Developer supply device

A developer supply device for supplying developer to a supply target, comprising:

• a casing configured to store the developer;
• a first plurality of electrodes located at a first most downstream position and positions between the casing and the first most downstream position to form a first traveling electric field to carry the developer toward the supply target, the first most downstream position being located a predetermined distance from the supply target;
• a second plurality of electrodes located at a second most downstream position and positions between the casing and the second most downstream position to form a second traveling electric field different from the first traveling electric field to carry the developer toward the supply target, the second most downstream position being located the predetermined distance from the supply target;
• and
• a power circuit configured to supply a first voltage and a second voltage respectively to the first plurality of electrodes and the second plurality of electrodes such that a phase of voltage change of a first most downstream electrode of the first plurality of electrodes located at the first most downstream position and a phase of voltage change of a second most downstream electrode of the second plurality of electrodes located at the second most downstream position shift with respect to each other, and wherein the voltage change of the first voltage and the voltage change of the second voltage have a same frequency.