Abstract: A method for processing page description language commands improves the efficiency of the digital work flow in graphic arts. The method first translates the page description language commands into a structured object display list. The display list is then examined to identify the occurrence of specific predefined properties of graphical objects. The display list is modified to correct or eliminate the properties, and the corresponding page description language commands are modified accordingly. The specific predefined properties that are identified include spurious contours, double contours, redundant colors and inks, useless clips, tight continuous tone clips, blends, degenerate strokes, and strokes having unprintable thickness.

Abstract: Disclosed is a method for improving computer aided graphical design with a design rule checker. A preferred embodiment of the invention is a computer program which when loaded in a computer checks a graphical design for conformity to a set of graphical design rules such as printability rules, legal packaging rules, company style rules, and aesthetic rules. The program may be operated in an interactive mode to provide feedback while a design is being created, or in a batch mode after the design is completed. Specific rules can be customized and adapted for appropriate printing processes, company styles, legal rules, and aesthetics.

Abstract: In scanning devices used for opto-mechanical processing of a substrate covered with a photo-sensitive material, it is highly desirable to be able to achieve accurate control of the carriage utilized for scanning the substrate. To accomplish this, the carriage is moved along a rectilinear guide by use of a linear motor, preferably under computer control. The linear motor includes a winding which is composed of a number of isolated conductors attached to the rectilinear guide orthogonally to the longitudinal axis of the guide. The winding is connected to the control computer through a controllable current source. The linear motor also includes a solid-state commutator coupled to magnetically propel the carriage in accordance with current supplied to the winding from the controllable current source based on instructions from the control computer.