An image forming apparatus includes an image forming device, an electric current detector, and a controller. The image forming device includes a latent image bearer, a charging rotator, a charging power supply, a latent image writing unit, and a developing unit. The controller (i) determines an uneven electric resistance of the charging rotator in a direction of rotation of the charging rotator, based on a detection result by the electric current detector, (ii) perform, at a predetermined timing, data construction processing to construct change pattern data to change an output value of a voltage from the charging power supply according to a predetermined pattern, based on the uneven electric resistance, and (iii) perform, in a print job to form a toner image in response to an instruction, voltage changing processing to charge the latent image bearer while changing the output value of the voltage, based on the change pattern data.