Print quality issues concerning inkjet printing of colour and electronics on paper

The market value of the digital printing technologies electrophotography and inkjet is expected to grow during this decade. The introduction of multicolour high speed inkjet machines in recent years has again turned print quality into an important issue. In addition, the combination of digital printing and traditional printing technologies for variable data print production requires paper and ink which gives good and comparable print quality using different printing technologies. Printed electronics, most commonly utilizing the printing technologies screen, gravure, flexography or inkjet, is forecasted a bright future. The interest in paper as print media for printed electronics and flexible electronics has recently increased, mainly due to the widespread usage of paper, the low cost of paper, and due to the fact that paper is produced mainly from natural renewable resources. The requirements on the print concern here not primarily the visual impression, but rather the functionality, for example the conductivity of printed tracks.We have studied the effect of surface treatment of paper on inkjet print quality; we have looked more closely at the effect of different paper surface parameters, and shown that these parameters can have a large impact on both chroma and detail reproduction when printing with pigmented inkjet inks. Combination of inkjet with traditional printing technologies can give good print quality when carefully combining printing technology, ink and print media. Moreover, some knowledge concerning printing of colour may be transferred to the field of printed electronics, although the prerequisites on the print products are quite different. We have studied how the surface properties of coated paper affects the electrical conductivity and the print quality of inkjet printed electronics. In addition, coating of paper surfaces by laboratory methods and evaluation of functionality has been performed. The work is a base for our ongoing research on adding of functionalities to paper and packaging in a flexible and cost efficient way by utilization of printing technologies and novel materials.