Toner replenishing system

Developer container (20) arranged so that it is rotated when the developer is to be unloaded, comprising: a hollow body; a flange part (20a, Fig. 34A) contiguous to one end of said body and forming a wall around a discharge mouth (23) that is smaller in diameter than said flange part (20a); a lid (25, 26) that closes said discharge mouth (23) and that can be removed to open said discharge mouth (23) by means of an opening device; said flange part including at least one coupling part (57, 106, 85a) engageable with a drive means (58, 28) causing said body to rotate to discharge the developer.