Method and a device for producing separation images having the effect of being orthogonally screened

摘要

A method and a device for producing separation images which are essentially orthogonally screened for reproducing an original multicolor image. In one embodiment, the original image is mounted on a drum which is rotated in a Y direction. A sensor is moved in an X direction, essentially orthogonal to the Y direction, axially of the drum adjacent the drum's surface, and senses the several colors of the original image on a point by point basis. The distances in the X and Y directions between the scanned points on the original image are changed for each separation image according to trigonometric relationships. Thus, separation images are produced which have equal screen ruling and different screen angles relative to a Y direction. The method and apparatus produce signals which are applied to some form of device or devices which actually generate the separations for use in multicolor printing or the like.