# US 12,216,421 B2 · 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 12,216,421 B2 - Document ID: US12216421B2 - Status: Granted - Kind: B2 - Application number: 18/376,577 - Filed: 2023-10-04 - Published: 2024-05-16 - Granted: 2025-02-04 - Earliest claimed: 2022-11-11 - Assignees: Konica Minolta, Inc. - Applicants: Konica Minolta, Inc. - Inventors: Taizou Oonishi; Yu Harashima; Masashi Saito; Kazunori Nishinoue; Tsutomu Sakamaki - Web page: https://patentgrep.com/patent/US12216421B2 ## CPC - G03G 15/205: {specially for the mode of operation, e.g. standby, warming-up, error (G03G15/2046 takes precedence)} - G03G 15/20: for fixing, e.g. by using heat - G03G 15/2032: {Retractable heating or pressure unit} - G03G 2215/00455: Continuous web, i.e. roll - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An image forming apparatus including: an image former that forms an image on a recording material; includes a fixer that has a first fixing member having an elastic layer, a second fixing member that forms a fixing nip with the first fixing member, and an external heater that heats the first fixing member from outside, and fixes the image on the recording material by heating and pressing the conveyed recording material at the fixing nip; and a hardware processor that executes a thermal expansion mode, in which in the thermal expansion mode, the hardware processor causes the external heater to heat the first fixing member to a temperature higher than a temperature during normal printing. ## Claims ### Claim 1 An image forming apparatus comprising: an image former that forms an image on a recording material; a fixer comprising a first fixing member having an elastic layer, a second fixing member that forms a fixing nip with the first fixing member, and an external heater that heats the first fixing member from outside, the second fixing member having a second heater for heating the second fixing member to a temperature during normal printing such that the fixer fixes the image on the recording material by heating and pressing the conveyed recording material at the fixing nip; and a hardware processor that executes a thermal expansion mode, wherein in the thermal expansion mode, the hardware processor causes the external heater to heat the first fixing member to a temperature higher than the temperature during normal printing, and wherein the thermal expansion mode is executable during printing. ### Claim 2 (depends on 1) The image forming apparatus according to claim 1, wherein the hardware processor determines, based on a predetermined condition set in advance, whether or not the execution of the thermal expansion mode is possible. ### Claim 3 (depends on 2) The image forming apparatus according to claim 2, wherein the hardware processor determines, based on a printing condition as the predetermined condition, whether or not the execution of the thermal expansion mode is possible. ### Claim 4 (depends on 1) The image forming apparatus according to claim 1, wherein the hardware processor receives an instruction from a user, and the hardware processor executes the thermal expansion mode upon receiving an execution instruction. ### Claim 5 (depends on 1) The image forming apparatus according to claim 1, further comprising a first detector that detects a state of the image on the recording material after the fixing or detects a conveyance state of the recording material on a downstream side of the fixer, wherein the hardware processor executes the thermal expansion mode according to a result of the detection by the first detector. ### Claim 6 (depends on 1) The image forming apparatus according to claim 1, further comprising a second detector that detects a state of the first fixing member, wherein the hardware processor detects a state of the first fixing member, and the hardware processor executes the thermal expansion mode according to a result of the detection by the second detector. ### Claim 7 (depends on 6) The image forming apparatus according to claim 6, wherein the hardware processor ends the thermal expansion mode being executed according to the result of the detection by the second detector. ### Claim 8 (depends on 1) The image forming apparatus according to claim 1, wherein the hardware processor determines, based on a type of a failure of conveyance of the recording medium or a frequency of a failure of conveyance of the recording medium, whether or not the execution of the thermal expansion mode is possible. ### Claim 9 (depends on 1) The image forming apparatus according to claim 1, wherein the external heater is a rotating body in which a heating source is disposed and which rotates while being in pressure contact with an outer peripheral surface of the first fixing member, the image forming apparatus further comprises a pressure setting mechanism that changes a pressure contact force of the external heater to the first fixing member, and the hardware processor sets the pressure contact force to a pressure higher than a pressure during normal printing when the thermal expansion mode is executed. ### Claim 10 (depends on 1) The image forming apparatus according to claim 1, further comprising a pressure contact releasing mechanism that separates the first fixing member and the second fixing member from each other by moving at least one of the first fixing member and the second fixing member, wherein the hardware processor causes the pressure contact releasing mechanism to separate the first fixing member and the second fixing member from each other when the thermal expansion mode is executed. ### Claim 11 (depends on 1) The image forming apparatus according to claim 1, wherein in the thermal expansion mode, the hardware processor sets a rotation speed of the first fixing member to a rotation speed higher than a rotation speed during normal printing. ### Claim 12 (depends on 1) The image forming apparatus according to claim 1, wherein the recording material is a continuous sheet. ### Claim 13 (depends on 1) The image forming apparatus according to claim 1, wherein the thermal expansion mode is executed during printing.