A toner conveyance device includes a conveyance path including a flowing-in portion to receive toner and a discharge portion to discharge the toner, a conveying screw to convey the toner from the flowing-in portion to the discharge portion, and a toner loosener disposed in at least one of the flowing-in portion and the discharge portion. The toner loosener includes at least one loosening portion to be vibrated by contact with the conveying screw and a support to cantilever the loosening portion. The loosening portion includes a first contact portion and a second contact portion disposed farther than the first contact portion from the support. A distance from the support to the second contact portion is longer than a distance from the support to the first contact portion in a longitudinal direction of the conveying screw.

Provided is an image formation device including a photoreceptor configured to carry a toner image and a developer configured to form the toner image on a surface of the photoreceptor and configured such that the developer is a replaceable development unit, the image formation device including: a development bias application section configured to apply a development bias to between the photoreceptor and the developer; a stabilization control section configured to perform image stabilization control of determining a development bias value to be used in future by changing the development bias while measuring a density of the toner image formed by the developer, thereby obtaining the toner image with a target density; and a life determination section configured to determine expiration of use of the development unit when the development bias value determined by the stabilization control falls outside a preset acceptable range.

An image forming apparatus is provided. The image forming apparatus includes a chassis having an opening, a cover, photosensitive members, an intermediate transfer belt, a primary-transfer member, a secondary-transfer roller, a cleaner device, an external-sheet inlet, a waste toner container, a connector, and a conveying roller, which is arranged within the feeding path to feed the recording sheet inserted through the external-sheet inlet in the feeding path. The conveying roller is mounted on the waste toner container and removable from the chassis along with the waste toner container.

An image forming apparatus includes an image forming unit for forming an image on a sheet and a sheet conveying unit for conveying the sheet along a conveying path extending in a substantially horizontal direction in a lower portion of the image forming unit. The image forming apparatus includes a recovery container which is provided in front of the image forming unit and above the conveying path, and accommodates the waste toner discharged from the image forming unit. The image forming apparatus includes a waste toner conveying pipe that conveys the waste toner discharged from the image forming unit to the recovery container, without passing through the rear portion and the side portion of the image forming unit.

An image forming apparatus includes a chassis having an opening, a cover, photosensitive members, an intermediate transfer belt, a primary-transfer member, a secondary-transfer roller, a cleaner device, an external-sheet inlet, a waste toner container, a connector, and a conveying roller, which is arranged within the feeding path to feed the recording sheet inserted through the external-sheet inlet in the feeding path. The conveying roller is mounted on the waste toner container and removable from the chassis along with the waste toner container.

A process cartridge having a drum cartridge and a toner cartridge is provided. The drum cartridge includes a photosensitive drum, a cleaner, a conveyer tube, a developing roller, and a developing device. The toner cartridge is attachable to the drum cartridge and is located on a side of the developing roller opposite to the photosensitive drum in an attaching direction. The toner cartridge includes a waste toner container to store the toner conveyed through the conveyer tube and a toner container to store the toner to be supplied to the photosensitive drum. The toner container communicates with a developing chamber in the developing device and is located at least partly between the waste toner container and the developing chamber. The conveyer tube extends in the attaching direction and is arranged to overlap the photosensitive drum, the toner container, and the waste toner container in a view along an axial direction.

An image forming apparatus includes a chassis having an opening, a cover, photosensitive members, an intermediate transfer belt, a primary-transfer member, a secondary-transfer roller, a cleaner device, an external-sheet inlet, a waste toner container, a connector, and a conveying roller, which is arranged within the feeding path to feed the recording sheet inserted through the external-sheet inlet in the feeding path. The conveying roller is mounted on the waste toner container and removable from the chassis along with the waste toner container.

An image forming apparatus includes a main frame, a plurality of process cartridges, a cartridge-supporting body, a belt, a waste toner cartridge, a contact-separation mechanism, and a collective conveying unit. Each process cartridge includes a photosensitive drum and a drum cleaning unit collecting waste toner on the drum. The cartridge-supporting body is movable between an internal position inside the frame and an external position outside the frame. The belt confronts the process cartridges in the internal position. The waste toner cartridge accommodates the waste toner collected from the drums. The contact-separation mechanism moves the cartridge-supporting body between a contact position where the drums are in contact with the belt and a separated position where the drums are out of contact with the belt. The collective conveying unit aggregates waste toner collected from drums and conveys collectively the aggregated waste toner to the waste toner cartridge.

An image forming apparatus includes a main frame, a plurality of process cartridges, a cartridge-supporting body, a belt, a waste toner cartridge, a contact-separation mechanism, and a collective conveying unit. Each process cartridge includes a photosensitive drum and a drum cleaning unit collecting waste toner on the drum. The cartridge-supporting body is movable between an internal position inside the frame and an external position outside the frame. The belt confronts the process cartridges in the internal position. The waste toner cartridge accommodates the waste toner collected from the drums. The contact-separation mechanism moves the cartridge-supporting body between a contact position where the drums are in contact with the belt and a separated position where the drums are out of contact with the belt. The collective conveying unit aggregates waste toner collected from drums and conveys collectively the aggregated waste toner to the waste toner cartridge.

A toner conveying device includes a drop conveyance passage, an inclined conveyance passage, a conveyor, and a flexible sheet. Toner drops by its own weight through the drop conveyance passage. The inclined conveyance passage communicates with a lower end of the drop conveyance passage and extends obliquely downward. The conveyor has a coil shape or screw shape, is disposed in the inclined conveyance passage, and rotates in a specified direction to convey the toner obliquely downward. The flexible sheet is disposed in the drop conveyance passage, has a leading end to contact the conveyor, and swings in conjunction with rotation of the conveyor.