An elastic force of an elastic member 11 required for rotating a driven rotational body 8b is decreased.

A first rotational body 8d and a second rotational body 9a arranged downstream of a driven rotational body 8b in a drive train that transmits a driving force from a driving rotational body 7 to a driven member 4 are included. The first rotational body 8d rotates in synchronization with the driven rotational body 8b. The second rotational body 9a is rotated by the first rotational body 8d and rotates the driven member 4. The first rotational body 8d rotates without rotating the second rotational body 9a when the driven rotational body 8b rotates by an elastic force of an elastic member 11.

A cartridge for an electrophotographic image forming apparatus includes a developing roller, a rotatable member for transmitting a rotational force to the developing roller, a coupling member, and a frame. The coupling member is capable of moving between a first coupling member position in which the coupling axis is substantially coaxial with the rotational axis of the rotatable member and a second coupling member position in which the coupling axis is not coaxial with the rotational axis of the rotatable member. When the frame is in a first frame position, the coupling member is in the first coupling member position and a rotational force receiving portion of the coupling member engages with a rotational force applying portion of the apparatus, and, when the frame is in the second frame position, the coupling member is in the second coupling member position and the rotational force receiving portion engages with the rotational force applying portion.

A developing device includes a rotatable developing member, a developing container, a first communication opening, a second communication opening, a first feeding screw including a first rotation shaft, first and second blade portions, a second feeding screw including a second rotation shaft, third and fourth blade portions, a developer discharge opening provided upstream of an upstream end of the second communication opening in a first direction, and a third communication opening provided upstream of the upstream end of the second communication opening in the first direction. In a second direction opposite to the first direction, the third communication opening overlaps with the second blade portion. In the first direction, the third communication opening overlaps with the fourth blade portion. In the first direction, a downstream end of the third communication opening is positioned downstream of a downstream end of the developer discharge opening.

A developing cartridge includes: a casing; a developer container; a developing roller; an unsealing mechanism; a first rotary body; a second rotary body; and a delayed transmission mechanism. The developer container is sealed to accommodate developer. The unsealing mechanism unseals the developer container. The first rotary body is provided at the unsealing mechanism. A drive force from a drive source is transmitted to the first rotary body and the second rotary body. The second rotary body transmits the drive force to the developing roller. The delayed transmission mechanism delays transmission of the drive force to the second rotary body for at least a prescribed time after transmission of the drive force to the first rotary body is initiated. The prescribed time is equivalent to a time that elapses from a moment the unsealing mechanism begins rotating to a moment the unsealing mechanism has unsealed the developer container.

An image forming apparatus cartridge includes a coupling member having an axis about which the coupling member is rotatable. The coupling member includes a first end portion operatively connected to a developer roller and a developer supplying roller and a second end portion for receiving a rotational force. The coupling member is movable between a first position in which the axis of the coupling member is substantially parallel to and offset from the axis of the developer roller, a second position in which the axis of the coupling member is inclined with respect to the position of the axis when the coupling member is in the first position, and a third position in which the axis of the coupling member is inclined with respect to the position of the axis when the coupling member is in the first position in a direction opposite to the direction the coupling member is inclined when in the second position.

An electrophotographic image forming apparatus comprises a main assembly that includes moving force applying portion, a main assembly engaging portion having a driving shaft and a rotational force applying portion provided on the driving shaft, and an electrophotographic photosensitive drum. A cartridge is dismountable from the main assembly without dismounting the electrophotographic photosensitive drum from the main assembly. The cartridge includes a developing roller for developing a latent image formed on the electrophotographic photosensitive drum, a rotatable member for transmitting a rotational force to the developing roller, and a coupling member including a rotational force receiving portion engageable with the rotational force applying portion to receive a rotational force from the main assembly engaging portion, and a rotational force transmitting portion for transmitting the rotational force to the rotatable member. The cartridge also includes a frame including a moving force receiving portion that receives a moving force from the moving force applying portion, the frame supporting the developing roller and the rotatable member.

A cartridge for an electrophotographic image forming apparatus includes a developing roller, a rotatable member for transmitting a rotational force to the developing roller, a coupling member, and a frame. The coupling member is capable of moving between a first coupling member position in which the coupling axis is substantially coaxial with the rotational axis of the rotatable member and a second coupling member position in which the coupling axis is not coaxial with the rotational axis of the rotatable member. When the frame is in a first frame position, the coupling member is in the first coupling member position and a rotational force receiving portion of the coupling member engages with a rotational force applying portion of the apparatus, and, when the frame is in the second frame position, the coupling member is in the second coupling member position and the rotational force receiving portion engages with the rotational force applying portion.

A developing device includes a rotatable developing member, a developing container, a first communication opening, a second communication opening, a first feeding screw including a first rotation shaft, first and second blade portions, a second feeding screw including a second rotation shaft, third and fourth blade portions, a developer discharge opening provided upstream of an upstream end of the second communication opening in a first direction, and a third communication opening provided upstream of the upstream end of the second communication opening in the first direction. In a second direction opposite to the first direction, the third communication opening overlaps with the second blade portion. In the first direction, the third communication opening overlaps with the fourth blade portion. In the first direction, a downstream end of the third communication opening is positioned downstream of a downstream end of the developer discharge opening.

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 cartridge includes a coupling member having an axis about which the coupling member is rotatable. The coupling member includes a first end portion operatively connected to a developer roller and a developer supplying roller and a second end portion for receiving a rotational force. The coupling member is movable between a first position in which the axis of the coupling member is substantially parallel to and offset from the axis of the developer roller, a second position in which the axis of the coupling member is inclined with respect to the position of the axis when the coupling member is in the first position, and a third position in which the axis of the coupling member is inclined with respect to the position of the axis when the coupling member is in the first position in a direction opposite to the direction the coupling member is inclined when in the second position.