Thread: Printer Forming a Character

The printer's processor reads the instructions for one line of print from the print buffer and translates it into the dot patterns needed to print each character on the line. The printer's processor also decides the best travel direction for the printhead to print the line: whether to travel left to right or right to left. The processor also controls the movement of the paper, advancing it a single line, advancing it to the top of the next page, or feeding an entire page.



As we discussed earlier, a dot matrix printer forms its characters with a pattern of dots. Characters are formed in stage, depending on the number of pins in the printhead which is commonly either 9 or 24. A 9-pin printhead, in which the pins are arranged in a single column forms characters by printing the appropriate dots in a series of connecting columns. Nine-pin dot matrix printers are capable of only draft quality print and are commonly used for forms, whereas 24-pin printers are used in high-end dot matrix applications.