An image forming apparatus according to this disclosure includes: a charging roller that charges a surface of a photoconductor drum; a development unit that forms a toner image on the surface of the photoconductor drum; an image density sensor that detects density of the formed toner image; a charge power supply that applies a bias voltage to the charging roller; a development power supply that applies a bias voltage to the development unit; and a controller. The controller causes the charge and development power supplies to output respective predetermined bias voltages for predetermined time, and is capable of executing a contact and separation determination mode in which a contact and separation state of the charging roller is determined based on whether or not an image is detected by the image density sensor after output of the respective bias voltages.