 or greater, and a unit of the following general formula (2): wherein R7 represents an alkyl group or a cycloalkyl group. ### Claim 17 (depends on 16) The two-component developer according to claim 16, wherein the unit of the general formula (1) is a partial structure of the vinyl polymer formed from at least one vinyl polymerizable monomer selected from the group consisting of 2-methyl-1-phenyl-2-propen-1-one, 3-methyl-1-phenyl-3-buten-1-one, and 2-methyl-1-tolyl-2-propen-1-one. ### Claim 18 (depends on 16) The two-component developer according to claim 16, wherein a weight ratio of the unit of the general formula (1) and the unit of the general formula (2) used at the time of forming the copolymer resin is 10/90 to 90/10. ### Claim 19 (depends on 18) The two-component developer according to claim 18, wherein the weight ratio of the unit of the general formula (1) and the unit of the general formula (2) used at the time of forming the copolymer resin is 50/50 to 80/20. ### Claim 20 (depends on 16) The two-component developer according to claim 16, wherein a weight average molecular weight of the resin is 200,000 to 800,000.