Method and apparatus for synchronously controlling the printing speed of belt-type printing machine

Abstract

Method and apparatus for synchronously controlling a printing speed of a belt-type printing machine including a plate cylinder, a tension roll for adjusting a distance between the plate cylinder and the tension roll, and an endless printing belt detachably wound around the plate cylinder and the tension roll. According to the present invention, sprocket wheels each having thereround sprocket pins for engaging perforations of the endless printing belt are rotatably mounted on the plate cylinder so that the sprocket wheels have no function of driving the endless printing belt and are only intended to guide the belt along a predetermined path and prevent it from lateral movement relative to the plate cylinder. The endless printing belt is driven only by a frictional force between the peripheral surface of the plate cylinder and the belt. With independently detecting the number of rotation of the sprocket wheels, i.e. the travelling speed of the endless printing belt and the rotational speed of the plate cylinder, i.e. the reference speed of the printing machine, an error between these speeds, if any, is corrected to synchronously equalize these speeds by a differential gear unit to which main drive for driving the plate cylinder and sub-drive for correcting the error are inputted.

Dependencies are inferred from the claim text.