Electronic control of imaging system

Abstract

In a phototypesetter, an array of light emitting diodes is energized in synchronization with an associated staggered array of fiber optic filaments. The array of filaments is slanted relative to the direction of movement, and type may be set in both forward and reverse directions. Type font data is stored in a compressed form in a first microprocessor subsystem. That compressed data is expanded in real time for each character in a high speed microprocessor subsystem. Character image data in the form of character contours is written into alternating RAM groups. The contour data is then read from the RAM groups on a slice basis and color data is generated. The alternate RAM groups allow for proper coloring of overlapping character images. The expanded data is then handled by a logic unit to allow for the staggered fiber optic filaments and for the slant of the fiber optic filament head in both forward and reverse directions. The data bits for each slice of type is divided into odd and even bytes which are in turn written into and read from a random access memory in a sequence determined by a programmable read only memory. Memory control bits in the high speed subsystem are obtained directly from a microinstruction memory.