Image forming apparatus and toner supply method

An image forming apparatus comprising:

• a latent image carrying member that carries a latent image;
• an electrifying part that electrifies a surface of the latent image carrying member;
• a latent image writing part that writes the latent image on the latent image carrying member;
• a developing part that develops the latent image on the latent image carrying member by using toner and obtains a toner image;
• a transferring part that transfers the toner image on the latent image carrying member to a surface of an endless moving member in which the surface is moved in an endless manner or a recording member held on the surface of the endless moving member;
• a toner container that holds new toner to be supplied to the developing part;
• a toner supplying part that supplies the new toner held by the toner container to the developing part;
• a fog detecting part that detects fog of an image;
• and
• a toner supply amount determining part that, prior to supplying the new toner to the developing part, carries out a pre-toner-supply operation of supplying a predetermined amount of the new toner to the developing part, forms a fog detecting image after the pre-toner supply operation, detects fog in the fog detecting image by using the fog detecting part, and determines a new toner supply amount to be supplied to the developing part based on a detection result obtained from the fog detecting part detecting fog in the fog detecting image and an operational status of the developing part since supplying the new toner to the developing part the last time, wherein
• the toner supplying part supplies the new toner supply amount of the new toner determined by the toner supply amount determining part to the developing part.