HP Indigo prints are fully recyclable and can be placed in normal recycling collection. Deinking, or removing ink from paper fibers, is one of the key steps in the paper recycling process for manufacturing recycled graphic arts papers. Over the last few years, HP collaborated with a range of industry and academic deinking experts to gather lab-scale, pilot-scale and mill-scale deinking data that verify HP Indigo prints can be deinked in a typical graphic arts paper deinking mill configuration.
In June 2013, Voith Paper, a supplier of deinking equipment, and the Paper Technology Department of PMV Darmstadt, a German technical institute, conducted two pilot-scale trials with five percent and 10 percent HP Indigo feed. The research found that even with 10 percent HP Indigo feed, the pulp produced in the trials was suitable for standard and higher quality graphic arts recycled paper grades.
The trials were held at the Voith Paper Fiber Systems Technology Center in Ravensburg, Germany, for its near-mill-scale equipment, creating a realistic simulation of a standard graphic art deinking mill, including drum pulping, two flotations and one disperger. An important feature of the trial was that disperger energy typical of industry mills was used. A detailed report from the pilot trial will be published in the near future.
“These pilot plant trials have convincingly demonstrated the deinking ability of HP Indigo prints using standard 2-loop deinking processes,” says Jürgen Dockal, product development engineer, Voith Paper Ravensburg Fiber Systems Technology Center. “Proven equipment and standard deinking chemistry can be used, and parameters such as brightness development, ash content and yield are unaffected by the presence of up to 10 percent Liquid ElectroPhotographic prints.”
PMV-Darmstadt has made significant progress in developing a lab scale 2-loop test that correlates with the Voith Paper pilot trial. These results complement two previous deinking trials conducted with Arjowiggins Graphic in France in November 2011 and October 2012. In the mill-scale trials, 5% HP Indigo Liquid ElectroPhotographic prints (LEP) were added to the standard mill furnish. In both cases, high-quality deinked pulp was produced without affecting mill efficiencies.