To provide an image forming apparatus which can minimize a load of cleaning and control the density of an image appropriately.

A pattern 21 for measuring/controlling the density of toner whose length is a half of a length of a long side of a cleaning blade or less is formed on a surface of a photoreceptor 1. A large quantity of the patterns 21 are formed in a line along the longitudinal direction of the photoreceptor 1 and each pattern 21 is detected by each of photosensors 22 arranged corresponding to a large quantity of the patterns 21 in a toner density detecting apparatus 15. Further, the patterns 21 are imaged in different positions according to yellow(Y), magenta(M), cyan(C), and black(B), respectively.