The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 21, 1997
Filed:
Mar. 02, 1995
Thomas B Pritchard, Brush Prairie, WA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A data compression and decompression procedure for a serial printer handles data from a print swath that includes Y rows of pixel data. The procedure divides the print swath into N microbands of pixel data, with each microband including y rows of pixel data (where y.times.N.gtoreq.Y). The procedure compresses each microband of the pixel data by breaking up the microband into microblocks and comparing data in each microblock with a seed value to arrive at a compressed microblock based upon data differences from the seed value. Each microblock comprises a block of pixel data that is m bits wide by y rows high, where m is a small fraction of M bits of pixel data that are printable by the printhead across a sheet. All microbands of a swath are subjected to the data compression procedure so as to create positionally corresponding sets of compressed data microblocks for all of the microbands. In preparation for printing, the procedure decompresses all N microbands of raster data by acting on each set of compressed microblocks to recreate a set of N microbands of decompressed pixel data. The procedure then feeds the N microbands of decompressed raster data, in parallel, to the printhead.