Flexographic Printing of Linerboard

This paper addresses issues that are important to high quality flexographic printing of linerboard. The research includes a comparison of an objective measure of print quality to a subjective measure. The paper also identifies sheet properties that lead to improved print quality and the papermaking process variables that contributes to the development of those properties. An excellent correlation was obtained between subjective and objective measures of print quality. Hence, simple, readily available, cost-effective image analysis software and hardware may be used. The work also shows that print mottle is the overriding factor influencing perceived print quality. An excellent correlation was obtained between subjective and objective measures of print quality. Hence, simple, readily available, cost-effective image analysis software and hardware may be used. The work also shows that print mottle is the overriding factor influencing perceived print quality. By correlating sheet properties to print quality, a number of sheet physical properties that contribute to good printing were isolated. Those properties include L*a*b* color, Gurley air permeability, and to a lesser extent freeness and micro roughness. Additionally, it was observed that printing press clearance (loading) can have a major impact on print quality. By correlating sheet physical properties to papermaking process variables, it was determined that method of pressing, press impulse, calendering, and freeness impact these important sheet physical properties.