Ozone (O3) (of Greek: ozein = smell, due to its smell) is an unstable molecule consisting of three oxygen atoms.
For example Ozone forms with a thunderstorm. Because of it´s unloading lightning and the surrounding oxygen ozone is formed from the electric current zone.Modern printers and photocopiers work with a transfer role technology, which prevents the ozone formation and which older high voltage technology replaced as far as possible. A few older printers still have a high voltage unit using a corona wire, which is needed to charge the photoconductor drum or belt. These machines are equiped with an ozone filter to minimize ozone in the air surrounding the printer.