A cartridge includes a photosensitive drum, the movable member movable relative to the photosensitive drum to control an inclination angle of a drive transmission member. The movable member is movable between a first position for reducing an inclination angle of the drive transmission member relative to the photosensitive drum and a second position retracted from the first position. By this, driving connection can be smoothly carried out.

A developer cartridge may include: a first gear having a small-diameter gear portion and a large-diameter gear portion; and a second gear including: a first columnar portion centered on a second axis; a second columnar portion having a smaller diameter than the first columnar portion; a first engagement portion extending along a portion of a peripheral surface of the first columnar portion and engageable with the small-diameter gear portion; a second engagement portion extending along a portion of a peripheral surface of the second columnar portion and positioned closer to a housing than the first engagement portion in an axial direction and engageable with the large-diameter gear portion; and a protruding portion protruding in the axial direction and rotatable together with the first engagement portion and the second engagement portion. The second engagement portion may engage the large-diameter gear portion after the first engagement portion engages the small-diameter gear portion.

A driving force transmission mechanism is a mechanism for transmitting rotational force of the second rotor having a driving-side coupling to a first rotor having a driven-side coupling. The driving-side coupling includes a body and a plurality of second engaging members engaging with first engaging members of the driven-side coupling, each of the plurality of second engaging members has at an abutting point on an abutting surface of a corresponding first engaging member a first inclined surface inclined so as to be away from a rotation axis of the body from a downstream side toward an upstream side in a rotation direction of the body.

An image forming apparatus, having a first photosensitive drum, a first developing roller, a first shifting member movable between a contacting position and a separating position, a motor, a first joint, a first clutch operable in one of a transmittable condition and a discontinuing condition, a first shifting cam rotatable between a first position, in which the first shifting cam locates the first shifting member at the contacting position, and a second position, in which the first shifting cam locates the first shifting member at the separating position, and a first switching cam rotatable between a third position, in which the first switching cam places the first clutch in the transmittable condition, and a fourth position, in which the first switching cam places the first clutch in the discontinuing condition, alongside the first shifting cam rotating between the first position and the second position, is provided.

A rotation detector includes a motor, a current detector and a hardware processor. The motor includes coils of two or more phases and a rotor. The current detector detects currents flowing in coils of at least two phases among the coils of two or more phases. The hardware processor estimates an initial position of the rotor based on current values of the currents detected by the current detector to start the motor, controls an energization pattern on the phases to rotate and start the motor based on the estimated initial position, and determines whether the rotor stops or is rotating before completing the estimation of the initial position.

A rotating force transmitting part for an electrophotographic photosensitive drum for a main assembly of the electrophotographic image forming apparatus, wherein the main assembly of the electrophotographic image forming apparatus includes a driving shaft, to be driven by a motor, having the rotating force applying portion, and wherein the electrophotographic photosensitive drum is dismountable from the main assembly of the electrophotographic image forming apparatus in a direction substantial perpendicular with an axial direction of the driving shaft, the rotating force transmitting part includes a coupling member engageable with the rotational force applying portion to receive a rotational force for rotating the electrophotographic photosensitive drum in the state in which electrophotographic photosensitive drum is mounted to the main assembly of the electrophotographic image forming apparatus, wherein the coupling member being capable of taking a rotational force transmitting angular position for transmitting the rotational force for rotating the electrophotographic photosensitive drum to the electrophotographic photosensitive drum and a disengaging angular position in which the coupling member is inclined away from the axis of the electrophotographic photosensitive drum from the rotational force transmitting angular position, wherein when the process cartridge is dismounted from the main assembly of the electrophotographic image forming apparatus in a direction substantially perpendicular to the axis of the electrophotographic photosensitive drum, the coupling member moves from the rotational force transmitting angular position to the disengaging angular position.

In a toner container, a powder container that includes a container body configured to store toner, and is rotated by input of rotational drive of a drive output section of an image forming device while being set in the image forming device, the toner container includes an incompatible hole group, as a container-side engagement portion, on a front end surface facing downstream in an insertion direction when inserted in a direction parallel to a rotational center line of the rotational drive and set in the image forming device, the incompatible hole group has a hole shape that is engaged with a body-side projection portion of the drive output section protruding upstream in the insertion direction, and the rotational drive is input by rotation of the drive output section with the incompatible hole group and the body-side projection portion engaged with each other.

An image-forming apparatus includes a coupling recess to be engaged with a coupling protrusion to rotate the coupling protrusion, a second gear portion to be engaged with a gear to rotate the gear, and a driving force transmitter that is rotatable about a predetermined rotational axis. A torque required to rotate the gear is larger than a torque required to rotate the second gear portion in a state where the coupling recess does not engage the coupling protrusion.

A developing cartridge includes a casing to accommodate toner; an agitator to agitate the toner and rotatable about a first axis extending in a predetermined direction, the agitator including one end portion and another end portion in the predetermined direction, the agitator being movable in the predetermined direction between a first position and a second position; a first gear mounted to the one end portion and rotatable along with the agitator; an input gear engaging with the first gear; a second gear mounted to the another end portion and rotatable along with the agitator; a third gear; and a protrusion. The second gear is mounted to the another end portion while the first gear engages with the input gear in the first position. And the second gear is separated from the another end portion while the first gear engages with the input gear in the second position.

A replaceable unit for an electrophotographic image forming device includes a housing having a reservoir for holding toner. An electrical connector is positioned on a first side of the housing. The electrical connector includes an electrical contact for contacting a corresponding electrical contact in the image forming device. The electrical contact of the replaceable unit is electrically connected to processing circuitry mounted on the housing. The electrical connector is movable between a first position and a second position. The electrical contact of the replaceable unit moves outward from the first side of the housing along a side-to-side dimension of the housing when the electrical connector moves from the first position to the second position. The electrical contact of the replaceable unit faces downward when the electrical connector is in the second position permitting the corresponding electrical contact to contact the electrical contact of the replaceable unit from below.