摘要 |
In an offset duplicating machine, an implement for marking, such as perforating, slitting, scoring or the like, each printed sheet conveyed through the machine; for transverse marking, a first marking strip is affixed lengthwise on an impression cylinder and a rotatable counter-roller is mounted adjacent and at a skew inclination to the impression cylinder; the counter-roller has an outer surface of hyperboloidal shape which allows the strip to progressively mark the passing sheet. By grooving the counter-roller or by varying the distance separating it from the impression cylinder, additional marking strips may be affixed to the impression cylinder to provide various marking configurations on the printed sheet.
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