Printing medium feeder and image forming apparatus having the same

Abstract

A printing medium feeder and image forming apparatus are provided. The printing medium feeder includes a pickup unit configured to pick up printing medium, and a support arranged on a lower side of the pickup unit to selectively support the pickup unit or release supporting of the pickup unit, wherein as the support releases the supporting of the pickup unit, the other end portion of the pickup unit descends by self-weight on the basis of one end portion thereof to be seated on the printing medium.

What is claimed is: 
     
         1 . A printing medium feeder comprising:
 a pickup unit configured to pick up a printing medium; and   a support arranged on a lower side of the pickup unit to selectively support the pickup unit or release supporting of the pickup unit,   wherein as the support releases the supporting of the pickup unit, an other end portion of the pickup unit descends by a self-weight on a basis of one end portion thereof to be seated on the printing medium.   
     
     
         2 . The printing medium feeder of  claim 1 , wherein the support swings about a lower end portion thereof to support a part of a lower side of the pickup unit through an upper end portion thereof. 
     
     
         3 . The printing medium feeder of  claim 2 , wherein the support is pressed by a feed cassette mounted on a main body or the printing medium set on a feed tray and swings in a mounting direction of the feed cassette or in a printing medium setting direction to release the supporting of the pickup unit. 
     
     
         4 . The printing medium feeder of  claim 3 , wherein the support comprises an elastic member provided in the lower end portion thereof, and returns to its original position by the elastic member to support the pickup unit if the feed cassette secedes from its mounted position or the printing medium set on the feed tray is entirely consumed. 
     
     
         5 . The printing medium feeder of  claim 2 , wherein the support comprises a support roller provided on the upper end portion thereof to come in contact with and to slide along the part of the lower side of the pickup unit. 
     
     
         6 . The printing medium feeder of  claim 1 , wherein the pickup unit includes a guide projection formed to project from the lower side thereof in a side direction, and the support includes a support roller configured to support the guide projection. 
     
     
         7 . The printing medium feeder of  claim 1 , wherein the pickup unit further comprises a pressing member configured to elastically press the other end portion of the pickup unit so that a pickup roller arranged on the other end portion of the pickup unit presses the printing medium. 
     
     
         8 . The printing medium feeder of  claim 7 , wherein the pressing member is a torsion spring provided on a driving shaft that penetrates the one end portion of the pickup unit. 
     
     
         9 . The printing medium feeder of  claim 7 , wherein the pressing member that presses the other end portion of the pickup unit in a lower direction is a coil spring that presses from an upper portion of the pickup unit toward the lower side. 
     
     
         10 . The printing medium feeder of  claim 9 , wherein the coil spring has one end that is fixed to a part of a structure that is positioned on an upper side of the pickup unit and the other end that is fixed to an upper side of the other end portion of the pickup unit, and elastically presses the pickup unit. 
     
     
         11 . A printing medium feeder comprising:
 a pickup unit configured to pick up a printing medium; and   a support arranged on a lower side of the pickup unit,   wherein the support is selectively set to a first position in which the support supports the pickup unit or a second position in which the support is pressed by a feed cassette that is mounted on a main body or the printing medium that is set on a feed tray of an image forming apparatus to release the supporting of the pickup unit.   
     
     
         12 . The printing medium feeder of  claim 11 , wherein the pickup unit is rotated so that an other end portion thereof descends by self-weight on the basis of one end portion thereof to be seated on the printing medium as the support is rotated from the first position to the second position, and
 is rotated so that the other end portion thereof ascends on the basis of the one end portion thereof as the support is rotated from the second position to the first position.   
     
     
         13 . The printing medium feeder of  claim 12 , wherein the support comprises an elastic member provided in a lower end portion thereof to be elastically rotated from the second position to the first position. 
     
     
         14 . An image forming apparatus comprising:
 a main body;   a feed cassette detachably provided on the main body or a feed tray provided on the main body on which to set a printing medium; and   a printing medium feeder including a pickup unit configured to pick up the printing medium, and a support arranged on a lower side of the pickup unit to support the pickup unit in a first position and to release the supporting of the pickup unit in a second position,   wherein an other end portion of the pickup unit swings downward from the second position by self-weight on the basis of one end portion thereof so that a pickup roller of the pickup unit is seated on the printing medium.   
     
     
         15 . The image forming apparatus of  claim 14 , wherein the support is rotated from the first position to the second position as the support is pressed by the feed cassette mounted on the main body or the printing medium that is set in the feed tray. 
     
     
         16 . The image forming apparatus of  claim 15 , wherein the support is rotated from the second position to the first position as the support is released from being pressed by the feed cassette or the printing medium of the feed tray.