Abstract: A developing device includes a developer bearer, a developer regulator, a developer supply passage, and a stopper. The developer bearer includes a magnetic field generator and is configured to bear a developer containing toner and magnetic carriers and conveys the developer to a developing area by rotation. A stopper prevents the developer blocked by the developer regulator from moving to a surface of the developer bearer, while securing a supply path for passing the developer in the developer supply passage to the developer bearer between the stopper and an upper end of a side wall of the developer supply passage that is opposite to the developing bearer. A width of the supply path in a direction perpendicular to a direction of a rotation axis of the developer bearer is in a range of 7%-10% of a circumference of an outer diameter of the developing bearer.

Abstract: A developer conveyance device includes a downward conveyance path in which a developer falls under gravity, a transverse conveyance path communicating with a lower end of the downward conveyance path and extending in a transverse direction intersecting with the downward conveyance path, a transport screw disposed in the transverse conveyance path, and a floating member. The transport screw is configured to rotate in a predetermined direction to transport the developer in the transverse direction. The floating member is configured to contact the transport screw rotating in the predetermined direction to float in the downward conveyance path.

Abstract: A developing device includes a developer bearer, a developer regulator, a developer supply passage, and a stopper. The developer bearer includes a magnetic field generator and is configured to bear a developer containing toner and magnetic carriers and conveys the developer to a developing area by rotation. A stopper is configured to prevent the developer blocked by the developer regulator from moving to a surface of the developer bearer, while securing a supply path for passing the developer in the developer supply passage to the developer bearer between the stopper and an upper end of a side wall of the developer supply passage that is opposite to the developing bearer. A width of the supply path in a direction perpendicular to a direction of a rotation axis of the developer bearer is in a range of 7% or more and less than 10% of a circumference of an outer diameter of the developing bearer.

Abstract: A developer conveyance device includes a downward conveyance path in which a developer falls under gravity, a transverse conveyance path communicating with a lower end of the downward conveyance path and extending in a transverse direction intersecting with the downward conveyance path, a transport screw disposed in the transverse conveyance path, and a floating member. The transport screw is configured to rotate in a predetermined direction to transport the developer in the transverse direction. The floating member is configured to contact the transport screw rotating in the predetermined direction to float in the downward conveyance path.

Abstract: A cleaning device includes a brush roller configured to contact an image bearer while rotating to remove toner adhering to an image bearer, a bias applying device configured to apply a bias to the brush roller, and control circuitry configured to causes the bias applying device to apply a first bias in a first period from when the brush roller is new to when a cumulative travel distance or a cumulative rotation time of the brush roller reaches a predetermined value, and to apply a second bias in a second period after the first period. The first bias sends a first current through the brush roller, and the second bias sends a second current through the brush roller. The absolute value of the first current is smaller than the absolute value of the second current.