Multi-beam scanning device

A multi-beam scanning device, comprising:

• a light source that emits a plurality of light beams;
• a polygonal mirror that deflects the light beams emitted by said light source to scan;
• and
• an optical system that converges the deflected light beams on a plurality of objects to be scanned,
• said optical system including a plurality of fθ lenses and an optical path turning system that turns optical paths of the deflected light beams, respectively, said plurality of fθ lenses including at least a first fθ lens, a second fθ lens and a plurality of third fθ lenses, all the light beams deflected by said polygonal mirror passing through said first and second fθ lenses, each of the plurality of light beams passing through said first and second fθ lenses passing through a respective one of said plurality of third fθ lenses;
• said optical path turning system being configured such that optical path lengths of the optical paths of the deflected light beams are the same,
• said plurality of objects being arranged on one side of said polygonal mirror,
• said plurality of objects located at different distances from said polygonal mirror, respectively,
• one of said plurality of optical paths directed to an object located closest to said polygonal mirror includes a portion passing between said polygonal mirror and said first fθ lens.