Printers, methods, and apparatus to form an image on a substrate are disclosed. An example disclosed charge roller includes a dielectric outer layer (104) comprising an inner surface (106) and an outer surface (108), the outer surface (108) to be charged by a first external surface and to discharge onto a second external surface, and the dielectric outer layer (104) to substantially prevent charge transfer between the inner surface (106) and the outer surface (108), and an electrically conductive inner layer (102) to direct electrical charge toward and away from the inner surface (106) of the outer layer (104), and to be coupled to an electrical source to control a transfer of the electrical charge.