A sheet stacker (1; 100; 200) comprising : • A sheet flipping device for flipping a received sheet (S) around a flipping axis with respect to an orientation wherein the sheet (S) was received; • A holding device (20; 120; 220) for releasably holding at least a portion of the sheet (S) at least partially during the flipping of the sheet (S) by the sheet flipping device , wherein the holding device (20; 120; 220) is configured for movement of the held portion of the sheet (S) in a first direction (D) perpendicular to the flipping axis ; • a controller configured to control the sheet stacker (1; 100; 200), such that: i. in a first state a leading portion of the sheet (S) is received by the sheet flipping device and partially transported by the sheet flipping device without the leading portion being drawn against the holding device (20; 120; 220); ii. in a second state a trailing portion of the sheet (S) is drawn against the holding device (20; 120; 220) during the flipping motion of the sheet (S), characterized in that a sheet supply path for supplying sheet (S) to the sheet flipping device and the holding device (20; 120) are moveable with respect to one another between a first position wherein a portion of the sheet (S) may pass into the sheet flipping device without being adhered against the holding device (20; 120) and a second position wherein the holding device (20; 120) is able to draw a portion of the sheet (S) against it. • A sheet flipping device for flipping a received sheet (S) around a flipping axis with respect to an orientation wherein the sheet (S) was received; • A holding device (20; 120; 220) for releasably holding at least a portion of the sheet (S) at least partially during the flipping of the sheet (S) by the sheet flipping device , wherein the holding device (20; 120; 220) is configured for movement of the held portion of the sheet (S) in a first direction (D) perpendicular to the flipping axis ; • a controller configured to control the sheet stacker (1; 100; 200), such that: i. in a first state a leading portion of the sheet (S) is received by the sheet flipping device and partially transported by the sheet flipping device without the leading portion being drawn against the holding device (20; 120; 220); ii. in a second state a trailing portion of the sheet (S) is drawn against the holding device (20; 120; 220) during the flipping motion of the sheet (S), characterized in that a sheet supply path for supplying sheet (S) to the sheet flipping device and the holding device (20; 120) are moveable with respect to one another between a first position wherein a portion of the sheet (S) may pass into the sheet flipping device without being adhered against the holding device (20; 120) and a second position wherein the holding device (20; 120) is able to draw a portion of the sheet (S) against it. i. in a first state a leading portion of the sheet (S) is received by the sheet flipping device and partially transported by the sheet flipping device without the leading portion being drawn against the holding device (20; 120; 220); ii. in a second state a trailing portion of the sheet (S) is drawn against the holding device (20; 120; 220) during the flipping motion of the sheet (S), <EOS>