Patent claim: A transport mechanism 2 for transporting sheets S of a print medium along a transport path P in a printing system 1 comprisinga first conveyor device 20 having a first conveyor body 21 which is configured to hold a plurality of sheets S of print medium and is movable to convey the sheets S along the transport path P anda transfer system 50 comprising a second conveyor device 30 having a second conveyor body 31 which is configured to hold the sheets S and is movable to convey the sheets S further along the transport path P wherein the transfer system 50 is configured to transfer the sheets S from the first conveyor body 21 to the second conveyor body 31 in a transfer region T wherein the second conveyor body 31 is arranged adjacent the first conveyor body 21 in the transfer region T and the transfer system 50 includes suction means configured to provide an underpressure U2 at or in the second conveyor body 31 for contactless transfer of the sheets S from the first conveyor body 21 to the second conveyor body 31 wherein the second conveyor body 31 has a second carrier surface 32 configured to support the sheets S thereon and wherein the second conveyor device 30 provides regions 37 38 39 on the second carrier surface 32 of different airflow from the second underpressure U2 the second carrier surface 32 including a region of relatively higher suction force or airflow arranged in a central region 37 of the second carrier surface 32 with respect to the transport path for attracting a centre portion of the each sheet with respect to the transport path towards the second conveyor body 31 in the transfer region T.

Related passage: In another preferred embodiment a mechanical releasing means such as a scraper is used to make the receiving substrate leave pulley 13c.In a more preferred embodiment the receiving substrate is released from pulley 13c by pneumatic means e.g.by blowing airagainst the receiving substrate.The vacuum applicators at pulley 13c may be followed by a portion wherein the air pressure is larger than atmospheric pressure so that an air flow releases the receiving substrate from pulley 13c.A vacuum applicator applying either a constant or a varying vacuum may be combined with mechanical releasing means with pneumatic releasing means or with both.Additionally a mechanical guiding means such as a guiding plate or guiding wires at the nonprinted side of the receiving substrate may be used to assist the receiving substrate in bridging the gap between pulleys 13c and 13a.Instead of a mechanical guiding means pneumatic guiding means such as air jets may be used the air jets may arise from the exhaust i.e.the high pressure side of one or more vacuum applicators.If no ink is applied to the side borders of the receiving substrate so that the receiving substrate has unprinted side borders in the transportation direction additional side guiding means may be used.The side guiding means may include a narrow belt contacting the first unprinted border and a narrow belt contacting the second unprinted border of the receiving substrate the narrow belts press the receiving substrate against the vacuum belt e.g.along curve 31 in Fig.1 and are driven at the same speed as the vacuum belt.Fig.7 shows narrow belts 17 acting as side guiding means.