Paper feeding apparatus and image forming apparatus

Abstract

This paper feeding apparatus ( 100 ) includes a pickup roller ( 21 ) including a first portion ( 21 a) that picks up paper ( 150 ) in a first state where the paper is to be picked up and a second portion ( 21 b) that transports, in a second state where the paper is to be transported, the paper picked up in the first state and a friction pad ( 22 ) that suppresses transport of paper subsequent to the picked up paper, and the pickup roller is in surface contact such that a contact area between the first portion and the friction pad and a contact area between the second portion and the friction pad are substantially equal to each other.

1 - 20  (canceled) 
     
     
         21 . A printer including a paper feeding apparatus, comprising:
 a pickup roller that picks up paper by rotation; and   a friction pad arranged to face the pickup roller, wherein the pickup roller includes:
 a first portion that contacts with a surface of the paper that is stacked in a first state where the paper is to be picked up, and 
 a second portion that transports the paper picked up in the first state in a second state where the paper is to be transported, and 
   the friction pad has a width equal to widths of the first portion and the second portion.   
     
     
         22 . The printer according to  claim 21 , wherein:
 a surface of the first portion has a first curvature on a cross-sectional surface orthogonal to a rotation axis of the pickup roller,   a surface of the second portion has a second curvature on the cross-sectional surface orthogonal to the rotation axis of the pickup roller, and   the first curvature and the second curvature are equal to each other.   
     
     
         23 . The printer according to  claim 21 , further comprising:
 an urging portion that urges the friction pad toward the pickup roller, wherein   the urging portion includes a first urging portion and a second urging portion having urging force weaker than urging force of the first urging portion, and   the first urging portion of the urging portion urges the friction pad in the first state, and the second urging portion of the urging portion urges the friction pad in the second state.   
     
     
         24 . The printer according to  claim 22 , wherein a center of curvature of the first portion and a center of curvature of the second portion are different from each other. 
     
     
         25 . The printer according to  claim 21 , wherein an amount of protrusion of the pickup roller toward the friction pad is larger in the first state than in the second state. 
     
     
         26 . The printer according to  claim 22 , wherein:
 the center of curvature of the first portion is arranged closer to the first portion than a center of the pickup roller, and   the center of curvature of the second portion is arranged closer to the second portion than the center of the pickup roller.   
     
     
         27 . The printer according to  claim 26 , wherein the center of curvature of the second portion coincides with the rotation axis of the pickup roller. 
     
     
         28 . The printer according to  claim 22 , wherein the surface of the first portion and the surface of the second portion adjacent to the first portion are flush with each other. 
     
     
         29 . The printer according to  claim 23 , further comprising:
 a first friction pad holding member and a second friction pad holding member that hold the friction pad, wherein   the first friction pad holding member is arranged between the first urging portion and the second urging portion, and   the second friction pad holding member is arranged between the friction pad and the second urging portion.   
     
     
         30 . The printer according to  claim 29 , wherein:
 the first friction pad holding member includes a plate-like partition portion, and   the partition portion is arranged between the first urging portion and the second urging portion.   
     
     
         31 . The printer according to  claim 30 , wherein the partition portion includes an engaging portion that engages with the urging portion. 
     
     
         32 . The printer according to  claim 29 , wherein:
 movement of the first friction pad holding member toward the pickup roller is restricted in the second state, and   the second urging portion urges the second friction pad holding member in the second state.   
     
     
         33 . The printer according to  claim 29 , wherein:
 the first urging portion is a first spring portion that has a first pitch, and   the second urging portion is a second spring portion that has a second pitch larger than the first pitch.   
     
     
         34 . The printer according to  claim 33 , wherein the first spring portion has a natural length in the second state. 
     
     
         35 . The printer according to  claim 33 , wherein the urging portion is a single spring member. 
     
     
         36 . The printer according to  claim 29 , wherein the second friction pad holding member is movable relative to the first friction pad holding member. 
     
     
         37 . The printer according to  claim 36 , wherein the first friction pad holding member and the second friction pad holding member linearly move in a direction in which the urging portion expands and contracts. 
     
     
         38 . The printer according to  claim 36 , wherein the second friction pad holding member rotates with respect to the first friction pad holding member. 
     
     
         39 . The printer according to  claim 22 , wherein the pickup roller has a near-circular shape, as viewed along the axis. 
     
     
         40 . The printer according to  claim 21 , wherein the first portion is detachable.