Patent ID: 7248272
Filing Date: 2007-07-24
Classification: H04N

Abstract:
1. A method of correcting a predetermined adjustment value for an image forming apparatus forming an image of each of separated colors in accordance with said adjustment value, comprising: a first formation step of forming a first base image for a base color in accordance with the predetermined adjustment value, and forming a first correction image for a correction color to be a subject for correction in accordance with a value obtained by changing the predetermined adjustment value within a predetermined range; a first adjustment value determination step of determining a first adjustment value from the changed adjustment value based on a density output corresponding to the first base image and the first correction image from a sensor detecting the density of an image forming portion; an adjustment value candidate extraction step of extracting a plurality of adjustment value candidates that have periodical relation with the first adjustment value determined within said predetermined range in an adjustable range of an adjustment value; a selective adjustment value extraction step of extracting a plurality of selective adjustment values to be subject to adjustment from the extracted adjustment value candidates; an intermediate formation step of forming an intermediate base image for the base color in accordance with the predetermined adjustment value, and forming an intermediate correction image for the correction color in accordance with said extracted selective adjustment values; an intermediate adjustment value determination step of determining an intermediate adjustment value from said plurality of selective adjustment values based on the density output corresponding to the intermediate base image and the intermediate correction image from said sensor; an intermediate adjustment value candidate extraction step of extracting a plurality of intermediate adjustment value candidates that have periodical relation with said determined intermediate adjustment value in an adjustable range of an adjustment value; an execution step of repeatedly extracting a plurality of selective adjustment values to be subject to adjustment from the extracted intermediate adjustment value candidates by said selective adjustment value extraction step and executing each process at said intermediate formation step, intermediate adjustment value determination step and intermediate adjustment value candidate extraction step until the number of extracted intermediate adjustment value candidates becomes less than a predetermined number, if the number of extracted intermediate adjustment value candidates is the predetermined number or more; a final formation step of forming a final base image for the base color in accordance with the predetermined adjustment value, and forming a final correction image for the correction color in accordance with each of said extracted intermediate adjustment value candidates, if the number of intermediate adjustment value candidates extracted by said intermediate adjustment value candidate extraction step is less than the predetermined number; a final adjustment value determination step of determining a final adjustment value from said intermediate adjustment value candidates based on the density output corresponding to the final base image and the final correction image from said sensor; and a correction step of correcting the predetermined adjustment value for the correction color to the determined final adjustment value.