Connecting The Dots With CFD

Abstract

This article focuses on use of computational fluid dynamics (CFD) software in the design of ink-jet printers with accuracy equivalent to laser printers. CFD codes track sharp interfaces through arbitrary deformations and to apply the correct normal and tangential stress boundary conditions. CFD software solves the governing equations for fluid flow, heat transfer, and chemistry at several thousand discrete points on a computational grid in the flow domain. Engineers using CFD can obtain solutions for problems with complex geometries and boundary conditions. The CFD analysis yields values for fluid velocity and fluid temperature throughout the solution domain. CFD software cut the production time of the first ink-jet printer in the Lexmark International Inc, Lexington, KY, 7000 lines by helping engineers to determine the tolerances needed to align dots fired from the printhead on the printed page. Engineers at Lexmark have also developed custom lumped-parameter models that provide a faster but less comprehensive model of ink-jet operation, and use these frequently for parametric studies. The combination of the two modeling approaches is helping to improve the performance and reduce the cost of Lexmark printers.