Automatic on-line signature booklets finisher for electronic printers

In a signatures finishing system for on-line center folding of sets of signature sheets outputted by a reproduction system using a saddle compiler with two opposite sides forming an inverted "V";

• the improvement comprising:
• a pair of reversible folding rollers closely adjacent to said saddle compilor and forming a folding rollers nip;
• an input sheet feeding system for feeding the central area of each outputted signature sheet into said folding rollers nip for sequentially individually fully folding said signature sheets in said folding rollers nip as they are outputted by said reproduction system;
• a reversible drive for said folding rollers which is automatically reversed at a position which will sequentially stack each so folded signature sheet on said adjacent saddle compiler to form plural sheet compiled pre-folded signature sheet booklets, and
• a set ejector for ejecting said compiled folded signatures booklet from said saddle compiler fully through said same folding rollers nip to a booklet output system, while said reversible drive for said folding rollers is re-reversed.