Abstract: A method of buffering and controlling the tension of a print substrate moving through a web press comprises: supporting a loop of print substrate on a movable roller, wherein translational movement of the roller is controlled by a motor; and controlling the motor to achieve a sequence of roller movements arranged to control tension of the substrate during a sequence of variations in substrate velocity during a printing cycle.

Abstract: Apparatus for cyclically printing information on a moving web utilizes a stationary printing head at a printing station along the path traversed by the moving web and a roller which guides the web and sweeps the web across the printing head in the direction opposite to web advancement so that there is substantially no relative movement between the web and head as printing occurs. The roller is supported for sweeping movement back and forth over the printing head by means of a pivotal linkage driven by a crank which causes the guided web to engage the head during a sweep in one direction only. A cyclic drive for the linkage includes an eccentric gear set to modulate the speeds of the roller and web.