| 摘要 |
This invention relates to a printing press, comprising an impression cylinder and a plurality of printing units, which include plate cylinders, which are movable into and out of engagement with the impression cylinder, also comprising a driven central gear, which is coaxial to the impression cylinder and in mesh with all plate cylinder gears. To accomplish the object which resides in the provision of a printing press which is of that kind and which permits also the use of plate cylinders having a plate length which is not exactly equal to an integral multiple of the tooth pitch so that the peripheral length of the plate cylinder is not an integral multiple of the tooth pitch of the central gear, the central gear is operatively connected to a gear that is secured to the stub shaft of the impression cylinder by a gear train which includes a differential gear train, which has an input member that is adapted to be driven by an infinitely controllable transmission, a stepping motor or the like, at such a modifying speed that the impression cylinder will rotate at a peripheral velocity which is equal to the peripheral velocity of the plate cylinders.
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