Image forming system, image reading apparatus, and image processing method for high-accuracy colorimetry

Abstract

An image forming apparatus that prints an adjustment pattern on a sheet includes a generator and an image former. The adjustment pattern is for correcting a color value obtained by reading a second patch region on the sheet with a second reader based on a color value obtained by reading a first patch region on the sheet with a first reader. The generator generates image data of the adjustment pattern, and the image former performs printing based on the image data. The adjustment pattern includes a first patch printed in the first patch region and a second patch printed in a region other than the first patch region in the second patch region. The second patch includes a common color patch in a same color as a color of the first patch, and a size of the first patch is larger than a size of the second patch.

What is claimed is: 
     
         1 . An image forming system comprising:
 an image forming apparatus including an image former configured to form a patch on a sheet; and   an image reading apparatus that is connected to the image forming apparatus,   wherein the image reading apparatus includes:
 a first reader configured to read a first patch; and 
 a second reader configured to read a second patch, 
   wherein the second patch includes a patch in a same color as a color of the first patch,   wherein a size of the first patch is larger than a size of the second patch, and   wherein the image forming system is configured to correct a color value obtained by reading the second patch with the second reader, based on a color value obtained by reading the first patch with the first reader.   
     
     
         2 . The image forming system according to  claim 1 , wherein the first reader and the second reader are disposed on a conveyance path of the sheet on which the image former is configured to form the patch. 
     
     
         3 . An image processing method comprising:
 forming a first patch and a second patch on a sheet with an image former of an image forming apparatus, wherein the second patch includes a patch in a same color as a color of the first patch, and wherein a size of the first patch is larger than a size of the second patch;   reading the first patch with a first reader of an image reading apparatus that is connected to the image forming apparatus;   reading the second patch with a second reader of the image reading apparatus; and   correcting a color value obtained by reading the second patch with the second reader, based on a color value obtained by reading the first patch with the first reader.   
     
     
         4 . The image processing method according to  claim 3 , wherein reading the first patch with the first reader and reading the second patch with the second reader are performed on a conveyance path of the sheet on which the image former forms the patch. 
     
     
         5 . An image reading apparatus that is connected to an image forming apparatus, the image forming apparatus including an image former configured to form a patch on a sheet, the image reading apparatus comprising:
 a first reader configured to read a first patch; and   a second reader configured to read a second patch,   wherein the second patch includes a patch in a same color as a color of the first patch,   wherein a size of the first patch is larger than a size of the second patch, and   wherein the image reading apparatus is configured to correct a color value obtained by reading the second patch with the second reader, based on a color value obtained by reading the first patch with the first reader.   
     
     
         6 . An image processing method comprising:
 reading a first patch on a sheet with a first reader of an image reading apparatus that is connected to the image forming apparatus, the first patch having been formed on the sheet with an image former of the image forming apparatus;   reading a second patch on the sheet with a second reader of the image reading apparatus, the second patch having been formed on the sheet with the image former, wherein the second patch includes a patch in a same color as a color of the first patch, and wherein a size of the first patch is larger than a size of the second patch; and   correcting a color value obtained by reading the second patch with the second reader, based on a color value obtained by reading the first patch with the first reader.