An image forming apparatus includes an image former, a detector, and circuitry. The image former forms a toner pattern with a first line screen; and forms a toner image based on image data, with a second line screen. The detector detects density unevenness of the toner pattern, formed by the image former, in a main scanning direction. The circuitry is configured to calculate a first correction amount from the density unevenness detected by the detector; create a gradation correction table that reduces the density unevenness based on the first correction amount; and correct the first correction amount by a second correction amount corresponding to the second line screen, in a case where the first line screen is different from the second line screen.

An image forming apparatus includes a density detector that detects a density of a fog image formed on an image bearing member, a temporary determiner that determines a temporary fog margin which is a fog margin representing a difference between a developing bias to be applied to a toner bearing member and a charging bias to be applied to a charging device for charging the image bearing member based on a density detected by the density detector, and a corrector that corrects the temporary fog margin based on a change rate of a density detected by the density detector with respect to a change of a fog margin.

Disclosed is an image forming apparatus including: a fixation unit configured to heat a toner image formed corresponding to image data and fix the heated toner image onto a recording material; and a control unit configured to determine a fixation target temperature used by the fixation unit to heat the toner image on the basis of the image data, wherein the control unit performs a first determination to calculate a first target temperature on the basis of image density information in each of a plurality of regions in which the image data is divided in a main-scanning direction and a sub-scanning direction and a second determination to determine whether the image data is a text image, and determines the fixation target temperature on the basis of results of the first determination and the second determination.

An image-forming apparatus includes a generating unit that generates correction data for correcting an unevenness in light amount of an exposure head using a read image of a correction chart, and a correction unit that corrects image data for image formation based on the correction data. The exposure head includes light-emitting chips, each of which includes light-emitting elements. The correction chart includes a plurality of regions arranged in a direction, a first reference mark located on one side of the regions, and a second reference mark located on the other side of the regions. The generating unit determines partial regions respectively formed by the light-emitting chips within the regions based on positions of the first and second reference marks in the read image of the correction chart, and generates the correction data based on a result of measurement on the partial regions.

An image forming apparatus includes an image forming unit including a photosensitive member, a light source, and a developing roller, and a controller configured to control the image forming unit to form a detection image, obtain density data regarding density levels in a plurality of areas in the detection image at a plurality of positions in a scanning direction in which the photosensitive member is scanned with the light from the light source, generate, based on the density data, a first image forming condition for forming a first test image and a second image forming condition for forming a second test image, the second image forming condition being different from the first image forming condition, and control the image forming unit to form the first test image and the second test image, respectively based on the first image forming condition and the second image forming condition.

A hyperspectral imaging system, comprising an input polarizer arranged to receive and polarize a first light, a liquid crystal variable retarder to change a polarization of the first light in a wavelength-dependent manner, an output polarizer arranged to receive the wavelength-dependent polarized first light, a voltage source electrically connected to the liquid crystal variable retarder, a controller connected to the voltage source, the controller configured to control voltages applied to the liquid crystal variable retarder to control a retardance of the first light. A linear image sensor has a length extending in a direction to obtain images of the first light, the linear image sensor synchronized with the controller to collect the images as a function of retardance of the liquid crystal variable retarder after the first light passes through the output polarizer, for generation of an output signal corresponding to a portion of the linear image sensor.

An image forming apparatus for forming a toner image on a sheet, the image forming apparatus includes a main assembly; an image forming station provided in the main assembly and configured to form a toner image on the sheet; a fixing portion provided in the main assembly and configured to fix the toner image formed on the sheet, on the sheet, the fixing portion including a fixing rotatable member and a covering member covering the rotatable member; and a suction mechanism including a duct connected with an opening provided in the covering member and a fan configured to suck air inside the covering member through the duct, wherein the air sucked by the suction mechanism is discharged into a space in the main assembly other than a space through which the sheet passes.

An image forming apparatus includes a photoconductor, an optical scanner, a development device, a movable density sensor, a density sensor driver, and a processor. The optical scanner includes a light source to emit light, and irradiates a surface of the photoconductor in a main scanning direction with the light to form a latent image on the surface of the photoconductor. The development device develops the latent image into a toner image. The density sensor detects unevenness in density of the toner image in the main scanning direction. The density sensor driver moves the density sensor in the main scanning direction. The processor corrects a driving signal for the light source according to image data to reduce the unevenness in density in the main scanning direction, according to positional data of the density sensor in the main scanning direction and an output value of the density sensor.

An image forming apparatus includes a replenishment empty history recording portion, a post-empty attachment detecting portion, and an image creation restricting portion. The replenishment empty history recording portion records replenishment empty history information to a storage device in correspondence with one of the plurality of developer containers in which a replenishment empty state was detected in a first attachment portion. The post-empty attachment detecting portion detects whether or not a second attachment portion is in a post-empty container attached state where the developer container corresponding to the replenishment empty history information recorded in the storage device is attached to the second attachment portion. The image creation restricting portion, upon detection of the replenishment empty state, restricts an operation of an image creating device, and upon detection that the second attachment portion is in the post-empty container attached state, releases a restriction on the operation of the image creating device.

An image forming apparatus includes optical sensor units provided opposed to an image bearing member; light blockers provided between the image bearing member and the optical sensor units, respectively, the blockers being movable between locking and exposing positions, respectively; calibration members provided where the light is incident when the blockers are in the blocking positions, respectively, the calibration members calibrating data acquired by the optical sensor units; a movable link connected with the blockers; a switching portion for switching the blockers between the exposing and blocking positions; and a positioning portion for determining the blocking position, the positioning portion being disposed at a position where at least one of the blockers is contacted to the positioning portion when the blockers are switched from the exposing positions to the blocking positions.