Method for calibrating color image forming apparatus

Abstract

A calibration method for calibrating a color image forming apparatus includes detecting the color of a patch formed on a recording medium by the color image forming apparatus using a color sensor, converting a detected color signal in a first color specification system into a color signal in a second color specification system, and adjusting at least one of the image forming conditions for the color image forming apparatus, based on the color signal converted in the conversion step, where the conversion conditions in the color signal conversion are different depending on the attributes of the patch.

1 .- 9 . (canceled) 
     
     
         10 . A color image forming apparatus comprising:
 a sheet discharging portion to which a recording medium is discharged after an image formation;   a forming portion that forms a plurality of fixed patches in a row on the recording medium;   a detecting portion disposed on a recording medium conveying path to detect, before the recording medium is discharged to the sheet discharging portion, colors of the plurality of fixed patches formed on the recording medium;   a converting portion that converts a color signal, obtained by the detecting portion and corresponding to a detection signal in a first color specification system, into a color signal in a second color specification system as color signal conversion processes; and   an adjusting portion that adjusts an image forming condition for the color image forming apparatus, based on the color signal in the second color specification system,   wherein the plurality of fixed patches include plural kinds of patches, an order of formation and an order of detection of the plural kinds of patches being predetermined, and the converting portion uses a parameter of each of the plurality of fixed patches to be subject to color measurement to perform the color signal conversion processes for the respective patches based on the order of detection or detection positions of the plurality of fixed patches.   
     
     
         11 . A color image forming apparatus according to  claim 10 , wherein the color signal conversion processes include selecting a matrix used in converting the color signal in the first color specification system into the color signal in the second color specification system, or changing a look-up table used in converting the color signal in the first color specification system into the color signal in the second color specification system. 
     
     
         12 . A color image forming apparatus according to  claim 10 , wherein the plurality of fixed patches include a monochromatic patch formed with only black and a color mixture patch formed by yellow, magenta, and cyan. 
     
     
         13 . A method of adjusting a color image forming apparatus, comprising:
 forming a plurality of patches in a row on a recording medium;   fixing the plurality of patches to the recording medium;   detecting colors of the plurality of patches fixed to the recording medium in a medium conveying path before the recording medium is discharged to a sheet discharging portion;   converting a color signal, obtained in the detecting and corresponding to a detection signal in a first color specification system, into a color signal in a second color specification system as color signal conversion processes; and   adjusting an image forming condition for the color image forming apparatus, based on the color signal in the second color specification system,   wherein the plurality of patches fixed to the recording medium include plural kinds of patches, an order of formation and an order of detection of the plural kinds of patches being predetermined, and the converting uses a parameter of each of the plurality of patches fixed to the recording medium to be subject to color measurement to perform the color signal conversion processes for the respective patches based on the order of detection or detection positions of the plurality of patches fixed to the recording medium.   
     
     
         14 . A method according to  claim 13 , wherein the color signal conversion processes include selecting a matrix used in converting the color signal in the first color specification system into the color signal in the second color specification system, or changing a look-up table used in converting the color signal in the first color specification system into the color signal in the second color specification system. 
     
     
         15 . A method according to  claim 13 , wherein the plurality of patches fixed to the recording medium include a monochromatic patch formed with only black and a color mixture patch formed by yellow, magenta, and cyan.