Patent ID: 7729024
Filing Date: 2010-06-01
Classification: G03G,H04N

Abstract:
1. A color-drift correcting method of forming a plurality of images of different colors and superposing the images onto a transfer medium, the method comprising: forming at least three mark-patterns at respectively different portions on the transfer medium in a main scanning direction, each mark-pattern including a plurality of images of different colors, the colors including one reference color, at least one image oriented parallel to the main scanning direction, and at least one image oriented at an angle with respect to the main scanning direction; detecting positions of the images in the mark-patterns; calculating, for each mark-pattern, each color-drift amount of the images in the corresponding mark-pattern relative to a reference color image in the corresponding mark-pattern when each color image is assumed to be superposed on the transfer medium; first color-drift correcting that corrects the color-drift amount in a sub scanning direction and a skew relative to the reference color image being based on each color-drift amount so as to decide a corrected-image line as a virtual image line for each color; and second color-drift correcting that corrects the color-drift amount in the sub scanning direction so that the virtual image lines corresponding to each of the colors other than the reference color intersect with the virtual image line of the reference color at at least two points.