An image formation apparatus according to one or more embodiment may include: image formation parts each including a developer image development part, a developer container that accommodates a developer, and a deteriorated developer container that accommodates a deteriorated developer discharged from the developer image development part; a collection part that collects a value based on a history of printing rates of each of the image formation parts; a printing rate calculator that calculates a printing rate of a received print data; and an image formation part selector that selects, based on the value based on the history of printing rates of each of the image formation parts collected by the collection part and the printing rate of the received printed data calculated by the printing rate calculator, one of the image formation parts, to be used for performing printing of the received print data.

An image forming apparatus includes a developing device to contain a developer, the developer including a toner; a developer cartridge to supply the developer to the developing device; a toner concentration sensor to sense a toner concentration of the toner included in the developer contained in the developing device; and a controller. The controller controls, during a non-printing operation a sensor control voltage to adjust an output level of the toner concentration sensor, to control an output of the toner concentration sensor to satisfy a controlling condition, and detects an shape of the output of the toner concentration sensor after the controller controls the sensor control voltage to adjust the output level. The controller adjusts, during a printing operation, the output of the toner concentration sensor, based on the detected shape of the output of the toner concentration sensor, and adjusts supplying the developer from the developer cartridge to the developing device, according to the adjusted output of the toner concentration sensor, to control the toner concentration.

An image forming apparatus includes a permeability sensor configured to detect information on magnetic permeability of developer contained in a developer container for detecting toner density of the developer, and a controller configured to control a control voltage applied to the permeability sensor so that (i) a value of the control voltage that is applied to the permeability sensor in a case where a predetermined condition including a condition that the toner density of the developer contained in the developer container is a predetermined density is satisfied and an amount of the developer contained in the developer container is a first amount is greater than (ii) a value of the control voltage applied to the permeability sensor in a case where the predetermined condition is satisfied and the amount of the developer contained in the developer container is a second amount greater than the first amount.

According to one embodiment, there is provided a toner cartridge used in an image forming apparatus including a processor which forms a toner pattern image on a photoconductive member, transfers the toner pattern image on a medium, and changes an image forming condition based on a detection result obtained by optically detecting the toner pattern image transferred onto the medium, the toner cartridge including: a toner accommodating container accommodating a toner, and a memory. The memory stores reference data which is determined according to toner characteristics in the toner accommodating container, and is used for applying a reference value for an optical detection result of a toner pattern formed by the toner on the medium.

An image processing device includes: a fold unit that folds a first adjustment sheet including an adjustment pattern, over the adjustment pattern based on a predetermined reference fold position; an image reader that reads an image of the adjustment pattern with the first adjustment sheet folded by the fold unit unfolded; a position identifying unit that, based on a fold line in the image of the adjustment pattern read by the image reader, identifies a position of the fold line; and a position adjusting unit that adjusts a fold position of the fold unit based on a difference between the position of the fold line identified by the position identifying unit and the reference fold position. The image reader includes a scanner that scans the first adjustment sheet relatively in a direction along fold of the first adjustment sheet, and reads the image of the adjustment pattern.

A developer supply device includes a developer container, an adjustment mechanism, and a controller. The developer container is configured to supply developer by rotating. The adjustment mechanism is configured to adjust a rotation angle of the developer container. The controller is configured to control the rotation angle of the developer container by the adjustment mechanism according to a developer remaining amount in the developer container.

An image formation apparatus according to one or more embodiment may include: image formation parts each including a developer image development part, a developer container that accommodates a developer, and a deteriorated developer container that accommodates a deteriorated developer discharged from the developer image development part; a collection part that collects a value based on a history of printing rates of each of the image formation parts; a printing rate calculator that calculates a printing rate of a received print data; and an image formation part selector that selects, based on the value based on the history of printing rates of each of the image formation parts collected by the collection part and the printing rate of the received printed data calculated by the printing rate calculator, one of the image formation parts, to be used for performing printing of the received print data.

Provided is an image forming apparatus capable of preventing or suppressing occurrence of density unevenness even when a shearing force is applied between an image face on paper and a fixing belt. The image forming apparatus includes an image former, a fixer, and a controller. The image former forms a toner image constituted by a plurality of dots each containing a toner on paper. The fixer includes a fixing member moving at a first velocity and a pressure member forming a fixing nip portion with the fixing member and moving at a second velocity, and fixes the toner image on the paper at the fixing nip portion. When the first velocity and the second velocity at the fixing nip portion are different, the controller determines a toner amount to be attached to paper so as to make a toner amount distribution different in each of the dots before fixing.

An image forming device that forms a toner image on a surface of a photoreceptor, transfers the toner image to a recording material and outputs a printed recording material, includes: an intermediate transfer body that primarily transfers the toner image on the photoreceptor and secondarily transfers the toner image to the recording material; a cleaner that removes a toner left on the surface of the photoreceptor; a patch forming unit that forms a toner patch between two adjacent toner images when multiple toner images are continuously formed on the surface of the photoreceptor; a concentration detector that detects concentration of the toner patch primarily transferred to the intermediate transfer body from the photoreceptor; and a patch adjuster that adjusts toner amount used for forming the toner patch based on a result detected by the concentration detector.

An image forming apparatus includes a developing section, storage, a first calculation section, a comparing section, and an executing section. The developing section develops an electrostatic latent image with toner. The storage stores coverage rates. The first calculation section calculates a first coverage rate and a second coverage rate. The comparing section compares the first coverage rate with the second coverage rate. The first coverage rate includes one or more coverage rates stored earlier in the storage than the second coverage rate. The second coverage rate includes coverage rates of a specified number of latest images individually formed on the specified number of sheets. The running-in operation is driving the developing section. The executing section executes the running-in operation.