# US 10,871,736 B2 · Fixing device 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 10,871,736 B2 - Document ID: US10871736B2 - Status: Granted - Kind: B2 - Application number: 16/715,348 - Filed: 2019-12-16 - Published: 2020-08-06 - Granted: 2020-12-22 - Earliest claimed: 2019-01-31 - Assignees: Ricoh Company, Ltd. - Applicants: Daisuke Inoue; Tomoya Adachi; Yuusuke Furuichi - Inventors: Daisuke Inoue; Tomoya Adachi; Yuusuke Furuichi - Web page: https://patentgrep.com/patent/US10871736B2 ## CPC - G03G 15/2053: {Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating} - G03G 15/0189: {primary transfer to an intermediate transfer belt (G03G15/0184 takes precedence)} - G03G 15/2017: {Structural details of the fixing unit in general, e.g. cooling means, heat shielding means (G03G15/2053 takes precedence)} - G03G 15/657: {Feeding path after the transfer point and up to the fixing point, e.g. guides and feeding means for handling copy material carrying an unfused toner image} - G03G 15/2028: {with means for handling the copy material in the fixing nip, e.g. introduction guides, stripping means} - 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 an endless belt that rotates and a pressure rotator that rotates and presses against the endless belt to form a fixing nip between the endless belt and the pressure rotator, through which a recording medium bearing an image is conveyed. A heater is disposed inside a loop formed by the endless belt. The heater heats the endless belt. A conductor is disposed upstream from the pressure rotator in a recording medium conveyance direction and grounded. The conductor contacts and detects the recording medium. ## Claims ### Claim 1 A fixing device comprising: an endless belt configured to rotate; a pressure rotator configured to rotate and press against the endless belt to form a fixing nip between the endless belt and the pressure rotator, the fixing nip through which a recording medium bearing an image is conveyed; a heater disposed inside a loop formed by the endless belt, the heater configured to heat the endless belt; and a conductor disposed upstream from the pressure rotator in a recording medium conveyance direction and grounded, the conductor configured to contact the recording medium, ground the recording medium, and detect contact with the recording medium. ### Claim 2 (depends on 1) The fixing device according to claim 1, further comprising a resistance through which the conductor is grounded. ### Claim 3 (depends on 1) The fixing device according to claim 1, further comprising a capacitance element through which the conductor is grounded. ### Claim 4 (depends on 3) The fixing device according to claim 3, wherein the capacitance element includes a capacitor. ### Claim 5 (depends on 1) The fixing device according to claim 1, wherein the conductor is disposed within a conveyance span in an axial direction of the endless belt, the conveyance span where the recording medium having a minimum width of a plurality of widths of recording media is conveyed through the fixing device. ### Claim 6 (depends on 1) The fixing device according to claim 1, further comprising: a harness; and a fastener configured to fasten the harness to the conductor, wherein the conductor is grounded through the harness. ### Claim 7 (depends on 6) The fixing device according to claim 6, wherein the fastener includes a screw. ### Claim 8 (depends on 1) The fixing device according to claim 1, wherein the conductor contacts a back face of the recording medium, the back face being opposite a fixing face of the recording medium, the fixing face that bears the image to be fixed. ### Claim 9 (depends on 1) The fixing device according to claim 1, wherein the conductor includes a guide face configured to guide the recording medium to the fixing nip. ### Claim 10 (depends on 1) The fixing device according to claim 1, wherein the conductor includes a feeler. ### Claim 11 (depends on 1) The fixing device according to claim 1, wherein the conductor is disposed opposite substantially a center of the endless belt in an axial direction of the endless belt. ### Claim 12 An image forming apparatus comprising: an endless belt configured to rotate; a pressure rotator configured to rotate and press against the endless belt to form a fixing nip between the endless belt and the pressure rotator, the fixing nip through which a recording medium bearing an image is conveyed; a heater disposed inside a loop formed by the endless belt, the heater configured to heat the endless belt; a conductor disposed upstream from the pressure rotator in a recording medium conveyance direction and grounded, the conductor configured to contact and detect the recording medium; and a controller operatively connected to the conductor, the controller configured to change a rotation speed at which the pressure rotator rotates to convey the recording medium if the conductor does not detect that the recording medium contacts the conductor. ### Claim 13 (depends on 12) The image forming apparatus according to claim 12, wherein the controller controls the pressure rotator to rotate at an increased rotation speed when the recording medium is separated from the conductor. ### Claim 14 An image forming apparatus comprising: an image bearer configured to bear an image; and a fixing device configured to fix the image on a recording medium, the fixing device including: an endless belt configured to rotate; a pressure rotator configured to rotate and press against the endless belt to form a fixing nip between the endless belt and the pressure rotator, the fixing nip through which the recording medium bearing the image is conveyed; a heater disposed inside a loop formed by the endless belt, the heater configured to heat the endless belt; and a conductor disposed upstream from the pressure rotator in a recording medium conveyance direction and grounded, the conductor configured to contact the recording medium, ground the recording medium, and detect contact with the recording medium. ### Claim 15 (depends on 14) The image forming apparatus according to claim 14, further comprising an image transferor configured to transfer the image onto the recording medium and convey the recording medium downstream in the recording medium conveyance direction. ### Claim 16 (depends on 15) The image forming apparatus according to claim 15, further comprising a controller operatively connected to the conductor, the controller configured to change a conveyance speed at which the image transferor conveys the recording medium if the conductor does not detect that the recording medium contacts the conductor. ### Claim 17 (depends on 16) The image forming apparatus according to claim 16, wherein the image transferor includes a driving roller configured to rotate. ### Claim 18 (depends on 17) The image forming apparatus according to claim 17, wherein the controller controls the driving roller to rotate at an increased rotation speed when the recording medium is separated from the conductor. ### Claim 19 (depends on 14) The fixing device according to claim 14, wherein the conductor comprises a flat spring grounded through a wire. ### Claim 20 (depends on 14) The image forming apparatus according to claim 14, further comprising a controller operatively connected to the conductor, the controller configured to change a rotation speed at which the pressure rotator rotates to convey the recording medium if the conductor does not detect that the recording medium contacts the conductor.