February 12, 2009

Particles from laser printers may harm

Australian researchers found that the ultrafine particles of laser printers form from vapors produced when the printed image is fused to the paper.

Study leader Lidia Morawska of Queensland University of Technology's International Laboratory for Air Quality and Health said the researchers aimed to answer questions raised by earlier findings that almost one-third of popular laser printers emitted large numbers of ultrafine particles.

The tiny particles are potentially dangerous because they can penetrate deep into the lungs, Morawska said.

In the printing process, toner is melted and when it is hot, certain compounds evaporate and those vapors then nucleate or condense in the air, forming ultrafine particles, Morawska said in a statement. The material is the result of the condensation of organic compounds which originate from both the paper and hot toner.

The researchers compared a high-emitting printer with a low-emitting printer and found that there were two ways in which printers contributed to the formation of these particles.

The hotter the printer gets, the higher the likelihood of these particles forming, but the rate of change of the temperature also contributes, Morawska said. The printer with better temperature control emitted fewer particles.

The paper is available at: http://pubs.acs.org/doi/abs/10.1021/es802193n.