# US 12,455,514 B2 · Electrostatic image developing toner, electrostatic image developer, and toner cartridge > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,455,514 B2 - Document ID: US12455514B2 - Status: Granted - Kind: B2 - Application number: 17/512,178 - Filed: 2021-10-27 - Published: 2022-12-08 - Granted: 2025-10-28 - Earliest claimed: 2021-05-25 - Assignees: FUJIFILM Business Innovation Corp. - Applicants: FUJIFILM Business Innovation Corp. - Inventors: Atsushi Sugawara; Yoshimasa Fujihara; Shintaro Anno; Satoshi Miura; Daisuke Noguchi - Web page: https://patentgrep.com/patent/US12455514B2 ## CPC - G03G 9/0819: {characterised by the dimensions of the particles} - G03G 9/0825: {characterised by their structure; characterised by non-homogenuous distribution of components (microcapsular toners G03G9/093)} - G03G 9/0827: {characterised by their shape, e.g. degree of sphericity} - G03G 9/087: Binders for toner particles - G03G 9/08755: {Polyesters} - G03G 9/08782: {Waxes} - G03G 9/08788: {Block polymers} - G03G 9/09733: {Organic compounds (G03G9/08782 takes precedence)} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An electrostatic image developing toner includes a toner particle including a binder resin and a release agent. When a cross section of the toner particle is observed, the toner particle satisfies a condition (A1) below: Condition (A1): the toner particle includes one or more domains of the release agent, the one or more domains having a diameter equal to 8% or more and 30% or less of the maximum diameter of the toner particle, the one or more domains having a geometric center at a depth of R/2 or less below the surface of the toner particle, where R represents the distance between the geometric center of the toner particle and the surface of the toner particle, the one or more domains being entirely included in an inside portion of the toner particle which extends below a depth of 50 nm from the surface of the toner particle. ## Claims ### Claim 1 An electrostatic image developing toner comprising a toner particle including: a binder resin; and a release agent, wherein a cross section of the toner particle satisfies a condition (A1) below, Condition (A1): the toner particle includes one or more domains of the release agent, the one or more domains having a diameter equal to 8% or more and 30% or less of a maximum diameter of the toner particle, the one or more domains having a geometric center at a depth of R/2 or less below a surface of the toner particle, where R represents a distance between a geometric center of the toner particle and the surface of the toner particle, the one or more domains being entirely included in an inside portion of the toner particle, the inside portion extending below a depth of 50 nm from the surface of the toner particle, and wherein the release agent has a melting temperature of 65° C. or more and 75° C. or less. ### Claim 2 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the cross section of the toner particle satisfies a condition (A2) below, Condition (A2): the toner particle includes a plurality of domains of the release agent, the domains having a diameter equal to 8% or more and 30% or less of the maximum diameter of the toner particle, the domains having a geometric center at a depth of R/2 or less below the surface of the toner particle, where R represents a distance between the geometric center of the toner particle and the surface of the toner particle, the domains being entirely included in an inside portion of the toner particle, the inside portion extending below a depth of 50 nm from the surface of the toner particle. ### Claim 3 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the cross section of the toner particle satisfies a condition (B1) below, Condition (B1): the toner particle includes one or more domains of the release agent, the one or more domains having a diameter equal to 8% or more and 30% or less of the maximum diameter of the toner particle, the one or more domains having a geometric center at a depth of R/3 or less below the surface of the toner particle, where R represents a distance between the geometric center of the toner particle and the surface of the toner particle, the one or more domains being entirely included in an inside portion of the toner particle, the inside portion extending below a depth of 50 nm from the surface of the toner particle. ### Claim 4 (depends on 3) The electrostatic image developing toner according to claim 3, wherein the cross section of the toner particle satisfies a condition (B2) below, Condition (B2): the toner particle includes a plurality of domains of the release agent, the domains having a diameter equal to 8% or more and 30% or less of the maximum diameter of the toner particle, the domains having a geometric center at a depth of R/3 or less below the surface of the toner particle, where R represents a distance between the geometric center of the toner particle and the surface of the toner particle, the domains being entirely included in an inside portion of the toner particle, the inside portion extending below a depth of 50 nm from the surface of the toner particle. ### Claim 5 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the cross section of the toner particle satisfies a condition (C) below, Condition (C): the one or more domains of the release agent have a circularity of 0.92 or more and 1.00 or less. ### Claim 6 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the release agent having a melting temperature of 65° C. or more and 95° C. or less is an ester wax. ### Claim 7 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the binder resin included in the toner particle includes an amorphous resin, the amorphous resin including a polyester resin segment and a styrene acrylic resin segment. ### Claim 8 (depends on 7) The electrostatic image developing toner according to claim 7, wherein the binder resin included in the toner particle further includes a crystalline polyester resin. ### Claim 9 (depends on 1) The electrostatic image developing toner according to claim 1, wherein the electrostatic image developing toner comprises a plurality of the toner particles, and wherein a proportion of the plurality of toner particles to all toner particles in the electrostatic image developing toner is 30% by number or more. ### Claim 10 (depends on 9) The electrostatic image developing toner according to claim 9, wherein the proportion of the plurality of toner particles to all toner particles in the electrostatic image developing toner is 70% by number or more. ### Claim 11 (depends on 1) An electrostatic image developer comprising: the electrostatic image developing toner according to claim 1. ### Claim 12 (depends on 1) A toner cartridge detachably attachable to an image forming apparatus, the toner cartridge comprising: the electrostatic image developing toner according to claim 1.