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 an image forming unit configured to form an image, a conveyance unit configured to convey a sheet on which a test image has been formed, a sensor configured to read the test image on the sheet, while the sheet is being conveyed by the conveyance unit, and a controller. The controller causes the image forming unit to form a test image on each of a first sheet and a second sheet succeeding the first sheet, and based on a reading result of the test image on the first sheet read by the sensor and a reading result of the test image on the second sheet read by the sensor, suppresses density unevenness, in a conveyance direction in which the sheet is conveyed, of the image to be formed by the image forming unit.