Small particle adhesion: measurement and control

A number of technologies, including electrophotographic printing, require an understanding of particle–surface adhesion forces. At Xerox, we have developed and applied new techniques in order to understand the dependence of particle adhesion on physical properties, such as particle charge, shape and surface roughness. Atomic force microscopy and computer modeling were used to investigate the effects of surface roughness, external additives and applied electric fields on the adhesion of single particles. Centrifugal detachment was used to measure the adhesion force distribution of several hundred particles simultaneously and to determine its sensitivity to particle charge and size. Electric field detachment has enabled rapid characterizations of the adhesion of particle layers, providing insight into the roles of particle–surface contact area and nonuniform particle charging on the adhesion of ensembles of particles. The addition of digital photography to the detachment techniques has allowed in-situ visualization of particle detachment, enabling us to probe interparticle effects on adhesion.