Image forming apparatus, image forming method, and computer-readable non-transitory recording medium storing image forming program, for performing color cailibration by using reference

An image forming method capable of performing color calibration by using a reference document generated with use of a plurality of inks including CMY inks as a first color material, and a colorimeter outside an image forming apparatus, comprising:

• reading an image on a document and generating image data;
• forming an image on an image forming medium by using a plurality of toners including CMY toners as a second color material;
• and
• setting a correction coefficient for bringing a color of the reference document and a color of a toner image close to each other by using a first spectral reflectance of the reference document in a visible band, and a second spectral reflectance in the visible band of the toner image formed on the image forming medium with use of the toner, performing correction by multiplying the correction coefficient with a gradation value of each of RGB acquired by reading the reference document in the image reading step, generating a conversion formula from the each acquired gradation value of RGB to each device-independent value with use of the each corrected gradation value of RGB, and the each device-independent value acquired by measuring the reference document with use of the external colorimeter, and generating a color profile by using the conversion formula.

A computer-readable non-transitory recording medium storing an image forming program for controlling an image forming apparatus capable of performing color calibration by using a reference document generated with use of a plurality of inks including CMY inks as a first color material, and an external colorimeter, the image forming program causing the image forming apparatus to execute:

• reading an image on a document and generates image data;
• forming an image on an image forming medium by using a plurality of toners including CMY toners as a second color material;
• and
• setting a correction coefficient for bringing a color of the reference document and a color of a toner image close to each other by using a first spectral reflectance of the reference document in a visible band, and a second spectral reflectance in the visible band of the toner image formed on the image forming medium with use of the toner, performing correction by multiplying the correction coefficient with a gradation value of each of RGB acquired by reading the reference document, generating a conversion formula from the each acquired gradation value of RGB to each device-independent value by using the each corrected gradation value of RGB, and the each device-independent value acquired by measuring the reference document with use of the external colorimeter, and generating a color profile by using the conversion formula.