Abstract: When sheets (1, 2) with different sizes are processed to a mail item, sheets (1, 2) with different sizes in conveying direction are supplied along first and second conveyor tracks, gathered into a stack and then folded. The folding of the stacked set (7) takes place with at least one predetermined folding length (a). In response to a difference between the folding length (a) and the size of the sheet (2) of the second size, which is within a predetermined range, the conveyor tracks (5, 6) are controlled by the control structure (9) for combining at least the sheets (1, 2) with leading edges (10, 11) at a mutual distance in the conveying direction (3) and with trailing edges (12, 13) at a mutual distance in the conveying direction (3) to form the set (7). From the combining until the folding, the sheets (1, 2) are mutually fixed and during folding, at least one fold (14) is provided in the sheets (1, 2).

Abstract: The sheets (18) output from an office machine (10) are deposited in stacked form in a sheet depository (16). Combined with the sheet depository (16) is a tray or container (22) in which separating films (20) are stored. The separating films (20) are placed via a guiding device (26) onto the stack of sheets (18) in the sheet depository (16) in order to be able to separate associated groups of sheets (18) in a simple manner.