A descendant of the old-fashioned hand-cranked mimeograph machine. Modern duplicators make mono (one coloured) copies faster and cheaper than most photocopiers when copies are made in volume.

The duplicator first takes a digital "snapshot" of the image with a CCD, using a similar method to a home PC flatbed scanner. The duplicator is now ready to make a "master."

Special paper, similar to wax paper is fed off of a roll and through a thermal print head. The print head melts away the wax in the dark areas, and leaves the wax intact in the light areas. The finished master is then wrapped around and clamped to a special drum.

The duplicator drum consists of several layers of metal screens wrapped around a large metal form. In the bottom of the drum is a rubber roller which transfers liquid ink from the ink nozzles to the inside of the screen.

Once the master is made and clamped to the drum, the drum begins to rotate at a high speed. Sheets of paper are fed in from one end, pass rapidly between the drum and a rubber pressure roller, and are ejected from the other end into a collection bin to dry. Each time the drum rotates, one copy is made.

Duplicators are highly efficient when printing in large volumes, but costly and wasteful for small volumes. Each time you want to make a copy of a different original, the old master is ejected and a fresh one made.