A mechanism that enables developer replenishment by a simpler structure and a mechanism that enables more user-friendly developer replenishment are provided. An attachment port to which a developer supply bottle containing a developer stored therein is detachably attachable is disposed in an interior of an image forming apparatus. The developer supply bottle can be attached when the cover is in an open state. According to this image forming apparatus, when the developer supply bottle is attached to the attachment port, the developer inside the developer supply bottle moves into a developer housing chamber by its own weight.

A mechanism that enables developer replenishment by a simpler structure and a mechanism that enables more user-friendly developer replenishment are provided. An attachment port to which a developer supply bottle containing a developer stored therein is detachably attachable is disposed in an interior of an image forming apparatus. The developer supply bottle can be attached when the cover is in an open state. According to this image forming apparatus, when the developer supply bottle is attached to the attachment port, the developer inside the developer supply bottle moves into a developer housing chamber by its own weight.

An example image forming apparatus includes a frame, a first shaft supported by the frame, and a first coupler. The first coupler includes a body coupled to one end of the first shaft and a first protrusion protruding from the body in an axial direction of the first shaft, the first protrusion having a first surface and a second protrusion protruding from the first surface. The second protrusion is to lock with a groove to mount a cartridge on the frame, the first shaft is to provide a rotational force in a first rotational direction to rotate the second protrusion of the first coupler and to insert the second protrusion into the groove to lock with the cartridge, and the first surface of the first protrusion of the first coupler is to contact a second surface to transmit the rotational force to the second coupler in the first rotational direction.

Examples described herein relate to a system consistent with the disclosure. For instance, the system may comprise a printing device including hardware to adjust a velocity of a development unit within the printing device, a memory resource, and a controller in communication with the memory resource to determine an average usage condition of the printing device, wherein the average usage condition is based on at least one of a print coverage and a quantity of pages printed by the printing device, and adjust a velocity of the development unit based on the average usage condition.

An image forming apparatus includes a developer container to and from which the replenishment container is attachable and detachable and which includes an accommodating portion that accommodates developer and a replenishment port, an agitation member, an opening/closing member configured to be movable between a closed position and an open position, a drive source for driving the agitation member, and a control portion configured to control the drive source. The apparatus is configured such that image formation is not possible when the opening/closing member is at the open position, and the agitation member is capable of driving in a case where the opening/closing member is at the open position.

A toner conveying device includes a container, a rotating member having a protruding portion inside the container, and a stirring member of toner. A first region and a second region on the opposite side are provided inside the rotation trajectory of the rotating member in a state without contact with the inner surface of the container. The protruding portion is provided between a first position in which a second straight line that is perpendicular to a first straight line that divides the rotation trajectory and passes through the center of the rotating member and is in the second region, and a second position in which a third straight line that is perpendicular to a contact line passing through a contact point between the container and the stirring member, passes through the center at the time of deformation of the stirring member and is in the second region.

A developing apparatus includes: a developer tank that contains a developer; and conveyance members that convey the developer while agitating the developer. The conveyance members include a first screw and a second screw. The developer tank includes: a first storage chamber in which the first screw is provided; a second storage chamber in which the second screw is provided; a partition that separates the first storage chamber from the second storage chamber; and a flow area that opens the partition to flow the developer between the first storage chamber and the second storage chamber; a developer detection sensor that detects an amount of the developer thereof; a discharge port that discharges the developer; and a discharge guide that guides the developer to the discharge port. The developer detection sensor detects that the developer tank is full according to the amount of the developer.

A developing cartridge may include a developing roller, a casing capable of containing a developer therein, a developing electrode movable with the casing and the developing roller and pivotable about a developing roller shaft of the developing roller in a direction, a first lever movable relative to the casing, and a holder configured to hold the first lever relative to the casing, in case where the developing electrode pivots from one side of the direction to an other side of the direction, the first lever stops the pivotable movement of the developing electrode from one side of the direction to the other side of the direction and the holder prevents the first lever from coming off the holder from the one side of the direction to the other side of the direction.

An example device to develop an electrostatic latent includes first and second passages coupled to each other through first and second openings. A first stir-and-transport member located in the first passage includes a first helical blade to stir and transport a developer along the first passage in a first direction and to supply the developer to a developing roller. A second stir-and-transport member located in the second passage includes a second helical blade to stir and transport the developer along the second passage in a second direction. A developer discharge pipe is coupled to the developer container to communicate with a downstream side of the first passage. The first stir-and-transport member includes a first reverse helical blade having a pitch between approximately 0.5 times and 1.5 times the pitch of the first helical blade and located downstream of the first helical blade and disposed downstream of the second opening.

A toner conveyance device includes a vertical conveyance portion, a horizontal conveyance portion, a conveyance member, and a loosening member. The vertical conveyance portion conveys a toner or a developer containing the toner conveyed therein through an entry port connected to a main-body-side conveyance path by causing the toner or the developer to fall vertically. The horizontal conveyance portion is connected to a lower end of the vertical conveyance portion and conveys the toner or the developer in a horizontal direction by using the conveyance member arranged in the horizontal conveyance portion. The loosening member is arranged so as to be movable between a first position below a connection portion between the main-body-side conveyance path and the entry port and a second position protruding upward beyond the connection portion and reciprocates in a vertical direction at each of the first position and the second position.