To provide for temporary storage of freshly printed signatures (6), transported by a continuously moving product transport gripper chain (4, 5), a plurality of pocket structures (12), each of which includes a plurality of connected sheet-like elements (16,17) which, between each other, define pockets (15), are provided. The sheet-like elements are arranged for pivotable movement about an end portion to permit fan-like spreading out of the elements for reception in the pockets of, for example, one product or signature delivered by the transport system. Storage units are provided to store empty pocket structures and to receive pocket structures which are filled with signatures. The storage structures, preferably, are formed of separate sheet-like elements connected together, and engaging the signatures at marginal portions, so that access can be provided to the signature, for example from below, for compressed air or other drying gas, to dry the fresh ink on the signatures, for example when placed within the storage units (26). To space the sheet-like elements, preferably, a small projection or tab is placed on them at facing surfaces, in the region of the margins of the signatures, that is, in non-printed areas thereof.