Patent ID: 8644742

Claim:
A developer supply device configured to supply charged development agent to an intended device, comprising: a casing comprising a developer storage section configured to accommodate the development agent to be supplied; a transfer board comprising a plurality of transfer electrodes, the transfer board being configured to transfer the development agent from the developer storage section to the intended device in a predetermined developer transfer direction under a traveling-wave electric field generated when a transfer bias containing a multi-phase alternating-current voltage component is applied to the transfer electrodes, the transfer board being fixed onto an inner wall of the casing from the developer storage section to a downstream side in the developer transfer direction; a developer fluidizing unit comprising a movable member configured to move in a moving direction identical to the developer transfer direction while contacting a predetermined contact range of a developer transfer surface of the transfer board disposed along an inner wall of the developer storage section, the developer fluidizing unit being configured to fluidize the development agent stored in the developer storage section by movement of the movable member; and a developer level adjusting unit configured to adjust a level of the development agent stored in the developer storage section to be higher than a downstream end of the predetermined contact range of the developer transfer surface of the transfer board in the moving direction of the movable member, wherein the developer level adjusting unit comprises: a sub storage section that is configured to accommodate the development agent and disposed in a position horizontally adjacent to the developer storage section; a sub agitating member configured to agitate the development agent stored in the sub storage section; and a communication path through which the developer storage section horizontally communicates with the sub storage section and the development agent is transferred between the developer storage section and the sub storage section, wherein the communication path comprises: a developer introduction path configured to introduce the development agent from the sub storage section to the developer storage section; and a developer discharge path configured to discharge the development agent from the developer storage section to the sub storage section, and the developer discharge path being disposed in a different position from the developer introduction path in a width direction perpendicular to the developer transfer direction, the developer discharge path having a discharge opening on a side closer to the developer storage section than to the sub storage section, the discharge opening being open in a position higher than downstream end of the predetermined contact range of the developer transfer surface of the transfer board in the moving direction of the movable member.