# US 8,465,895 B2 · Electrostatic image developing toner, electrostatic image developer, toner cartridge, process cartridge, image forming method, and image forming apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,895 B2 - Document ID: US8465895B2 - Status: Granted - Kind: B2 - Application number: 13/106,332 - Filed: 2011-05-12 - Published: 2012-06-14 - Granted: 2013-06-18 - Earliest claimed: 2010-12-13 - Assignees: Fuji Xerox Co., Ltd. - Applicants: Yusuke Ikeda; Yukiaki Nakamura; Kiyohiro Yamanaka; Satoshi Kamiwaki - Inventors: Yusuke Ikeda; Yukiaki Nakamura; Kiyohiro Yamanaka; Satoshi Kamiwaki - Web page: https://patentgrep.com/patent/US8465895B2 ## CPC - G03G 9/09: Colouring agents for toner particles - G03G 9/0819: {characterised by the dimensions of the particles} - G03G 9/0827: {characterised by their shape, e.g. degree of sphericity} - G03G 9/08755: {Polyesters} - G03G 9/08782: {Waxes} - G03G 9/08795: {characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants} - G03G 9/08797: {characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature} - G03G 9/0904: {Carbon black} - G03G 9/0926: {characterised by physical or chemical properties} - G03G 9/09708: {Inorganic compounds} - G03G 9/09716: {treated with organic compounds} - G03G 2215/0609: magnetic brush - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An electrostatic image developing toner contains a binder resin and at least two different kinds of white pigments, wherein from about 10% by weight to about 30% by weight of the at least two kinds of white pigments is porous titanium oxide having a volume average particle diameter of from about 0.01 μm to about 1 μm, a particle size distribution (volume average particle size distribution index GSDv) of from 1.1 to 1.3 and a BET specific surface area of from about 250 m2/g to about 500 m2/g. ## Claims ### Claim 1 An electrostatic image developing toner comprising: a binder resin and at least two different kinds of white pigments, wherein from about 10% by weight to about 30% by weight of the at least two kinds of white pigments is porous titanium oxide having a volume average particle diameter of from about 0.01 μm to about 1 μm, a particle size distribution (volume average particle size distribution index GSDv) of from about 1.1 to about 1.3 and a BET specific surface area of from about 250 m2/g to about 500 m2/g. ### Claim 2 (depends on 1) The electrostatic image developing toner according to claim 1, wherein an average circularity of the porous titanium oxide is more than about 0.970 and less than about 0.990. ### Claim 3 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the porous titanium oxide is formed by aggregating a titanium oxide particle having a volume average particle diameter of from about 0.001 μm to about 0.05 μm. ### Claim 4 (depends on 1) The electrostatic image developing toner according to claim 1, wherein from about 10% by weight to about 50% by weight of the porous titanium oxide has an anatase type crystal structure. ### Claim 5 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the at least two kinds of white pigments contains rutile type titanium oxide having a rutile type crystal structure. ### Claim 6 (depends on 1) The electrostatic image developing toner according to claim 1, wherein a total content of the at least two kinds of white pigments is from about 5% by weight to about 50% by weight relative to the whole weight of the toner. ### Claim 7 (depends on 1) The electrostatic image developing toner according to claim 1, wherein a glass transition temperature of the binder resin is from about 50° C. to about 75° C. ### Claim 8 (depends on 1) The electrostatic image developing toner according to claim 1, wherein a weight average molecular weight of the binder resin is from about 8,000 to about 150,000. ### Claim 9 (depends on 1) The electrostatic image developing toner according to claim 1, wherein an acid number of the binder resin is from about 5 mg-KOH/g to about 30 mg-KOH/g. ### Claim 10 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the binder resin is a polyester resin. ### Claim 11 (depends on 10) The electrostatic image developing toner according to claim 10, wherein about 80% by mol or more of a polycarboxylic acid-derived component constituting the polyester resin is an aliphatic dicarboxylic acid. ### Claim 12 (depends on 10) The electrostatic image developing toner according to claim 10, wherein about 80% by mol or more of a polyol-derived component constituting the polyester resin is an aliphatic polyol. ### Claim 13 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the toner contains a release agent which is melted at any temperature of from about 70° C. to about 140° C. and has a melt viscosity of from about 1 centipoise to about 200 centipoises. ### Claim 14 (depends on 1) The electrostatic image developing toner according to claim 1, having a volume average particle size distribution index GSDv of about 1.30 or less. ### Claim 15 (depends on 1) The electrostatic image developing toner according to claim 1, having a shape constant SF1 (=((absolute maximum length of toner diameter)2/(projected area of toner))×(π/4)×100) of from about 110 to about 160. ### Claim 16 (depends on 1) An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 and a carrier. ### Claim 17 (depends on 16) The electrostatic image developer according to claim 16, wherein the carrier is a resin-coated carrier, and a resin particle and/or a conductive particle is dispersed in the resin-coated resin. ### Claim 18 (depends on 17) The electrostatic image developer according to claim 17, wherein an average particle diameter of the resin particle is from about 0.1 μm to about 2 μm. ### Claim 19 (depends on 17) The electrostatic image developer according to claim 17, wherein the conductive particle is carbon black. ### Claim 20 (depends on 1) A toner cartridge which is detachable against an image forming apparatus and accommodates the electrostatic image developing toner according to claim 1. ### Claim 21 (depends on 16) A process cartridge which includes a developer holding member, is detachable against an image forming apparatus and accommodates the electrostatic image developer according to claim 16. ### Claim 22 (depends on 16) An image forming method comprising: charging an image holding member; forming an electrostatic latent image on the surface of the image holding member; developing the electrostatic latent image formed on the surface of the image holding member with a developer containing a toner to form a toner image; transferring the toner image onto the surface of a transfer-receiving material; and fixing the toner image transferred onto the surface of the transfer-receiving material, wherein the electrostatic image developer according to claim 16 is used as the developer. ### Claim 23 (depends on 16) An image forming apparatus comprising: an image holding member; a charging unit that charges the image holding member; an exposure unit that exposes the charged image holding member to form an electrostatic latent image on the surface of the image holding member; a developing unit that develops the electrostatic latent image with a developer containing a toner to form a toner image; a transfer unit that transfers the toner image from the image holding member onto the surface of a transfer-receiving material; and a fixing unit that fixes the transferred toner image on the surface of the transfer-receiving material, wherein the electrostatic image developer according to claim 16 is used as the developer.