| 摘要 |
PROBLEM TO BE SOLVED: To prevent the occurrence of a defective image such as trailing end missing, etc., while coping with a wide situational change without making a device large in size and without increasing the cost. SOLUTION: A measurement patch image is formed by a black image forming part 10BK, the density of the patch image is read by an image density reading device 30, and the defective image such as the trailing end missing, etc., is detected based on the read image density, and the correction amount of the output in each of cyan, magenta and yellow image forming parts 10C, 10M and 10Y is decided by a control part 20 so as to correct the defective image. By forming a synthesized black image (black image formed by overlapping cyan, magenta and yellow images each other) based on the correction amount of the output in respective cyan, magenta and yellow image forming parts 10C, 10M and 10Y, the defective image caused by the black image forming part 10BK is corrected. |
