CODER AND DECODER FOR IMAGE DATA AND IMAGE FORMING DEVICE USING THEM

摘要

PROBLEM TO BE SOLVED: To enhance the efficiency of a magnification processing in the sub- scanning direction by discriminating a termination position of image data by one line of processed and coded image data for each line. SOLUTION: Image data are compressed by coding number of repetitive times of same kind and different kind of data with (FFh)-(81h) and (00h)-(7Fh) in pack bit compression and (80h) is used for a termination code of the compressed data. In the compression in the unit of lines, the termination code appears at a final position of the compression data of each line. When an OUT PUT circuit 407 to transfer print data from a data register 404 to a print section receives a PBMAG flag being a pack bit magnification flag from a video register 405, the output circuit 407 simply interprets the termination code of each line to be an end of a line and increments a counter in the sub-scanning direction according to a LineEND signal from a video sequencer 406.