Already in existence before the computer revolution,
the photocopier is regarded as rather old-fashioned.
Its basic function can now be done by a fax machine
or a combination of scanner and printer,
but fax machines take just one page at a time
and the scanner-printer combination can be time-consuming.
There are two main types of photocopier, analogue and digital.
An analogue copier works by shining light on to an original document,
reflecting its pattern on to a photosensitive printing drum.
This charges the drum, attracting ink,
which is then transferred to the copy paper
Analogue copiers offer the best value for money for simple copying operations.
With a digital copier, the original pattern is changed
into a digital signal by optical sensors.
This signal controls a laser
which shines on the drum
attracting ink in the same way as the analogue copier.
Large digital copiers reduce paper jams
because each page need to be scanned only once
Colour copiers do not cost much more than monochrome,
but buyers should check print quality on the cheaper models
The best models can make eight-and-a-half copies a minute
in colour and can also act as a printer and scanner.
The big stores usually have a good range of copiers in stock at reasonable prices,
but a local supplier may offer better advice
If you go to one, however, it makes sense to check the supplier's service
because copiers need more looking
after than other office machines