Dot Matrix refers to the way the printer creates characters or images on paper. This is done by several tiny pins, aligned in a column, striking an ink ribbon positioned between the pins and the paper, creating dots on the paper. Characters are composed of patterns of these dots by moving the printhead laterally across the page in very small increments.

The pins, contained in the printhead, are about one inch long and are driven by several hammers which force each pin into contact with the ink ribbon (and paper) at a certain time. The force on these hammers comes from the magnetic pull of small wire coils (solenoids) which are energized at a particular time, depending on the character to be printed. Timing of the signals sent to the solenoids is programmed into the printer for each character, and translated from information sent by the computer about which characters to print.

The major advantage of the dot matrix printer is that it is versatile, being able to print letters in italics or bold simply by changing the way dots are arranged on the paper. Additionally, dot matrix printers are relatively inexpensive compared to other methods such ads laser printing. Finally, dor matrix printers are used when impact on the paper is used to print carbon copies of forms, etc. The Proprinter has nine pins.

 

 

copied from http://bits.me.berkeley.edu/develop/PROPRNT3/DOTMATRX.HTM