Patent ID: 8237757

Claim:
An image forming method in an image forming apparatus, the apparatus including a first, second, third and fourth image forming units configured to form yellow, magenta, cyan, and black toner image and a transfer member, the first, second, third and fourth image forming units respectively having a photoreceptor and a developing unit which develops electrostatic image formed on the corresponding photoreceptor and collects toner remaining on the corresponding photoreceptor, and the transfer member which transfers the respective toner image formed on the respective photoreceptor of the first, second, third and fourth image forming units onto an image bearing member overlappingly, the method comprising: developing the electrostatic image formed on the corresponding photoreceptor in the fourth image forming unit with a larger developed amount of toner than the developed amount of toner for developing the electrostatic image formed on the corresponding photoreceptors in the first to third image forming units, the toner configured to satisfy conditions of Pa≧Pb≧Pc≧Pd and Pa>Pd, where Pa, Pb, Pc, and Pd indicate volume-based average particle diameters of toners to be developed on the photoreceptor in the order of development: moving the image hearing member to the first, second, third and fourth image forming units in order; and transferring the yellow, magenta, cyan and black toner image formed on the respective photoreceptor onto the image bearing member overlappingly.