Image forming apparatus and color registration method of the same

摘要

An image forming apparatus which obtains rotational variance factors of an intermediate transfer belt for each of plurality of colors based on locations with respect to second pattern image being obtained by a location calculation unit, corrects the location obtained with respect to a first pattern image based on the rotational variance factor obtained with respect to the color of the first pattern image, obtains an offset of another color with respect to a reference color based on the location after correction, and performs color registration based on the obtained offset to reduce the offset.

主权项

1. An image forming apparatus forming an image in a plurality of colors comprising a reference color, the apparatus comprising:
an image forming part forming a first pattern image and a second pattern image in the same color side by side in a main scanning direction, with respect to each of the plurality of colors; an intermediate transfer belt to which the first pattern image and the second pattern image formed by the image forming part are transferred, the intermediate transfer belt conveying the transferred first pattern image and second pattern image in a sub-scanning direction, which is perpendicular to the main scanning direction; a first sensing unit to sense an element of the first pattern image on the intermediate transfer belt; a second sensing unit to sense an element of the second pattern image on the intermediate transfer belt; a location calculation unit to obtain locations in the sub-scanning direction for the elements of the first pattern image and the second pattern image of the plurality of colors on the intermediate transfer belt based on results of sensing performed by the first and second sensing units; and a control unit to obtain rotational variance factors of the intermediate transfer belt for each of the plurality of colors based on the obtained locations with respect to the second pattern image obtained by the location calculation unit, to correct the location obtained with respect to the first pattern image based on the rotational variance factor obtained with respect to the color of the first pattern image, to obtain an offset of another color with respect to the reference color based on the location after correction, and to perform color registration based on the obtained offset to reduce the offset, wherein the first pattern image is an image for obtaining an offset of another color with respect to the reference color among the plurality of colors, and wherein the second pattern image is an image for obtaining a movement of the intermediate transfer belt in the sub-scanning direction.