Patent ID: 8863663

Claim:
A method for processing sheets on printing machines, the method comprising the steps of: providing a printing machine having a detector for controlling orientation and/or position of the sheets; providing a sheet suitable for use in the production of banknotes or security documents, said sheet being provided with at least one marking embedded in the sheet, which marking is embedded in the sheet during manufacturing thereof, prior to processing of the sheet on the printing machine, the marking being disposed in a selected location of the sheet and defining a unique orientation and/or position of the sheet; feeding the sheet into the printing machine; using the detector to check for the presence or absence of the marking at the selected location on the sheet and/or of characteristic features of the marking; issuing a warning signal if the marking is not detected at the selected location or if the characteristic features of the marking are not detected at the selected location; and printing the sheet using the printing machine if no warning signal is issued.