An apparatus and method for reading, processing, storing and later printing out stored data from an original document in which undesired data portions are prevented from being recorded. Portions of the printed original image which are desirably retained and recorded are printed with solid lines, while image portions, for instance, ledger lines, which are desirably not retained and recorded, are printed as optically fine discontinuous patterns. The original thus printed is scanned line by line. The analog signal which is produced by the scanning device has high frequency portions when an optically fine discontinuous pattern is scanned. These portions are eliminated by low-pass filtering or by determining the degree of correlation between the sensor output signal and stored data representing the optically fine discontinuous patterns.