Optical scanning device and image forming apparatus including the same

An optical scanning device comprising:

• a light source unit having a light emitting module that emits a laser beam;
• a collimator lens that collimates the laser beam emitted from the light source unit into a parallel light beam;
• a polygon mirror that rotates about a rotation axis extending along a top-bottom direction to reflect the laser beam emitted from the light source unit to scan a circumferential surface of an image carrying member in a main scanning direction;
• and
• an accommodating portion that houses the light source unit, the collimator lens, and the polygon mirror,
• wherein
• the accommodating portion has:
• a bottom wall part that stretches in a direction crossing the rotation axis of the polygon mirror;
• and
• a circumferential wall part that protrudes from a circumferential part of the bottom wall part and that surrounds, from radially outside, the collimator lens and the polygon mirror,
• the light emitting module includes:
• a laser diode that has a plurality of light emitting points that emit the laser beam;
• and
• a bracket that has a holding hole that holds the laser diode,
• the bracket is fixed to an outer circumferential surface of the circumferential wall part with the laser diode inserted in a light entrance hole formed in the circumferential wall part,
• the circumferential wall part has:
• a protruding part that protrudes from a circumferential part of the light entrance hole toward the bracket,
• the bracket has:
• a recessed part recessed from a circumferential part of the holding hole in a direction away from the circumferential wall part with the protruding part disposed in the recessed part receiving, and
• a space formed between the bracket and the circumferential wall part bends in a direction opposite to an emission direction of the laser beam between the recessed part and the protruding part.