Memory Allocation and Deallocation for Print Data in APA Printers
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-27
A method is described for effectively using memory and DMA to format and print data in high density APA (all-points-addressable) printers. Large amounts of memory are needed to store data; for example, one square inch of data in a 240 x 360 pel/inch resolution requires over 10,000 bytes of memory. Therefore, it is impractical to store an entire page of text, because the cost of adequate memory chips would be prohibitive, especially for low cost letter quality printers. This requires that the print data be formatted and "rasterized" (converted into dot patterns) in sections in RAM while printing is in progress. This method is intended for use on an R2T2 (Resistive Ribbon Thermal Transfer) technology printer , but the ideas presented here can be extended to a wide variety of print technologies.