EXPOSURE POSITION CONTROLLER FOR COLOR COPYING MACHINE

摘要

PURPOSE:To prevent a transfer image from having an overlap shift without making a device complex nor large in size by correcting a shift in the position of a scanning system by the displacement of a color separation filter. CONSTITUTION:An original 1 is mounted on a platen 2 and a scanning part 4 scans the original under the control of a control part 20. The green filter 5a of the color separation filter 6 is placed in an optical path during the 1st original scanning operation, and a photosensitive drum 13 is exposed to transfer its image to a copying form held on a transfer drum 14. The blue filter 5b and red filter 5c are placed in the optical path in the 2nd original scanning and the 3rd original scanning respectively to perform exposure and transfer similarly. A photosensor 17 detects the drum reaching a predetermined position and a photosensor 13 detects the specific position of the scanning part 4; and their outputs are sent to the control part 29. The controlpart 29 drives the filters 5a-5c by correcting their angles of rotation on the basis of the outputs of the sensors 17 and 13 to prevent a transfer image from shifting in position.