You can print an anti-copy pattern on your printouts. When printing, the letters themselves are not printed and the entire print is screen-toned lightly. The hidden letters appear when photocopied to easily distinguish the original from the copies.
Anti-Copy Pattern is available under the following conditions:
Paper Type: Plain paper
Quality: Standard
Tone Correction: Automatic
Access the printer driver, and then make the following settings.
More Options tab > Watermark Features > Anti-Copy Pattern