A cartridge attachable to and detachable from an image forming apparatus forming an image on a recording material, the cartridge includes: an image bearing member; a developer container that contains therein a developer; a developing member that is rotatable and carries the developer supplied from the developer container and supplies the developer to the image bearing member; a developer supplying member that is rotatable and provided in the developer container and in contact with the developing member to supply the developer to a surface of the developing member; and a contact member provided in the developer container and in contact with a surface of the developer supplying member, wherein the developer remaining on the image bearing member after image formation is collected to the developing member, and the developer collected to the developing member is collected into the developer container.

An example image forming apparatus includes a printing unit to print an image on a print medium using toner, a container having a hollow portion to accommodate waste toner discharged from the printing unit, a heater to apply heat to the container such that the waste toner becomes a waste toner viscous body, and a piston inserted in the hollow portion of the container movable between a first position blocking a first end portion of the hollow portion, a second position exposing the waste toner viscous body to a second end portion of the hollow portion to cool the waste toner viscous body to become a waste toner pellet, and a third position beyond the second position to separate the waste toner pellet from the second end portion of the hollow portion.

An imaging system includes a stirring device to stir a developer, a rotatable developer carrier to carry the developer a non-magnetic regulator, a secondary regulator, an excess developer conveyance path extending from the developer carrier and between the non-magnetic regulator and the secondary regulator, a toner supply path to supply a toner to the stirring device, and a merging portion where the toner supply path and the excess developer conveyance path merge. The non-magnetic regulator and the secondary regulator regulate the thickness of the developer carried by the developer carrier. Excess developer from the developer carrier is conveyed via the excess developer conveyance path. The merging region controls the supply of the toner from the toner supply path to the stirring device based, at least in part, on an amount of the excess developer received from the excess developer conveyance path.

An imaging system includes a rotatable image carrier; a rotatable developer carrier, a storage container, and an air flow generator. The developer carrier transfers toner to the image carrier at a developing region located between the image carrier and the developer carrier. The storage container stores the developer carrier. The air flow generator is separated from the storage container by a gap, and rotates in a rotational direction that is opposite to a rotational direction of the developer carrier, to channel an air flow through the gap when the air flow generator rotates.

A developing device includes a developer container, a developer carrier, and first and second members for stirring/conveying. The developer container includes a first partition wall between first and second chambers, a communication portion through which those chambers communicate at opposite ends of the first partition wall, a developer supply port, and a developer discharge portion. The first member stirs and conveys developer in the first chamber in a first direction. The second member stirs and conveys developer in the second chamber in a second direction and includes a regulating portion and a discharging blade. The developer container includes a second partition wall between the first chamber and the regulating portion. The gap from the upper end of the second partition wall to the inner surface of the developer container is larger than the gap thereto from the upper ends of a first helical blade and the regulating portion.

An image forming apparatus includes a black image carrier that holds toner images of black, a yellow image carrier that holds toner images of yellow, a magenta image carrier that holds toner images of magenta, a cyan image carrier that holds toner images of cyan, at least one spot-color image carrier, and multiple collecting units. The at least one spot-color image carrier holds toner images of a spot color other than black, yellow, magenta, and cyan. Each of the collecting units collects waste toner. The collecting units include a first collecting unit that collects waste toner removed from the black image carrier, and waste toner removed from the spot-color image carrier.

An image forming apparatus includes a black image carrier that holds toner images of black, a yellow image carrier that holds toner images of yellow, a magenta image carrier that holds toner images of magenta, a cyan image carrier that holds toner images of cyan, at least one spot-color image carrier, and multiple collecting units. The at least one spot-color image carrier holds toner images of a spot color other than black, yellow, magenta, and cyan. Each of the collecting units collects waste toner. The collecting units include a first collecting unit that collects waste toner removed from the black image carrier, and waste toner removed from the spot-color image carrier.

A developing device includes a developing container; a developing roller; a supplying roller; a first magnet including a first magnetic pole; a second magnet including second to fourth magnetic poles; and a regulating member. A maximum magnetic flux density of the second magnetic pole is larger in absolute value than a maximum magnetic flux density of the third magnetic pole in a normal direction to the supplying roller, and a maximum magnetic flux density of the third magnetic pole is larger in absolute value than a maximum magnetic flux density of the fourth magnetic pole in the normal direction. With respect to a rotational direction of the supplying roller, an angle between maximum magnetic flux density positions of the second and third magnetic poles is smaller than an angle between maximum magnetic flux density positions of the third and fourth magnetic poles by 10 degrees or more.

An image forming apparatus capable of forming images in mono-color and a plurality of colors includes first and second image forming units and a control unit. The image forming unit includes a rotatable image bearing member, a rotatable developing member that contacts the image bearing member to supply a developer to the surface thereof, and a developer supply member that supplies the developer to the developing member. The control unit switches between an image forming operation of forming an image on the image bearing member surface and a cleaning operation of removing an attached matter on the image bearing member surface with the developing member by controlling a voltage applied to the developing member and a voltage applied to the developer supply member.

A powder conveying device includes an inflow portion, a discharge portion, and a conveying screw. Powder flows into the inflow portion from outside of the powder conveying device. The powder flows out from the discharge portion to the outside of the powder conveying device. The conveying screw includes a shaft and conveys the powder from the inflow portion to the discharge portion in a conveying direction. A surface portion of the shaft at at least one of an upstream end or a downstream end of the shaft in the conveying direction, in at least one of the inflow portion or the discharge portion has a lower friction with the powder than another surface portion of the shaft at a position other than the at least one of the upstream end or the downstream end.