GERMANY • In an application report, Rheintacho announced it has a solution for quality control for this task: On an 8-colour flexo printing press, there is a web-inspection system whereby several individual frames are automatically sent to a monitor every second over the entire width of the material using a mobile camera. Since these are only snapshots, the operator has to check the print quality randomly, in addition to manually, while the machine is running.
The examination criteria are
- A positive typeface will often be printed in a differently coloured, recessed negative typeface. The two images have to be superimposed precisely, so that the base material, such as white paper, does not show through on the edges of the font.
- The typeface may not fray at the edges
- There may not be any printing lapses (the printed image appears porous).
Its solution is to use its RT Strobe 10000 LED stationary stroboscope so the complete web width can be illuminated, and quality control is quicker and more effective, the company said. Printing errors that only occur at the edges of the material web can be recognised.
The brightness can be adjusted to the material/printing image so that reflections can be prevented. The strobe has 480 high-power LEDs and can illuminate up to a 100 cm (39”) area, according to the company.