| 摘要 |
To permit selective operation of two printing couples (1, 2, 4, 5) for printing, on a continuous web (7) respectively double-image prime printing (FIG. 1), single-image prime printing (FIGS. 3, 5), while permitting flying plate changes of one of the plates of a disengaged printing couple, or prime and verso printing (FIG. 7), two impression cylinders are provided, engageable with the blanket cylinders of the respective printing couples, the impression cylinders being spaced from each other by a gap sufficient to permit passage of the web therebtween when the system operates in the prime-and-verso printing mode, with a gap sufficient so that freshly printed subject matter will not be smeared by contact with the respective impression cylinders. All the gearing is arranged on one side of the machine and a single main drive gear (8) is in selective driving engagement with gears located on shafts coupled to the respective cylinders, selective engagement and disengagement and direction of rotation being effected by engagement of clutches (9, 10, 11) located at the ends of the shafts. The arrangement of the gears and clutches permits easy assembly and maintenance.
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