Characterization of Liquid Developers for Continuous Tone Electrography

The relatively small particle sizes and lack of threshold development forces make liquid development a particularly suitable candidate for the development of continuously varying surface charge densities in pictorial electrography. The characterization of such developers has been pursued by studying their response to continuous and discrete surface charge density wedges on a computer-controlled test fixture. Results have been interpreted in terms of standard models of liquid development, and in most cases allow the extraction of the effective area coverage provided by the developer per unit of input surface charge density (the imagewise pattern of charge deposited by whatever electrographic writing device is employed). Examples of materials displaying linear and nonlinear responses to varying surface charge densities will be shown.