Carbonless Copy-Paper-NCR-in Sheet

Carbonless copy paper works in a fairly simple way. It consists of sheets of paper that are coated on the bottom and/or the top with a reactive. The back of the first sheet is coated with micro-encapsulated dye. The top of the middle sheet is coated with a clay that quickly reacts with the dye to form a permanent mark. The back of the middle sheet is also coated with the dye. The lowermost sheet is coated on the top surface with the clay with no coating applied to the back side. When someone writes on the sheets, the pressure from the point of the writing instrument causes the micro-capsules to break and spill their dye. Since the capsules are so small, the print obtained is very accurate. Carbonless copy paper was also available in a self-contained version that had both the ink and the clay on the same side of the paper.