Washington, December 3 : A team of German and Australian researchers has unearthed evidence that laser printers release particulates into the air.
Researchers at the Fraunhofer Wilhelm Klauditz Institute WKI in Braunschweig say that they found these evidence while investigating, in collaboration with colleagues from Queensland University of Technology QUT in Brisbane, whether laser printers release pathogenic toner dust into the ambient air.
They said that they also wanted to know what kind of particles could the printers really emit, and in what quantities.
Numerous reports in the past have suggested that laser printers release hardly any particles of toner into the air, say researchers.
"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," the researcher adds.
The team have even developed a process to determine and compare the quantity, size and chemical composition of the emitted particles, with technical and financial assistance coming from the printer and copier manufacturers in the German Association for Information Technology, Telecommunications and New Media (BITKOM).
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," says WKI scientist Dr. Michael Wensing.
The team say that high temperatures cause volatile substances such as paraffins and silicon oils to evaporate, which then accumulate as ulta-fine particles.
The Braunschweig scientists 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.
The researchers even studied whether filters available on the market to reduce such printer emissions are of 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," they say.