Patent ID: 8457524

Claim:
A developing unit usable with an image forming apparatus, the developing unit comprising: a first frame to support a photoconductive medium; a second frame to support a developing member to apply a developer to the photoconductive medium, the second frame movable between a first position in which the photoconductive medium is at a developing gap from the developing member, and a second position in which the photoconductive medium is away from the developing member by a distance exceeding the developing gap; and a positioning unit to move the second frame from a current position in accordance with mounting and demounting of the developing unit to and from the image forming apparatus wherein the positioning unit comprises: a reciprocatingly movable member disposed within at least a portion of the first frame, and having at least one first protrusion formed thereon; and a second protrusion formed on the second frame to selectively contact the first protrusion according to a reciprocating movement of the reciprocatingly movable member.