| 摘要 |
PROBLEM TO BE SOLVED: To eliminate, in reading patch images between sheets, a reading error occurring when a sheet enters a secondary transfer part to improve accuracy in color shift correction, so as to provide print images with less color shift.SOLUTION: An image forming apparatus includes: a pattern creation unit 10 that forms a plurality of patch groups at equal intervals in a sub scanning direction taking patch images in respective colors as one group; an image position detector 400 that detects positions of the patch groups; a patch position calculation unit 11 that calculates a distance between the patch groups from the detection value; a patch position comparison unit 12 that compares the distance between the patch groups with a preset reference distance; an abnormality determination unit 13 that determines if data on the compared distance between the patch groups falls within a predetermined allowable value, and when the data is equal to or larger than the allowable value, determines that the data is an abnormal value; and a patch image control unit 14 that performs predetermined processing when the data is determined to be the abnormal value. |
