# US 11,442,376 B2 · Developing apparatus, process cartridge, 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 11,442,376 B2 - Document ID: US11442376B2 - Status: Granted - Kind: B2 - Application number: 17/469,042 - Filed: 2021-09-08 - Published: 2022-03-17 - Granted: 2022-09-13 - Earliest claimed: 2020-09-11 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Kazunari Hagiwara; Taichi Sato; Takahiro Kawamoto; Yasukazu Ikami; Shoko Funaki - Web page: https://patentgrep.com/patent/US11442376B2 ## CPC - G03G 15/0812: {characterised by the developer regulating means, e.g. structure of doctor blade} - G03G 9/09725: {Silicon-oxides; Silicates} - G03G 21/1814: {Details of parts of process cartridge, e.g. for charging, transfer, cleaning, developing (G03G21/1835 takes precedence)} - G03G 9/093: Encapsulated toner particles - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract A developer used in a developing apparatus equipped with a metal blade includes a toner base particle and external additives, the external additives including a silica particle with a particle diameter of 5 nm or more and 25 nm or less and an inorganic spacer particle with a particle diameter of 50 nm or more and 150 nm or less, and an area occupancy of the silica particle on a surface of the toner base particle is 40% or more. ## Claims ### Claim 1 A developing apparatus, comprising: a developing frame configured to store a developer; a developer bearing member rotatably supported by the developing frame and configured to bear the developer; and a regulation member including a metal blade, the metal blade having one end fixed to the developing frame and the other end arranged in contact with the developer bearing member, the regulation member regulating a thickness of the developer borne on the developer bearing member, wherein the developer includes a toner base particle and external additives, the external additives include a silica particle with a particle diameter of 5 nm or more and 25 nm or less, and an inorganic spacer particle with a particle diameter of 50 nm or more and 150 nm or less, and an area occupancy of the silica particle on a surface of the toner base particle is 40% or more. ### Claim 2 (depends on 1) The developing apparatus according to claim 1, wherein the other end of the metal blade is arranged to extend toward an upstream side in a rotation direction of the developer bearing member. ### Claim 3 (depends on 2) The developing apparatus according to claim 2, wherein, in a state in which the developer bearing member is not assembled and the regulation member is assembled in the developing frame, when looking along a rotation axis direction of the developer bearing member, and when the developer bearing member is imaginarily assembled into the developing frame, an intersection, at which a front edge surface at the other end of the metal blade intersects an abutment surface thereof abutting with the developer bearing member, is positioned within an imaginary outer diameter circumference of the developer bearing member, and is positioned in a first imaginary area which is located on one side of the first imaginary plane where the metal blade is present, when a first imaginary plane passing a rotation center of the developer bearing member and being parallel to the abutment surface is a reference. ### Claim 4 (depends on 3) The developing apparatus according to claim 3, wherein when the first imaginary plane and a second imaginary plane perpendicular to the first imaginary plane are references, the intersection is positioned on a downstream side of the second imaginary plane and on an upstream side of the first imaginary plane in the rotation direction of the developer bearing member, within the first imaginary area. ### Claim 5 (depends on 3) The developing apparatus according to claim 3, wherein when the first imaginary plane and a second imaginary plane perpendicular to the first imaginary plane are references, the intersection is positioned on an upstream side of the second imaginary plane and on a downstream side of the first imaginary plane in the rotation direction of the developer bearing member, within the first imaginary area. ### Claim 6 (depends on 1) The developing apparatus according to claim 1, wherein a bias, with the same polarity as a regular charging polarity of the developer, relative to the developer bearing member, is applied to the metal blade. ### Claim 7 (depends on 1) The developing apparatus to claim 1, wherein a charging polarity of the inorganic spacer particle is the same as the regular charging polarity of the developer. ### Claim 8 (depends on 1) The developing apparatus according to claim 1, wherein the silica particle is fixed to the surface of the toner base particle. ### Claim 9 (depends on 1) The developing apparatus according to claim 1, wherein the inorganic spacer particle is another silica particle. ### Claim 10 (depends on 1) The developing apparatus according to claim 1, wherein the particle diameter of the inorganic spacer particle is 80 nm or more and 150 nm or less, and the area occupancy of the silica particle on the surface of the toner base particle is 45% or more. ### Claim 11 (depends on 10) The developing apparatus according to claim 10, wherein the area occupancy of the silica particle on the surface of the toner base particle is 75% or less. ### Claim 12 (depends on 1) A process cartridge comprising: the developing apparatus according to claim 1, and an image bearing member configured to bear a developer image, the process cartridge being removably attachable to an image forming apparatus. ### Claim 13 (depends on 12) An image forming apparatus comprising: the process cartridge according to claim 12; and a transfer member. ### Claim 14 (depends on 1) An image forming apparatus comprising: the developing apparatus according to claim 1; and a transfer member.