# US 10,481,516 B2 · Charging member, charging device, 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 10,481,516 B2 - Document ID: US10481516B2 - Status: Granted - Kind: B2 - Application number: 16/105,317 - Filed: 2018-08-20 - Published: 2019-09-26 - Granted: 2019-11-19 - Earliest claimed: 2018-03-20 - Assignees: Fuji Xerox Co., Ltd. - Applicants: Fuji Xerox Co., Ltd. - Inventors: Yasuhiko Kinuta; Yuki Tagawa - Web page: https://patentgrep.com/patent/US10481516B2 ## CPC - G03G 15/0233: {Structure, details of the charging member, e.g. chemical composition, surface properties} - G03G 21/1814: {Details of parts of process cartridge, e.g. for charging, transfer, cleaning, developing (G03G21/1835 takes precedence)} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract A charging member includes: a cylindrical or columnar conductive base material; and an elastic portion provided on the conductive base material, in which Re and Rc satisfy Re>Rc, where Re is an outer diameter of a charging member at a position of 5 mm from an axial end portion of an elastic portion, and Rc is the maximum value of an outer diameter of the charging member at an axial center of the elastic portion, and a cylindrical or columnar charging member has a value of Ac/Aa of 1.0 or less, in which Ac is the maximum amplitude value in a periodic region from 1.5 mm to 6 mm in a case of periodically analyzing a surface shape of the charging member in a circumferential direction, and Aa is the maximum amplitude value in a periodic region from 1.5 mm to 6 mm in a case of periodically analyzing a surface shape of the charging member in an axial direction. ## Claims ### Claim 1 A charging member comprising: a cylindrical or columnar conductive base material; and an elastic portion provided on the conductive base material, wherein a value of an outer diameter of the charging member at a position of 5 mm from an axial end portion of the elastic portion is greater than a maximum value of an outer diameter of the charging member at an axial center of the elastic portion. ### Claim 2 (depends on 1) The charging member according to claim 1, wherein in a case of periodically analyzing a surface shape of the elastic portion in a circumferential direction, a value of a maximum amplitude value at an axial center of the elastic portion in a periodic region from 1.5 mm to 6 mm, is 0.4 μm or more. ### Claim 3 (depends on 2) The charging member according to claim 2, wherein the value of the maximum amplitude value at the axial center of the elastic portion in the periodic region from 1.5 mm to 6 mm, is from 0.4 μm to 1.0 μm. ### Claim 4 (depends on 1) The charging member according to claim 1, wherein in a case of periodically analyzing a surface shape of the elastic portion in a circumferential direction, a value of a ratio of a maximum amplitude value at a position of 5 mm from an axial end portion of the elastic portion in a periodic region from 1.5 mm to 6 mm and a maximum amplitude value at an axial center of the elastic portion in the periodic region from 1.5 mm to 6 mm, is 1.0 or less. ### Claim 5 (depends on 4) The charging member according to claim 4, wherein the value of the ratio of the maximum amplitude value at the position of 5 mm from the axial end portion of the elastic portion in the periodic region from 1.5 mm to 6 mm and the maximum amplitude value at the axial center of the elastic portion in the periodic region from 1.5 mm to 6 mm, is 0.8 or less. ### Claim 6 (depends on 1) The charging member according to claim 1, wherein in a case of periodically analyzing a surface shape of the elastic portion in a circumferential direction, a value of a maximum amplitude value at a position of 5 mm from an axial end portion of the elastic portion in a periodic region from 1.5 mm to 6 mm, is from 0.4 μm to 0.8 μm. ### Claim 7 (depends on 6) The charging member according to claim 6, wherein the value of the maximum amplitude value at the position of 5 mm from the axial end portion of the elastic portion in the periodic region from 1.5 mm to 6 mm, is from 0.4 μm to 0.7 μm. ### Claim 8 (depends on 1) The charging member according to claim 1, wherein a difference between the value of the outer diameter of the charging member at the position of 5 mm from the axial end portion of the elastic portion and the value of the maximum value of the outer diameter of the charging member at the axial center of the elastic portion is from 0.05 mm to 0.5 mm. ### Claim 9 (depends on 8) The charging member according to claim 8, wherein the difference between the value of the outer diameter of the charging member at the position of 5 mm from the axial end portion of the elastic portion and the value of the maximum value of the outer diameter of the charging member at the axial center of the elastic portion is from 0.25 mm to 0.5 mm. ### Claim 10 (depends on 1) A charging device comprising the charging member according to claim 1. ### Claim 11 (depends on 1) A process cartridge, comprising: an