If the computer industry were one giant pantomime then the role ofty, the inkjet is fast becoming the leading force. Cinderella would be played by the inkjet printer. And after shouting 'look behind you' at the two ugly sisters (played by Dot Matrix and Daisy Wheel) for years, we've seen the inkjet finally win the day and relegate the older technologies to the 'also ran' bin.
Along with its Prince Charming, the laser printer, it has finally won the hearts and minds of the market. So much so that, according to market research firm Dataquest, unit sales of inkjet printers in the US have shot from 10.1 million in 1996 to 11.7 million in 1997 and are expected to be 13.1 million this year. (If you want a laugh, check out Dataquest's figures for 1992, when unit sales for inkjet printers went from 382,000 to 618,000 units).
For a long time the inkjet sat outside of the mainstream printing fraternity.
Part of the problem was price and print quality - one was too high and the other too low. Bizarrely though, it was the right rather than the usual way round - the price was too low and the quality too high. People shied away from something too good to be true.
Although to be fair, in the early days you needed special paper and the ink delivery systems weren't as good as they could have been. That led to messy printing and even messier maintenance. But all the same, customers never really trusted such an obviously good deal. Now the systems are clean and efficient and colourful. The inkjet is here to stay.
Despite all the technological developments, the basic premise that defines and separates inkjet and laser printers still stands. Laser printers are more expensive but cheaper to run, producing higher quality documents at faster speed. Inkjets on the other hand are slower and produce a slighter inferior output, but they can print colour images at near photo quality.
Of course, as the sales increase, so the technology hots up and more is demanded of the inkjet's very basic mechanism. Despite the growth in the market, there are currently four main players driving the technology forward - Hewlett Packard, Canon, Lexmark and Epson. Although the term inkjet is being banded around with impunity, there are two distinct technologies that make up the inkjet market - bubble jet and inkjet (with a third, Epson's piezoelectric printing already making its way to the swimming pool to reserve a place with its towel).
The inkjet relies on blobs of ink to make up the printed character, much like a dot matrix printer. But instead of firing pins, the inkjet print head flings wet ink and quietly hopes it lands in the vicinity of the print character. The print head has a number of holes or nozzles in it (anywhere between 50 and 250) and, just like the dot matrix printer (to which the inkjet owes a conceptual debt), the more holes the better the print quality.
There is some discussion as to who came up with the idea first - Canon's bubble jet is said to predate the inkjet by a couple of years. In fact, there is an apocryphal sounding story of a Canon researcher who accidentally put a hot soldering iron on a syringe full of ink. Instead of being sacked for gross incompetence, the other engineers fell on the fact that ink spurted out of the needle and built a printer around it.
Hewlett Packard, not to be outdone, claims that in 1979 the thermal inkjet was pioneered in its laboratories. Apparently, some years before 1979, a Hewlett Packard engineer was watching a coffee maker percolate and came up with the idea of heating ink to get it on the page. (There are unconfirmed reports that several other manufacturers are developing their own inkjet discovery story and should be releasing them soon.)
Whoever invented it, the concept remains the same and that is to get the ink to come out of the head at high speed. Basically, an element heats the ink to 300/400 degrees centigrade within a second or so. The ink around the element immediately vaporises and expands, thus pushing the ink over the edge of the print head rather like an unfortunate commuter on a crowded underground platform.
Each pin is fired separately, creating the character in several passes.
The early print heads used to create a sixth of an inch swaith (the depth of the line created in on pass), whereas newer heads create a swaith of one third of an inch, meaning more passes are needed to make a character, but the character is better defined.
But the latest technology on the block comes from Epson. After holidaying in the doldrums for a few years, it has come home in and attempt to regain the glory of the old days - when dot matrix printers ruled the earth and Epson made nearly all of them - with its piezo technology. The piezo system still flings ink at the page with the same wild abandon as the other systems, but achieves it without heating the ink. Instead, it forces the ink out by using the piezoelectric effect.
The piezoelectric effect occurs when certain crystals, for example, quartz and Rochelle salt, produce a small electric current if they are squeezed or stretched. This process can effectively be reversed by applying a small current to the crystal, making it grow or shrink as required. Epson has built this response into a pump that reacts very quickly to changes in the current applied to it, and since the ink is under a higher pressure it means it comes out faster.
This, combined with the time saved by not having to heat up the ink, means the head runs faster and more efficiently. It is also, Epson argues, cheaper to run because with no heating there is less stress and strain on the mechanism and therefore fewer parts to fail.
