# US 2023/0067291 A1 · Fixing device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0067291 A1 - Document ID: US20230067291A1 - Status: Published application - Kind: A1 - Application number: 17/948,693 - Filed: 2022-09-20 - Published: 2023-03-02 - Earliest claimed: 2021-08-25 - Assignees: Toshiba Tec Kabushiki Kaisha - Applicants: Toshiba Tec Kabushiki Kaisha - Inventors: Kousei MIYASHITA - Web page: https://patentgrep.com/patent/US20230067291A1 ## CPC - G03G 15/2053: {Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating} - G03G 15/2042: {specially for the axial heat partition} - G03G 2215/2035: the fixing nip having a stationary belt support member opposing a pressure member - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract A fixing device includes a cylinder, a heater, a contact body, and a soaking member. The heater has a first surface and an opposing second surface. The heater includes a heating element extending along a longitudinal direction of the heater. The first surface engages with an inner surface of the cylinder. The contact body is configured to engage with the inner surface of the cylinder. The contact body is configured to be heated at a first position along the longitudinal direction at a first temperature increase rate and at a second position along the longitudinal direction at a second temperature increase rate that is lower than the first temperature increase rate. The soaking member is positioned to engage with the opposing second surface of the heater. The soaking member has a second thermal capacity lower than a first thermal capacity at the respective second and first positions. ## Claims ### Claim 1 A fixing device comprising: a film-shaped cylinder configured to come into contact with a sheet and to rotate, the sheet moving in a first direction; a heater having a first surface and an opposing second surface, the heater including a heating element extending along a longitudinal direction of the heater that is perpendicular to the first direction, the first surface being configured to engage with an inner surface of the film-shaped cylinder; a contact body configured to engage with the inner surface of the film-shaped cylinder, the contact body configured to be heated (i) at a first position along the longitudinal direction at a first temperature increase rate and (ii) at a second position along the longitudinal direction at a second temperature increase rate that is lower than the first temperature increase rate; and a soaking member positioned to engage with the opposing second surface of the heater, the soaking member having a second thermal capacity per unit length at the second position along the longitudinal direction that is lower than a first thermal capacity per unit length at the first position along the longitudinal direction. ### Claim 2 (depends on 1) The fixing device of claim 1, wherein a second volume of the soaking member per unit length at the second position is lower than a first volume of the soaking member per unit length at the first position. ### Claim 3 (depends on 1) The fixing device of claim 1, wherein a second contact length between the soaking member and the heater at the second position is shorter than a first contact length between the soaking member and the heater at the first position. ### Claim 4 (depends on 1) The fixing device of claim 1, wherein the soaking member includes: a first portion that is present only at the first position, and a second portion that is adjacent to the first portion, is present at least at the second position, has a smaller contact area with the heater per unit length in the longitudinal direction than the first portion, is shorter than the first portion in the longitudinal direction, and comes into contact with the heater. ### Claim 5 (depends on 1) The fixing device of claim 1, wherein the heating element includes a plurality of heating elements disposed at intervals along the longitudinal direction. ### Claim 6 (depends on 1) The fixing device of claim 1, wherein the contact body includes a support member configured to support the heater and slide along the inner surface of the film-shaped cylinder, the support member including sliding ribs disposed at intervals along the longitudinal direction. ### Claim 7 (depends on 1) The fixing device of claim 1, wherein the contact body includes: a support member configured to support heater; and a guide member disposed opposite to the heater with respect to the support member, the guide member including a plurality of guide ribs disposed at intervals along the longitudinal direction that are configured to slide along the inner surface of the film-shaped cylinder. ### Claim 8 (depends on 1) The fixing device of claim 1, wherein the contact body includes a thermometer positioned to engage with the inner surface of the film-shaped cylinder to detect a temperature of the film-shaped cylinder. ### Claim 9 (depends on 1) The fixing device of claim 1, wherein the contact body includes a thermosensitive element positioned to engage with the soaking member at the second position to detect a temperature of the soaking member, the thermosensitive element including at least one of a thermometer or a thermostat. ### Claim 10 (depends on 1) The fixing device of claim 1, wherein the soaking member at least one of (i) includes a groove extending through the soaking member at the second position and having an opening toward the heater, or (ii) includes a through hole extending through the soaking member at the second position and having openings at sides of the soaking member that are perpendicular to the heater, or (iii) defines a notch adjacent the heater at the second position.