# US 2021/0278780 A1 · Image forming apparatus to suppress unnecessary exposure of photoconductive body > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0278780 A1 - Document ID: US20210278780A1 - Status: Published application - Kind: A1 - Application number: 17/192,414 - Filed: 2021-03-04 - Published: 2021-09-09 - Earliest claimed: 2020-03-09 - Assignees: Brother Kogyo Kabushiki Kaisha - Applicants: Brother Kogyo Kabushiki Kaisha - Inventors: Sota YANAGIHARA; Yusuke IKEGAMI; Kotaro HARUTA; Shoichiro NISHIMURA - Web page: https://patentgrep.com/patent/US20210278780A1 ## CPC - G03G 15/043: with means for controlling illumination or exposure (G03G15/041 takes precedence) - G03G 15/04036: {Details of illuminating systems, e.g. lamps, reflectors (lamp housings for copying cameras, reflex exposure lighting G03B27/542)} - G03G 21/1666: {for the exposure unit} - G03G 21/1676: {for the developer unit} - G03G 21/1832: {Shielding members, shutter, e.g. light, heat shielding, prevention of toner scattering} - G03G 15/0896: {Arrangements or disposition of the complete developer unit or parts thereof not provided for by groups G03G15/08 - G03G15/0894} - G03G 2215/08: Details of powder developing device not concerning the development directly - G03G 2221/1609: protective arrangements for preventing damage - G03G 2221/1654: Locks and means for positioning or alignment - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An image forming apparatus includes a photoconductive body, a light source, a deflector to deflect a light beam from the light source, a scanning optical system to image the deflected light beam onto the photoconductive body, a developing unit to supply developer to the photoconductive body, an optical sensor to detect the deflected light beam, a moving mechanism to move the developing unit to a first position and to a second position, and a controller configured to start driving the deflector, when the developing unit is in the second position, the light source to emit the light beam, thereby obtaining a detection signal of the light beam from the optical sensor, and after obtaining the detection signal of the light beam from the optical sensor, control the moving mechanism to move the developing unit to the first position. ## Claims ### Claim 1 An image forming apparatus comprising: a photoconductive body; a light source configured to emit a light beam; a deflector configured to deflect the light beam emitted by the light source; a scanning optical system configured to image the light beam deflected by the deflector onto the photoconductive body; a developing unit including a developing roller configured to supply developer to the photoconductive body; an optical sensor configured to detect the light beam deflected by the deflector; a moving mechanism configured to move the developing unit to a first position where an optical path of the light beam from the scanning optical system to the photoconductive body is opened, and to a second position where the optical path is closed; and a controller configured to: start driving the deflector; when the developing unit is in the second position, cause the light source to emit the light beam, thereby obtaining a detection signal of the light beam from the optical sensor; and after obtaining the detection signal, control the moving mechanism to move the developing unit to the first position. ### Claim 2 (depends on 1) The image forming apparatus according to claim 1, wherein the developing roller is configured to: be in contact with the photoconductive body when the developing unit is in the first position; and be separated from the photoconductive body when the developing unit is in the second position. ### Claim 3 (depends on 1) The image forming apparatus according to claim 1, wherein the controller is further configured to, before starting driving the deflector, control the moving mechanism to move the developing unit to the second position. ### Claim 4 (depends on 1) The image forming apparatus according to claim 1, wherein the controller is further configured to, after obtaining the detection signal, control the light source to emit the light beam only within a particular range in a scanning direction in which the light beam is scanned by the deflector, the particular range including a range in which the optical sensor detects the light beam, the particular range being outside an exposure scanning range in which the photoconductive body is exposed to the light beam. ### Claim 5 (depends on 1) The image forming apparatus according to claim 1, further comprising a guide configured to guide the developing unit, wherein the developing unit is configured to move between the first position and the second position while being guided by the guide. ### Claim 6 (depends on 1) The image forming apparatus according to claim 1, wherein the developing unit is configured to move between the first position and the second position while rotating around a particular axis. ### Claim 7 (depends on 1) The image forming apparatus according to claim 1, further comprising a spring configured to press the developing unit toward the photoconductive body, wherein the moving mechanism is further configured to move the developing unit to the second position against a pressing force from the spring. ### Claim 8 (depends on 7) The image forming