| 摘要 |
PURPOSE:To prevent the leakage of secret due to recopying by enclosing an arbitrary area with continuous recognizing lines (erasure lines) by means of an image reading sensor and forming plural segments in that area. CONSTITUTION:An arbitrary area on a copying sheet S is enclosed with the continuous erasure lines LL, and erasure lines LL1 to LL4 partition the area to form two or more segments. A group in a company, etc., having a digital copying machine that can perform trimming copying and masking copying, sets a switch to a trimming copying mode, for instance. As long as a user marks information that he would like to keep secret in a frame of a specific density formed on an original and on the sheet S used as transfer paper, a copy of the information cannot be taken as an image even someone tries to copy it. Thus, the leakage of secret due to recopying can be prevented. |
