Patent ID: 8262082

Claim:
A printing medium supplying unit of an image forming apparatus, comprising: a medium supplying unit frame; a loading plate movably coupled to the medium supplying unit frame, the loading plate including a surface for supporting a plurality of printing media thereon, the loading plate being movable between a knock up state and a knock down state a pickup roller disposed at a location in relation to the loading plate such that, when the loading plate is in the knock up state, the pick up roller is capable of contacting at least one of the plurality of printing media supported on the surface of the loading plate to pick up the at least one of the plurality of printing media, and, when the loading plate is in the knock down state, the pickup roller is spaced apart from the plurality of printing media, the loading plate being positioned in a knock up state such that the pickup roller allows to contact and to pick up at least one of the plurality of printing media supported on the surface of the loading plate, or the loading plate being positioned in a knock down state such that the pickup roller is spaced apart from the plurality of printing media; and a loading plate moving unit having a cam formed with a plurality of prominence portions and a plurality of depressed portions to repeatedly move the loading plate in opposite directions when the loading plate is in the knock down state and arranged to rotate in interlocked manner with the pickup roller, the loading plate moving unit being configured to cooperate with a portion of the loading plate to impart movements of the loading plate in opposite directions when the loading plate is in the knock down state.