Liquid Toner Fails German Mill’s De-Inking Trial: HP’s Response

By | November 9, 2010

Earlier this year, paper engineers at a German paper mill noticed a significant “dirtying” of the paper pulp, with “alarming” numbers of dirt specks showing up in control samples. Ultimately, liquid toner prints from a photo book printer were identified as the source.

Although the percentage of liquid toner prints was less than 10% of the total volume of recycled stock being processed, the mill ultimately diluted the stock even further. Ultimately, the mill’s report concluded that liquid toner prints not be used for recycling.

To view the actual report (courtesy of Genesis Marketing), click here.

In today’s world of green everything, this report really caught my eye. HP has long indicated that its prints are de-inkable, but as the volume of digitally printed photo books grows, the question becomes whether these extremely heavy coverages change the de-inking equation. If so, what impact does this have on recommendations for de-inking of liquid toner prints?

I contacted HP for its take on the issue. It took a little while, but here is the response from Jeffrey Belson, regulatory manager, Indigo division, HP:

HP has not seen or analyzed print or pulp samples from the incident INGEDE described in its Oct. 2010 press release on a German deinking mill. HP has already established plans to engage with the mill described in the press release to help assess and understand this incident.

HP Indigo’s Deinking Research program, and HP’s expertise in printing technology, could be of significant assistance in identifying the prints involved, analyzing the deinking mill incident and supporting additional tests as appropriate.

The Deinking Research program continues to emphasize collaboration, scientific research and the identification of solutions that meet the common objectives of the paper-making, printing and deinking industries.

Western Michigan University, working under the direction of NewPage Corporation, has completed a successful pilot-scale trial that confirmed deinkability of a batch consisting of 5% HP Indigo prints (a random mix of customer prints) and 95% standard mixed office waste furnish using NewPage’s standard process conditions.

HP considers this positive pilot trial result and additional research from HP’s Indigo division to provide a foundation for understanding deinkability at other wood-free deinking mills.

Note that the trial was 5%, while the German mill was working under a 10% max, so the volume of liquid toner prints could have been up to double what was used in the NewPage trial. We also don’t know the coverage used in the NewPage trial and how this might affect the percentage of liquid toner prints allowable in a batch.

Clearly, we still have a lot to learn about the impact of digital inks on the recycling process. Watch for this to grow on the radar screen with the tidal shift toward inkjet, as well.

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9 thoughts on “Liquid Toner Fails German Mill’s De-Inking Trial: HP’s Response

  1. John Roberds

    My understanding is that the De-Inking industry association in Europe, INGEDE, announced at drupa in 2008 that both inkjet and liquid toner printed material failed to meet their standards for de-inking. Here is a link to their press release:

    HP says that Indigo output can be recycled if the mill uses specific processes, e.g., changing their chemistry, but most mills can’t afford the cost of the modifications to their plants just to accommodate liquid toner and inkjet prints. HP has tried to ignore the issue or confuse the discussion but the reality is that de-inking isn’t working with Indigo output and they don’t have a viable solution.

    It will be interesting to see how this is worked out because I imagine it is hard for a de-inking mill to exclude liquid toner output from their raw materials in order to avoid contamination of their product. HP seems to want to avoid this issue, at least publicly, but that won’t make it go away. Heidi’s reporting is important to get them to address what is a big problem for recycling printing.

  2. Pat Berger

    This is just the beginning of total disregard for the paper recycling industry.

    The recycling industry has been warning of this type of problem for years.

    The most sophisticated recycling mill in Europe couldn’t get the job done

    Does the book manufacturer get charged for the 140 tons of waste or downgraded paper.

    It is quite possible that there could be an outright ban on this type of printing technology.

    Will Inkjet will be next cause of a major mill problem?

    Printing companies that practice good paper recycling house keeping now have a premium product. Good clean recycleble and deinkable fiber should be worth a few cents more per pound.

    As always if the industry doesn’t clean up it’s act some government will show you the way.

  3. Anuraag

    I wonder if this is specific to liquid ink or just that HP Indigo produces the most photo books in that region.

  4. Axel Fischer (INGEDE)

    @Heidi: There are already special recycling plants to handle this material: they produce corrugated board. But for any special treatment, the material has to be collected separately from other graphic paper. The first step is already being done. Recovered paper merchants will not pay for Indigo waste at photobook printers any more (that material has been premium quality at a premium refund compared to household collection). This fraction will now be taken separately. Liquid toner prints will be excluded in the specifications of recovered paper for deinking.

    @Anuraag: This is specific to liquid toner. Only liquid toner leaves these thin, elastic, large film bits that slip through the screens and cannot be removed completely.

    @Pat: Yes, we had our first press release when we saw these problems in the lab nine years ago. HP has done a lot of questioning our methods and designing experiments to simulate conditions under which Indigo prints are claimed to be deinkable. But this incident now is real — real overprint, a real mill, real process conditions and a real huge damage. More than 100,000 Euro missing at the end of the day. The mill is definitely not happy about this, but you can see this as the ultimate and most expensive trial in the best mill you can imagine – no further simulations necessary. And no assistance of HP to identify the prints or analyze the incident. We will suggest to HP to rather analyze why the process conditions of their pilot plant trials differ so much from European reality.

    @Heidi: Less than 10 percent was a first cautious estimate. After re-calculating all inputs and mixing, the mill now says the input must have been less than 3 percent.

    @Robert: Right. Changing the chemistry for a compound of less than 3 percent (and usually way less) is something no mill can afford. The chemistry suggested by HP leads to significant yield losses for the majority of the raw material. If you process 2,000 tons of recovered paper a day, losing only 1 percent would mean 20 tons less product and 20 tons more waste to dispose – every day. With the HP chemistry, yield losses in the lab are above 10 percent.

    Keeping liquid toner prints away from the paper recovery stream is actually difficult. What we can do is collect it separately at the printer (overprint, test runs etc.). We can not at the consumer level. Here only some labelling can help. We will see how the German EPA will handle this. There is a line in our environmental law saying if a new product harms an existing recycling cycle, it has to be labelled. This could become the first application of this rule.

  5. Axel Fischer (INGEDE)

    I forgot to clarify one point: Other than the original headline might suggest to the hasty reader, this has not been an intentional trial. It was an expensive accident the mill would rather have avoided.

  6. Axel Fischer (INGEDE)

    @Pat: No, the printer will not and cannot be charged. There have been indications but no proof that Indigo can cause problems. His waste paper was believed to be suitable raw material. From now on the situation is different.

  7. Pat Berger

    Heidi just about anything is recyclable. If it can be done profitable someone will do it.

    The HP INDIGO cured inks are a plastic.

    If you would take various colored sheets of plastic .002 thick, shred them into very small pieces about about .1mm to 1mm in sizes, throw them into a batch of pulp how would get the colored plastic out of the pulp?

    This is the same problem that the recyclers are having to deal with.

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