The present invention relates to a semi-circular stack sheet feeding device having a lower supply platform, which can be loaded with imbricated stacks of sheets, having a delivery and diverting device, which transports the imbricated stack of sheets in a first delivery direction along the underside of a diverting drum as well as transporting said stack around said drum upwardly onto a removal platform in a second delivery direction, and having a removal device for removing the arriving, top-most sheet on the removal platform in a delivery direction opposite to the second delivery direction.
In the semi-circular stack sheet feeding device according to German Patent Application No. 2,502,790.1, an end switch is arranged at the end of the removal platform, which quickly shuts off the drive of the delivery and diverting device when it is activated by the leading edge of the uppermost sheet of the stack of such sheets lying on the removal platform. Because the removal device is usually controlled independently of the delivery of sheets onto the removal platform, an unequal imbrication of the sheets lying on the removal platform can lead to the problem that the top sheet is grasped by the removal device before such sheet reaches the end switch. This can lead to malfunctions during the further transport of the sheets delivered by the removal device. An unequal imbrication of the sheets lying on the removal platform does not result only when the sheets laid on the supply platform have been unequally imbricated. It can also be caused by the fact that the imbrication does not uniformly decrease as the sheets leave the diverting drum because of varying friction between successive sheets. It can occur that some sheets maintain the greater imbrication received during their travel around the diverting drum, and, therefore, the imbrication is completely eliminated in other sheets.