Summary

After anilox-letterpress and flexo, keyless inking systems have now also reached offset printing. More than 350 such printing couples are already in operation world-wide - the majority in Japan, but also in Europe and the U.S.A. - and it is predicted that this figure will have doubled by the end of 1990. The versatility of the inking system configurations would seem to indicate that a great deal still appears to be in a "state of flux". With this research project, IFRA has set out to clarify the situation, and to highlight development shortfalls that continue to exist. These include the optimisation of the inking systems, on the one hand with regard to reaction time and on the other hand over- sensitivity to damping system fluctuations, increasing the exactness of the inking systems themselves, and last but not least, the wear of the doctor blade on the relatively rough, ceramic-coated engraved roller (anilox roller), which results in a changed ink transfer behaviour. Although this project represents only an initial approach to the many problems involved, it provides a basis on which other projects aimed at achieving solutions can build. Accordingly, we recently started a project that shall investigate the emulsifying behaviour of offset inks in anilox inking systems and seek ways to delay this by so-called refresh systems. Another, as yet unresolved, problem concerns the requirement for different ink film thicknesses, or pigment concentrations respectively, in colour printing, with a single and consistent cell volume of thetengraved rollers. We at IFRA are convinced that anilox-offset is the correct way to combine printing quality and efficiency. But no success can be achieved without first investing a great deal of effort. As a research organisation, we are willing to make our contribution.