A rotation device includes: a rotary body having a recess in an outer peripheral surface thereof; and a brush configured to come into contact with the outer peripheral surface of the rotary body to remove a foreign matter adhering to the outer peripheral surface, in which the brush is separated from the outer peripheral surface of the rotary body in a state where rotation of the rotary body is stopped.

An image forming apparatus includes: a drawer movable between an inner position and an outer position and supporting a first cartridge including a first photosensitive drum and a first discharge part and a second cartridge including a second photosensitive drum and a second discharge part; and a waste toner box including a first coupling part coupled with the first discharge part and a second coupling part coupled with the second discharge part, in a state where the first cartridge and the second cartridge are supported by the drawer at an inner position and the waste toner box is mounted to the apparatus main body, the waste toner box being movable between a first/second position where the first coupling part and the first discharge part are coupled/decoupled and the second coupling part and the second discharge part are coupled/decoupled.

A drum cartridge is mountable in and dismountable from an image forming apparatus without including a developing device. The drum cartridge includes an image bearing member, a charging member, and a cleaning member. The cleaning member includes an elastic layer contacting the charging member. The elastic layer includes a foam member and is made of a material having Asker-C hardness of 5-30 degrees.

An image forming apparatus includes an image bearing member, a transfer roller, an electric energy supply member, a voltage source, a detector, and a controller for adjusting a transfer voltage. A circumferential length 2K of the transfer roller and a distance k measured along an outer periphery of the transfer roller from the electric energy supplying member to the transfer roller satisfy 0.8K≤k≤1.2K. The controller controls the voltage source so as to satisfy 0.7T≤t≤1.3T, where 2T is time required for one full rotation of the transfer roller, and t is time during which the voltage source supplies the test current or the test voltage per one level in the operation of a setting mode.

An image forming apparatus includes: a drawer movable between an inner position and an outer position and supporting a first cartridge including a first photosensitive drum and a first discharge part and a second cartridge including a second photosensitive drum and a second discharge part; and a waste toner box including a first coupling part coupled with the first discharge part and a second coupling part coupled with the second discharge part, in a state where the first cartridge and the second cartridge are supported by the drawer at an inner position and the waste toner box is mounted to the apparatus main body, the waste toner box being movable between a first/second position where the first coupling part and the first discharge part are coupled/decoupled and the second coupling part and the second discharge part are coupled/decoupled.

A clutch device includes a sector gear, a cam, an electromagnetic solenoid, a first lever, a second lever, a first spring, and a second spring. The cam includes a slide portion. The first lever engages with the electromagnetic solenoid and includes a first restricting portion. The second lever includes a hook and a second restricting portion. The first spring is configured to urge the second lever in a direction in which the first restricting portion and the second restricting portion contact each other. The second spring is configured to, when the electromagnetic solenoid is in a de-energized state, move the first lever. The slide portion of the cam has a surface configured to, when the electromagnetic solenoid is in an energized state, press the hook in a direction opposite to an urging direction of the first spring such that the second restricting portion is separated from the first restricting portion.

A drive transmitting member including: a gear portion that is formed of a first resin and has gear teeth; and a flange portion that is formed of a second resin, in which the flange portion includes a shaft portion that transmits driving force from the gear teeth to a drive transmitted member, and a rotation stopper (i) that stops rotation of the gear portion with respect to the flange portion at an outer periphery of the flange portion and (ii) that is larger than an external form of the shaft portion, so that the shaft portion and the rotation stopper are integrally molded in the flange portion, and the gear portion has a shape that covers the rotation stopper and is not overlapped with the shaft portion as viewed in an axial direction of the shaft portion.

An image forming apparatus includes: a drawer movable between an inner position and an outer position and supporting a first cartridge including a first photosensitive drum and a first discharge part and a second cartridge including a second photosensitive drum and a second discharge part; and a waste toner box including a first coupling part coupled with the first discharge part and a second coupling part coupled with the second discharge part, in a state where the first cartridge and the second cartridge are supported by the drawer at an inner position and the waste toner box is mounted to the apparatus main body, the waste toner box being movable between a first/second position where the first coupling part and the first discharge part are coupled/decoupled and the second coupling part and the second discharge part are coupled/decoupled.

An image forming apparatus includes an image bearing member 7, a transfer roller 8, an electric energy supply member 9, a voltage source E2, a detecting means 32 a controlling means 50 for adjusting a transfer voltage. A circumferential length 2K of the transfer roller, and a distance k measured along an outer periphery of the transfer roller from the electric energy supplying portion to the transfer portion satisfy 0.8Kk1.2K. The controller controls the voltage source so as to satisfy 0.7Tt1.3T, where 2T is time required for one full rotation of the transfer roller, and t is time during which the voltage source supplies in the test current or the test voltage per one level in the operation of the setting mode.

A drive transmitting member including: a gear portion that is formed of a first resin and has gear teeth; and a flange portion that is formed of a second resin, in which the flange portion includes a shaft portion that transmits driving force from the gear teeth to a drive transmitted member, and a rotation stopper (i) that stops rotation of the gear portion with respect to the flange portion at an outer periphery of the flange portion and (ii) that is larger than an external form of the shaft portion, so that the shaft portion and the rotation stopper are integrally molded in the flange portion, and the gear portion has a shape that covers the rotation stopper and is not overlapped with the shaft portion as viewed in an axial direction of the shaft portion.