Abstract: A high speed, low cost real time graphic image printing system includes a host data processing system, a laser printer having a plug connector for receiving a font cartridge storing information defining an image of a printable character, and a cartridge pluggably connected to the font cartridge plug connector. A first communication path carries print commands from the host to the printer while a second communication path carries image defining information between the host and the data store. In operation the host writes information defining a portion of an image to be printed into a portion of the data store corresponding to a selected character and then commands the printing of the selected character. A ping-pong double buffer arrangement allows the host to write a next image portion while information defining a current image portion is read by the printer to form a print image.

Abstract: A high speed, low cost real time graphic image printing system includes a host data processing system, a laser printer having a font cartridge port, a font cartridge that is writable in real time by the host to facilitate high speed printing of graphic images and an expander cartridge. The expander cartridge plugs into the printer font cartridge port and in turn provides ports for pluggably receiving both a read only font cartridge and a real time font cartridge that is writable by the host. The expander cartridge serves as a multiplexer to couple a selected one of the two font cartridges to the printer.