Patent ID: 6912316

Claim:
A method of compressing source image data for a hard copy device, the method comprising: storing the source image data in units of bytes, in a memory in rows and columns; transposing bytes at each column of the source image data to bytes at each row of the source image data; determining start information, said start information containing header information and containing information on a chain that was the starting point where compression on the source image data is started; encoding a plurality of sequential chains and generating compressed data including said encoded chains; each one of said sequential chains corresponding to one selected from among a current chain alone and the current chain with at least one chain succeeding the current chain, said selecting being in dependence upon whether a dictionary contains chains having same value as the current chain, the dictionary being composed of chains preceding the current chain; and including said start information in said compressed data, each chain being composed of at least two consecutive bytes at a row, neighboring bytes at each row having neighboring memory addresses, offset of neighboring bytes at each column corresponding to width of row of the source image data.