Importance

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Abstract

In a printing press, a ductor assembly for transferring ink from a slowly rotating fountain roll to a rapidly rotating ink receiving roll includes a carriage and first and second idler rolls supported in counterrotating engagement on the carriage. In one embodiment, the ductor assembly moves between a first position in which the first idler roll contacts and picks up ink from the fountain roll, and a second position in which the second idler roll contacts and transfers ink to the ink receiving roll. The ductor assembly is driven to rotate at a speed intermediate the speeds of the fountain roll and the ink receiving roll, in a direction the same as the direction of rotation of the second idler roll about its own axis, and opposite to the direction of rotation of the first idler roll about its axis. When the ductor assembly moves to the second position, the surface of the second idler roll which contacts the ink receiving roll is moving in the same direction as the surface of the ink receiving roll, and is moving with a speed about equal to the speed of the ink receiving roll. This minimizes speed mismatch. In another embodiment, the rotating ductor assembly is fixed in position and the ink receiving roll moves into and out of contact with the ductor assembly.

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First Claim