moved along the rods of the non slidable part 24 the tray 52 is provided with a vertical and horizontal toothed strip 50 51 to ensure that sheets brought into the tray do not curl up and vanish from the tray 52 the front edge of a sheet of paper is thus retained by the teeth a scale graduation is mounted on the non slidable part and indicates the position of the slidable part 23 fig2 is a diagram showing a printer 30 with an outlet opening 31 the sheet collecting device is in the delivery position first position against the printer the numbering of the parts of the sheet collecting device is identical to the numbering used in fig1 fig3 is again a diagram showing the printer 30 with the outlet opening 31 the sheet collecting device has now been placed in the second position collecting position against the printer by means of the castors 21 the sheet collecting device can be turned through 180 u00b0 in order to move the sheet collecting device from the delivery position to the collecting position fig4 to 8 show the operation of the sheet collecting device in the delivery position in fig4 a copy sheet 40 leaves the printer 30 via the outlet opening in fig5 said sheet 40 reaches the slidable part 23 of the front edge stopper and is prevented by a toothed strip 50 51 in fig1 from any further passage or pushing into the front.