An image forming apparatus includes a latent image bearer, a developing device, a supplier, and a controller. The controller controls the supplier according to a detection result of a toner density by the toner density sensor and a toner density target value to adjust the toner density of developer in the developing device. The controller is configured to correct the toner density target value and an imaging condition affecting a toner adhesion amount of an output image separately from the toner density, according to a component adhesion deterioration degree being a deterioration degree of carrier due to adhesion of a toner component, obtained based on at least an average image area ratio of the output image, and a coating abrasion deterioration degree being a progression degree of deterioration due to coating abrasion of the carrier, obtained based on at least the average image area ratio of the output image.

An image forming apparatus includes an image bearing member, a developing device, a supplying device, and a controller. The controller can execute a normal supply mode and a forced supply mode on the basis of a difference between a toner supply amount in the normal supply mode and a supply amount of the toner to be supplied to the developing device. In a case where the flag is set when a predetermined time is elapsed after the difference exceeds the predetermined threshold, image formation is effected and then interrupted, and then the controller executes the operation in the forced supply mode, and in a case where the flag is reset when the predetermined time is elapsed after the difference exceeds the predetermined threshold, the image formation is effected and then said controller continues an image forming operation without executing the operation in the forced supply mode.

A developing device includes a developer bearing member and carrier to develop an electrostatic latent image formed on an image bearing member, a developing container, a conveying screw which conveys the developer, and an inductance sensor which includes a detecting portion which detects magnetic permeability of the developer in the developing container. If the inductance sensor is not attached to the developing container and a predetermined magnetic material is disposed in contact with the detection portion, an output value when the detecting portion detects magnetic permeability of the predetermined magnetic material is A, and if the inductance sensor is not attached to the developing container and the predetermined magnetic material is disposed 1 mm away from the detection portion in a vertical direction passing through the detection portion, an output value when the detecting portion detects magnetic permeability of the predetermined magnetic material is B, with B/A0.1 being satisfied.

A developing device includes a the conveying screw having a rotary shaft portion, and a first blade portion that conveys developer accommodated in a developing container in a conveying direction. The first blade portion is spirally formed on an outer circumferential surface of a rotary shaft portion, and a second blade portion is disposed downstream of the first blade portion in the conveying direction and conveys the developer accommodated in the developing container in the conveying direction. The second blade portion is spirally formed on an outer circumferential surface of the rotary shaft portion, and at least a portion of the first blade portion is disposed facing the detecting portion. At least a portion of the second blade portion is disposed within one pitch downstream of the first blade portion from a downstream end of the detection portion with respect to the conveying direction, and a pitch of the second blade portion is less than a pitch of the first blade portion.

A cartridge is provided that includes a first accommodating portion configured to accommodate toner, a first rotation shaft configured to be rotatable about a first rotation axis line, a first flexible member fixed to the first rotation shaft, a first magnetized member provided on the first flexible member, a second accommodating portion configured to accommodate toner to be supplied to the first accommodating portion and being aligned with the first accommodating portion in a first direction, a second rotation shaft configured to be rotatable about a second rotation axis line, a second flexible member fixed to the second rotation shaft, a second magnetized member provided on the second flexible member, and a magnetism sensing sensor provided between the first rotation axis line and the second rotation axis line in the first direction, and configured to sense magnetism in a sensing-capable range.

An image forming apparatus includes a development device and a slide member. The slide member is capable of reciprocating in the longitudinal direction of the development device, and removably supports the development device. The development device and the slide member include a locating pin and a locating hole that are fitted together when the development device and the slide member approach each other. The locating hole includes an opening inclined portion. The locating pin includes: a tip inclined portion; and a locating inclined portion that is continuous in the circumferential direction of the tip inclined portion, is arranged opposite the opening inclined portion in the longitudinal direction of the development device and has a smaller inclination angle than the tip inclined portion.

There is provided an image forming apparatus including: an image bearing member; a development device configured to include a developer accommodation portion configured to accommodate a developer including a toner and a carrier; a detection portion configured to detect a toner density of the developer accommodated in the developer accommodation portion; a developer replenishment container configured to replenish the developer to the developer accommodation portion; a storage portion configured to store information specific to the toner accommodated in the developer replenishment container; a control portion configured to set a target toner density of the developer based on the information stored in the storage portion and then control the toner density of the developer accommodated in the developer accommodation portion based on a result detected by the detection portion so that the toner density of the developer accommodated in the developer accommodation portion is the target toner density of the developer.

A developing device includes a development container, a first conveyance member, a second conveyance member, a developer carrier, and a toner concentration sensor. The first conveyance member and the second conveyance member are rotatably supported in the development container, and convey the developer, while stirring the developer, in mutually opposite directions along a longitudinal direction of the development container. The first conveyance member includes a rotation shaft and a first conveyance blade helically formed on an outer circumferential part of the rotation shaft. The first conveyance blade includes a cutout portion formed by removing part of the first conveyance blade in a facing region with respect to the toner concentration sensor.

An image forming apparatus includes an image carrying member, a charging device, an exposure device, a developing device, a toner container, a toner concentration sensor, a toner charge amount detection portion, and a control portion. The developing device includes a developer carrying member carrying a two-component developer and develops an electrostatic latent image into a toner image. The toner concentration sensor detects a toner concentration in the developing device. The toner charge amount detection portion detects a toner charge amount in the developing device. Based on a result of detection by the toner concentration sensor, the control portion controls replenishment of the developing device with the toner from the toner container. Based on the toner charge amount detected by the toner charge amount detection portion, the control portion executes first target value changing control of changing a target value of the toner concentration.

An image forming apparatus includes an image forming portion, a toner container, a control portion, and a storage portion. The control portion corrects, based on an integrated consumption amount of toner from a start of use of a developing device, a target value of a toner concentration in a two-component developer in the developing device. The storage portion stores a first integrated consumption amount that is the integrated consumption amount on a first production line of the image forming apparatus. The control portion calculates a second integrated consumption amount that is the integrated consumption amount in a setup operation for the image forming apparatus and an image output operation performed after a start of use thereof, and uses a sum of the first integrated consumption amount and the second integrated consumption amount to determine a correction value for correcting the target value of the toner concentration.