Research into the Electrokinetic Properties of Electrographic Liquid Developers

A well-known method based on electrophoretic measurements was applied to evaluating the main parameters of liquid electrographic developers, that is, electrokinetic characteristics (e.g., mobilities, charge, and ￠ potential of particles), as well as the size and numerical concentration of particles. The generalization of this method for polydisperse systems is dealt with, taking into account the possible dispersion of the charges of particles. This allows evaluation of an error in determining the mean values of parameters and sets the limits of applicability of the method. A modification of the calculation is suggested, which would allow the mean concentration of particles to be determined. For a number of systems employed in practice it is shown that the electrokinetic properties of liquid electrographic developers depend on the nature of pigments and their chemical modification (e.g., by the aid of surfactants), and on the parameters of a binder and a dispersion medium. A number of relations are derived from the research work done, which allow the optimum choice of the parameters of liquid electrographic developers to be made.