| 摘要 |
A technique of applying a protective layer and an absorbing layer to a wrapping material for wrapping a product, such as a candy bar or potato chips. The protective layer prevents a laser marking tool from puncturing the film. The absorbing layer absorbs radiation from the laser marking tool to show a sequence of symbols and characters, such as a date, bar codes, an image or a logo. Another technique for marking codes on a thin film may include applying a thermal coating or ink on a thin film. A device with a ribbonless, non-contact thermal print head may apply heat to specific portions of the thermal coating to mark symbols and characters. The portions of the thermal coating exposed to heat will change color. |
