| 摘要 |
Device for axially reciprocating a printing-unit roller having a stationary shaft and a roller jacket rotatably driven by friction drive, the device being disposed within the printing-unit roller and being driven by rotational movement of the printing-unit roller, including drive means for effecting axial reciprocation of the printing-unit roller at a speed reduced with respect to the rotational speed of the printing-unit roller including two roller bearings disposed within the printing-unit roller between the roller jacket and the shaft, a first bushing revolving as a cage associated with the roller bearings and being formed with a first groove, a second bushing fixed in the roller jacket and formed with a second groove, one of the grooves being of elliptic form, and a ball being received simultaneously in both of the grooves and being rollable therein. |
