Patent ID: 8180258

Claim:
An image forming apparatus comprising: an image holder on which an electrostatic latent image due to a difference in a charging potential is formed; a developing unit that transfers toners to the electrostatic latent image formed on the image holder to form a visual image; a transfer device that transfers the visual image onto a recording sheet; and a supporting structure that supports the image holder and the developing unit, wherein the developing unit includes: a rotary body of which supporting shaft is supported at both ends by the supporting structure and which is rotatable around an axial line of the supporting shaft; a plurality of developer units that are arranged in a circumferential direction and supported by the rotary body and respectively have developer holders for holding developers to develop the electrostatic latent image of the image holder; and toner cartridges provided to supplement toners to the developer units, respectively so as to be attached to or detached from the rotary body, the plurality of developer units and the toner cartridges are alternately arranged in the circumferential direction of the rotary body, at least one of the plurality of toner cartridges is larger than the other toner cartridges in the circumferential direction of the rotary body, the supporting structure is provided with a replacing mouth that permits each of the toner cartridges to be inserted in or pulled out from the rotary body in an axial direction thereof, and the replacing mouth is located at a position that, when a first developer holder stops at a position used when executing development in opposition to the image holder, a second toner cartridge that supplements the toner to a second developer unit is capable of being replaced, the second developer unit being different from and arranged adjacently to a first developer unit provided with the first developer holder.