PURPOSE: To attain an image formation of high definition by carrying out positioning of each color dot in a sub scanning direction in the color image forming device simply and with high precision and preventing color slippage.
CONSTITUTION: In the color image forming device obtaining a multi color or a full color image by placing a multiple number of main scanning exposure devices 120, 220, 320, and 420 carrying out scanning and exposure in a multiple number of positions on an image forming body 11 concerning the sub scanning movement direction of one image forming body, a multiple number of electrifying devices corresponding to positions irradiated by each scanning beam by this exposure device, and a multiple number of developing devices 130..., forming a superposed toner image on the image forming body, and then, transferring, and fixing this, writing of each image of the sub scanning direction is matched by forming a developing pattern in a non image forming part in the vicinity of an edge of the image forming body by an electrifying device which is most upstream in the sub scanning direction of the non image range on the surface side edge of the image forming body, the main scanning exposure device, and the developing device, having the developing pattern irradiated by the main scanning beams of the multiple number of main scanning exposure devices downstream, receiving the reflected beam at a beam receiving sensor, having the developing pattern detection signal generated in the sub scanning direction, and starting writing of the image after a specified timing.
MIWA TADASHI
SATO HISAO
OKANE ATSUSHI
MATSUOKA ISAO
IKEDA TADAYOSHI