image holding member; and a charging device configured to charge a surface of the image holding member, wherein the charging device includes the charging member according to claim 1, the charging member being disposed in contact with the surface of the image holding member, and wherein the process cartridge is detachable from an image forming apparatus. ### Claim 12 (depends on 1) An image forming apparatus, comprising: an image holding member; a charging device configured to charge a surface of the image holding member, wherein the charging device includes the charging member according to claim 1, the charging member being disposed in contact with the surface of the image holding member; an exposing device configured to expose the surface of the charged image holding member to form a latent image; a developing device configured to develop the latent image, which has been formed on the surface of the image holding member, with a toner to form a toner image; and a transferring device configured to transfer the toner image, which has been formed on the surface of the image holding member, onto a recording medium. ### Claim 13 A cylindrical or columnar charging member, wherein a ratio of a value of a maximum amplitude value in a periodic region from 1.5 mm to 6 mm in a case of periodically analyzing a surface shape of the charging member in a circumferential direction and a maximum amplitude value in the periodic region from 1.5 mm to 6 mm in a case of periodically analyzing a surface shape of the charging member in an axial direction, is 1.0 or less. ### Claim 14 (depends on 13) The charging member according to claim 13, wherein the ratio of the value of the maximum amplitude value in the periodic region from 1.5 mm to 6 mm in the case of periodically analyzing the surface shape of the charging member in the circumferential direction and the maximum amplitude value in the periodic region from 1.5 mm to 6 mm in the case of periodically analyzing the surface shape of the charging member in the axial direction, is 0.8 or less. ### Claim 15 (depends on 14) The charging member according to claim 14, wherein the ratio of the value of the maximum amplitude value in the periodic region from 1.5 mm to 6 mm in the case of periodically analyzing the surface shape of the charging member in the circumferential direction and the maximum amplitude value in the periodic region from 1.5 mm to 6 mm in the case of periodically analyzing the surface shape of the charging member in the axial direction, is 0.7 or less. ### Claim 16 (depends on 13) The charging member according to claim 13, wherein a value of the maximum amplitude value in the periodic region from 1.5 mm to 6 mm in the case of periodically analyzing the surface shape of the charging member in the circumferential direction, is from 0.2 μm to 1.0 μm. ### Claim 17 (depends on 16) The charging member according to claim 16, wherein the value of the maximum amplitude value in the periodic region from 1.5 mm to 6 mm in the case of periodically analyzing the surface shape of the charging member in the circumferential direction, is from 0.4 μm to 0.8 μm. ### Claim 18 (depends on 13) The charging member according to claim 13, wherein a value of the maximum amplitude value in the periodic region from 1.5 mm to 6 mm in the case of periodically analyzing the surface shape of the charging member in the axial direction, is from 0.3 μm to 1.1 μm. ### Claim 19 (depends on 18) The charging member according to claim 18, wherein the value of the maximum amplitude value in the periodic region from 1.5 mm to 6 mm in the case of periodically analyzing the surface shape of the charging member in the axial direction, is from 0.7 μm to 1.0 μm. ### Claim 20 (depends on 13) A charging device comprising the charging member according to claim 13. ### Claim 21 (depends on 13) A process cartridge, comprising: an image holding member; and a charging device configured to charge a surface of the image holding member, wherein the charging device includes the charging member according to claim 13, the charging member being disposed in contact with the surface of the image holding member, and wherein the process cartridge is detachable from an image forming apparatus. ### Claim 22 (depends on 13) An image forming apparatus, comprising: an image holding member; a charging device configured to charge a surface of the image holding member, wherein the charging device includes the charging member according to claim 13, the charging member being disposed in contact with the surface of the image holding member; an exposing device configured to expose the surface of the charged image holding member to form a latent image; a developing device configured to develop the latent image, which has been formed on the surface of the image holding member, with a toner to form a toner image; and a transferring device configured to transfer the toner image, which has been formed on the surface of the image holding member, onto a recording medium.