Principle of carbonless
Carbonless is a paper that instantly and automatically transfers a text or an image from one sheet to another by the interaction of two special coatings under the pressure of a ballpoint pen or a dot matrix printer. The first coating, CB (Coated Back), is composed of pressure-sensitive microcapsules. The walls of these microcapsules are made of gelatine and they contain dissolved dyes. Pressure or impact breaks the microcapsules, releasing these dyes which are transferred to the CF coating (Coated Front). The CF coating absorbs and reacts with the dye to give a sharp, intense black image.
The carbonless system is characterized by three different types of paper:
- CB (Coated BACK), always the top sheet. It is coated on the back with microcapsules. It transmits the image.
- CFB (Coated FRONT and BACK), the middle sheet. It is coated on the front with reactive material (CF) and on the back with microcapsules (CB). It receives and transmits the image.
- CF (Coated FRONT), always the bottom sheet. It is coated on the front with a special absorbent and reactive material. It receives the image.