Image forming apparatus that controls supply bias for supplying and collecting developer

An image forming apparatus comprising:

• an image carrier configured to be driven to rotate and on which an electrostatic latent image is to be formed;
• a development unit configured to develop, using a developer, the electrostatic latent image formed on the image carrier and form a developer image in a region where the image carrier faces the development unit;
• a supply unit configured to output a supply bias, supply the developer to the development unit, and collect the developer from the development unit;
• and
• a control unit configured to control the supply bias in a region in a single recording medium based on a length of a non-image region where the developer image is not formed in a rotation direction of the image carrier.

An image forming apparatus comprising:

• an image carrier configured to be driven to rotate and on which an electrostatic latent image is to be formed;
• a development unit configured to develop, using a developer, the electrostatic latent image formed on the image carrier and form a developer image in a region where the image carrier faces the development unit;
• a supply unit configured to output a supply bias, supply the developer to the development unit, and collect the developer from the development unit;
• and
• a control unit configured to control the supply bias based on a length of a non-image region where the developer image is not formed in a rotation direction of the image carrier,
• wherein the control unit is further configured to widen an interval between successive recording mediums to control the supply bias if control of the supply bias cannot be performed in a region of the interval between the successive recording mediums.