US Patent 7360757 Stack conditioning apparatus and method for use in bookbinding

Apparatus for conditioning an edge of a stack of sheets to be bound so that sheets having coated surfaces and the like can be reliably bound. The apparatus includes a stack clamping mechanism configured to secure the stack of sheets and a piercing member configured to produce a piercing action substantially in a piercing plane. Also provided is a positioning mechanism configured to control relative movement of the stack clamping mechanism and the piercing mechanism so that the sheets of the stack pass through the piercing plane, with the drive mechanism being configured to drive the piercing member into the edge of the stack at least once for each sheet of the stack passing through the piercing plane.