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 lubricant replacement case for an image forming apparatus includes a housing including a plurality of storage compartments to accommodate at least one lubricant unit. The plurality of storage compartments include at least one storage compartment for unused lubricant to be inserted into the image forming apparatus and at least one storage compartment for used lubricant to be retrieved from the image forming apparatus.

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 process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The cartridge includes an electrophotographic photosensitive drum, a developing roller, a drum unit containing the drum, a developing unit containing the roller and being movable so the roller contacts and is spaced from the drum, and a first force receiver receiving a force from a main-assembly first force applier by movement of a door from open to closed positions when mounting the cartridge and a second force receiver movable from a stand-by position by movement of the first force receiver by a force received from the first force applier. The second force receiver takes a projected position receiving a force from the second force applier to move the developing unit so the roller moves out of contact with the drum, the projected position being higher than the stand-by position.

An image forming apparatus includes a housing, a drum cartridge, a developing cartridge including a developing roller and movable between a contact position and a spaced position, a first spacing member configured to move the developing cartridge between the contact position and the spaced position, a first cam configured to move the first spacing member, and a lock member movable between a lock position at which the photoconductive drum is locked to the housing and a lock releasing position at which the lock of the photoconductive drum with respect to the housing is released. The lock member is configured to move from the lock releasing position to the lock position by being pushed by the first spacing member.

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 includes a main body provided with a mounting portion and an interference member, and a toner cartridge inserted into the mounting portion. The toner cartridge includes a housing containing toner, a coupling portion, a front cover coupled to one end of the housing via the coupling portion, and a switching member to weaken a coupling force of the coupling portion by interfering with the interference member when the toner cartridge is mounted on the mounting portion.

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 printing drum mounting system and method of assembling the mounting system. The mounting system comprising a rotatable shaft; a first mount and a second mount arrangeable on the shaft to clamp a printing drum therebetween, wherein the first mount comprises a first engaging surface to form a mating contact with a corresponding first end surface of the printing drum and the second mount comprises a second engaging surface to form a mating contact with a corresponding end surface of the printing drum; a double-walled flexure to flexibly mount the first engaging surface and the shaft, the flexure to provide the first engaging surface with a single degree of freedom of axial movement relative to the shaft and to maintain mating contact between the first engaging surface and the first end surface of the printing drum as the printing drum thermally expands and contracts; and a releasable fixing to align and rigidly engage the second engaging surface relative to the shaft.

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.