| 摘要 |
1,237,724. Printing apparatus. SOC. NEBIOLO S.p.A. 8 Oct., 1968 [14 Oct., 1967], No. 47550/68. Heading B6C. [Also in Division F2] To prevent loss of printing register due to torsional twisting of co-operating sheet-carrying members in a printing press, engaging impression cylinders and/or transfer cylinders are provided with auxiliary synchronizing means which correct deviations from the nominal register imposed by the drive to the cylinders. Gripper-bearing cylinders 3, 8 each carry a length of toothed gearing, that on cylinder 3 following an arc of a circle concentric with the cylinder axis C1. The length of gearing on cylinder 8 also follows an arc of a circule, smaller in diameter than that of the length on cylinder 3 and mounted eccentrically with respect to the axis of cylinder 8. As the cylinders 3 and 8 rotate the toothed arcs mounted on them come into contact. Initially the teeth at the ends of the arcs engage, and due to the different diameters of the arcs considerable play exists and relative distortions due to torsion are accommodated. When the central parts of the arcs engage however, no play is possible, and the cylinders are forcibly brought into synchronism during transfer of sheets between grippers 24 and 23. Transfer cylinders linking two rotary offset printing units may be synchronized by pairs in this way, so that a sheet may receive two impressions in register. |
