A developer unit for an image forming apparatus is provided. The image forming apparatus includes a developer device having a developer agent carrier and a developer agent supplier, a developer agent container arranged in an upper position with respect to the developer device, and a curved wall, which separates the developer device from the developer agent container; is curved toward the developer agent container; and is formed to have a feeding opening and a collecting opening, and a conveyer, which is arranged along the developer agent supplier and conveys the developer agent toward the collecting opening. The curved wall is arranged to be in proximity to the conveyer and to fit with outlines of the conveyer.