# US 5,705,305 A · Developer for developing electrostatic latent image > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,705,305 A - Document ID: US5705305A - Status: Granted - Kind: A - Application number: 08/589,469 - Filed: 1996-01-22 - Granted: 1998-01-06 - Earliest claimed: 1995-01-31 - Assignees: Brother Kogyo Kabushiki Kaishi - Inventors: Mitsuru Ohta; Noriaki Satoh - Web page: https://patentgrep.com/patent/US5705305A ## CPC - G03G 9/09716: {treated with organic compounds} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract A developer for developing an electrostatic latent image formed on an photosensitive body, including a toner, a fluidity improving material, a cleaning material, and hydrophobic fine particles obtained by treating surfaces of the fine particles with silicone, the treated fine particles containing not less than 5% of the silicone. ## Claims ### Claim 1 A developer for developing an electrostatic latent image formed on a photosensitive body, comprising: a toner; a fluidity improving material; a cleaning material; and hydrophobic fine particles obtained by treating surfaces of said fine particles with silicone oil, the treated fine particles containing not less than 5% of said silicone oil, said fine particles comprising crystalline titanium oxide obtained by a sulfuric acid method and consisting of one of a rutile-type titanium dioxide and anatase-type titanium dioxide. ### Claim 2 A process for developing an electrostatic latent image, comprising: forming an image on a photosensitive body; developing said image with a developer to form a toner image; and transferring said toner image onto a recording medium, wherein said developer comprises: a magnetic toner; a carrier; fine particles of hydrophobic silica; fine particles of alumina; and fine particles of crystalline titanium oxide having surfaces treated with silicone oil, the treated fine particles containing not less than 10% of said silicone oil, and wherein said fine particles of crystalline titanium are selected from the group consisting of one of a rutile-type titanium dioxide and anatase-type titanium dioxide, and wherein said crystalline titanium oxide is obtained by a sulfuric-acid method. ### Claim 3 (depends on 1) A developer according to claim 1, further comprising a carrier, wherein said toner comprises a magnetic toner. ### Claim 4 (depends on 1) A developer according to claim 1, wherein said fluidity improving material is selected from the group consisting of a fine powder of an inorganic compound such as silica, aluminum oxide and titanium oxide, a fine powder of acrylic resin, a fine powder of polyvinylfluoride, a fine powder of polyolefin, and a fine powder of polyamide. ### Claim 5 (depends on 1) A developer according to claim 1, wherein said cleaning material is selected from the group consisting of fine particles of alumina, and fine particles of a hard material such as carbide, nitride, carbonate, zirconium silicate, and magnesium oxide. ### Claim 6 A developer for developing an electrostatic latent image formed on a photosensitive body, comprising: a toner; a fluidity improving material; a cleaning material; and fine particles of crystalline titanium oxide having surfaces treated with silicone oil, said fine particles of crystalline titanium oxide being obtained by a sulfuric acid method and consisting of one of a rutile-type titanium dioxide and anatase-type titanium dioxide. ### Claim 7 (depends on 6) A developer according to claim 6, further comprising a carrier, wherein said toner comprises a magnetic toner. ### Claim 8 (depends on 6) A developer according to claim 6, wherein the treated fine particles contain not less than 5% of said silicone oil. ### Claim 9 A developer for developing an electrostatic latent image formed on a photosensitive body, comprising: a magnetic toner; a carrier; fine particles of hydrophobic silica; fine particles of alumina; and fine particles of crystalline titanium oxide having surfaces treated with silicone oil, the treated fine particles containing not less than 10% of said silicone oil, said fine particles of crystalline titanium oxide being obtained by a sulfuric acid method and consisting of one of a rutile-type titanium dioxide and anatase-type titanium dioxide. ### Claim 10 (depends on 9) A developer according to claim 9, wherein said magnetic toner comprises: a binder resin; a magnetic powder; a releasing agent; and a charge control material. ### Claim 11 (depends on 10) A developer according to claim 10, wherein said binder resin comprises at least one resin selected from the group consisting of polystyrene, polyacrylate, polymethacrylate, vinyl resin, polyester resin, polyethylene, polypropylene, polyvinylchloride, polyacrylonitrile, polyether, polycarbonate, cellulosic resin, polyamide, and a copolymer of two or more monomers of the resins. ### Claim 12 (depends on 10) A developer according to claim 10, wherein said magnetic powder comprises a magnetic or magnetizable powder selected from the group consisting of a fine powder of metal such as iron, manganese, nickel, cobalt, and chromium, and a fine powder of metal oxide such as magnetite, hematite, and ferrite. ### Claim 13 (depends on 10) A developer according to claim 10, wherein said releasing agent is selected from the group consisting of polyalkylene such as polyethylene and polypropylene, and a natural wax such as carnauba wax, candelilla wax, and rice wax. ### Claim 14 (depends on 10) A developer according to claim 10, wherein said charge control material is selected from the group consisting of nigrosine dye, quaternary ammonium salt, alkoxylated amine, alkylamide, a metal complex of azoic dye, and a metal salt of higher fatty acid. ### Claim 15 (depends on 9) A developer according to claim 9, wherein said carrier comprises a magnetic powder selected from the group consisting of a powder of iron, a powder of nickel, a powder of cobalt, and a powder of ferrite. ### Claim 16 (depends on 15) A developer according to claim 15, wherein said carrier further comprises at least one resin contained to coat said magnetic material, said at least one resin being selected from the group consisting of fluororesin, styrene resin, acrylic resin, silicone resin, epoxy resin, polyester resin, and polyalkylene resin. ### Claim 17 (depends on 1) A developer according to claim 1, wherein said treated fine particles contain 5 to 15% of said silicone oil. ### Claim 18 (depends on 1) A developer according to claim 1, wherein said treated fine particles contain 5 to 15% of said silicone oil. ### Claim 19 (depends on 8) A developer according to claim 8, wherein said treated fine particles contain 5 to 15% of said silicone oil. ### Claim 20 (depends on 19) A developer according to claim 19, wherein said treated fine particles contain 10 to 15% of said silicone oil. ### Claim 21 (depends on 9) A developer according to claim 9, wherein said treated fine particles contain 10 to 15% of said silicone oil. ### Claim 22 (depends on 9) A developer according to claim 9, wherein said treated fine particles contain 10 to 15% of said silicone oil. ### Claim 23 A process for developing an electrostatic latent image, comprising: forming an image on a photosensitive body; developing said image with a developer to form a toner image; and transferring said toner image onto a recording medium, wherein said developer comprises: a toner; a fluidity improving material; a cleaning material; and hydrophobic fine particles obtained by treating surfaces of said fine particles with silicone oil, the treated fine particles containing not less than 5 % of said silicone oil, wherein said fine particles comprise crystalline titanium oxide selected from the group consisting of one of a rutile-type titanium dioxide and anatase-type titanium dioxide, and wherein said crystalline titanium oxide is obtained by a sulfuric-acid method. ### Claim 24 A process for developing an electrostatic latent image, comprising: forming an image on a photosensitive body; developing said image with a developer to form a toner image; and transferring said toner image onto a recording medium, wherein said developer comprises: a toner; a fluidity improving material; a cleaning material; and fine particles of crystalline titanium oxide having surfaces treated with silicone oil, wherein said fine particles of crystalline titanium oxide are obtained by a sulfuric-acid method and consist of one of a rutile-type titanium dioxide and anatase-type titanium dioxide. ### Claim 25 (depends on 24) A developer according to claim 24, wherein said treated fine particles contain 10 to 15% of said silicone oil.