Motion of surface charge on layered organic photoconductor

Abstract

The motion of charge along the surface of a photoconductor can lead to degradation of the latent charge image in the time between the image formation and development steps in electrophotographic printers. Using a high resolution charge probe, we observe the time evolution of the latent image directly, and are able to examine this charge transport process in detail. The lateral spreading is characterized by measuring the rate at which the edge width of a charge step broadens. The spreading rate is found to be independent of both the surface potential and the voltage contrast. The results are compared to the predictions of two simple charge transport models: linear transport characterized by a sheet conductance and conduction by means of enhanced mobility of the surface charge comprising the image itself. The latter results in strong surface potential and contrast dependence of the spreading, while the former predicts no dependence at all, in agreement with observations.