Patent ID: 8452213

Claim:
An image forming apparatus comprising: a plurality of cartridges each of which comprises a photoconductor; a plurality of exposure units each of which is movable between an exposure position proximate to a corresponding photoconductor and a retreating position away from the corresponding photoconductor, a plurality of light-emitting parts being arranged in each exposure unit and configured to expose the corresponding photoconductor to light, each exposure unit having a guide rib; a support frame configured to support the cartridges and allowed to be pulled out from a casing of the apparatus, the support frame comprising a pair of side plates extending in a direction perpendicular to a main direction in which the light-emitting parts are arranged, each of the side plates having guide slots each configured to allow the guide rib of a corresponding exposure unit to be slid inside the guide slot to guide movement of the corresponding exposure unit between the exposure position and the retreating position; and a plurality of arm parts, which are respectively swingably mounted to the support frame and by which the plurality of exposure units are supported in such a manner that each exposure unit is independently movable between the exposure position and the retreating position, wherein the guide rib of each exposure unit is configured to protrude outward in the main direction, each of the guide slots extends in an exposure direction in which a light beam is emitted from the exposure unit to the corresponding photoconductor, and comprises a positioning portion configured to position the corresponding exposure unit in a position in a subordinate direction that is perpendicular to the main direction and to the exposure direction, and a guide portion configured to guide the guide rib moving to the positioning portion.