Prevention of inkjet nozzle clogging
A common cause of failure in inkjet printing is clogging of the jet nozzle by oversized pigment or foreign large particulates. Manufacturers are always looking for changes in formulation, production, and QC to ensure that the ink will pass through nozzles without blockage. Many techniques are available for sizing particles, but most only provide information on size and relative concentration, not absolute concentration. Single Particle Optical Sizing, SPOS, sizes and counts each particle that passes through the detection zone, providing much a higher resolution and quantitative accuracy than most calculated methods, allowing for significant improvements in final product. A brief introduction to the SPOS technique will be presented, followed by examples of measurements made on a variety of inkjet inks at various stages of processing, showing how this data can be used to improve inks from the formulation stage, through production, and ultimately to the printed product.