Device and method for separating value documents, in particular banknotes, and value document processing system

An apparatus for singling value documents, comprising:

• a feeding device, which is adapted to feed a respectively uppermost value document of a stack of value documents to a picking device which is adapted to pick the value document from the stack,
• a conveying device, which is adapted to receive the stack and to convey it relative to the feeding device,
• at least one distance sensor, which is adapted to detect at least one distance of a gap present between the respectively uppermost value document of the stack and the feeding device and to generate at least one corresponding distance sensor signal, said distance signal representing a measure of the gap between the respectively uppermost value document and the feeding device and/or characterizing a size, position, and/or location of the gap between the respectively uppermost value document and the feeding device,
• at least one stack sensor which is adapted to detect a height and/or a density of the stack of value documents and to generate at least one corresponding stack sensor signal, and
• a control device, which is adapted to control the conveyance of the stack relative to the feeding device and/or the location of the feeding device relative to the stack, to the respectively uppermost value document of the stack, on the basis of the at least one distance sensor signal and the at least one stack sensor signal.