An image forming apparatus includes an image forming section to form a correction pattern, a reading unit to read the pattern and generate first data, a color converter to convert the first data into second data, a memory to store density conversion data for a recording medium, a determiner to determine whether the memory contains the conversion data for the recording medium the pattern is formed, an acquisition unit to acquire spectral measured by an external colorimeter the memory does not contain the conversion data, a first density converter to convert the spectral data into density data, a density conversion data generator to correlate the second data and the density data and generate the conversion data, a second density converter to convert the second data into the density data using the conversion data, and a correction curve generator to generate correction curve data based on the density data.

An image forming apparatus includes: an image former that forms an image on a transfer paper sheet; a colorimeter that reads the image; a conveyor that conveys the transfer paper sheet in the image formation and the reading of the image; and a controller that controls the formation of the image, and the reading and the conveyance of the image, wherein when a first conveyance velocity is a velocity at which the transfer paper sheet is conveyed when the image is formed by the image former, a second conveyance velocity is a velocity that is lower than the first conveyance velocity, and a long paper sheet having a longer transfer sheet length than a predetermined threshold value is used as the transfer paper sheet in an adjustment mode, the controller controls the image former and the conveyor, and controls the colorimeter and the conveyor.

An image forming apparatus includes: an image former that forms an image on a transfer paper sheet; a colorimeter that reads the image; a conveyor that conveys the transfer paper sheet in the image formation and the reading of the image; and a controller that controls the formation of the image, and the reading and the conveyance of the image, wherein when a first conveyance velocity is a velocity at which the transfer paper sheet is conveyed when the image is formed by the image former, a second conveyance velocity is a velocity that is lower than the first conveyance velocity, and a long paper sheet having a longer transfer sheet length than a predetermined threshold value is used as the transfer paper sheet in an adjustment mode, the controller controls the image former and the conveyor, and controls the colorimeter and the conveyor.

An image forming apparatus includes an image forming section to form a correction pattern, a reading unit to read the pattern and generate first data, a color converter to convert the first data into second data, a memory to store density conversion data for a recording medium, a determiner to determine whether the memory contains the conversion data for the recording medium the pattern is formed, an acquisition unit to acquire spectral measured by an external colorimeter the memory does not contain the conversion data, a first density converter to convert the spectral data into density data, a density conversion data generator to correlate the second data and the density data and generate the conversion data, a second density converter to convert the second data into the density data using the conversion data, and a correction curve generator to generate correction curve data based on the density data.

An image forming system includes an image forming section that prints an image on a recording medium and outputs the recording medium, a color measurement section that measures color of the image printed by the image forming section, an imaging unit that captures the image printed by the image forming section, and an analyzer that analyzes, based on the image captured by the imaging unit, whether or not the image subjected to color measurement by the color measurement section has an abnormality. When the analyzer determines that the image has an abnormality, the color measurement section does not output a color measurement result of the image having the abnormality.