Printing technology, Print off

Printing technology, Print off

 

Jun 5th 2007
From Economist.com

 

Printers are getting smaller and faster

Zink Imaging

 

PRINTING technologies have come a long way since the early days of personal computing. Running off a lot of copies of a picture or producing home-made, sharp-looking business documents has never been easier. That is because modern-day inkjets and laser printers are everyman technologies. And for those without their own, photograph-printing kiosks are dribbled along high streets and in airports the world over.

 

But that is not to say there is little room for improvement. Printers are cumbersome and slow gadgets that do not travel well. They are expensive, too, largely because of the cost of ink cartridges, which habitually run dry at the most inconvenient moments.

 

ZINK Imaging is a company attempting to do away with this latter annoyance. It has ignored the main assumption of printing?that ink is applied to paper?and chosen to start the other way round: with the ink in the paper instead.

 

ZINK’s paper is coated with three layers of chemicals, each colourless and crystalline. Its print heads activate these chemicals, melting them with tiny pulses of heat as a sheet passes through it. (Laser printers also use heat. They contain hot internal devices called fusing assemblies which fuse powdery toner to paper fibres.)

 

The top layer of ZINK’s paper turns yellow with heat. Its middle layer turns magenta. Its bottom goes a deep cyan, like “a multi-layer birthday cake” according to Stephen Herchen, the company’s chief technology officer. The trick is to melt with precision. The three primary colours can be mixed in varying proportions to create every possible hue. Melting the top layer, thus releasing yellow, is achieved by applying a short pulse of heat. Melting only the middle layer is possible with longer and slightly cooler pulses, which penetrate the top layer without activating it. Producing colour from just the bottom layer requires even longer pulses with even lower temperatures. Printing a 5cm by 8cm colour photograph requires 200m heat pulses in 30 seconds.

 

Such flashy technology does not come cheap. A scrap of special paper small enough for a printer the size of a camera phone will cost around 20 cents. But by pricing the cost of ink into the paper, the cost of each print out should be easy to calculate and more people might choose to share printers, as they increasingly share photos online. Putting more of the technology into the paper allows printers to become smaller and lighter, too. ZINK Imaging showed off a wireless pocket-size model at a technology conference in January and hopes its printers could soon find their way into hand-held devices such as digital cameras.

 

Another new approach to printing is to keep the ink in the print head but also to keep the print head in one place. That requires, of course, that inkjet print heads span the width of the paper they print on?rather like the line printers that serviced early mainframe computers.

 

Last year Hewlett-Packard put this technology, which it calls Edgeline, into its photograph-printing kiosks and it has recently started selling two models of office printers with it in. The advantage is speed. The technology is fast because there is no need to wait for the print head to shuffle across. HP’s new office printers have 50,000 nozzles in their print heads, each delivering yellow, magenta, cyan or black ink, or a clear substance which helps those colours bond to paper.

 

That number is beaten by a prototype desktop printer designed by Silverbrook Research, a company based in Sydney, Australia. In March it announced its version of the technology, with 70,400 nozzles capable of printing 60 typical pages per minute, or a standard-sized photograph in two seconds. Next year’s holiday snaps should be ready in no time at all.