Fuser assemblies, xerographic apparatuses including the fuser assemblies, and methods of fusing toner on media in xerographic apparatuses are disclosed. An embodiment of the fuser assemblies comprises a first roll including an electrically-conductive first surface; an electrically-conductive second surface, the first surface and the second surface defining a nip therebetween at which toner is fused on a medium; at least one voltage sensor for sensing a first voltage difference between the first surface and the second surface; and at least one power supply connected to the first surface and the second surface. A controller is connected to each voltage sensor and each power supply. The controller receives a signal from each voltage sensor indicating the first voltage difference, and the controller controls each power supply to produce a second voltage difference between the first surface and the second surface based on the first voltage difference.