Laser printers and photocopiers, which are usually based on the same principle, use high temperatures to fix the printed image on paper. As a result, substances can be released from the device, paper and toner. There has also been increasing public discussion in recent years about the health effects of the particles emitted by these devices.
Emissions from laser printers and photocopiers
Laser printers and photocopying systems based on the so-called "electrophotographic" principle are frequently used in everyday work, as they provide fast printing and document authenticity at comparatively low prices. The printed image is applied to the paper with a suitable material ("toner") and this material is then fixed at high temperatures (approx. 200 °C). In addition to the toner, the paper is also heated and both materials can release substances. In addition, laser printer housings and circuit boards are often treated with flame retardants for safety reasons.
Emissions from toner and paper
Toner consists of a large number of different substances and is mostly based on carbon black. In addition, some toners contain heavy metals and solvents. Users should avoid direct exposure to toner dust for health reasons. Modern printing systems therefore usually contain separators in the fan area to prevent the unintentional release of toner into the environment. Heating the paper - especially recycled paper - can lead to the release of substances contained in the paper (e.g. solvent residues, brighteners, etc.). The abrasion of calcium has also been reported. With older printing systems, the electrostatic charging of the toner could also lead to the formation of ozone. However, modern systems no longer emit ozone.
Release of particels
In addition to chemical emissions, the release of ultrafine particles (< 100 nm) from laser printers has also been detected. These particles are not unintentionally released toner particles, which have a larger diameter. Instead, these particles are generated in the fuser unit due to high temperatures. A similar effect can also be observed in household appliances with a heating unit (e.g. toasters). Chemical substances are suddenly released at high temperatures and condense into small particles in the air. For this reason, a large proportion of the released particles (approx. 99.8% - 98%) can be vaporized.
Discussions about negative effects on health
When laser printers and copiers are used and maintained properly, no toner particles are released during operation. However, if the user is exposed to toner particles, this can have negative health consequences. With regard to chemical emissions, the minimization principle (see also section below) and the guide values for indoor air apply. Overall, the acute health effects of printer emissions were investigated in a project by the German Social Accident Insurance (DGUV) and the results were published in 2014. In this study, 52 test subjects were exposed to printer emissions for 75 minutes using a standardized procedure. The authors came to the following conclusion: "Based on these results, we believe that the high short-term exposure in the manner in which it occurred should not be classified as a cause for concern from a clinical perspective."
Emission testing and the "Blue Angel"
Emissions from electronic devices are tested in so-called emission test chambers. For laser printers and copiers, there are criteria for the amount of chemical compounds and ultrafine particles released as well as various operational parameters (e.g. energy consumption). The devices must be tested according to a precisely defined procedure. Devices that meet the criteria can be awarded a "Blue Angel" (award criteria DE-UZ 205219).