Ink jet color graphics printing

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Print Data Flow And Structures Referring to FIG.
4, input data to be printed is taken from a host central processing unit (CPU) 20 and processed in a controller (not shown) which conventionally comprises a microprocessor, a control program ROM, a data memory and associated control and interface circuitry.
FIG.
4 shows the data flow and control elements used in the controller to implement invention.
Input data from CPU 20 is initially stored in a raw input buffer 22.
Data in the raw input buffer is parsed (parser 23) and converted to tokens (token buffer 24) which are passed on to a page formatter 26.
Graphics data is accumulated in a separate graphics buffer 28.
As the page formatter 26 composes the page, it creates tasks for the print mechanism which are passed through a task buffer 30 to a process task module 32.
The task processor 32 takes the tasks created by the formatter and prepares them for consumption by the mechanism control code 34.
Graphics data from the graphics buffer 28 is transformed by the process task 32 to form bit image data in the bit image buffer 40 for easier access by the mechanism control code.
The mechanism control 34 runs the motors 44 and feeds the print head 46 with data from the bit image buffer 40.
The superpixel strategy for color printing is effected within this data transformation from raster plane graphics format to a bit image format.
This transformation occurs within the process task module 32 of the system firmware.
Before describing the process task in greater detail, it is helpful to examine the data structures employed in this system.
Data Structures FIG.
5 is a conceptual diagram of the graphics buffer 28 of FIG.
4.
The graphics buffer includes 8 multi-plane raster rows.
Also shown in FIG.
5 are pointers RdPtr (pronounced "read-pointer"); GBstart (pronounced "GB-start"); and GBend (pronounced "GB-end").
These pointers are discussed below.
FIG.
6 is a conceptual diagram of one of the multi-plane raster rows, e