Method of, and apparatus for, processing sheets of different formats

A method of processing sheets of different formats, comprising:

• feeding the sheets of different formats in a feeding direction one behind the other, and at a certain feeding speed, to at least two collecting drums, the at least two collecting drums each having essentially cylindrical lateral surfaces,
• driving each of the at least two collecting drums about a respective axis of rotation at a circumferential speed, the circumferential speed corresponding essentially to the feeding speed of the sheets,
• temporarily securing at least some of the sheets on one of the at least two collecting drums to form a sheet stack,
• detaching the sheet stack from the at least one of the at least two collecting drums, and
• bringing together the sheets or the sheet stack detached from the at least one of the at least two collecting drums with sheets or a sheet stack detached from another one of the at least two collecting drums.