PARTICLE CHARGE, MOBILITY, AND XI-POTENTIAL IN NONPOLAR COLLOIDS

Nonpolar colloidal dispersions are used as inks for electrophoretic de velopment of electrostatic latent images. The need for a modification of the classical relation between the charge and the zeta potential of particles in these dispersions is confirmed by an independent experim ental determination of the particle charge and mobility, using the ser ies-capacitor technique introduced in a previous publication. In addit ion to the charged toner particles, the inks contain surfactant micell e ions of both polarities with their mobilities, in general, differing by orders of magnitude. It is shown that, in spite of this complex co m position of charge species, it is possible to obtain an estimate of the density and mobility of each species from an accurate interpretati on of experimental results based on the theoretical model of the techn ique.