A PostScript Printer Controller Embedded with Lempel-Ziv Data Compression Function

Abstract

The use of data compression with PostScript printers with advanced color and high-quality imaging capabilities makes possible a substantial saving of work memory. The Lempel-Ziv algorithm is known for its high compression ratio, but it affects printer performance due to its slow speed. The printer controller developed by the authors, using content-addressable memory in the compression accelerator, realizes high-speed operation of 50 Mbytes/s and a high compression ratio by virtue of its parallel and exhaustive data search function. By means of this accelerator, the page image is compressed for storage. Partially decompressing only the bit images needed for rasterizing can reduce work memory. The efficiency of memory usage and overhead at the time of compression are studied for various images and the optimum parameters are investigated. © 1999 Scripta Technica.