Paper Feed Cassette and Image Forming Apparatus

Abstract

A paper feed cassette provided with a size detection mechanism that detects the size of paper contained in the paper feed cassette, the size detection mechanism including: a link plate that moves along a paper feed direction with movement of side limitation plates in the width direction; a size detection member that is provided relative to the link plate, that moves with movement of the link plate along the paper feed direction, and that can enter a state in which the size detection member is abutting or not abutting an externally provided size detection sensor in the width direction of the paper; and a biasing member that provides the link plate with a biasing force in a direction of the movement of the link plate.

What is claimed is: 
     
         1 . A paper feed cassette provided with a size detection mechanism that detects the size of paper contained in the paper feed cassette,
 the size detection mechanism including:
 a pair of side limitation plates that abuts opposite lateral sides of the paper from a width direction intersecting a paper feed direction of the paper; 
 a link member that moves along the paper feed direction with movement of the side limitation plates in the width direction; 
 a size detection member that is provided relative to the link member, that moves with movement of the link member along the paper feed direction, and that can enter a state in which the size detection member is abutting or not abutting an externally provided size detection sensor in the width direction of the paper; and 
 a biasing member that provides the link member with a biasing force in a direction of the movement of the link member. 
   
     
     
         2 . The paper feed cassette according to  claim 1 , wherein
 a direction in which the link member is biased by the biasing member is a direction in which the limitation plates abut the paper in the width direction of the paper.   
     
     
         3 . The paper feed cassette according to  claim 1 , wherein
 the link member biased by the biasing member causes the pair of side limitation plates to press the paper.   
     
     
         4 . The paper feed cassette according to  claim 1 , wherein
 the size detection mechanism further includes a coupling rod that couples the link member to the size detection member.   
     
     
         5 . The paper feed cassette according to  claim 1 , comprising a bottom surface forming the bottom of the paper feed cassette, wherein
 the pair of side limitation plates is disposed on the inner surface side of the bottom surface, and   the link member is disposed on the outer surface side of the bottom surface.   
     
     
         6 . The paper feed cassette according to  claim 1 , wherein
 the link member has a rotation fulcrum at an inner position in the width direction,   the size detection member is shaft-supported at the link member at an outer position in the width direction as seen from the rotation fulcrum, and   the biasing member is biasing the link member in a direction that causes the link member to pivot around the rotation fulcrum.   
     
     
         7 . An image forming apparatus comprising:
 an image forming unit; and   a paper feed unit that stores a plurality of sheets of paper to be transported to the image forming unit,   the paper feed unit including a paper feed cassette that accumulates and stores the paper,   the paper feed cassette having a size detection mechanism that detects the size of the paper contained in the paper feed cassette,   the size detection mechanism including
 a pair of side limitation plates that abuts opposite lateral sides of the paper from a width direction intersecting a paper feed direction of the paper, 
 a link member that moves along the paper feed direction with movement of the side limitation plates in the width direction, 
 a size detection member that is provided relative to the link member, that moves with movement of the link member along the paper feed direction, and that can enter a state in which the size detection member is abutting or not abutting an externally provided size detection sensor in the width direction of the paper, and 
 a biasing member that provides the link member with a biasing force in a direction of the movement of the link member.