Optical scanning device and image forming apparatus

An optical scanning device comprising:

• a light source for emitting a laser beam;
• a deflection body for deflecting by reflection of the laser beam emitted from the light source;
• a scanning lens for scanning the laser beam deflected by the deflection body on a surface of a photosensitive body at a constant speed in a main-scanning direction;
• a reflection body having a surface including a reflection surface for reflecting the laser beam deflected towards the outside of the photosensitive body and having passed through the scanning lens, a first region that is arranged at an opposite side in a direction of travel of the laser beam along the main-scanning direction with respect to the reflection surface, and a second region that is arranged at a lower side with respect to the reflection surface;
• and
• a synchronizing sensor for receiving the laser beam reflected by the reflection surface to send out a detection signal of the receipt of the laser beam,
• wherein the reflection surface is composed of a curved arc surface depressed from both edges towards a center in the main-scanning direction,
• the reflection body is configured such that a center of the reflection surface in the main-scanning direction is provided at a position displaced by a predetermined range in a direction of travel of the laser beam along the main-scanning direction from a center of the reflection body in the main-scanning direction, and
• an installation space is arranged on the first region and the second region for attaching the reflection body to the optical scanning device.