We regularly hear reports that laser printers release pathogenic toner dust into the ambient air. How much of it can we believe? What kind of particles do the printers really emit, and in what quantities? Researchers at the Fraunhofer Wilhelm Klauditz Institute WKI in Braunschweig are investigating this question in collaboration with colleagues from Queensland University of Technology QUT in Brisbane, Australia.
The results are surprising: Contrary to numerous reports, laser printers release hardly any particles of toner into the air. “But what some printers do emit are ultra-fine particles made of volatile organic-chemical substances,” says WKI head of department Prof. Dr. Tunga Salthammer. “One essential property of these ultra-fine particles is their volatility, which indicates that we are not looking at toner dust.”
So where do these ultra-fine particles come from? And how can their emergence be explained? To discover the answer, the scientists have developed a process that enables them to determine and compare the quantity, size and chemical composition of the emitted particles. Technical and financial support was provided by the printer and copier manufacturers in the German Association for Information Technology, Telecommunications and New Media (BITKOM). Depending on their dimensions, the printers are housed in a test chamber measuring one or 24 cubic meters. Particle analyzers count the particles and measure their size distribution. To discover the source, the researchers also examined modified printers that “print” without any paper or toner. “The amazing thing is that the ultra-fine particles are still produced even in this case. The cause is the fixing unit – a component that heats up as high as 220°C during the printing process in order to fix the toner particles on the paper,” explains WKI scientist Dr. Michael Wensing. The high temperatures cause volatile substances such as paraffins and silicon oils to evaporate, and these accumulate as ulta-fine particles.
The scientists from Braunschweig observed similar phenomena – the formation of ultra-fine particles of volatile organic substances when heated – during typical household activities such as cooking, baking, or making toast. Filters are available on the market to reduce these printer emissions. But are they any use? “Our investigations show that the various external filters on offer for printers operate in very different ways. As the ultra-fine particles are not emitted from a specific part of the printer, but also from the paper output, for instance, a filter can only have a limited effect.”
Prof. Dr. Tunga Salthammer | alfa
Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University
Direct conversion of non-neuronal cells into nerve cells
03.07.2018 | Universitätsmedizin der Johannes Gutenberg-Universität Mainz
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences