In the beginning there was the teletype terminal. This electro-mechanical bit of clunky technology would whisk the selected letter into position before a little hammer punched an impression of the line-up letter onto the paper.

The ink was supplied on a ribbon. The early ribbons were impregnated with ink that gradually faded. So along came plastic ribbons which produced a sharper image.

So back in the 1980s all printers pretended to be teletype terminals. Nobody had dreamt up printer-drivers. If you wanted bold or italic, you put what was called 'the escape code' into the document. This involved holding down the escape key and typing the letter B or I. The printer would not print the letter but start printing in the style chosen.

Early computer printers were typewriters without a keyboard. Evolution is a slow business so you could buy computer printers with keyboards for many years. Early printers could double as a typewriter.

You could change the font by fitting a new print head. There was a short era of the 'daisy wheel' printer which had the characters arranged like petals around the centre. This would make a fearful noise as it stamped out the letters. If not fixed down it could jump off the table.

Letters are fine for the Latin alphabet with its limited number of characters. But in Asia where pictograms required thousands of images, a new solution was required. Instead of solid letters, they invented 'dot matrix' technology which composed letters in a series of dots. Any character or shape can be composed with little dots.

Again, it was a little hammer that punched the ink from a ribbon onto the paper. Evolution, as we noted , is a slow business. Somebody came up with the idea of little heaters that would melt the plastic on the ribbon onto the paper.

Instead of a little wire pushing the ink from the ribbon onto the paper, one bright spark discovered that a spot of ink could be fired at the paper by super-heating it. So the ink-jet was born. Without a ribbon which could only have one ink, colour printing became a possibility.

While all this was going on, the laser printer was evolving from the photocopier. It would have happened much quicker if patents and the operation of the real-world monopolists had not prevented various innovators to bringing this technology to the office.

Computer magazines would carefully explain how it was technically impossible for one machine to act as both a photocopier and printer so don't believe everything you read in the technical press until you have checked who pays for all the advertising.

The laser has long been recognised as top quality. However, the dye-sublimation process has capped laser technology. This process returns to the  use of a ribbon that is permeated with solid dye which is vaporised by a heater. This  condenses on the paper and produces the  most intense colours. Inkjets can deposit 1200 dots per inch but the inks have to be placed alongside each other to create a coloured image. Vaporised dyes can be added on top of each other.

The cost of printers has tumbled as the technology became intrinsically simpler. In the early days of computing, the talk was of a paperless office. But there seems little chance that were are going to give up our printers.

Picture technologies Scanning

© Charles Jones 2001-6  

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