Servo Control of Multinozzle Ink-Jet Operating Point

Synchronous electrostatic ink-jet printing requires precise assembly of printhead components and maintenance of ink-jet parameters within a narrow operating range to ensure accurate drop placement and thus acceptable print quality. Multinozzle printing requires additional attention to and control of parameters that may create variations in nozzle-to-nozzle performance. Some ink-jet parameters can be controlled by careful machine design, precise machining of parts, accurate initial setup, and regulation of specific independently controllable parameters (e.g., ink temperature); other ink-jet properties, which depend upon complex interactions, cannot be controlled so easily. Rather, they must be controlled indirectly via a closed loop servo. A set of sensed parameters, controlling variables, and servo algorithms have been determined and demonstrated on an experimental multinozzle continuous ink-jet printer. This processor-based servo system has made reliable high-quality ink-jet microprinting possible in a machine application.