Optical scanning device and image forming device

An image forming device comprising:

• a plurality of image carriers including first and second image carriers;
• and
• an optical scanning device that individually scans a plurality of the image carriers using respective light beams modulated based on image information,
• wherein the optical scanning device comprises:
• a light source including a first light emitting portion that outputs a first light beam and a second light emitting portion that outputs a second light beam;
• an optical deflector that deflects a plurality of light beams from the light source;
• and
• a scanning optical system that includes an optical splitter that splits incident light into transmitted light and reflected light and individually guides each of the first and second light beams deflected by the optical deflector to corresponding one of the image carriers,
• wherein the first and second light beams are incident to the optical splitter such that principal rays of the first and second light beams that are incident to the optical splitter are nonparallel to each other in a plane orthogonal to a main-scanning direction, and
• the transmitted light of the first light beam from the optical splitter is guided to the first image carrier, the reflected light of the second light beam from the optical splitter is guided to the second image carrier, and the transmitted light of the second light beam from the optical splitter and the reflected light of the first light beam from the optical splitter reach none of the image carriers.