DEVELOPING DEVICE

PURPOSE:To easily attract electrostatically charged toner on a developing roller so as to prevent the toner from being scattered in the middle of recovering developer by switching and controlling a bias circuit so that bias voltage higher than the bias voltage at the time of developing may be impressed on the developing roller at the time of recovering the developer. CONSTITUTION:When the life of the developer comes to an end and it must be exchanged, a developer cartridge is attached to the upper part of a developing tank, and a sealing material is peeled off. At such a time, a motor-driven shutter is stile closed. Next, when a switch for exchanging the developer 26 is turned on, a shutter 7 for opening/closing a developer discharge port from the developing tank to a recovering container is moved upward so as to open the discharge port by developer recovery controller 25. As soon as the developing roller 2, a stirring roller 3 and a carrying means 6 are driven, a switching signal is outputted to the bias circuit 23 by a bias voltage switching means 28 so that the bias voltage may be larger. Thus, the electrostatically charged toner is attracted on the developing roller and prevented from being scattered.