Deinking is one of the less glamorous environmental issues relevant to paper and print. It is a crucial part of the paper recycling process and quite a complicated process...
Remember that it is not possible to distinguish between different print processes when waste paper is sorted.Current deinking techniques have been developed for offset and gravure inks.
During deinking hydrophobic (water-repellent) ink particles are separated from hydrophilic (water-attracted) paper fibres. Water-based inks, therefore, cannot be removed in this way and stain the fibres and can render a batch of pulp not fit for purspose.
This problem applies to digital printing with liquid toner (inkjet) inks and flexography inks.
Liquid toner (Indigo) inks present a different problem in the deinking process. Due to the ink forming a film, small pieces of ink film become attached to the surface of the paper and can be very difficult to remove.
Dry toner inks do not present any problems during deinking.
It may suprise some people to learn that there is an industry body (INGEDE) that deals solely with issues around deinking. Visit their website to learn more about the processes and issues: www.ingede.com
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