Patent ID: 8116673

Claim:
A printing medium supplying unit, comprising: a printing medium loading plate configured to move up and down, and to hold thereon an amount of printing medium; a rotation shaft; a pickup roller disposed on the rotation shaft; and an elevation control unit configured to adjust an elevation height of the printing medium loading plate such that a standby position of the printing medium loading plate varies based on the amount of the printing medium loaded on the printing medium loading plate, the elevation control unit including: an external force receiving unit configured to press and release the printing medium loading plate such that the printing medium loading plate moves up and down between the standby position and a supply position, the external force receiving unit being coupled to the rotation shaft and having a contact radius that varies in an axial direction of the rotation shaft; and an external force applying unit configured to apply an external force to the external force receiving unit to adjust a position in which the external force receiving unit presses the printing medium loading plate, wherein the standby position of the printing medium loading plate is a position of the printing medium loading plate in which the printing medium is not being supplied from the printing medium supplying unit, and the supply position of the printing medium loading plate is a position of the printing medium loading plate in which the printing medium loading plate supplies the printing medium to an image forming unit.