Image-forming device

Abstract

An image-forming device has a plurality of cylindrical image-carrying members, and an optical scanning unit. The plurality of cylindrical image-carrying members is provided in a main casing for rotating about respective rotational axes. The rotational axes are parallel to one another and juxtaposed in a single direction. The optical scanning unit is provided in the main casing and has a plurality of laser generators, a single rotatable polygon mirror, a plurality of mirrors, and a plurality of lenses. The plurality of laser generators is provided one-to-one relationship to the plurality of image-carrying members to emit respective laser beams. The single rotatable polygon mirror deflects the respective laser beams to scan the respective image-carrying members therewith. The plurality of mirrors is provided one-to-one relationship to the plurality of image-carrying members to guide the respective laser beams along respective optical paths to the respective image-carrying members. The plurality of lenses is provided one-to-one relationship to the plurality of image-carrying members and provided in the respective optical paths and between the respective mirrors and the respective image-carrying members. Distances from the respective mirrors to the respective image-carrying members being equal to one another.

1 . An image-forming device comprising:
 a main casing;   a plurality of image-carrying members, provided in the main casing, for rotating about respective rotational axes, and juxtaposed in a sheet conveying direction; and   an optical scanning unit provided in the main casing comprising:   a plurality of laser generators provided one-to-one relationship to the plurality of image-carrying members to emit respective laser beams;   an optical deflector that deflects the respective laser beams to scan the respective image-carrying members therewith;   a plurality of mirrors, each of the plurality of mirrors corresponding to one of the plurality of image-carrying members to guide the respective laser beams along respective optical paths to the respective image-carrying members, each of the plurality of mirrors including a mirror member arranged along the respective optical paths to the respective image-carrying members and closest to the respective image-carrying members; and   a plurality of lenses, each of the plurality of lenses corresponding to one of the plurality of image-carrying members, and each lens of the plurality of lenses being provided in the respective optical path of the corresponding image-carrying members, and between the respective mirrors and the respective image-carrying members, wherein   distances from the respective mirror members and the respective image-carrying members are equal to one another, and wherein   the optical seaming unit comprises a plurality of adjusting mechanisms having a one-to-one relationship to the plurality of mirrors for adjusting orientations of the respective mirror members.   
     
     
         2 . The image-forming device according to  claim 1 , wherein the optical scanning unit has a casing accommodating the plurality of the laser generators, the optical deflector, the plurality of mirrors, and the plurality of lenses, and the optical deflector is single and positioned in a center portion of the casing. 
     
     
         3 . The image-forming device according to  claim 1 , further comprising:
 a plurality of developing units, each of the plurality of developing units corresponding to one of the plurality of image-carrying members, to develop a scanned image on the respective image-carrying members and to transfer a developed image to a recording medium; and   a fixing unit that fixes the transferred developed image to the recording medium, wherein   the casing has a plurality of apertures and each aperture corresponds to one of the plurality of image-carrying members, and wherein   the apertures allow the respective laser beams to pass to the respective image-carrying members therethrough, and each of the plurality of apertures is provided on an opposite side of the fixing unit with respect to a corresponding image-carrying member.   
     
     
         4 . The image-forming device according to  claim 3 , further comprising a cooling unit provided between the fixing unit and the optical scanning unit for cooling the fixing unit. 
     
     
         5 . The image-forming device according to  claim 3 , wherein
 the plurality of developing units supply developer of different colors to the respective image-carrying members, and each of the developing units is positioned on the opposite side of the fixing unit with respect to the corresponding image-carrying member.   
     
     
         6 . The image-forming device according to  claim 2 , further comprising a discharge tray provided in an upper surface of the main casing for receiving a recording medium after an image has been formed thereon, wherein
 the casing has a nonuniform height along a single direction.   
     
     
         7 . The image-forming device according to  claim 1 , wherein the plurality of image-carrying members is attachable to and detachable from the main casing and is movable integrally in the sheet conveying direction. 
     
     
         8 . The image-forming device according to  claim 1 , wherein each of the plurality of adjusting mechanisms is positioned on one end of the respective mirror members. 
     
     
         9 . The image-forming device according to  claim 8 , wherein each of the plurality of adjusting mechanisms comprises:
 an adjusting bar member which is inclined relative to a reflective surface of the respective mirror members; and   a position changing member for moving the adjusting bar member to adjust orientations of the respective mirror members.   
     
     
         10 . The image-forming device according to  claim 1 , wherein each of the plurality of lenses corrects a face tangle error. 
     
     
         11 . An image-forming device comprising:
 a main casing;   a plurality of image-carrying members juxtaposed in a sheet conveying direction in the main casing, each of the plurality of image-carrying members rotating about a rotational axis; and   an optical scanning unit provided in the main casing, the optical scanning unit comprising:
 a plurality of laser generators provided one-to-one relationship to the plurality of image-carrying members to emit a laser beam, respectively; 
 an optical deflector that deflects the laser beams from the laser generators; and 
 a plurality of optical systems provided one-to-one relationship to the plurality of laser generators, each of the plurality of optical systems guiding the deflected laser beam to a corresponding image-carrying member, each of the plurality of optical systems including
 a mirror that reflects the deflected laser beam to the corresponding image-carrying member, the mirror being arranged closest to the image-carrying member; 
 an adjusting mechanism that adjusts an orientation of the mirror; and 
 a lens provided between the mirror and the corresponding image-carrying member to guide the reflected laser beam thereon, wherein a distance between the mirror and the image-carrying member is identical to a distance of a mirror and an image-carrying member in an adjacent optical system. 
 
   
     
     
         12 . The image-forming device according to  claim 11 , wherein the optical scanning unit has a casing accommodating the plurality of the laser generators, the optical deflector, the plurality of optical systems, and the optical deflector is single and positioned in a center portion of the casing. 
     
     
         13 . The image-forming device according to  claim 11 , further comprising:
 a plurality of developing unit, each of the plurality of developing units corresponding to one of the plurality of image-carrying members, to develop a scanned image on the respective image-carrying members and to transfer a developed image to a recording medium; and   a fixing unit that fixes the transferred developed image to the recording medium, wherein   the casing has a plurality of apertures and each aperture corresponds to one of the plurality of image-carrying members, and wherein   the apertures allow the respective laser beams to pass to the respective image-carrying members therethrough, and each of the plurality of apertures is provided on an opposite side of the fixing unit with respect to a corresponding image-carrying member.   
     
     
         14 . The image-forming device according to  claim 13 , further comprising a cooling unit provided between the fixing unit and the optical scanning unit for cooling the fixing unit. 
     
     
         15 . The image-forming device according to  claim 13 , wherein
 the plurality of developing units supply developer of different colors to the respective image-carrying members, and each of the developing units is positioned on the opposite side of the fixing unit with respect to the corresponding image-carrying member.   
     
     
         16 . The image-forming device according to  claim 12 , further comprising a discharge tray provided in an upper surface of the main casing for receiving a recording medium after an image has been formed thereon, wherein
 the casing has a nonuniform height along a single direction.   
     
     
         17 . The image-forming device according to  claim 11 , wherein the plurality of image-carrying members is attachable to and detachable from the main, casing and is movable integrally in the sheet conveying direction. 
     
     
         18 . The image-forming device according to  claim 11 , wherein the adjusting mechanism is positioned on one end of the mirror. 
     
     
         19 . The image-forming device according to  claim 18 , wherein the adjusting mechanism comprises:
 an adjusting bar member which is inclined relative to a reflective surface of the mirror; and   a position changing member for moving the adjusting bar member to change a positional relationship of the reflecting mirror to the optical deflector.