Intaglio printing press systems for recto-verso intaglio-printing of sheets for the production of banknotes and like securities

An intaglio printing press system for recto-verso printing of sheets for the production of banknotes and securities, wherein the intaglio printing press system comprises first and second intaglio printing units each comprising an impression cylinder cooperating with a plate cylinder carrying at least one intaglio printing plate which is inked by an inking system and wiped by a wiping system, said first and second intaglio printing units being operatively-coupled to one another directly by a sheet transporting system comprising a chain conveyor system with spaced-apart gripper bars for transporting the sheets from the first intaglio printing unit where recto printing is performed to the second intaglio printing unit where verso printing is performed, said first and second intaglio printing units being disposed in a tandem configuration such that said impression cylinder and said plate cylinder of the first intaglio printing unit rotate in the same directions as said impression cylinder and said plate cylinder of the second intaglio printing unit, said sheet transporting system further comprising a sheet transfer arrangement for performing reversal of the sheet transport direction of the sheets before transfer thereof directly to impression cylinder of the second intaglio printing unit;

• wherein the sheets are taken away from the impression cylinder of the first intaglio printing unit by said chain conveyor system with a leading edge of the sheets held by the chain conveyor system and wherein said sheet transfer arrangement comprises a first transfer drum or cylinder placed at a downstream end of the chain conveyor system for getting hold of a trailing edge of the sheets transported by the chain conveyor system;
• wherein said sheet transfer arrangement further comprises a second transfer drum or cylinder placed between the impression cylinder of the second intaglio printing unit and said first transfer drum or cylinder for transferring the sheets from the first transfer drum or cylinder directly to the impression cylinder of the second intaglio printing unit.