Method and apparatus for correcting edge interval of record signal in an optical record/read-out apparatus

A record signal correcting apparatus for use in an optical recording/read-out apparatus wherein record signals are recorded that have a mark length bound by opposite edges and having an edge width extending therebetween, comprising:

• (a) means for recording on an optical disk N times, where N is an integer, a record pattern sequence B of record signals including a plurality of patterns A each having an n edge width, where n is an integer, and respectively being recorded in various combinations of said n edge widths;
• (b) means for reading out said recorded pattern B as a signal from the optical disk;
• (c) means for classifying the read-out signal into one of said patterns A and for obtaining for each edge position of each said pattern A, a shift quantity associated with said edge position relative to an edge position indicating an ideal recording position thereof;
• (d) means for generating and storing therein a table containing relationships between said shift quantities and said patterns A;
• (e) means for collating a record signal of data being recorded and having a pattern of the n edge widths with the patterns stored in said table to obtain a match;
• and
• (f) means for independently correcting head and tail edge shifts for each of said patterns A by a corresponding one of said shift quantities retrieved from said table responsive to the match resulting from said collating.