Flexographic printing press - has block belt tensioning cylinder forming auxiliary driving roller

摘要

The flexographic printing press has a frame containing guide rollers and an impression cylinder for the strip material to be printed. The printing mechanism has a supporting cylinder, two coaxial sprockets and a tensioning cylinder, while the printing block is mounted on a perforated endless belt. A drive mechanism for the belt acts via the sprockets, while an auxiliary one prevents the sprocket teeth jumping between the perforations. The tensioning cylinder (13) forms the driving roller for the auxiliary drive mechanism (17), while the supporting cylinder (3) rotates freely. The impression cylinder (2) is in fixed bearings in the frame (15), while the belt with tensioning and supporting cylinders is adjustable in the frame in relation to the strip material passing round the impression cylinder. An adjusting unit (32) is provided to the auxiliary drive, exerting an additional force on the belt (8) such as to be greater than the difference between the rearwards displacement force generated when the block passes through the gap (1) between the strip material and supporting cylinder and the maximum force generated by the sprockets (6) on the belt. When not printing, this force is less than the maximum exerted by the sprockets. ADVANTAGE - Simple matching of main and auxiliary drive mechanisms.