Device for treating substrates

A device for treating substrates (1) having a separation system (2), with which processed substrate (1) can be separated into at least one waste part (9) and at least one blank (10), wherein the separation system (2) comprises a transport cylinder (3) and a stripping cylinder (4) associated therewith, and the transport cylinder (3) has means for securing a replaceable packing (5), along with first and second openings (12, 13) which, when the packing (5) is secured, are at least partially covered by perforations that may be formed in the packing (5), wherein first air supply means (14) for supplying air to the first openings (12) and second air supply means (15) for supplying air to the second openings (13) independently of the supply of air to the first openings (12) are provided, and the first and/or the second air supply means (14, 15) are switchable between a suction air supply and a blower air supply.