| 摘要 |
The invention relates to a rotary printing unit of a flexographic printing machine, in particular for plastic films, having cylinders arranged axially in parallel, namely a forme cylinder having the printing forme on its outer surface, a back pressure cylinder assigned to the forme cylinder, and having rollers of an inking unit bearing against the forme cylinder, the axes of the cylinders and rollers having gearwheels which mesh with one another. The dimensions of the printed image printed off on the material to be printed are dependent on the circumference of the engaged forme cylinder. In order to make the dimensions of the printed image independent of the forme cylinder, provision is made according to the invention for the back pressure cylinder to have an outer tubular casing which is mounted rotatably on bodies located in the tubular casing, for each body to be mounted so as to be rotatable eccentrically on the axis of the back pressure cylinder, and for at least one of the eccentric bodies to be operatively connected to an actuating element for its rotary adjustment about the axis of the back pressure cylinder. The back pressure cylinder can thus always be pressed against the forme cylinder when printing is to be carried out. The printing forme located on the forme cylinder no longer prints with each revolution of the forme cylinder, but only when the back pressure cylinder is pressed against it. The eccentric bodies can also be arranged in the gearwheels in order to adjust the axis of the back pressure cylinder. Figure 1 is particularly suitable for illustrating the invention. <IMAGE>
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