Patent ID: 8526865

Claim:
An image forming device comprising: a developer carrying body having a developer supporting surface configured to support developer including a plurality of fine particles; and a developer supply device configured to supply the developer to the developer carrying body, while transferring the developer along a developer transfer path, wherein the developer supply device comprises: a plurality of transfer electrodes arranged along a developer transfer surface facing the developer transfer path, in a developer transfer direction; and a transfer voltage applying unit which is electrically connected to the plurality of transfer electrodes and is configured to apply traveling-wave shaped transfer voltages to the plurality of transfer electrodes, wherein the developer comprises a fine particle charged in a positive polarity and a fine particle charged in an negative polarity, and wherein the transfer voltage applying unit is configured to apply the traveling-wave shaped transfer voltages having waveforms, the waveforms making a fly height of the fine particle charged in the positive polarity higher than a fly height of the fine particle charged in the negative polarity, to the plurality of transfer electrodes, and the waveforms being respectively shaped such that a rising edge is steeper than a falling edge, to the plurality of transfer electrodes.