Method of cleaning developing agent stuck to image carrier in image forming apparatus

An image forming apparatus comprising:

• an image carrier;
• a drive unit configured to rotationally drive the image carrier;
• a developing unit configured to supply a developing agent to the image carrier being rotationally driven and form a developing agent image;
• a transfer unit configured to transfer the developing agent image from the rotationally driven image carrier to a recording medium;
• an applying unit configured to apply a voltage of a first polarity or a voltage of a second polarity to the transfer unit;
• a cleaning unit that is disposed downstream of the transfer unit in a rotation direction of the image carrier and configured to clean a surface of the image carrier by coming into contact with the rotationally driven image carrier;
• a process cartridge configured to house the image carrier, the developing unit, and the cleaning unit;
• and
• a control unit configured to control the drive unit, the developing unit, and the applying unit,
• wherein the control unit is configured to execute supply processing for supplying a developing agent between the cleaning unit and the image carrier in a case where the image forming apparatus is not new and the process cartridge is new, and
• the supply processing includes:
• rotationally driving the image carrier by the drive unit;
• forming a first developing agent image on the image carrier by the developing unit;
• applying, by the applying unit, a transfer voltage of the first polarity to the transfer unit to transfer the first developing agent image from the image carrier to the transfer unit in a first period including a period in which the first developing agent image carried on the image carrier passes the transfer unit;
• and
• applying, by the applying unit, a transfer voltage of the second polarity to the transfer unit to transfer the developing agent image from the transfer unit to the image carrier in a second period after the first developing agent image carried on the image carrier passes the transfer unit.