PURPOSE: To make the acceleration of charge injection compatible with the stable formation of a toner visible image and to obtain excellent transfer characteristic by using two-component developer, electrostatically charging a photosensitive body through conductive magnetic carrier and forming the visible image by the use of insulating magnetic toner.

CONSTITUTION: The two-component developer 6 constituted of the conductive magnetic carrier 8 and the insulating magnetic toner 7 is used, and the charge injection is performed to the surface of the photosensitive body 100 from a developing sleeve 200 through the carrier 8. Meanwhile, the toner 7 is stuck to an exposed and destaticized area, and the visible image 12 is formed. It is desirable that the rate of the insulating toner to the developer 6 is about 1-5%, which is considerably small in comparison with the conventional two- component developer. Thus, electric resistance becomes low as entire developer and the charge injection to the surface of the photosensitive body through the carrier 8 becomes excellent.