Abstract
To discuss charge generation on small particles by a rolling friction, a model experiment was performed. In the experiment, a single layer of dielectric spherical particles of 10μm in diameter, as a simulant of electrophotographic toner, was pinched by two flat electrodes, and a current generation between the two electrodes was measured with sliding of the upper electrode. The current generation was explained by 'condenser model', in which work function difference between two contacting surfaces is assumed as electromotive force of the charge transfer. Nevertheless the final amount of charge on particles did not correspond to the order of magnitude of the measured current and even did not depend on electrode materials. The result implied that the charge determining process is not the contact electrification but the charge relaxation from the charged spheres.