In the normal operation of ink jet printheads, ink drops are extruded through a nozzle, producing plugs with the same diameter as the nozzle. However, Xaar has observed that under certain circumstances a smaller, faster drop is emitted from the centre of the nozzle. These unusual drops have about one quarter the diameter of the nozzle and about twice the velocity of normal operation. The Study Group was asked to consider possible mechanisms that could lead to this behaviour. If the production of such microdrops can be understood, a practical design might be viable, so allowing printing with much higher resolution and with reduced ink usage.

Problem presented by
Steve Temple (Xaar)

Background reading
The X factor, an interview with Steve, Xaar's Technical Director, in the Spring 2006 issue of Catalyst, the newsletter of the Cambridge Science Park.

Study Group contributors
James Healy (University of Southampton)
John Hinch (University of Cambridge)
Sam Howison (University of Cambridge)
Hilary Ockendon (University of Oxford)
John Ockendon (University of Oxford)
David Parker (University of Edinburgh)
Colin Please (University of Southampton)
Christopher Voyce (University of Southampton)