How the serial dot matrix printers work?
As the printer head moves in horizontal direction, the printhead controller sends electrical signals which forces the appropriate wires to strike against the inked ribbon, making dots on the paper and forming the desired characters. The most commonly used printer heads has 9 print wires in one column (9-pin printheads) or 24 print wires in two columns (24-pin printheads), for better print quality. In some heavy-duty dot matrix printers there are also used 18 wire print heads (18-pin printheads) which have 2 columns, 9 wires in each. The printing process of a 9-pin printer head is shown at the picture bellow: Serial 9-pin dot matrix printer in action The distance between wires in column may give us the vertical printing resolution. For example: 9 wire print head with distance 0.35 mm between adjacent wires will result in 25.4/0.35=72.5 dots/inch (dots per inch DPI) vertical printing resolution for one pass printed line of characters. 24 wire print heads has 2 columns – 12 wires in each,
