Spinning cylinder has the drop on fast printing

A spinning cylinder technology can deliver up to 400,000 drops per second from each channel – about 20 times faster than a conventional inkjet print head – offering digital print speeds of up to 10m/s at resolutions comparable to offset printing. It also offers potential for greatly accelerated rapid prototype production and other applications that involve the targeted delivery of small drops of liquid. Daniel Hall, CEO and founder of Cambridge start-up company Inkski, has been working on the technology since 2004. “It is similar to inkjet technology, but very much faster,” he says. “Having worked in digital processing, I was aware of the speeds that can be achieved in delivering data and how printing is one of the hold-ups.” Lilo, or Light Initiated Liquid Offset, relies on forming drops in a regular array on a rapidly rotating cylinder, using a photonic trigger to eject drops. The drops, being very small, can be held on the cylinder by surface tension. There is a closely maintained balance between the surface tension forces holding the drops on and the centrifugal force tending to throw them off, with acceleration forces in excess of 1000g. A laser is used to trigger drop release. The Lilo technique uses standard inks and offers a similar cost profile to conventional standard methods of digital printing, so cost per page should be similar – with the added benefit that printed pages can be delivered a great deal faster. Also, as there are no nozzles, there should be no problems of clogging and smudging, while the technology is also said to be compatible with very wide arrays. Hall believes the solution would make personalised newspaper editions feasible in the printing world. In the design office, it would allow designs to be printed out a great deal more quickly on printers and copiers. With inkjet printing being increasingly used as a basis for rapid prototyping and rapid, short-run manufacturing, a 20-fold increase in speed could reduce production times from hours to minutes. Pointers * Technology can deliver 400,000 drops per second, as compared with conventional inkjet print heads that can deliver 10,000 to 25,000 drops per second * There are no jets to clog * Droplets are held on the surface of a rapidly rotating cylinder by surface tension and laser triggers their release