Acoustic characterisation of film splitting in a HSWO printing nip

An acoustic technique for investigation of ink film splitting was further developed and applied to monitor printing of light weight coated (LWC) papers on a heat-set web offset (HSWO) press. The acoustic average power from the nip exit was found to decrease with decreasing ink amount and ink tack and increasing fountain solution amount. When printing on the lower side, the average power increased with surface pore area of the LWC papers, presumably connected to tack build during the extended contact time with the blanket. The method is non-destructive, statistical, and readily automatable, with applications both as on-line sensor and research tool for probing dynamic interactions during ink transfer.