Patent ID: 7941082
Filing Date: 2011-05-10
Classification: G03G

Abstract:
1. A color-image forming apparatus comprising: a direct-transfer control unit that causes a black image forming unit to form a black image to be transferred onto a transfer sheet being conveyed along a conveying path; an indirect-transfer control unit that causes a plurality of color image forming units other than the black image forming unit and an intermediate transfer member to form, on the intermediate transfer member, a multi-color image in a superimposed manner to be transferred onto the transfer sheet being conveyed along the conveying path; a positional-alignment control unit that performs positional alignment by detecting amounts of main-scanning and sub-scanning directional misalignment of color images that are formed by the color image forming units other than the black image forming unit and then transferred onto the intermediate transfer member in the superimposed manner and correcting the misalignment; a secondary transfer unit that is located at a position on the conveying path of the transfer sheet at which both the multi-color image, which is formed on the intermediate transfer member in the superimposed manner under control of the indirect-transfer control unit, and the black image, which is formed and transferred onto the transfer sheet under control of the direct-transfer control unit, join together in a superimposed manner, and that is provided movable close to and apart from the intermediate transfer member; a secondary-transfer control unit that moves the secondary transfer unit close to and apart from the intermediate transfer member; and a print control unit that causes the secondary-transfer control unit to move the secondary transfer unit apart from the intermediate transfer member, causes the direct-transfer control unit to cause the black image forming unit to form the black image and transfer the black image onto the transfer sheet being conveyed along the conveying path, and causes the positional-alignment control unit to perform the positional alignment.