1. An image forming apparatus, comprising: a latent image bearer; a developing device to develop a latent image on the latent image bearer using a developer including a toner and a carrier; a toner density sensor to detect a toner density of the developer in the developing device; a supplier to supply the toner to the developing device; and a controller to control the supplier according to a detection result of the toner density by the toner density sensor and a toner density target value to adjust the toner density of the developer in the developing device, wherein the controller is configured to correct the toner density target value and an imaging condition affecting a toner adhesion amount of an output image separately from the toner density, according to a component adhesion deterioration degree being a deterioration degree of the carrier due to adhesion of a toner component, obtained based on at least an average image area ratio of the output image, and a coating abrasion deterioration degree being a progression degree of deterioration due to coating abrasion of the carrier, obtained based on at least the average image area ratio of the output image.