Details:
Summary:
Scumming produces major quality problems in rotogravure printing. It causes a discolouration of the non-image area and is particularly noticeable when printing on clear film. This can cause entire print runs to be rejected. There is currently little knowledge and understanding of causes for scumming. This paper discusses the results obtained from an extensive industrial trial to evaluate the effect of the cylinder surface on the level of scumming. A rotogravure cylinder was used, with the bands of different surface characteristics. The press was monitored for temperature using thermocouples and doctor blade load with strain gauges attached to the blades. The prints were then produced at a number of controlled conditions. The prints produced have been measured using densitometry and spectrophotometry. The results have shown it is necessary to measure using the colour space data, even with process colours. The different surfaces showed a significant difference in the level of scumming on the substrates used. A relationship has been identified between the surface and level of scumming.