Development device and image forming apparatus including the same

A development device includes a developer container, a developer bearing member, a mixing/transporting member, an opening/closing member, and a drive mechanism. The developer container contains a developer. The developer bearing member is rotatably supported by the developer container. The developer bearing member also has a surface facing an image bearing member on which an electrostatic latent image is to be formed. The developer is borne on the surface of the developer bearing member. The mixing/transporting member mixes and transports the developer in the developer container. The opening/closing member opens and closes a developer outlet for discharging an excess of the developer in the developer container. The drive mechanism drives the opening/closing member in association with driving of the developer bearing member or the mixing/transporting member to open the developer outlet.