Unfortunately, the technology used in laser printers makes ozone an inherent by-product of the printing process. The level of emission depends on where and how a printer is kept. Areas with large concentrations of dust, small enclosed offices or poorly ventilated rooms can cause high ozone intensity. Some printers contain filters to limit ozone concentration to levels below standards which have been established by various bodies – the American Conference of Governmental Industrial Hygienists, for example. After a certain number of pages have passed through a printer (usually about 150,000) the filter should be replaced by an authorised service engineer.
Power-saving abilities are also becoming important in laser printer design. The Environmental Protection Agency (EPA) has stipulated that for a printer to gain Energy Star Compliance, it must dramatically reduce its power consumption when not being used. The power saver usually works by warming up the printer only when it is sent a job. If the printer is left idle for a certain period of time, the printer’s power consumption is reduced. Usually this period of time can be altered by the user and, if preferred, the power saver can be turned off altogether.