Stacking unit for articles sheet form

A stacker (1) for bank notes (2) having a feeding device (3) for depositing the bank notes (2) in a storage pocket (4) with variable capacity, the storage pocket (4) having a contact surface (5) against which the bank notes (2) deposited in the storage pocket (4) lie with one edge (6), and a storage tray (7) on which the bank notes (2) are stacked in the storage pocket (4) flat and parallel to the storage tray (7), and the storage tray (7) of the storage pocket (4) being mounted movably for changing the capacity of the storage pocket (4), characterized in that the storage pocket (4) is disposed with contact surface (5) at an angle (α) to the horizontal (8) so that the bank notes (2) stacked in the storage pocket (4) lie with their edges (6) against the contact surface (5) and the resulting frictional force between the edges (6) of the bank notes (2) and the contact surface (5) substantially compensates the slope descending force acting on the stack (10) formed of bank notes (2) in the direction of the storage tray (7), and the feeding device (3) exerts a force on the stack (10) when depositing a bank note (2) at least as of a certain stack thickness (c), thereby moving the storage tray (7) so as to enlarge the capacity of the storage pocket (4), and the angle (α) between the contact surface (5) and the horizontal (8) is between 20° and 30°.