Measurements of toner adhesion are usually at least one order of magnitude larger than predicted by image force calculations that model the toner charge by locating it in the center of the toner particle. In order to account for this discrepancy, it has been suggested that either the toner charge is not uniformly distributed on the surface or that van der Waals forces dominate toner adhesion. We propose an alternative model of toner adhesion, which takes into account a recent result that shows that there is an electrostatic proximity force of adhesion at the contact point between a toner particle and a conductive plane.