Evaluation of Pressure Variations Generated During Flexographic Post-Print of Corrugated Board and Effects of Mechanical Properties of Printing Forms on Printed Banding

The effect of pressure variations, generated by the use of different printing forms, on printed banding in post-printing of corrugated board was studied. Pressure variations were measured by placing a pressure sensor between the printing form and the corrugated board during printing in a laboratory press. Differently designed printing forms, with different mechanical properties, and one single-wall B-flute corrugated board were used in the investigations. A strong correlation was found between the printed banding, coinciding with the washboarding structure, and the pressure variations in the printing nip. The pressure variations were affected by the compressibility modulus and bending stiffness of the printing forms. A higher compressibility modulus gave higher pressure variations, and a mid magnitude of bending stiffness gave lower pressure variations.