# US 7,608,373 B2 · Toner for developing electrostatic latent image, developer using the toner, and process cartridge, image forming apparatus and image forming method using the developer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,373 B2 - Document ID: US7608373B2 - Status: Granted - Kind: B2 - Application number: 11/338,700 - Filed: 2006-01-25 - Published: 2006-08-03 - Granted: 2009-10-27 - Earliest claimed: 2005-01-25 - Assignees: Ricoh Company, Ltd. - Inventors: Akihiro Kotsugai; Satoshi Mochizuki; Sonoh Matsuoka; Takuya Saito - Web page: https://patentgrep.com/patent/US7608373B2 ## CPC - G03G 9/0906: {Organic dyes} - G03G 9/0922: {Formazane dyes; Nitro and Nitroso dyes; Quinone imides; Azomethine dyes} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract A toner is provided containing a parent particulate material, which contains; a first colorant, a second colorant, and a binder resin, wherein the first colorant contains an organic pigment having a primary particle diameter distribution with a median diameter of from 0.08 to 0.12 μm, and the second colorant contains an organic pigment having a primary particle diameter distribution with a median diameter of from 0.01 to 0.06 μm, and each of the first colorant and second colorant have the following formula (1) ## Claims ### Claim 1 A toner, comprising: a parent particulate material, comprising; a first colorant, a second colorant, and a binder resin, wherein the first colorant comprises an organic pigment having a primary particle diameter distribution with a median diameter of from 0.08 to 0.12 μm, and the second colorant comprises an organic pigment having a primary particle diameter distribution with a median diameter of from 0.01 to 0.06 μm, and each of said first colorant and second colorant having the following formula (1) ### Claim 2 (depends on 1) The toner of claim 1, wherein the binder resin comprises a polyester resin. ### Claim 3 (depends on 1) The toner of claim 1, wherein the binder resin comprises a modified polyester resin. ### Claim 4 (depends on 2) The toner of claim 2, wherein the polyester resin is a mixture of a modified polyester resin and a non-modified polyester resin. ### Claim 5 (depends on 1) The toner of claim 1, wherein the toner has an average circularity of from 0.90 to 0.99. ### Claim 6 (depends on 1) The toner of claim 1, wherein the toner has a shape factor SF-1 of from 100 to 150 and a shape factor SF-2 of from 100 to 140. ### Claim 7 (depends on 1) The toner of claim 1, wherein the toner has a volume-average particle diameter (Dv) of from 2 to 7 μm and a ratio (Dv/Dn) of the volume-average particle diameter (Dv) to a number-average particle diameter (Dn) thereof not greater than 1.25. ### Claim 8 (depends on 1) The toner of claim 1, wherein a mixing ratio of the first colorant to the second colorant is from 10/90 to 50/50 by weight. ### Claim 9 (depends on 1) The toner of claim 1, wherein the toner is prepared by a method comprising: dissolving a toner composition including a prepolymer in a solvent to prepare an oil drop; and dispersing the oil drop in an aqueous medium to be subjected to at least one of an elongation reaction and a crosslinking reaction. ### Claim 10 (depends on 9) The toner of claim 9, wherein the toner composition including a prepolymer comprises a masterbatch comprising the binder resin and the first and second colorants. ### Claim 11 (depends on 1) A two-component developer, comprising: the toner according to claim 1; and a carrier comprising a magnetic particulate material. ### Claim 12 (depends on 11) The two-component developer of claim 11, wherein the toner has an average circularity of from 0.90 to 0.99. ### Claim 13 (depends on 11) The two-component developer of claim 11, wherein the toner has a shape factor SF-1 of from 100 to 150 and a shape factor SF-2 of from 100 to 140. ### Claim 14 (depends on 11) The two-component developer of claim 11, wherein the toner has a volume-average particle diameter (Dv) of from 2 to 7 μm and a ratio (Dv/Dn) of the volume-average particle diameter (Dv) to a number-average particle diameter (Dn) thereof not greater than 1.25. ### Claim 15 (depends on 11) The two-component developer of claim 11, wherein a mixing ratio of the first colorant to the second colorant is from 10/90 to 50/50 by weight. ### Claim 16 (depends on 1) A process cartridge detachable from an image forming apparatus, comprising: an image developer configured to develop an electrostatic latent image with the toner according to claim 1; and at least one of an electrophotographic photoreceptor, a charger and a cleaner. ### Claim 17 (depends on 11) An image forming apparatus, comprising: an image bearer; a charger configured to charge the image bearer to form an electrostatic latent image thereon; an image developer configured to develop the electrostatic latent image with a developer including a toner to form a toner image thereon; a transferer configured to transfer the toner image onto a transfer sheet; and a fixer configured to fix the toner image on the transfer sheet, wherein the developer is the two-component developer according to claim 11. ### Claim 18 (depends on 17) The image forming apparatus of claim 17, wherein a mixing ratio of the first colorant to the second colorant in the toner of the developer is from 10/90 to 50/50 by weight. ### Claim 19 (depends on 11) An image forming method, comprising: charging an image bearer to form an electrostatic latent image thereon; developing the electrostatic latent image with a developer including a toner to form a toner image thereon; transferring the toner image onto a transfer sheet; and fixing the toner image on the transfer sheet, wherein the developer is the two-component developer according to claim 11. ### Claim 20 (depends on 19) The image forming method of claim 19, wherein a mixing ratio of the first colorant to the second colorant in the toner of the developer is from 10/90 to 50/50 by weight.