Page "Printer (computing)" Paragraph 35

Line printers, as the name implies, print an entire line of text at a time.

Three principal designs existed.

In drum printers, a drum carries the entire character set of the printer repeated in each column that is to be printed.

In chain printers, also known as train printers, the character set is arranged multiple times around a chain that travels horizontally past the print line.

In either case, to print a line, precisely timed hammers strike against the back of the paper at the exact moment that the correct character to be printed is passing in front of the paper.

The paper presses forward against a ribbon which then presses against the character form and the impression of the character form is printed onto the paper.