apparatus according to claim 7, wherein the moving mechanism comprises a cam, wherein the developing unit comprises a pressed member configured to be pressed by the cam, and wherein the moving mechanism is further configured to move the cam, thereby moving the developing unit to the second position against the pressing force from the spring. ### Claim 9 (depends on 1) The image forming apparatus according to claim 1, further comprising: a plurality of photoconductive bodies including the said photoconductive body; a plurality of light sources including the said light source; and a plurality of developing units including the said developing unit, wherein the deflector is further configured to deflect a plurality of light beams emitted by the plurality of light sources, respectively, wherein the scanning optical system is further configured to image the plurality of light beams deflected by the deflector onto the plurality of photoconductive bodies, respectively, and wherein the optical sensor is positioned to detect a particular light beam deflected by the deflector, the particular light beam being, after deflected by the deflector, imaged by the scanning optical system onto a particular one of the plurality of photoconductive bodies. ### Claim 10 (depends on 1) The image forming apparatus according to claim 1, further comprising: a sheet conveyor configured to convey a sheet; and a transfer device configured to transfer the developer on the photoconductive body onto the sheet, wherein the controller is further configured to, after starting conveying the sheet by the sheet conveyor, control the moving mechanism to move the developing unit from the second position to the first position, and cause the transfer device to transfer the developer onto the sheet being conveyed by the sheet conveyor. ### Claim 11 (depends on 1) The image forming apparatus according to claim 1, wherein the deflector includes a polygon mirror configured to rotate to deflect the light beam emitted by the light source, and wherein the controller is further configured to control the light source to emit the light beam after a rotational speed of the polygon mirror reaches a particular rotational speed for imaging the light beam onto the photoconductive body. ### Claim 12 An image forming apparatus comprising: a first photoconductive body; a second photoconductive body; a first light source configured to emit a first light beam; a second light source configured to emit a second light beam; a deflector configured to deflect the first light beam emitted by the first light source and the second light beam emitted by the second light source; a scanning optical system configured to image the first light beam deflected by the deflector onto the first photoconductive body, and image the second light beam deflected by the deflector onto the second photoconductive body; a first developing unit including a first developing roller configured to supply developer to the first photoconductive body; a second developing unit including a second developing roller configured to supply developer to the second photoconductive body; an optical sensor configured to detect the first light beam deflected by the deflector; a moving mechanism configured to move the second developing unit to a first position where an optical path of the first light beam from the scanning optical system to the first photoconductive body is opened, and to a second position where the optical path is closed; and a controller configured to: start driving the deflector; when the second developing unit is in the second position, cause the first light source to emit the first light beam, thereby obtaining a detection signal of the first light beam from the optical sensor; and after obtaining the detecting signal, control the moving mechanism to move the second developing unit to the first position. ### Claim 13 (depends on 12) The image forming apparatus according to claim 12, wherein the second developing roller is configured to: be in contact with the second photoconductive body when the second developing unit is in the first position; and be separated from the second photoconductive body when the second developing unit is in the second position. ### Claim 14 (depends on 12) The image forming apparatus according to claim 12, wherein the controller is further configured to, before starting driving the deflector, control the moving mechanism to move the second developing unit to the second position. ### Claim 15 (depends on 12) The image forming apparatus according to claim 12, wherein the controller is further configured to, after obtaining the detection signal, control the first light source to emit the first light beam only within a particular range in a scanning direction in which the first light beam is scanned by the deflector, the particular range including a range in which the optical sensor detects the first light beam, the particular range being outside an exposure scanning range in which the first photoconductive body is exposed to the first light beam. ### Claim 16 (depends on 12) The image forming apparatus according to claim 12, further comprising a guide configured to guide the second developing unit, wherein the second developing unit is configured to move between the first position and the second position while being guided by the guide.