Folder of a printing press

The invention relates to a folding apparatus (10) of a printing machine, in particular a web-fed rotary printing machine, having a first Langsfalzeinheit (12) or a cartridge assembly, as seen with a in the direction of transport of a printing material of the first Langsfalzeinheit (12) or the cartridge assembly downstream cutting unit (13) to be separated from the printing material by cross-cutting specimens, and optionally with a saw in the conveying direction of the printing material of the cutting unit (13) arranged downstream Querfalzeinheit and / or second Langsfalzeinheit (17). According to the invention seen in the direction of transport of printing material downstream of the cutting unit (13) along the transport path of the copies through the folder at least one sensor (22) positioned, which detects the items measured and transmits a measuring signal to a control unit, wherein the Steuerungseiheit on basis of said or each sensor provided (22) measuring signal determines the position of the copies in the folder relative to a machine angle, and wherein the control unit of the so-determined location of copies and of freely configurable limit values ​​for the position of the copies causes depends a stopper and / or a warning message or generated.