Beam deflector, light scanning unit and image forming apparatus having the same

An image forming apparatus, comprising:

• a light source;
• an image forming unit comprising a photosensitive body to form an image on a printing medium;
• and
• a beam deflector comprising:
• a base;
• a polygon mirror to reflect a light beam emitted from the light source toward the photosensitive body;
• a mirror driving unit comprising a rotor shaft erected from the base, and a rotor to support the polygon mirror and to rotate about the rotor shaft;
• a friction member to selectively contact and be separated from the rotor to obstruct and release rotation of the rotor, respectively;
• and
• a friction member driving unit to drive the friction member.

An image forming apparatus to perform a printing operation, the image forming apparatus comprising:

• a light source to emit a light beam;
• a polygon mirror to reflect the light beam to a photosensitive body;
• a rotor to rotate the polygon mirror;
• and
• a friction member to contact the rotor to obstruct rotation of the rotor when the printing operation is complete, and to separate from the rotor during performance of the printing operation.

A beam deflector, comprising:

• a polygon mirror to reflect a light beam;
• a mirror driving unit comprising a rotor shaft disposed through a central opening of the polygon mirror and a rotor to rotate the polygon mirror with respect to the rotor shaft;
• and
• a friction member to selectively contact or separate from the rotor to obstruct and release rotation of the rotor.