Paper feeding apparatus and image forming apparatus having the same

Abstract

A paper feeding apparatus capable of preventing noises generated when picking up and transferring paper, and an image forming apparatus having the same. The paper feeding apparatus according to the present invention comprises a pickup unit, which is disposed upstream of a paper cassette relative to the direction in which the uppermost sheet of paper loaded in the paper cassette moves, to pick up the uppermost sheet of paper, and a lifting unit which lifts the sheet of paper vertically to reduce friction between the paper and the paper beneath it when the pickup unit picks up the sheets of paper.

1 . A paper feeding apparatus comprising:
 a pickup unit, arranged at one end of a printable medium, to pick up the printable medium and to feed the printable medium to an image forming apparatus; and   a transfer unit to transfer the printable medium picked up by the pickup unit to the image forming apparatus, the transfer unit comprising a transfer roller arranged to transfer the printable medium picked up from the pickup unit; a transfer guide spaced at a distance from an outer circumference of the transfer roller to guide the printable medium; and a plurality of idle rollers disposed in the interior of the transfer guide to come into rolling contact with the printable medium.   
     
     
         2 . The apparatus according to  claim 1 , wherein:
 the transfer unit comprises an alignment roller to align the leading portions of the printable medium, and   among the plurality of idle rollers, the idle roller disposed in the final position along the direction in which the printable medium travels is disposed within the range of approximately −15° to approximately +5° from a predetermined point on the outer circumference of the transfer roller;   wherein the predetermined point is the point on the outer circumference where a tangent line, drawn from a contact portion between the alignment rollers to the outer circumference of the transfer roller, tangentially intersects the outer circumference of the alignment roller.   
     
     
         3 . The apparatus according to  claim 1 , wherein:
 the plurality of idle rollers comprise a first plurality of idle rollers and a second plurality of idle rollers; and   the first plurality of idle rollers and the second plurality of idle rollers are disposed along the width of the transfer roller.   
     
     
         4 . The apparatus according to  claim 1 , wherein each idle roller in the first plurality of idle rollers partially overlaps at least one idle roller in the second plurality of idle rollers. 
     
     
         5 . The apparatus according to  claim 1 , wherein:
 each idle roller in the plurality of idle rollers comprises a rotation shaft; and   the transfer unit comprises a guide cover to fix the rotation shafts of the plurality of idle rollers.   
     
     
         6 . The apparatus according to  claim 1 , further comprising a lifting unit to lift another end of the printable medium when the pickup unit picks up the end of the printable medium. 
     
     
         7 . A feeding apparatus comprising:
 a transfer roller arranged to transfer an individual sheet of printable media picked up from a paper cassette to be fed into an image forming apparatus;   a transfer guide spaced at a distance from an outer circumference of the transfer roller to guide a printable medium; and   a plurality of idle rollers disposed in the interior of the transfer guide to come into rolling contact with the printable medium.   
     
     
         8 . The apparatus according to  claim 7 , wherein the transfer unit comprises an alignment roller to align the leading portions of a plurality of print media, and
 among the plurality of idle rollers, the idle roller disposed in the final position along the direction in which the sheet of paper travels is disposed within the range of approximately −15° to approximately +5° from a predetermined point on the outer circumference of the transfer roller;   wherein the predetermined point is the point on the outer circumference where a tangent line, drawn from a contact portion between the alignment rollers to the outer circumference of the transfer roller, tangentially intersects the outer circumference of the alignment roller.   
     
     
         9 . The apparatus according to  claim 7 , wherein:
 the plurality of idle rollers comprise a first plurality of idle rollers and a second plurality of idle rollers; and   the first plurality of idle rollers and the second plurality of idle rollers are disposed along the width of the transfer roller.   
     
     
         10 . The apparatus according to  claim 7 , wherein each idle roller in the first plurality of idle rollers partially overlaps at least one idle roller in the second plurality of idle rollers. 
     
     
         11 . The apparatus according to  claim 7 , wherein:
 each idle roller in the plurality of idle rollers comprise a rotation shaft; and   the transfer unit comprises a guide cover to fix the rotation shafts of the plurality of idle rollers.