Arjowiggins already had a strong relationship with HP producing papers certified for its printing machines, but following customer queries in the wake of liquid toner problems at a German de-inking mill last year it decided to open up its advanced Greenfield mill for industrial scale pilots.

"There's a natural synergy between digital printing and recycling paper - they're both aimed at reducing waste," said John Cooper, customer support director at Arjowiggins Graphics. "We want to open up Greenfield, use our expertise and know how to offer input from a practical point of view.

"We have to do the work on an industrial scale to resolve this and I have a vision to set up Greenfield as a centre of excellence for de-inking digital print."

Initial discussions for the project began in April, and a three-month pilot is expected to go ahead by the end of the year.

HP's Nils Miller described the relationship as "a wonderful fit of objectives", adding that while there are no fixed timescales as yet, "Drupa is such an important event, it's a logical goal to not only have successful results under our belt, but also to have something we can publish by then".

HP is a member of the DPDA (digital print de-inking alliance) although the trials are not part of that project, nor is the european de-inking body Ingede party to the scheme. Miller said that HP was undertaking a number of approaches in working with partners on de-inking, but that one to one partnerships can prove particularly successful as it is easier to work under confidentiality agreements.

However Cooper said that the results of the initiative would be shared "in the fullness of time".

Ingede's Axel Fischer said that "the special changes in deinking chemistry that HP has been discussing for a while might work [at Greenfield], so this plant with its wood-free raw material and specialised equipment could show reasonable results for deinking with some inkjet in the mix.

"But this is in no way representative nor comparable to a state-of-the-art newsprint mill processing the wood-containing paper which is the bulk in the european market." He added that the Greenfield mill had a higher loss ratio than a standard newsprint deinking mill would tolerate.
 
Cooper agreed that "Greenfield is different to other facilities used to produce newsprint. I'm not sure there is a direct correlation."

Miller added that while new chemical processes developed at HP Labs may offer profitable results, the goal at Greenfield was to improve deinking for digital print by better understanding and modelling the methods already in place, and optimising them to provide better yields and lower costs.