Home Computer: The printing process

PRINTERS are independent pieces of equipment and versions of most popular printers are available that will work with PC or PC-compatible computers, as well as other types of machine, such as Apple, Amiga or Acorn, writes Nigel Willmott.

Printers usually come with a piece of software called a printer driver that allows them to operate with different types of computer, although sometimes extra hardware is needed in the printer, so you need to check that the version of the printer will work with your type of computer.

The different types of printer are based on very different technologies.

Dot matrix printers may be dying out, but the first type of personal computer printer - the daisy wheel - is already effectively deceased. However, there are probably hundreds of thousands of daisy wheel printers still in use and they can still be picked up second-hand or as remaindered items. Daisy wheel printers use the same circular wheels of type as electronic typewriters, from which they were developed. The characters are, as with a typewriter, hammered on to the paper through an inked ribbon. This slow, antediluvian technology survived such a long time because print quality was better than from dot matrix printers.

Dot matrix printers form characters from a cluster of pinpoint-size print heads, either using a matrix of nine or twenty-four 'pins', producing characters via an inked ribbon from a series of dots rather like a newspaper photograph. While much quicker than a daisy wheel, it produces the well-known slightly faded look, known even at its best as 'near letter quality' (NLQ).

The next technology chronologically is the laser printer, which uses a combination of lasers and the electro-photographic process used in phocopiers to imprint the image on the page from cartridges of fine black toner. Developed for bulk printing by mainframe computer systems, miniaturisation has made them small enough and cheap enough to use with personal computers.

The newest technology, ink jets, work by squirting tiny jets of ink at the paper to form characters and patterns. These are a compromise between the high quality of lasers and the cheapness of dot matrix.

However the ink does 'spread' slightly at the edges if you look closely, so anyone considering doing regular desk top publishing work, whether parish or professional newsletter, should certainly spend the extra on a laser.