However, colour is now where it's at and the big new market for the inkjet is photo-real images - pictures as good as photographs. As digital cameras and photo grabbing equipment finally look like set to take off, consumers now have an inexpensive method to print out family pictures and businesses have a cheap way to produce good looking reports.
A good example of this is Hewlett Packard's PhotoSmart PC photography system. Launched in September 1997, it plays directly to the new photo-real market, containing a digital camera, scanner and printer. Despite the time factor (up to 20 minutes to print an A4 page of full colour) and the need for special papers, the market for good quality colour images is growing.
But to produce photo quality images some serious work has had to be done on the inkjet.
The most common system for assigning colour values in the computer is RGB (red, blue, green), which corresponds to the red, green and blue phosphors used in computer screens. If eight bits of data - giving 256 levels - are used to represent each of these primary colours, it gives a total of 16.7 million combinations of colours. But one of the inherent difficulties with colour printing is that it works differently on paper than on-screen.
Adding the primary colours on a screen together, you get white, alas adding the same colours together on paper gives you black. The primary colours for printing are cyan, magenta and yellow (CMY), and it is common to add black ink to the mix as it works better for printing text (and it means you don't have to mix colours to make black for text). This is known as CMYK or four-colour printing.
Luckily, it is quite easy to convert from RGB to CMYK, unluckily, it's not so easy to get the colours looking right. The solution is to use a table of colour values to make the match as close as possible - something that is generally built into the printer driver.
That's the theory. The practice is even more complicated. A big problem comes with creating continuous tone images like say, skin tone where one colour blends into another seamlessly. Some printers, in particular expensive dye sublimation printers, are capable of continuous tone images, but most others can only make primary colour combinations. However, an alternative to this process of continuous tone comes in the form of dithering.
In dithering, the driver software analyses the image, creates patterns of pixels and lays down dots of neighbouring colours in various patterns to create the appearance (effectively an optical illusion) of blending colours. It is much the same illusion that a poster creates - walk up close and the dots stand back leaving only the image. The hard work is in hiding the dithering patterns so they will not detract from the image.
The manufacturers of photo quality printers have used a number of tricks to hide these patterns. One is to decrease the size of the dot on the page. Where an older 300dpi dot would measure around 100 microns, a modern 1200dpi printer dot measures 60 microns. It is considered that dots larger than 30 microns are over the visibility threshold - a toner particle is about 10 microns and a particle in a film negative is one micron.
Another trick is to increase the resolution of the printer. Low-end inkjet printers are available in a wide variety of resolutions ranging from 600dpi x 300dpi or 600dpi x 600dpi. However, a new generation of printer head is providing better definition in models like the 1440dpi x 720dpi Epson Stylus and the 1200dpi x 1200dpi Lexmark 7200. Some products have resolution enhancement that improves the output quality above the straight addressable resolution output.
A new solution is to add extra colours to the process, giving a total of seven - black, cyan, magenta, yellow, light cyan, light magenta and light yellow. Newer printers use the light versions of cyan, magenta and yellow to provide much clearer, crisper images. With two extra colours - typically a light cyan and a light magenta - lighter areas of the image like skin tones and skies can be improved.
Most printers have separate cartridges for each of the inks, although some use a single black cartridge and a separate single cartridge for blue, yellow and red ink. If one of the colours in the three-colour cartridge runs out, the entire cartridge has to be replaced, so it comes as no surprise that manufactures make a lot of their money on consumables.
Some bottom-end printers use a three-colour cartridge without a separate black reservoir. To obtain a monochrome output, either the three colours are mixed or the user must manually swap the three-colour cartridge for a black cartridge. This year will see these five, six and seven-colour products rapidly replacing older models.
A lot of this market is for the home or small business user. Inkjets are seen as a cheap answer to a lot of businesses and home users' problems.
The £150 to £180 price point has been well established for a while, but now this is the price for an entry-level colour printer.
It is worth noting that the lowly dot matrix printer is still slugging it out in the market. Despite there being a shrinking number sold, it is unlikely to go away while there remains a need for printing on multipart stationery.
Inkjets have for a long time filled the cheap-printer-with-OK-output niche, now they are actually creating a niche of their own. As other photo realistic printers price themselves too high for most general uses, the new breed of inkjet is making that market its own.
Firm says enterprise business has performed 'weaker than originally expected'
Top executives from nine VARs, including Computacenter, Bell Integration, XMA, ANS and Epaton, weigh in on which server, storage and networking technologies will be red hot next year
Are partners encouraged by the big changes coming to Cisco next year? Josh Budd, content editor of CRN sister publication Channelnomics Europe, finds out
Thomas Kurian will join the company next week and transition into the top role in January