Patent ID: 8109134

Claim:
A method for determining a degree of hardening or drying of one or more printed ink and/or coating films on a substrate selected from the group consisting of paper, cardboard, plastic film and composite materials, wherein a mass production printing processes selected from the group consisting of intaglio printing, flexographic printing, screen printing or offset printing is used, the method comprising: measuring a change in the mechanical and/or viscoelastic properties of the ink and/or coating films on the substrate resulting from the hardening or drying process wherein measuring the change in the mechanical and/or viscoelastic properties of the ink and/or coating films comprises generating a surface wave in the ink and/or coating film and measuring the energy density on the transit path of the surface wave; and determining the degree of hardening or drying indirectly based on the measured change in the mechanical and/or viscoelastic properties of the ink and/or coating films.