Most digital printing machines are based on photocopier technology using different coloured powders baked onto the surface of the paper to produce the image - although some do use their own specialist inks.
Inkjet printers (office desktops, photo and large format 'sign printing' machines) also come under the banner of digital printing.
Digital printing has a higher cost per page than lithographic printing but this price is usually offset by avoiding the cost of all the technical steps required to 'make-ready' a modern lithographic printing press.
The quality is not yet up
to the standard of modern litho printing - but the man in the street would
find it difficult to spot the difference.
These systems work directly from electronic
data and avoid the intermediate stage of printing plates. Because these
machines use an inherently four-colour process (CMYK) there is no cost saving
to be made from using one or two-colour designs.
For more information about
printing processes visit Wikipedia - click here.