Stacking unit for articles sheet form

Stacker 1 for sheet-shaped objects is described having feeding device 3 for depositing sheet-shaped objects 2 in storage pocket 4 with variable capacity. Storage pocket 4 has contact surface 5 against which sheet-shaped objects 2 deposited in storage pocket 4 lie with one edge 6 , and storage tray 7 on which sheet-shaped objects 2 are stacked in storage pocket 4 flat and parallel to storage tray 7 . Storage tray 7 is mounted movably for changing the capacity of storage pocket 4 . Storage pocket 4 is disposed with contact surface 5 at an angle to the horizontal so that sheet-shaped objects 2 stacked in storage pocket 4 rest with their edges 6 on contact surface 5 and the resulting frictional force between edges 6 of sheet-shaped objects 2 and contact surface 5 substantially compensates the slope descending force acting on stack 10 formed of sheet-shaped objects 2 in the direction of storage tray 7 . Feeding device 3 exerts a force on stack 10 when depositing sheet-shaped object 2 at least as of certain stack thickness c, thereby moving storage tray 7 so as to enlarge the capacity of storage pocket 4.