Some Effects of Fluid Jet Dynamics on Ink Jet Printing

Synchronous ink jet printing systems use a small fluid ink stream, as produced by a pressurized ink through a small orifice, to produce ink images on a recording surface. The initial stream breaks up into a uniform sequence of similar droplets as a result of velocity variations injected by the orifice assembly. As the droplets form, individual droplets receive charges by induction. The charges imparted to droplets determine their flight path through an orthogonal deflection field to the recording surface or, alternatively, to an ink dump. The mechanism of drop formation, drop charging, drop deflection, and aerodynamic interactions between drops, and how these influence an ink jet printer's performance, are discussed. In addition, since the fluid dynamics limit the range of applications for ink jet printing, some limiting factors are described.