| 摘要 |
<p>A printing belt (12) extends around a rotatable cylinder (30) having independently rotatable belt drive sprockets (40) at the opposite ends thereof. A torque-assist drive (86, 90, 114, 116 etcetera) connected with the cylinder is selectively operable in response to sensors (eg. 62) for imparting supplemental traction to the belt for preventing relative slippage between the belt and drive sprockets.</p> |
