A photosensitive member unit includes a photosensitive member, a transfer roller, a mounting portion capable of mounting a development unit including a development roller, a first gear and a second gear each provided at one end of the photosensitive member in an axial direction of the photosensitive member, and a third gear provided at one end of the transfer roller in an axial direction of the photosensitive member and configured to engage with the second gear. The first gear, the second gear, and the third gear are helical gears. A direction in which helical teeth of the first gear are inclined is opposite to a direction in which helical teeth of the second gear are inclined, and the direction in which the helical teeth of the first gear are inclined matches a direction in which helical teeth of the third gear are inclined.

A second unit includes a restricted portion that comes into contact with a restricting portion provided to a body of an apparatus, the restricted portion coming into contact with the restricting portion, in order to restrict the movement of a developer carrier in a direction to make contact with an image carrier, when a developing cartridge has not reached a predetermined attachment position, and not coming into contact with the restricting portion when the developing cartridge is in the predetermined attachment position.

An image forming apparatus includes a developer bearing member, a supply member, first and second voltage application units, and a control unit. Assuming that a difference between a voltage to be applied to the developer bearing member by the first voltage application unit and a voltage to be applied to the supply member by the second voltage application unit in the image forming operation is defined as a first supply contrast, and a difference between the voltage to be applied to the developer bearing member by the first voltage application unit and the voltage to be applied to the supply member by the second voltage application unit in the preliminary rotation operation is defined as a second supply contrast, the control unit controls the second supply contrast to be less than the first supply contrast or to have polarity reversed from polarity of the first supply contrast.

In a developing unit, one of a frame body and an end portion member, which sandwich a bearing member rotatably supporting a developing roller in an axis direction of the developing roller, includes a hole portion depressed in the axis direction on s surface facing the bearing member, the other of the frame body and the end portion member includes a protruding portion inserted into the hole portion, the protruding portion includes a first region that is press-fitted into an inner wall surface of the hole portion, and a second region that faces the inner wall surface with a gap therebetween, and at least the gap is filled with an adhesive via a communication hole that extends in a direction intersecting the rotation axis direction such that the gap leads to an outside of the frame body.

A second unit includes a restricted portion that comes into contact with a restricting portion provided to a body of an apparatus, the restricted portion coming into contact with the restricting portion, in order to restrict the movement of a developer carrier in a direction to make contact with an image carrier, when a developing cartridge has not reached a predetermined attachment position, and not coming into contact with the restricting portion when the developing cartridge is in the predetermined attachment position.

An image forming apparatus includes an image bearing member, a developing member that supplies a developer of a regular polarity, a developer supply member that supplies developer to the developing member, and a control unit that applies a first voltage to the developing member and a second voltage to the developer supply member. The control unit executes an image forming operation, and a rotational operation in which the developer supply member rotates in a state in which the first voltage of a regular polarity is applied thereto. The rotational operation includes a first rotational operation in which a potential difference is a first potential difference and a second rotational operation in which the developing member and the developer supply member rotate in a state in which the second voltage having the same polarity as the regular polarity and having a greater absolute value is applied.

An image forming apparatus including a main body casing, a drum cartridge and a developing cartridge. The main body casing has an opening and a slot extending in from the opening toward an inside of the main body casing along a first direction. The drum cartridge and the developing cartridge are arranged in a second direction intersecting the first direction in a state where the drum cartridge and the developing cartridge are attached to the slot. The main body casing includes a drum guide groove configured to guide movement of the drum cartridge. The drum cartridge includes a drum protrusion configured to be engaged with the drum guide groove. A width of the drum guide groove in the second direction is decreased toward the inside of the main body casing from the opening.

Provided is an image forming apparatus, including: an image bearing member; an exposure unit; a developing member which is rotatable at a rotation speed different from the image bearing member; a developer supply member; a developing voltage-applying unit; a supply voltage-applying unit; and a control unit. The control unit controls execution of: an image forming operation in which a developer image is formed by supplying developer on the image bearing member; and a cleaning operation which removes a substance adhered to the image bearing member using the developing member. In the cleaning operation, the control unit controls the developing voltage-applying unit or the supply voltage-applying unit so that the cleaning force using the developing member becomes stronger than that in the image forming operation.

An image forming apparatus includes a developing roller, a motor, a motor control portion configured to control the motor, a drive switching unit configured to switch between transmission and non-transmission of the rotational driving force of the motor relative to the developing roller, a current detection portion configured to detect a current value of a current to the motor, and an acquisition unit configured to acquire information relating to a rotation amount of the developing roller. The acquisition unit is configured to acquire the information relating to the rotation amount of the developing roller on the basis of a transmission timing at which the rotational driving force is allowed to be transmitted to the developing roller by the drive switching unit and a non-transmission timing at which the rotational driving force is prevented from being transmitting to the developing roller by the drive switching unit.

An image forming apparatus includes a developer bearing member, a supply member, first and second voltage application units, and a control unit. Assuming that a difference between a voltage to be applied to the developer bearing member by the first voltage application unit and a voltage to be applied to the supply member by the second voltage application unit in the image forming operation is defined as a first supply contrast, and a difference between the voltage to be applied to the developer bearing member by the first voltage application unit and the voltage to be applied to the supply member by the second voltage application unit in the preliminary rotation operation is defined as a second supply contrast, the control unit controls the second supply contrast to be less than the first supply contrast or to have polarity reversed from polarity of the first supply contrast.