An image formation device includes: an image formation section configured to develop, using toner, an electrostatic latent image formed on an image carrier based on job image information, thereby transferring a first image onto continuous paper; a hardware processor configured to determine whether or not a serial printing distance is equal to or shorter than a first threshold, wherein the serial printing distance is a distance at which the first image is printed on the continuous paper, and control the image formation section to print the first image on the continuous paper when the serial printing distance is equal to or shorter than a first threshold, and to decrease the proportion of deteriorated toner in a developer by printing the first image and a second image on the continuous paper when the serial printing distance exceeds a first threshold, wherein the second image is based on an image information.

An image forming apparatus includes: an image carrier; a developing unit which supplies a toner contained in a developer to the image carrier; a lubricant supply unit which supplies a lubricant to the image carrier; a lubricant amount detection unit which detects an amount of the lubricant which is supplied to the image carrier from the lubricant supply unit and is thereafter incorporated into the developing unit from the image carrier; and a control unit which controls the developing unit to discharge the lubricant from the developing unit according to the amount of the lubricant detected by the lubricant amount detection unit.

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.

The developing device includes a developing roller, a developer conveying unit, a developer discharge unit, and an air discharge port. The developer conveying unit includes a developing chamber provided with the developing roller and extending in a longitudinal direction of the developing roller, a stirring chamber arranged in parallel to the developing chamber, and a barrier wall having a first communication port and a second communication port, at respective ends in the longitudinal direction, to connect the developing chamber with the stirring chamber. The developer discharge unit extends from the developer conveying unit in the longitudinal direction of the developing roller and includes a developer discharge port to discharge excess developer. The air discharge port is to house a filter to filter a developer, the air discharge port being provided between the developer conveying unit and the developer discharge unit to discharge air in the developer conveying unit.

A developing device includes a developer container, a developer carrier, and first and second members for stirring/conveying. The developing container has a first partition wall between first and second chambers, communication portions 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 second partition wall is lower than the first partition wall, and an upper end part of the second partition wall is between upper and lower end parts of the rotary shaft of the second stirring/conveying member.

In an image forming apparatus, a calibration controller controls an exposure device to form a toner patch image for calibration in a non-printable area outside a printable area in a main scanning direction, and executes at least one of density adjustment and gradation adjustment based on a density measurement value of the toner patch image. A toner refresh controller controls the exposure device to form a toner band for toner refresh in accordance with a coverage rate. Further, when the length of the toner band to be formed in the non-printable area exceeds a predetermined threshold value, the toner refresh controller forms at least a part of the toner band to be formed in the non-printable area in parallel with a subsequent page image.

An image forming apparatus measures, using a toner concentration sensor installed in a developing apparatus of the image forming apparatus, a toner concentration of a developer stored in the developing apparatus to obtain an output waveform. The image forming apparatus calculates, based on the output waveform, a first characteristic value corresponding to a volume of the developer. Based on a result of comparing the first characteristic value with a reference value calculated from a reference output waveform obtained in an initial state of the developing apparatus, the image forming apparatus determines whether to execute a discharge mode for discharging the developer from the developing apparatus and to control an amount of the developer. The image forming apparatus discharges, according to a result of the determining, a portion of the developer from the developing apparatus by controlling a driving speed of the developing apparatus when the discharge mode is executed.

A toner cartridge for an imaging apparatus includes a housing to accommodate toner, and an inlet port and an outlet port formed in the housing. The outlet port supplies the toner to a developing device of the imaging apparatus. The inlet port receives a residual toner removed from an image carrier of the developing device as a recycled toner.

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.

A device to develop an electrostatic latent image in an imaging apparatus includes first and second passages coupled to each other through first and second openings to form a circulation passage. A first stir-and-transport member is located in the first passage and includes a first helical blade to stir and transport a developer from the first opening to the second opening along the first passage in a first direction and to supply the developer to a developing roller. A second stir-and-transport member is located in the second passage and includes a second helical blade to stir and transport the developer from the second opening to the first opening along the second passage in a second direction. A developer discharge pipe is coupled to the developer container to communicate with a downstream side of the first passage. The first stir-and-transport member includes a first reverse helical blade located downstream of the first helical blade and disposed downstream of the second opening. The pitch of the first reverse helical blade is between approximately 0.5 times and 1.5 times the pitch of the first helical blade.