Abstract: A drive system for use with a printing apparatus is disclosed. The drive system includes a plurality of process units, with each unit being adapted for effecting a respective repeat operation on a web of material fed along a path defined at least in part by the process units. The drive system further includes an electrically powered rotary motor corresponding to each of the process units or to one or more rotary elements within a process unit. A control system operates to regulate the running speed and angular phasing of each of the motors individually in relation to a predetermined master standard programmed into the control system. The control system is adapted to vary the relative phase angles of the outputs of one or more of the rotary motors by a preselected factor proportionate to the overall running speed of the apparatus in order to maintain accurate registration of each of the process units relative to the web material throughout a substantial range of operating speeds.