Quantification of piling

Piling problems can occur in many lithographic printing applications. It involves the build up of material on the blanket surface which leads to unacceptable print quality. To remedy the problem the blankets need to be cleaned during the production. This cleaning takes time and materials to complete, adding cost to the production. The aim of this work program has been to understand the performance of a heat set web offset press with respect to piling, to allow subsequent optimization. This paper presents results from a large experimental programme evaluating the problem of piling. There are a number of different techniques available for the measurement of piling, which are discussed and compared experimentally during the program. The parameters assessed include paper, blankets ink and fountain solution. A design of experiment approach was required for the trial to facilitate the analysis, reducing the number of trials by seventy five percent. The results show the impact of the different process parameters on the piling and the print quality.