Toner contained in a toner container is used for replenishing a developing unit via an intermediate hopper. A toner sensor detects emptiness for the toner on an upstream side of a conveyance screw of the intermediate hopper in terms of the toner conveyance direction. Every time the toner sensor detects emptiness, the controller drives a rotation mechanism so that the toner is ejected from the toner container. Based on a drive history of a conveyance-purpose motor, the controller calculates a toner conveyance amount conveyed from the intermediate hopper between a time when the toner sensor detects emptiness and a time when the toner sensor detects emptiness again. When the calculated toner conveyance amount has been equal to or smaller than a first conveyance amount threshold value successively, the controller determines that the toner container is in a nearly empty state.

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 apparatus includes: a latent image carrier on which a latent image is formed; a developing device that stores a developer, and develops the latent image formed on the latent image carrier using the developer; a concentration acquirer that acquires a concentration of the developer stored in the developing device; an atmospheric pressure acquirer that acquires an atmospheric pressure value at a position in which the image forming apparatus is installed; and a corrector that corrects the concentration detected by the concentration acquirer, on the basis of the atmospheric pressure value acquired by the atmospheric pressure acquirer.

A toner cartridge for use with an image forming apparatus includes a memory storing identification data of the toner cartridge and parameter information including image formation process parameters dependent on toner characteristic or ambient conditions. A transceiver unit communicates with the image forming apparatus to send the process parameter information stored in the memory to the image forming apparatus when the identification data is authentic.

A screw is rotated to replenish toner from a hopper to a developing device. Rotation of the screw, toner stored in the hopper, and a toner density in the developing device are detected. Whether or not to replenish toner from the hopper to the developing device is controlled based on a detection result of rotation of the screw. The number of rotations of the screw during a predetermined time period is acquired. The predetermined time period corresponds to a time period during which the replenishment processing is being executed and over which a state in which toner in the hopper is detected is changed to a state in which toner in the hopper is not detected. An abnormality of the hopper is detected if the number of rotations in the predetermined time period is larger than a predetermined number.

An image forming apparatus includes a developing device that stores a developer including toner, an image carrier that carries a toner image produced by part of the toner stored in the developing device, and a controller, wherein the controller determines a deterioration state of the toner, immediately before being supplied to a recording medium from the image carrier, based on a deterioration amount correlating to deterioration of the toner stored in the developing device.

An image forming apparatus includes a developing device that forms a toner image on a sheet; a supply device provided with a cartridge for accommodating toner and supplying the toner in the cartridge to the developing device; a sensor that acquires a physical quantity relating to an amount of toner in the developing device; a timer that counts time; and a controller that drives the supply device until a condition that the acquired physical quantity indicates that the amount of toner is equal to or greater than a predetermined value is satisfied when a condition that the physical quantity indicates that the amount of toner becomes small is satisfied, counts time during which the supply device is being driven with the timer, and determines that the amount of toner in the cartridge becomes smaller than a predetermined amount if the counted time is longer than a predetermined threshold value.

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 processing apparatus includes an image forming unit of an electrophotographic method, a detection processing unit, and a determination processing unit. The detection processing unit detects a streaky image along a sub-scanning direction from a first image and a second image among images indicated by image data. The first image has a print density equal to or more than a predetermined reference print-density value, and the second image has a print density less than the reference print-density value. The determination processing unit determines a cause of abnormality in the image forming unit based on a detection result of the streaky image by the detection processing unit for each of the first image and the second image.

An image forming apparatus is provided. The image forming apparatus includes a sensor to detect a toner concentration, and a processor to control a rendering of image-forming data to form an image on an image forming medium, according to a level of toner concentration saving that is adjusted based on the detected toner concentration.