An image forming apparatus is configured to, based on a reading result of a test image, generate data that is used to adjust image forming positions of toner images to be formed by an image forming unit, control an image forming position of a first toner image to be formed by the image forming unit in a first contact state based on first data, the first toner image being transferred to a first sheet, and control an image forming position of a second toner image to be formed by the image forming unit in a second contact state based on second data that is different from the first data, the second toner image being transferred to a second sheet, wherein a type of the second sheet is the same type as the type of the first sheet.

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 reading apparatus includes a conveyance roller to convey a sheet, a light source to illuminate an image on the sheet while being moved in a predetermined direction above the conveyed sheet, a reading sensor to read the image on the sheet while being moved in the predetermined direction above the conveyed sheet, and a controller. The controller controls the reading sensor to read a first image for generating a color profile on a first sheet after the light source emits light for a duration of a first time. The controller controls the reading sensor to read a second image for detecting density unevenness in a main scanning direction of the image forming apparatus on a second sheet after the light source emits light for a duration of a second time shorter than the first time.

A color measurement device includes a conveying roller unit that conveys a sheet in a conveying direction, a color sensor that is movable in a direction orthogonal to the conveying direction and measures a color of an image formed on the sheet, a white reference plate having a reference surface for measurement by the color sensor for calibration of the color sensor, lifting rollers that move with the color sensor and retain the sheet, and slid-on members that protrude to a level higher than the reference surface in a perpendicular direction to the reference surface. When the color sensor moves such that at least part of the lifting rollers overlaps the white reference plate as viewed from the perpendicular direction, the lifting rollers are brought into contact with the slid-on members, whereby a space is formed between the lifting rollers and the reference surface.

An image forming apparatus includes an image processor configured to convert image data based on a first conversion condition; an image forming unit configured to form an image on a sheet based on the image data converted by the image processor, the image forming unit having an image bearing member on which the image is to be formed, a transfer unit configured to transfer the image from the image bearing member onto the sheet, and a fixing unit configured to fix the image to the sheet; a conveyance roller configured to convey the sheet having the image fixed thereto; a reading unit configured to read a pattern image on the sheet conveyed by the conveyance roller; and a detector configured to detect a pattern image on the image bearing member.

The control unit executes a mode of detecting the image density of the toner image for control. The control unit sets the target toner density so that the target toner density becomes smaller than before execution of the mode and also set the target transfer current so that the target transfer current becomes smaller, in a case where the image density detected in the mode is higher by a predetermined threshold or more than a reference density.

An image inspection apparatus includes the following. A reader reads a sheet in which an image is printed, reads the sheet together with a background, and obtains a read image. A background member is provided in a position which is to be a background of the sheet when the sheet is read by the reader. A hardware processor extracts sheet outline information of the sheet from the read image and measures a misalignment of a position of the image with relation to the sheet based on the extracted sheet outline information. The hardware processor performs control based on a measured result of the misalignment of the position of the image. The hardware processor adjusts a degree of control performed based on the measured result of the misalignment of the position of the image according to a density difference between the sheet and the background member.

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.

There is provided an image forming system including an image forming apparatus including a hardware processor that forms an image on a recording material, and the image forming system includes: a first detector that detects recording material information on the recording material; a recording material storage that stores the recording material; and a controller that specifies one type of the recording material from type candidates of the recording material based on an execution result of test printing, by executing the test printing under an image forming condition that is set in accordance with one or more type candidates of the recording material, the one or more type candidates being extracted based on the recording material information detected by the first detector.

An image forming apparatus includes an image forming unit configured to form an image on a sheet based on image forming condition, a reader configured to convey the sheet and read a test image on the sheet while the sheet is conveyed, and a controller configured to control the image forming unit to form the image and the test image on a same sheet, control the reader to read the test image on the same sheet, and generate the image forming condition for adjusting a density of an image to be formed by the image forming unit, based on a reading result of the test image by the reader.