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Summary:
Higher efficiency of the whole production chain, from paper making to printed product, is one of the key issues when optimising different processes. Fan-out and register errors caused by web widening and lateral movements of paper web are of serious concern for newspaper printers. The existing control methods for web widening (fan-out controls) cannot sufficiently compensate for the widening variation if different reels have unequal widening tendencies. In this study, measurement data was gathered and analysed from paper mills and from a printing press. The aim was to clarify the reasons for web widening and lateral movements of the paper web. Fan-out and register errors have been traditionally measured with time consuming colour register measurements. In this study a set of line-scan cameras was used to measure web width and position before and after the printing units in a coldsetoffset press. This arrangement allowed non-stop, on-line measurement and thus several hundreds of reels were analysed. The method for dynamic web deformation measurement is introduced. The effect of paper properties and press conditions on paper web widening and lateral movements in the press is discussed.