Printing by determining target color values based on first color outputs, determining current color values based on current color outputs, and calculating color compensation values to compensate for a difference between the target color values and the current color values.

An image forming apparatus, configured to operate in first and second modes of which color gamut is different from each other, includes an exposure unit configured to expose a photosensitive drum; a developing roller configured to form a toner image; a detection unit configured to detect density of the toner image transferred to an intermediate transfer member; and a controller configured to adjust the density based on a value of input image data. A dithering process for the controller's controlling of the exposure unit is different depending on whether the operation is in the first mode or the second mode, and in at least a part of the input image data, the density of the toner image formed by the dithering process in the first mode is higher than the density of the toner image formed by the dithering process in the second mode.

An image forming apparatus includes: an image forming unit configured to form an image on a sheet; a fixing unit configured to fix the image on the sheet; a reader configured to read a pattern image on the sheet downstream of the fixing unit in a conveying direction in which the sheet is conveyed; and a controller configured to: control the image forming unit to form the image and the pattern image on a same sheet; control the fixing unit to fix the image and the pattern image on the same sheet; control the reader to read the pattern image on the same sheet; and control a density of an image to be formed on a sheet subsequent to the same sheet based on a result of reading the pattern image by the reader and reference data.

An image forming apparatus, configured to operate in first and second modes of which color gamut is different from each other, includes an exposure unit configured to expose a photosensitive drum; a developing roller configured to form a toner image; a detection unit configured to detect density of the toner image transferred to an intermediate transfer member; and a controller configured to adjust the density based on a value of input image data. A dithering process for the controller's controlling of the exposure unit is different depending on whether the operation is in the first mode or the second mode, and in at least a part of the input image data, the density of the toner image formed by the dithering process in the first mode is higher than the density of the toner image formed by the dithering process in the second mode.

An image forming apparatus includes an image forming device to form an image on an image bearer based on a prescribed image-forming condition, and circuitry to change the prescribed image-forming condition and correct image-density unevenness in an image-width direction orthogonal to an image conveyance direction of the image bearer. In the image forming apparatus, the circuitry calculates a corrective value of the prescribed image-forming condition for each one of positions in the image-width direction, based on unevenness-in-density corrective values for the multiple positions in the image-width direction and relational values indicating a relation between the multiple unevenness-in-density corrective values and the corrective value of the prescribed image-forming condition, and the circuitry corrects the image-density unevenness in the image-width direction based on the corrective value of the prescribed image-forming condition. In the image forming apparatus, the multiple relational values correspond to portions in the image-width direction.

In an image forming apparatus, an image forming unit configured to form a toner image on a transfer medium includes four sets of a photoconductor drum and a development roller, respectively, for forming toner images of first, second, third and fourth colors, arranged in this order, in a direction opposite to a direction of movement of the transfer medium moving toward a detector configured to detect a toner image formed on the transfer medium. A controller executes a bias-corrective test image forming process in which a first bias-corrective test image of the first color is arranged in a position downstream of other three first bias-corrective test images, and a second bias-corrective test image of the first color is arranged in a position between two first bias-corrective test images selected among other three first bias-corrective test images, in the direction of movement of the transfer medium.

An image forming apparatus includes an image forming unit configured to form an image on a sheet; a fixing unit configured to fix the image on the sheet; a reader configured to read a pattern image on the sheet downstream of the fixing unit in a conveying direction in which the sheet is conveyed; and a controller configured to control the image forming unit to form the image and the pattern image on a same sheet, control the fixing unit to fix the image and the pattern image on the same sheet, control the reader to read the pattern image on the same sheet, and control a density of an image to be formed on a sheet subsequent to the same sheet based on a result of reading the pattern image by the reader and reference data.

An image forming apparatus includes an image forming unit, a fixing unit, an image analyzer, and a temperature controller configured to control a temperature of the fixing unit in accordance to a target temperature. The image analyzer is configured to analyze image data for forming the toner image by the image forming unit, to evaluate a continuity of pixels of an image contained in the image data. The temperature controller is configured to change the target temperature based on analysis results of the image analyzer such that a value of the target temperature in a case where the image data contains an image with a continuity of pixels equal to or smaller than a predetermined value is higher than a value of the target temperature in a case where the image data contains no image with a continuity of pixels equal to or smaller than the predetermined value.

An image forming apparatus includes a developing roller configured to develop an electrostatic latent image on a photosensitive drum to form a toner image; a belt onto which the toner image is transferred; a detection unit configured to detect a density of an image for detection formed on the belt; and a controller configured to perform hue adjustment based on a detection result of the detection unit. The image forming apparatus performs image formation in a second mode using a color gamut different from a color gamut in a first mode, and the controller obtains a lookup table, which indicates a correlation between image data to be used and input image data in the second mode, based on the detection result in the first mode and a correlation of density between the first mode and the second mode.

A printing apparatus includes: plural image forming units accommodating colorants of the same color; and a controller that forms an image of one color using the plural image forming units.