An image forming apparatus includes a toner pattern bearer to bear a first toner pattern having a first image area and a second toner pattern having a second image area different from the first image area. A toner adhesion amount detector detects a toner adhesion amount of toner of each of the first toner pattern and the second toner pattern. A toner degradation rate calculator calculates a first deviation in the toner adhesion amount of the first toner pattern and a second deviation in the toner adhesion amount of the second toner pattern based on the toner adhesion amount detected by the toner adhesion amount detector. The toner degradation rate calculator compares the first deviation with the second deviation and calculates a toner degradation rate based on a comparison result.

An image forming apparatus includes an image forming device, an image density detector, and a processor. The processor controls the image forming device to form a first test toner image, and controls the image density detector to detect an image density at the plurality of positions of the first test toner image. The processor adjusts an image forming condition so that the image density detected at each of the plurality of positions becomes a target image density, controls the image forming device to form a second test toner image based on the adjusted image forming condition, controls the image density detector to detect an image density at the plurality of positions of the second test toner image, determines whether a streak exists in the second test toner image based on the detected image densities, and executes a countermeasure to prevent an occurrence of the streak.

An image forming apparatus includes a light-receiving unit that includes light-receiving elements arranged along a movement direction of a target formed on an image carrier, and is arranged so as to receive light emitted from a light-emitting unit and specularly reflected off the image carrier; a member configured to limit a size, in the movement direction, of diffused reflection light that is incident on the light-receiving unit; a selection unit configured to select whether or not each of the light-receiving elements in the light-receiving unit is an effective light-receiving element; a generation unit configured to generate a detection signal from an output of the effective light-receiving element; and a detection unit configured to detect a target formed on the image carrier based on the detection signal.

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 conversion unit, an image bearing member, an image forming unit that forms an image on the image bearing member based on image data converted by the conversion unit, a measuring unit that measures a measurement image on the image bearing member, and a controller that controls the image forming unit to form a first measurement image, controls the measuring unit to measure the first measurement image, and generates a conversion condition based on a result of measurement of the first measurement image and a first feedback condition. In forming a chromatic color image after a predetermined number of monochrome images, the controller controls the image forming unit to form a second measurement image, controls the measuring unit to measure the second measurement image, and generates the conversion condition based on a result of measurement of the second measurement image and a second feedback condition.

Provided is an image forming apparatus capable of reducing power consumption by optimizing preliminary operation of a sensor. In the image forming apparatus, when tone characteristics adjustment is instructed (Step S1003: Y), tone characteristics adjustment (Step S1006) is executed after calibration (Step S1004), while when mixed-color correction is instructed (Step S1007: Y), mixed-color correction processing (Step S1009) is executed after calibration (Step S1008). Further, in the case where mixed-color correction is executed after tone characteristics adjustment, the preliminary light emission time in calibration is set shorter than when mixed-color correction is executed without performing gray adjustment first.

An image formation system includes an image forming section that includes a belt and a roller. The image forming section forms, in a predetermined region of a sheet, either: a first patch image for performing tone correction of a toner image formed on the sheet, or a second patch image for monitoring color variation of the toner image formed on the sheet. The image forming system further includes a controller that controls the image forming section to form only one of the first patch image and the second patch image on any one sheet.

An image forming apparatus includes an irradiation unit for irradiating an image carrier having a detection image with light; a light-receiving unit for receiving reflected light of the light irradiated by the irradiation unit and outputting a detection signal corresponding to a light-receiving amount of the reflected light including a specular-reflected light component; and a detection unit for detecting one of position information and density information of the detection image based on a signal corresponding to a difference between a value of the detection signal corresponding to the light-receiving amount of the reflected light from a first position where the detection image is formed and a value of the detection signal corresponding to the light-receiving amount of the reflected light from a second position different from the first position.

An image forming apparatus includes a plurality of image forming units, an exposure device, and circuitry. Each image forming unit includes an image bearer, a charger, and a developer bearer. The circuitry acquires an image-density cycle fluctuation in a visible image for each image forming unit and performs image-density fluctuation-reduction control to cyclically change image forming conditions to reduce the image-density cycle fluctuation. The circuitry performs: first fluctuation-reduction control to correct a developing bias to cancel an image-density cycle fluctuation of a high-density image pattern; second fluctuation-reduction control to, after the first fluctuation-reduction control, correct a charging bias to cancel an image-density cycle fluctuation of a first low-density image pattern; and third fluctuation-reduction control to, after the first and second fluctuation-reduction controls, correct an exposure light amount to cancel an image-density cycle fluctuation of a second low-density image pattern.

An image forming apparatus including a hardware processor and an image former that forms a measurement pattern on a recording medium under control of the hardware processor, wherein the hardware processor acquires image data obtained by reading a recording medium surface on which the measurement pattern is formed, calculates gradation characteristics at positions of correction points arranged along a direction orthogonal to a conveyance direction of the recording medium on a basis of the acquired image data, and corrects density unevenness of the measurement pattern in the direction orthogonal to the conveyance direction by correction values at the positions of the correction points calculated on the basis of the gradation characteristics, and the measurement pattern includes a first image having a maximum gradation value, second images that are adjacent to the first image on an upstream side in the conveyance direction and whose gradation values change stepwise and in ascending order in the conveyance direction, and third images that are adjacent to the first image on a downstream side in the conveyance direction and whose gradation values change stepwise and in descending order in the conveyance direction.