Type of Devices:

Dot Matrix Printers

These printers are raster output devices needing scan conversion of vector images prior to printing. It contains 7 to 24 thin pins of stiff pieces of wires which may be individually fired to strike a ribbon against the paper. Thin wires are arranged in the form of matrix on a printer head which moves horizontally across the paper. Printing mechanism includes the electromagnetic release of one or more of spring steel mounted wires. Hence, the addressability of a dot-matrix printer need not be restricted by the physical distance between pins on the print head. There may be two columns of pins, offset vertically by one-half the interpin spacing.

Otherwise, two passes over the paper may be used to achieve the same effect, by advancing the paper by one-half the interpin spacing among the first and second passes.

Coloured ribbons may be utilized to produce colour hardcopy. Two approaches are possible. The first is utilizing multiple print heads, each head with a different colour ribbon. On the other hand and more commonly, a single print head is utilized with a multicoloured ribbon.