Paper run

As paper traveling in is printing technique to transport the paper sheets ( sheet run ) and the paper web within the print engine designated by the feeder to the tray. In addition to the rollers of the printing unit, suction and blowing air are used for this purpose.

When setting up the printing machine at the beginning of a print job, the paper flow is set first, then the color guide and register accuracy during the proofing . For a good print result in color printing, the paper flow in the entire printing unit must only fluctuate by a small fraction of a millimeter. This is the Passer determined -Accuracy and with the grid: the aim is that precisely as possible inkwell Drops on ink cup-drop falls, even if the paper flow from one color to the next, from printing unit to printing unit a distance of over ten meters has For example, in rotogravure printing for weekly magazines with a circulation of millions such as Stern or Der Spiegel .

In multi-color printing, this register accuracy is checked at the edge with test strips and monitored by electronic measuring and control devices (using sensors and register regulators ), which can only compensate for small fluctuations, but no general errors in the paper flow. The register accuracy with a given raster over sometimes up to seven color printing units is ultimately an overall measure of the quality of the printing operation, including the exact paper flow.

The wider the printing units and the faster they run, the more important it is to have a good paper flow. This is also decisively influenced by the uniformity of the fibers in paper production. Today's gravure presses achieve printing widths of 2.80 m and running speeds of 60,000 cylinder revolutions per hour. Bad paper flow can lead to large amounts of waste : printing results that may not be used in the end product, i.e. that represent scrap.