Image forming apparatus

An image forming apparatus comprising:

• a plurality of photosensitive members;
• a scanner unit configured to scan said photosensitive members with laser beams in accordance with image information, wherein said scanner unit includes light sources corresponding to said photosensitive members, respectively, a rotatable polygonal mirror configured to reflect and deflect the laser beams emitted from said light sources, and a plurality of reflecting members configured to reflect the laser beams, respectively, reflected by said rotatable polygonal mirror;
• a fixing unit configured to fix, on a recording material, toner images formed on said photosensitive members and then superposed on the recording material, and
• a discharge tray configured to receive the recording material on which the images are formed and which is discharged from an inside of said image forming apparatus,
• wherein said scanner unit is provided between said plurality of photosensitive members and said discharge tray with respect to a vertical direction,
• wherein selected ones of the laser beams emitted from said light sources are reflected by said rotatable polygonal mirror toward a side where said fixing unit is provided, and remaining ones of the laser beams are reflected by said rotatable polygonal mirror toward a side opposite from the side where said fixing unit is provided,
• wherein as seen in an axial direction of said photosensitive members, of the selected ones of the laser beams reflected by said rotatable polygonal mirror toward the side where said fixing unit is provided, the laser beam reflected toward a first reflecting member provided at a position remotest from said rotatable polygonal mirror among the plurality of reflecting members travels downward relative to an arrangement direction of said photosensitive members,
• wherein a rotational axis of said rotatable polygonal mirror is inclined relative to a direction perpendicular to the arrangement direction of said photosensitive members,
• wherein as seen in an axial direction of said photosensitive members, of the remaining ones of the laser beams, the laser beam reflected toward a second reflecting member provided at a position remotest from said rotatable polygonal mirror among the plurality of reflecting members travels upward relative to the arrangement direction of said photosensitive members, and
• wherein an optical path length from said rotatable polygonal mirror to said first reflecting member is longer than an optical path length from said rotatable polygonal mirror to said second reflecting member.