Raster image processor

Claim 1

In a raster image processor for filling and reading out a page-size raster image memory with bit representations of graphical and type characters using codes of said graphical and type characters which are expanded with said bit representations of each character stored in the form of n-bit words in consecutive addresses in a second memory adapted for input by an asynchronous bus connected to said raster image processor, said processor being adapted for conversion of said data stored in said raster image memory into a serial pixel-bit stream for a raster output scanner to obtain a printed page, the improvement therein comprising a synchronous raster image bus for connecting said processor to said raster image memory; said raster image processor including: a. a microprogrammable central processing unit; b. a raster image bus interface connected to said synchronous raster image bus; c. a raster output scanner interface connected to said raster output scanner; d. an VME interface connected to said asynchronous bus; and e. a synchronous raster image processor bus connecting said microprogrammable central processing unit (CPU) to said raster image bus interface, to said raster output scanner interface and to said interface which is connected to the asynchronous bus.