Sheet separating/conveying mechanism and sheet conveying apparatus therewith

Abstract

A sheet separating/conveying mechanism 30 has an upper unit 30 a in which a paper feed roller 31 and other components are arranged and a lower unit 30 b in which a separating roller 32, an arm member 36, and other components are arranged. The arm member 36 is U-shaped as seen in a plan view by being composed of a left and a right movable lever 36 a that are mutually parallel and that make contact with both ends of a center shaft 23 b and a pivot shaft 36 b that supports the movable levers 36 a so that they are rotatable in a direction indicated by arrow BB′. The movable levers 36 a have locking holes 39 formed at the tip ends thereof, and the lower ends of tension springs 38 are locked in those locking holes 39. The lower unit 30 b is fitted with an applied force adjusting member 45 on which locking portions 42 a and 42 b are formed to protrude therefrom leftward and rightward that permit adjustment of the positions at which the upper ends of the tension springs 38 are locked.

1 . A sheet separating/conveying mechanism comprising: 
 a paper feed roller for feeding a sheet in a sheet conveying direction;    a separating member pressed onto a lower part of said paper feed roller or taken away therefrom in a direction approximately perpendicular to the sheet conveying direction; and    force applying means for pressing said separating member onto said paper feed roller, said force applying means permitting an applied force to be adjusted independently at both sides of said separating member in an axial direction thereof,    wherein said sheet separating/conveying mechanism separates and conveys only a topmost sheet from a stack of sheets.    
   
   
       2 . The sheet separating/conveying mechanism of  claim 1 , 
 wherein said force applying means includes: 
 two tension springs that apply the force to both sides of said separating member in the axial direction thereof; and  
 an applied force adjusting member provided with, one at each of left and right sides thereof, locking portions for locking one ends of the tension springs,  
   wherein said locking portions each have a plurality of engagement grooves formed therein at different positions in a direction of expansion/contraction of said tension springs.    
   
   
       3 . The sheet separating/conveying mechanism of  claim 2 , 
 wherein said engagement grooves are formed stepwise along upper edges of said locking portions, and a flexible sheet member is attached above said locking portions so as to close open ends of said engagement grooves, said sheet member being retractable to a position where said sheet member leaves open the open ends.    
   
   
       4 . The sheet separating/conveying mechanism of  claim 2 , 
 wherein, on said applied force adjusting member, for each of said locking portions, as many marking symbols as said engagement grooves formed therein are provided.    
   
   
       5 . The sheet separating/conveying mechanism of  claim 3 , 
 wherein, on said applied force adjusting member, for each of said locking portions, as many marking symbols as said engagement grooves formed therein are provided.    
   
   
       6 . The sheet separating/conveying mechanism of  claim 4 , 
 wherein said marking symbols are provided to correspond to arrangement of said engagement grooves.    
   
   
       7 . The sheet separating/conveying mechanism of  claim 5 , 
 wherein said marking symbols are provided to correspond to arrangement of said engagement grooves.    
   
   
       8 . The sheet separating/conveying mechanism of  claim 1 , 
 wherein said separating member is a separating roller composed of a roller body formed of an elastic material and a center shaft that penetrates a center of rotation of the roller body.    
   
   
       9 . The sheet separating/conveying mechanism of  claim 8 , 
 wherein said separating roller is provided with a torque limiter that permits said roller body to rotate only when a driving force stronger than a predetermined level is applied.    
   
   
       10 . The sheet separating/conveying mechanism of  claim 8 , 
 wherein, in said locking portions, mutually corresponding ones of said engagement grooves are formed, with consideration given to arrangement of said roller body in an axial direction thereof and a position of a center of gravity of said separating roller, in such positions that the force applied by the tension springs acts equally at left and right sides of said roller body.    
   
   
       11 . The sheet separating/conveying mechanism of  claim 9 , 
 wherein, in said locking portions, mutually corresponding ones of said engagement grooves are formed, with consideration given to arrangement of said roller body in an axial direction thereof and a position of a center of gravity of said separating roller, in such positions that the force applied by the tension springs acts equally at left and right sides of said roller body.    
   
   
       12 . The sheet separating/conveying mechanism of  claim 1 , 
 wherein said force applying means has movable levers that are rotatably supported at one ends thereof and that have said tension springs coupled to the other ends thereof, so that said movable levers apply the force applied by the tension springs to said separating member by making contact therewith, and rotary follower members are provided in parts of said separating member where said separating member makes contact with said movable levers.    
   
   
       13 . The sheet separating/conveying mechanism of  claim 12 , 
 wherein said separating member is a separating roller composed of a roller body formed of an elastic material and a center shaft that penetrates a center of rotation of the roller body, and said rotary follower members are fitted at both ends of said center shaft.    
   
   
       14 . The sheet separating/conveying mechanism of  claim 13 , 
 wherein said rotary follower members are bearings.    
   
   
       15 . A sheet conveying apparatus comprising the sheet separating/conveying mechanism of  claim 1.