Image processing apparatus and method having a plurality of image forming units for performing image formation using predetermined colors

An image processing method in an image processing apparatus having a reader for reading an original image and a plurality of image forming units for performing image formation using predetermined colors, comprising:

• a pattern forming steps of parallely forming pattern images by outputting pattern data to each of the image forming units;
• a pattern image density measuring steps of obtaining pattern image density data by measuring densities of the pattern images formed by the respective image forming units by using a plurality of measuring units, each unit corresponding to a different color;
• a pattern image correction control step, of controlling gradation correction characteristics, of image data to be output to each of the image forming units, in accordance with the pattern image density data;
• and
• a reading characteristics correcting step, of correcting reading characteristics of each of the measuring units in accordance with pattern image data read by using the reader of pattern images formed on a recording medium and the pattern image density data obtained in said pattern image density measuring step.

A computer readable memory which stores a program code of image processing in an image processing apparatus having a reader for reading an original image and a plurality of image forming units for performing image formation using predetermined colors, comprising:

• a code of a pattern forming steps of parallel forming pattern images by outputting pattern data to each of the image forming units;
• a code of an image pattern density measuring steps of obtaining image pattern density data by measuring densities of the pattern images formed by the respective image forming units by using a plurality of measuring units, each unit corresponding to a different color;
• a code of a pattern image correction control step of controlling gradation correction characteristics, of image data to be output to each of the image forming units, in accordance with the pattern image density data:
• and
• a code of a reading characteristics correcting step, of correcting reading characteristics of each of the measuring units in accordance with Pattern image data read by using the reader of pattern images formed on a recording medium and the pattern image density data obtained in said pattern image density measuring step.