Abstract: A charging apparatus and method used in an image forming apparatus uses a charging apparatus to apply a charging potential to a photosensitive body, a voltage measuring device that measures the charging potential and outputs a measured charging potential signal, an environmental condition sensor which senses at least one environmental condition and outputs an environmental condition signal, and adjustable voltage application which applies an applied voltage to said charging member, and a controller, where the controller controls an amount of the applied voltage applied to the charging member in accordance with the charging potential signal and the environmental signal, where the applied voltage is adjusted to compensate for the sensed environmental condition.