AVS 57th International Symposium & Exhibition
    Frontiers in Inkjet Technology Topical Conference Monday Sessions
       Session IJ+BI+MN-MoM

Paper IJ+BI+MN-MoM3
Upper and Lower Bounds for the Stability of Inkjet Printed Lines

Monday, October 18, 2010, 9:00 am, Room Tesuque

Session: Frontiers in Inkjet Technology
Presenter: B. Derby, University of Manchester, UK
Authors: B. Derby, University of Manchester, UK
J. Stringer, University of Manchester, UK
Correspondent: Click to Email
Many applications for inkjet printing require the ability to print continuous linear features. Inkjet printing achieves this through the overlap and coalescence of a series of liquid drops on a planar substrate, which then transform to a solid through phase change or solvent loss. In order to produce regular parallel sided printed lines, the intermediate fluid thread must retain morphhological stability prior to solidification. Drying fluid drops often show considerable hysteresis between the advancing and receding contact angles. This behaviour is shown to impose upper and lower bounds for the width of a line formed by the overlap of printed drops. The lower bound for line width is determined by the minimum separation distance for spreading drops to spread, overlap and coalesce. However, for liquids with zero receding contact angles (as is the case for many evaporating solvents) there is a further limit for parallel sided lines [1]. The upper bound for line width is determined by a dynamic fluid instability that occurs through competing fluid flows between the spreading and coalescence processes [2]. This dynamic instability is a function of both drop spacing and the rate of droplet deposition. By considering both the upper and lower bound limits we can construct a map in a parameter space defined by drop size, drop spacing, drop/substrate contact angle and linear printing velocity that shows the conditions under which stable linear features can be printed.