DEVELOPER REPLENISHING DEVICE

PROBLEM TO BE SOLVED: To prevent developer from being leaked from the developer discharging aperture of a developer storing container and a storing container attaching part and to reduce the rotational load of the developer storing container in the case of attaching/detaching the developer storing container to/from the storing container attaching part. SOLUTION: A flexible seal member 14 sticking and sealing the periphery of the developer discharging aperture 11A is formed so that its entire winding length may be longer than the outer periphery length of an opening/closing cover 13, and is wound round the outer periphery of the cover 13 in a direction parallel with the moving direction of the cover 13 so as to form a loosened part 14a, and also one part of the member 14 is stuck and fixed on the periphery of the aperture 11A. After the loosened part 14a of the member 14 is smoothed by the relative movement of a container main body 11 and the cover 13, the adhesive surface on the periphery of the aperture 11A is peeled and the aperture 11A is made open.