ELECTRONIC IMAGE PROCESSING SYSTEM

An electronic image processing system for converting character font data into image data utilizable by a raster output scanning device, such as a ROS printer, capable of formatting the image data in a plurality of scan lines onto an imaging medium includes a main memory having character font data stored therein and an input memory for receiving character font data from the main memory. In order to achieve reproduction of characters of different shades and tones, the system further includes a data pattern memory responsive to a predetermined address signal for providing a predetermined pattern of data defining a desired grey-scale tone for the image data; a band buffer memory capable of storing image data representing a predetermined number of scan lines constituting an image band, the band buffer memory having enable input lines and associated data input lines; means coupled to the input memory for addressing the input memory to access character font data therefrom; means coupled to the band buffer memory for applying character font data accessed from the input memory to respective enable input lines of the band buffer memory; means coupled to the data pattern memory for applying the predetermined address signal to the data pattern memory; means coupled to the band buffer memory for applying the predetermined pattern of data accessed from the data pattern memory to respective data input lines of the band buffer memory; and means for addressing the band buffer memory to load into an addressed memory location the predetermined pattern of data only with respect to those data lines whose associated enable input lines are enabled by the character font data.