An image forming apparatus includes an acquisition unit and a determination unit. The acquisition unit acquires a print setting about at least one of items including a size of a recording medium used for printing, a type of the recording medium, and a conveyance speed of the recording medium. The determination unit determines a printing method to be executed among a plurality of printing methods including a first printing method for drawing an image having a density and a second printing method for drawing an image having a density that is higher than the density of an image printed by the first printing method. Where the print setting is acquired by the acquisition unit, the determination unit determines whether to permit execution of printing by the second printing method based on the print setting acquired by the acquisition unit.

An image forming apparatus including a housing, a toner cartridge, and a drum unit. The drum unit is movable through the opening between an accommodated position where the drum unit is positioned in the housing and a pulled-out position where the drum unit is pulled out of the housing. The drum unit includes a photosensitive drum and a developing unit. The photosensitive drum is rotatable about a first axis extending in a second direction. The developing unit includes a magnetic roller, a developer container, a first auger and a second auger. The magnetic roller is positioned between the toner cartridge and the photosensitive drum. The magnetic roller faces a surface of the photosensitive drum. The developer container is formed with an inlet allowing the toner to be replenished from the toner cartridge. The first auger is positioned in the developer container. The second auger is positioned in the developer container.

A developing device includes a developer carrier to carry a developer, a conveyance path to circulate the developer and supply the developer to the developer carrier, a discharge path extending from the conveyance path and including a discharge port to discharge a portion of the developer, as excess developer, and a valve body provided between the conveyance path and the discharge port. The valve body includes an inlet side oriented toward the conveyance path and an outlet side disposed opposite the inlet side to allow a passage of the the excess developer from the conveyance path through the valve body toward the discharge port, when a pressure applied to the inlet side is greater than a pressure threshold value.

An image forming system includes a toner container and an image forming apparatus to which the toner container is detachably mountable. The image forming apparatus includes a mounting portion to which the toner container is detachably mountable. The toner container includes an accommodating portion configured to accommodate toner, a discharge portion provided with an opening for discharging the toner in the accommodating portion to outside of the toner container, a rotatable member rotatable, relative to the discharge portion, about a rotational axis in a first rotational direction and a second rotational direction that is opposite to the first rotational direction, and a projection provided below the opening of the discharge portion, the projection having inner peripheral surface such that, when the toner container is oriented in a predetermined direction in which the rotational axis extends in a direction of gravity and at least a part of the discharge portion is below the accommodating portion, the inner peripheral surface faces inward in a radial direction of an imaginary circle centered on the rotational axis.

A developer supply container is detachably mountable to a developer receiving apparatus including a developer receiving portion provided with a receiving opening for receiving a developer, and a portion-to-be-engaged 11b integrally displaceable with the developer receiving portion. The developer supply container includes a discharging portion provided with a shutter opening for discharging the developer accommodated in the developer accommodating portion. An operation portion 21 displaces the developer receiving portion to bring the receiving opening into communication with the shutter opening by engagement between the engaging portion 21d and the portion-to-be-engaged 11b by a predetermined operation executed after the developer supply container is mounted to a predetermined position of the developer receiving apparatus.

A cartridge includes a shutter that opens and closes when the cartridge is attached and detached to a developing unit or image forming apparatus. The cartridge includes a casing having a chamber with a first opening at one end portion allowing toner to flow out of the casing. The cartridge includes a cover that covers the first opening, movable with the casing and having a second opening allowing toner to flow out of the cover. The shutter is located at the one end portion and has a protrusion further from the one end portion than the cover. The developing unit supports the protrusion when the cartridge is mounted thereon, and the casing pivots with the cover relative to the developing unit between a first position where the shutter closes the second opening and a second position where a third opening of the shutter overlaps the second opening.

A toner container includes an elongated container main body, a toner discharge port, a first rotation member configured to convey the toner toward the toner discharge port, a support plate provided in the container main body and disposed in such a way as to face the wall surface, and an opening and closing member provided between the wall surface and the support plate and supported by the support plate in such a way as to be able to move between a closing position and an opening position. The support plate includes a first opening portion formed at a position corresponding to the toner discharge port and larger than the toner discharge port in size, and a film member attached to the support plate in such a way as to cover the first opening portion and including a second opening portion formed at a position corresponding to the toner discharge port.

An image forming apparatus includes a photosensitive drum, a developing member, an applying device forming a developing potential on the developing member, a driver rotationally driving the developing member, and a controller. The controller selectively executes an operation in first and second modes by controlling a circumferential speed ratio of a circumferential speed of the developing member to a circumferential speed of the drum and a potential difference between a surface potential of the image bearing member in a region where an electrostatic latent image is formed and the developing potential. In the first mode, the ratio is a first ratio of 50% to 100% and the potential difference is a first potential difference, and in the second mode the ratio is a second ratio larger than the first ratio and less than 150% and the potential difference is a second potential difference less than the first potential difference.

A developer supply container detachably mountable to a developer receiving apparatus, the developer supply container includes an accommodating portion for accommodating a developer; a discharge opening for discharging the developer accommodated in the accommodating portion from the developer supply container; a developer feeding portion for feeding the developer in the accommodating portion toward the discharge opening; a rotatable drive receiving portion for receiving a rotational force; a drive transmitting portion for transmitting the rotational force received by the drive receiving portion to the feeding portion; a portion-to-be-detected for detecting rotation of the drive receiving portion; a contact surface for contacting a rotatable member provided in the developer receiving apparatus; wherein the drive receiving portion, the portion-to-be-detected and the contact are formed integrally.

A powder transporting device includes a first agitating and transporting section that agitates and transports powder, a receiving section that receives the powder from the first agitating and transporting section, a second agitating and transporting section that is arranged below the first agitating and transporting section in a vertical direction and agitates and transports the powder, an upward transport section that is arranged on a downstream side in a transport direction of the second agitating and transporting section and transports the powder transported from the second agitating and transporting section to the first agitating and transporting section above, and a speed increasing section that increases a rotation of a rotating shaft of any one of the first agitating and transporting section, the second agitating and transporting section, or the receiving section and transmits the rotation to the upward transport section.