An image forming apparatus includes a developing device; a developer supply container including an accommodating portion for accommodating a developer, a projected portion projected from the accommodating portion, and a discharge opening for discharging the developer; and a developer supplying device for storing the developer to be supplied to the developing device. The developer supply container is mounted to the developer supplying device. The developer supplying device includes i) a storage portion configured to store the developer, ii) an opening configured to insert the projected portion into the storage portion, iii) an abutting portion abutting to the developer supply container to set the projected portion at a predetermined position relative to the storage portion, iv) a shield portion at least a part of which is vertically below the projected portion of the developer supply container.

In a toner conveying device, a conveyance path of toner is formed in the casing. A conveyance screw is supported by two support portions of the casing so as to be rotated in the conveyance path and convey the toner along the conveyance path. A low friction portion is provided on an inner side surface of the casing facing the conveyance screw, in a middle of the two support portions. The low friction portion has a lower friction coefficient with the conveyance screw than the other portions of the inner side surface. In a region along a longitudinal direction of the conveyance screw including the low friction portion, a space between the low friction portion and the conveyance screw is narrower than a space between the conveyance screw and portions of the inner side surface other than the portion on which the low friction portion is provided.

An image forming apparatus includes a lock mechanism, a first determination processing portion, and a regulation processing portion. The lock mechanism is configured to regulate attachment and detachment of the developer storage portion attached to the attachment portion. The first determination processing portion determines whether or not the developer storage portion attached to the attachment portion is a developer storage portion of a predetermined specific type. The regulation processing portion, when the developer storage portion attached to the attachment portion has been determined to be a developer storage portion of the specific type, causes the lock mechanism to regulate attachment and detachment of the developer storage portion.

A developing device develops, with developer, an electrostatic latent image formed on an image carrying member, and includes a developing tank, a developer carrying member, and a drive input portion. The developing tank stores the developer and has a receiving port and a discharge port through which the developer is received and discharged respectively. The developer carrying member rotates in the developing tank while carrying the developer. The drive input portion receives a rotational force from outside the developing device and transmit the rotational force to a driven rotation shaft that is a rotation shaft of the developer carrying member. The receiving port, the discharge port, and the drive input portion are provided in the developing tank to be close to an end of the developing tank in a longitudinal direction of the developing tank.

An example developing device includes a housing to contain a developer and having an opening, a developing sleeve provided in the housing and partially exposed to the outside of the housing through the opening, a magnetic member including a plurality of magnetic poles and located inside the developing sleeve, and an elastic member blocking an inflow of air through a space between a downstream edge of the opening in a rotation direction of the developing sleeve and an outer circumferential surface of the developing sleeve. The elastic member includes a fixed portion fixed to the housing at a position adjacent to the downstream edge of the opening and an extension portion extending from the fixed portion in a bent form in the rotation direction of the developing sleeve to be elastically in contact with the surface of the developing sleeve.

A developing device includes a developer carrying member for carrying and feeding a developer, first and second chambers for circulating the developer, and a partition wall. A first feeding member feeds the developer in the first chamber in a first feeding direction, and a second feeding member feeds the developer in the second chamber. The second feeding member includes a shaft, a first helical portion for feeding the developer in a second feeding direction, and a second helical portion for feeding the developer in the first feeding direction. The second helical portion is provided on the shaft and provided downstream of the first helical portion via a region where no helical portion is provided. A rib is provided on a first inner surface of the second chamber, with the rib disposed opposite the region where no helical portion is provided and extending upwardly in a vertical direction.

A developing apparatus is provided with a third communication port downstream of a first communication port of a partition wall. The third communication port is disposed at a position facing a return screw when viewed from a horizontal direction. A lower end of the third communication port is located above a lower end of the first communication port. Because the first communication port is practically enlarged to the return screw, the delivery of the developer from an agitating chamber to a developing chamber is not suppressed even if fluidity of the developer drops. Accordingly, the developer is hardly rotated with a developing sleeve. Still further, because a partition wall prevents the developer from entering the third communication port, the discharge of the developer is hardly suppressed. This arrangement makes it possible to reduce an occurrence of image defect caused by the delivery and discharge of the developer.

An agitating screw at a first communication port delivering a developer from a collecting chamber to a developing chamber is formed to be a multiple-threaded screw. The use of the multiple-threaded screw makes it possible to increase a developer surface level at the first communication port. If the developer surface level becomes too high within the collecting chamber, an image defect caused by entrainment of the developer by the developing sleeve may occur. Then, an arrangement is made such that the developer surface level does not become so high that may cause the entrainment of the developer by accelerating delivery of the developer at the first communication port. Thus, the use of the multiple-threaded screw makes it possible to accelerate the delivery of the developer and to reduce an image defect otherwise caused by the entrainment of the developer.

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.

An image forming apparatus has a developing portion; a toner storing container; and a supply path capable of supplying toner to the developing portion from the toner storing container, where the toner storing container is attachably and detachably provided to the supply path, and the toner storing container has a screw-like conveying member configured to convey the toner; a discharge portion configured to discharge the toner toward the supply path; and a first cleaning member arranged at an end portion of the conveying member and configured to clean the discharge portion by scraping the toner on the discharge portion based on a rotation of the conveying member.