Patent ID: 7744079

Claim:
A system for processing paper postal items, comprising a first station a second station; and a transport track extending through said stations for transporting stacks of at least two paper postal items in a transport direction through said first station and from said first station into and through said second station; wherein each of said stations comprises: at least one first circulatable surface on a first side of the transport track for guiding postal item material along the transport track; at least one second circulatable surface, opposite of the at least one first circulatable surface for exerting a normal force towards said at least one first circulatable surface; a first drive for driving at least one of the circulatable surfaces of the first station; and a second drive for driving at least one of the circulatable surfaces of the second station; wherein the first drive is controlled for driving the at least one of the first station's circulatable surfaces at a first circumferential speed; wherein the second drive is controlled for driving the at least one of the second station's circulatable surfaces at a second circumferential speed higher than said first circumferential speed; wherein said circulatable surfaces in at least a downstream section of the transport track in said first station and said circulatable surfaces in at least an upstream section of the transport track in said second station are arranged such that, in operation, for each of the stacks, the highest normal force exerted on the stack by said circulatable surfaces in at least a downstream section of the transport track in said first station is substantially larger or smaller than the highest normal force exerted on the stack by said circulatable surfaces in at least an upstream section of the transport track in said second station; and wherein in at least said first and second stations, the circulatable surfaces are arranged such that, in operation, for each of the stacks, the highest normal force exerted onto an engaged by said circulatable surfaces in a downstream section of the transport track in said station is substantially larger or substantially smaller than the highest normal force exerted on said postal item by said circulatable surfaces in an upstream section of the transport track in said station.