Quick fire digital printing

A high-speed inkjet technology combines the productivity benefits of a digital process with the high throughput and quality of traditional 'offset' printing.

Dr Daniel Hall, founder of Cambridge, UK-based Inkski, has developed the 'LILO' or Light Initiated Liquid Offset technology, which uses a spinning cylinder to quick fire drops of ink.

'Conventional ink jet printing has many advantages: It is relatively cheap, can handle a wide range of inks and is non-contact. But the major problem is that it is too slow, a tenth of the speed of offset printing. This is because the ink needs to flow back into the chambers behind each nozzle before firing and this reloading of ink takes a finite amount of time.'

Inkski sidestepped this problem by developing an innovative new print head.

'Instead of refilling the chamber, drops of ink are created continuously in an array on the outer surface of a rapidly spinning cylinder. Individual drops are activated by a laser and selectively fired from the surface of the 'jetting cylinder' onto paper, to form the image, ' said Hall.

Inkski have demonstrated that the approach is capable of firing drops at a rate of 400,000 drops per second from each channel or about 20 times the speed of a conventional inkjet printhead, offering digital print speeds up to 10m/sec at resolutions comparable to offset printing.

The LILO technology will make short-runs economical, reduce the cost of collating publications as pages are printed in sequence, and improve work-flow by enabling printers to swap between jobs without the time-consuming set-up times for plates.

It uses standard inks and has the cost-profile of digital printing, which means that the production cost per leaflet doesn't change with quantity printed. Additionally it reduces the burden of maintenance as it has no nozzles. These frequently get blocked on a conventional ink-jet and need regular cleaning and priming before each use.