Weight-balanced polygonal mirror, light scanning unit using the polygonal mirror, and image forming apparatus

An image forming apparatus comprising:

• a light scanning unit comprising a light source to emit a light beam, and a polygonal mirror to deflect the light beam emitted from the light source;
• and
• a developing unit configured to develop an electrostatic latent image formed according to the light beam emitted from the light scanning unit,
• wherein the polygonal mirror comprises a plurality of reflection surfaces that are formed in an outer portion of the polygonal mirror and rotate around a rotational axis and an internal surface that defines a hole, and
• the internal surface of the polygonal mirror is bonded to a motor unit that supports and rotates the polygonal mirror using an adhesive at respective bonding positions of the motor unit that are near reference positions at which lines extended from vertices of the polygonal mirror to center of the polygonal mirror are respectively intersected with the internal surface of the polygonal mirror.

An image forming apparatus comprising:

• a light scanning unit comprising a light source to emit a light beam, and a polygonal mirror to deflect the light beam emitted from the light source;
• and
• a developing unit configured to develop an electrostatic latent image formed according to the light beam emitted from the light scanning unit;
• wherein the polygonal mirror comprises a plurality of reflection surfaces that are formed in an outer portion of the polygonal mirror and rotate around a rotational axis and an internal surface that defines a hole,
• the internal surface of the polygonal mirror is bonded to a motor unit that supports and rotates the polygonal mirror using an adhesive at respective bonding positions of the motor unit, and
• the bonding positions are nearer to first positions at which lines extended from vertices of the polygonal mirror to center of the polygonal mirror are respectively intersected with the internal surface of the polygonal mirror than second positions at which lines extended perpendicularly from the plurality of reflection surfaces of the polygonal mirror to center of the polygonal mirror are respectively intersected with the internal surface of the polygonal mirror.