High-speed color correcting scanner for making color printing plates

Claim 1

A high-speed color correcting scanner for multicolor printing, comprising: a transparent object having a multicolor pattern including a plurality of different colors; a plurality of printing plates having a number equal to the number of said object different colors; each plate supplied with one of a plurality of different photosensitive printing inks, each containing said object different colors; said different colors having different reflectivities in said respective printing inks whereby uncontrolled relative amounts of said respective inks produce thereon an impaired image of said object multicolor pattern a mandrel rotatable on a lengthwise axis in one position and having a hollow one end peripherally supporting said object and an opposite end peripherally supporting said plates; said object and plates disposed end-to-end on said mandrel; light means linearly movable interiorly of said mandrel one end on said mandrel axis in synchronism with said mandrel rotation for successively illuminating different spots on said object pattern to reflect therefrom multicolor light including said different colors varying in intensity as said mandrel is rotated; a plurality of photocell means deriving respective different color lights from a plurality of parallel-ray multicolor light beam components of said reflected multicolor light for translation into a plurality of voltages varying in magnitude in correspondence with the varying intensities of said derived respective different color lights; each translated voltage representing one of said object pattern different colors; a plurality of sources of actinic light, said sources having a number equal to the number of said different colors in said object multicolor pattern; a plurality of light modulators, each connected to one of said sources; said sources and said modulators connected theRewith movable adjacent to said respective plate inks on a common axis separated from and in parallel relationship with said mandrel axis in synchronism with said mandrel rotation; an analog computer interconnecting said photocell means and said modulators for converting said translated voltages varying in magnitude into a plurality of other voltages varying in magnitude and having a number equal to the number of said translated voltages to control the relative amounts of said respective inks on a predetermined percentage basis on said plates to produce in said printing inks an improved image of said object multicolor pattern, including: a plurality of cathode-ray tubes, each having a screen provided with an area of light together with horizontal and vertical deflecting elements; said light areas having equal intensities on said screens; said tubes arranged in a number of groups, each containing a number of tubes; said last-mentioned respective numbers being equal to the number of said translated voltages; said deflecting elements of said tubes in said respective tube groups activated by different combinations of two of said translated voltages for moving said light areas in coordinate forms on said screens; and a number of groups of photographic films, each group having a number of films; said last-mentioned respective numbers being equal to the number of said tube groups and the number of tubes in each tube group; each film divided into a number of equal squares arranged in a coordinate form; said squares of each film in each film group encoded with different degrees of light transparencies in relation to different combinations of two voltages in a plurality of different coordinate voltages varying in magnitude and corresponding to said respective translated voltages; said film coordinate voltages of said respective film groups having preselected different relative magnitudes related to said improved image of said multicolor pattern produced in said printing inks, said encoded films of said film groups so mounted on said screens of said tubes in said tube groups, respectively, as to dispose said film two coordinate voltages in correspondence with said two translated voltages activating said deflecting elements of said tubes in said tube groups, whereby said deflecting elements so activated move said light areas in said coordinate forms on said screens to simultaneously scan said film squares in turn in corresponding coordinate forms on said films in said respective film groups for simultaneously generating said other voltages as functions of said film encoded light transparencies of said respective film groups: said other voltages varying in magnitude for activating said modulators to apply corresponding amounts of actinic light from said sources onto said respective printing inks to control the relative amounts thereof with regard to said predetermined percentage basis to improve the images of said successively illuminated different spots of said object multicolor pattern on said respective printing inks as said mandrel is rotated; and optical means interposed between said object and said photocell means and movable linearly on an axis parallel with said mandrel axis and in synchronism with said light means movement and said mandrel rotation for splitting said reflected multicolor light into said parallel-ray multicolor light components at said photocell means.