One example of a mobile imaging device includes a single ion source, a ground connector, and an interface. The single ion source is to erase and write to an electronic paper display by depositing charges onto an imaging surface of the electronic paper display as the imaging device and the electronic paper display are moved relative to each other. The electronic paper display includes a ground return path. The ground connector maintains an electrical connection to the ground return path as the imaging device and the electronic paper display are moved relative to each other during erasing or writing to the electronic paper display. The interface is for transferring data between the imaging device and a computing device.