Developing device, image forming apparatus, and development control method

The developing device according to claim 1, wherein

• the case includes:
• a first conveyance chamber and a second conveyance chamber disposed in parallel and extending in a predetermined direction;
• and
• connection paths located at both ends of the first conveyance chamber and the second conveyance chamber in the predetermined direction and connecting interior spaces of the first conveyance chamber and the second conveyance chamber,
• the stirring screw includes:
• a first stirring screw configured to rotate around a first rotational axis parallel to the predetermined direction to convey the developer in the predetermined direction to a first side inside the first conveyance chamber while stirring the developer;
• and
• a second stirring screw configured to rotate around a second rotational axis parallel to the predetermined direction to convey the developer oppositely in the predetermined direction to a second side inside the second conveyance chamber while stirring the developer,
• the discharge port is located downstream of the second conveyance chamber in a direction along which the developer is conveyed, and
• the restriction portion includes a reverse screw configured to rotate around the second rotational axis together with the second stirring screw to convey the developer in a direction opposite a direction of conveyance by the second stirring screw.

A development control method used by a developing device, the developing device comprising:

• a case storing developer;
• a stirring screw configured to circulate the developer inside the case while stirring the developer;
• a discharge port for discharging the developer from the case;
• and
• a restriction portion disposed between the stirring screw and the discharge port and configured to restrict movement of the developer toward the discharge port depending on a drive speed of the stirring screw,
• the development control method comprising:
• driving the stirring screw such that, during a discharge period other than a development process period in which a development process using the developer is performed, a mean drive speed of the stirring screw per unit time is less than the mean drive speed during the development process period to move the developer toward the discharge port through the restriction portion.