The signatures are gathered into book blocks in the SigmaCollator gathering machine. In order to be able to drive the printer and the signature folder at  a continuous speed, the SigmaCollator must process the paper without interruption. The perpetual signature flow is handled through the fact that the sheets are stacked alternately in two gathering trays into book blocks. The fully automated SigmaCollator changes the format and thickness cycle-precisely during production.

Buffering /intermediate delivery
Between the SigmaCollator and the perfect binder, SigmaBinder, a buffer system is inserted which can uncouple upstream and downstream processes when required. The buffer can also  be used as intermediate delivery for signature stacks which, for example, are to be fed to other finishing processes.