The Cutting Edge: Computing / Technology / Innovation : Do-It-Yourself Color Printing : Computers: A new generation of thermal ink-jet printers puts the entire spectrum within the financial grasp of small businesses and hobbyists.
Time was when high-quality color printing was the territory of professional companies with the need and ability to spend tens of thousands of dollars on the presses and other machines of the trade.
No more. A new generation of color-capable thermal ink-jet computer printers has brought the entire spectrum of colors within the financial grasp of small businesses, home offices and hobbyists.
The new jet printers, from Hewlett-Packard, Canon and others, provide excellent results at prices starting at less than $400. Fancier models can cost up to $3,000, still a far cry from the bad old days.
Although black-output-only thermal ink-jet printers have been on the market for a decade, their popularity is suddenly way up. Hewlett-Packard, for example, has sold 10 million ink jets in the past 10 years--half of those in the past 12 months, and nearly half of these were color-capable.
Early generations of ink-jet printers had some shortcomings. The ink smeared easily, and a drop of water could wash the print right off the paper. But both the ink and the paper have improved over the years, and smearing is no longer a real concern.
A common problem with some ink jets is clogging of the tiny print head nozzles, but some models, such as the newer Hewlett-Packards, employ a disposable print head--it’s part of the ink cartridge, so every new cartridge has a new print head.
How do ink jets compare to other types of printers? Laser printers--which use technology similar to that in photocopiers--still have an edge in output quality, but ink jets are closing the gap. Most people can barely see the difference between text printed on the two, although elaborate graphics make the distinctions between laser and ink jet quality more apparent.
Lasers remain faster, though. Machines vary, but laser printers can generally kick out pages two or three times as fast as ink jets. Emily Dickinson would have done just fine with an ink jet, but Tolstoy would have needed a laser, one of the eight-to-12-page-per-minute monsters that can be had for less than $1,000 these days.
Only very expensive laser printers provide color. On the other hand, some color ink-jet printers can’t print really true blacks for regular text.
There are also some dot matrix printers that do a nice job of peppering correspondence with color sentences, but these cost as much as an ink jet. These days, dot matrix is useful mainly for printing on multilayered carbons.
Most printers measure output quality in terms of dots per inch. Until recently, 300-by-300 dpi was about the best resolution you could buy; now 600-by-300 dpi is becoming common, and 600-by-600 is increasingly common for lasers.
But the numbers don’t really tell you which printer will produce better-looking output for your purposes. Before buying, look at samples of the kind of work you’ll be doing, using the software you’ll want to use.
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Color Ink-Jet Printers: How They Work Ink-jet printers work by spraying tiny drops of ink from cartridges with built-in print heads. The ink passes through nozzles half the width of a human hair. As the paper rolls the width of a human hair. As the paper rolls through the printer, the cartridges move back and forth on a track, spraying precise amount of ink, line by line, across the page. In a color ink-jet printer, each cartridge contains one of three primary ink colors: cyan, magenta and yellow. When combined in varying amounts, these colors are able to create an approximation of the visual color spectrum. In some printers, a black ink cartridge is added for sharper shadows and text.
INK JETS: MAGNIFIED VIEW During the printing of a document, a printer program sends a code to the printer driver, whose software translates the code into a language the printer understands. The printer then outputs this information to the paper as a series of tiny dots--as small as 1/600th of an inch in diameter--from between 50 and 100 nozzles in the print head.
INK CARTRIDGE AND PRINT NOZZLE: MAGNIFIED VIEW 1. Initial state, with ink-jet fluid at rest. 2. A resistor is heated by an electrical charge, which causes the ink to from a vapor bubble. 3. The vapor bubble grows and ink is ejected out of the nozzle. 4. The bubble collapses and a drop of ink breaks off. 5. As the drop flies toward the paper, the nozzle returns to its original state, ready to form another drop.
Sources: Hewlett Packard; MacUser Magazine
