Feed device with controlled envelope separation

Abstract

In a mailpiece feed device designed to be mounted upstream from a franking machine, and comprising at least a mailpiece feed zone for receiving a stack of mailpieces supported by a plurality of drive rollers and a separation zone for individually selecting the mailpieces, there are provided control means for varying the speed of rotation of said plurality of drive rollers when, at the outlet of said separation zone, a measurement of a gap between successive mailpieces differs from a predefined gap by a predetermined correction threshold.

1 . A mailpiece feed device designed to be mounted upstream from a franking machine, and comprising at least a mailpiece feed zone for receiving a stack of mailpieces supported by a plurality of drive rollers and a separation zone for individually selecting the mailpieces, wherein said mailpiece feed device further comprises control means for varying the speed of rotation of said plurality of drive rollers when, at the outlet of said separation zone, a measurement of a gap between successive mailpieces differs from a predefined gap by a predetermined correction threshold. 
     
     
         2 . A feed device according to  claim 1 , wherein said predetermined correction threshold lies within the range plus or minus 8% to 12% of said predefined gap. 
     
     
         3 . A feed device according to  claim 1 , wherein the speed of rotation of said plurality of drive rollers is varied incrementally. 
     
     
         4 . A feed device according to  claim 3 , wherein the size of said increments lies in the range 4% of said predefined value to 10% of said predefined value. 
     
     
         5 . A feed device according to  claim 1 , wherein said measurement is an instantaneous value obtained during detection of passage of a plurality of successive mailpieces. 
     
     
         6 . A feed device according to  claim 1 , wherein said measurement is a mean value obtained during detection of passage of a plurality of successive mailpieces. 
     
     
         7 . A control method of controlling the drive rollers supporting a stack of mailpieces at a feed zone of a mailpiece feed device designed to be mounted upstream from a franking machine, a separation zone of said mailpiece feed device individually selecting the mailpieces at the outlet of said feed zone, said control method consisting in varying the speed of rotation of said plurality of drive rollers when, at the outlet of said separation zone, a measurement of a gap between successive mailpieces differs from a predefined gap by a predetermined correction threshold. 
     
     
         8 . A method according to  claim 7 , wherein said predetermined correction threshold lies within the range plus or minus 8% to 12% of said predefined gap. 
     
     
         9 . A method according to  claim 7 , wherein the speed of rotation of said plurality of drive rollers is varied incrementally. 
     
     
         10 . A method according to  claim 9 , wherein the size of said increments lies in the range 4% of said predefined value to 10% of said predefined value. 
     
     
         11 . A method according to  claim 7 , wherein said measurement is an instantaneous value obtained during detection of passage of a plurality of successive mailpieces. 
     
     
         12 . A method according to  claim 7 , wherein said measurement is a mean value obtained during detection of passage of a plurality of successive mailpieces.