The relationship between tack and linting in offset printing of newsprint grades

Abstract

Linting is the removal of material from the surface of newsprint grades during offset printing. Excessive linting can reduce image quality and press productivity. Ink tack is the force exerted by the filaments of the ink film as it splits. For this study, ink tack at the exit of a laboratory printing nip was measured for seven batches of newsprint and eight batches of an improved, higher brightness newsprint grade. The average measured tack for the seven batches of newsprint was 30% higher than for the eight batches of improved newsprint. For these batches, we measured lint using tape pulls after printing 8000 copies on a sheet-fed offset press with solid blocks and 50% screen. The average lint on solid and 50% screen was 32% and 28% higher, respectively, for the improved newsprint compared with the newsprint. The apparent inverse relationship between lint and tack force was unexpected.