Apparatus and method for stacking media sheets

Abstract

An apparatus and method for stacking sheets of media traveling along a web use exit rollers arranged in a contoured pattern to shape each sheet. Shaping a sheet, stiffens the sheet and prevents drooping and thereby prevents scratching preceding sheets. Twist rollers positioned between the entrance and exit rollers twist each belt and improves tracking.

1 . An apparatus for stacking sheets of material traveling along a conveyor, comprising: 
 a plurality of entrance rollers;    a plurality of exit rollers downstream of said plurality of entrance rollers arranged horizontally in a contoured pattern;    a plurality of conveyor belts, one for each said roller of said plurality of exit rollers, each said conveyor belt twisting between an associated one of said plurality of entrance rollers and an associated one of said plurality of exit rollers; and    means for pinching said belts and improving tracking of said belts on said entrance and exit rollers.    
   
   
       2 . An apparatus according to  claim 1  wherein said means includes: 
 a first plurality of twist rollers positioned between said plurality of entrance rollers and said plurality of exit rollers; and    a second plurality of twist rollers positioned between said plurality of entrance rollers and said first plurality of twist rollers.    
   
   
       3 . An apparatus according to  claim 2  wherein all belt twisting occurs between said first plurality of twist rollers and said second plurality of twist rollers.  
   
   
       4 . An apparatus according to  claim 1  wherein said plurality of exit rollers are arranged in a U-shaped contoured pattern.  
   
   
       5 . An apparatus for stacking sheets of material traveling along a conveyor, comprising: 
 a plurality of entrance rollers;    a plurality of exit rollers downstream of said plurality of entrance rollers arranged horizontally in a contoured pattern;    a first plurality of twist rollers downstream of said plurality of entrance rollers;    a second plurality of twist rollers upstream of said plurality of exit rollers;    a plurality of conveyor belts, one for each said roller of said plurality of exit rollers, each said conveyor belt twisting from an associated one of said first plurality of twist rollers to an associated one of said second plurality of twist rollers.    
   
   
       6 . An apparatus according to  claim 1  wherein said plurality of exit rollers are arranged in a U-shaped contoured pattern.  
   
   
       7 . A method for stacking sheets of material traveling along a conveyor, comprising the steps of: 
 aligning a plurality of entrance rollers horizontally;    arranging a plurality of exit rollers horizontally in a contoured pattern;    providing a plurality of conveyor belts, one for each said roller of said plurality of exit rollers;    positioning a pair of twist rollers for each said conveyor belt between the entrance and exit rollers;    twisting each said conveyor belt during travel between associated twist rollers; and    passing said sheet along said contoured exit rollers whereby said sheet adopts the contoured pattern of said exit rollers.    
   
   
       8 . A method according to  claim 7  including the step of arranging said exit rollers in a U-shaped contoured pattern.  
   
   
       9 . A method according to  claim 7  including the steps of pinching said belts between said entrance and exit rollers and improving tracking.