a single sheet collecting device for stacking sheets of paper or plastic has at least one transport element and at least one stop unit arranged in a transport path of the sheets . first and second deflecting parts are arranged along the transport path of the sheets for moving the sheets during transport for a moment out of a transport plane of the sheets . the first and second deflecting parts are adjustable from a first position for top stacking the sheets into a second position for bottom stacking the sheets and vice versa .