Drive means is provided for printing apparatus of the kind comprising a plurality of process units (12-20) each for effecting a respective repeat operation on web (22) or sheet material fed along a feed path defined at least in part by said units (12-20). The drive means comprises an electrically powered rotary motor (25-40) individual to each said unit (12-20) or to one or more rotary elements (14a, 14b, 16a, 16b, 18a, 18b, 20a, 20b) within a unit, and control means (42) operating to regulate the running speed and angular phasing of each said motor (25-40) individually in relation to a predetermined master standard programmed in to the control means (42). The control means (42) further includes speed correction means for varying the relative phase angles of one or more of the motor drive outputs by a preselected factor proportionate to the overall running speed of the apparatus to maintain accurate registration relative to the material of the various operations carried out by said units (12-20) throughout a substantial range of operating speeds.