Image forming apparatus

An image forming apparatus comprising:

• an image former to form a toner image;
• a transfer device including:
• a transfer belt;
• and
• a transfer roller facing the image former with the transfer belt between the transfer roller and the image former,
• to transfer the toner image from the image former onto the transfer belt using the transfer roller;
• and
• a voltage applier to apply a voltage to the transfer roller;
• a separator to separate the transfer device from the image former;
• and
• circuitry configured to:
• determine whether the voltage applied to the transfer roller is greater than or equal to a predetermined threshold;
• and
• in response to a determination that the voltage is greater than or equal to the threshold value:
• control the separator to separate the transfer device from the image former;
• and
• drive the transfer belt to rotate in a forward direction or a backward direction to perform a foreign-matter removal operation.