Methods for making false watermarks in a fibrous substrate
US7828922B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 24, 2007 |
| Grant date | Nov 9, 2010 |
| Priority date | — |
| Expiry date | Dec 4, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24802
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Methods of making fibrous webs having a visible transparency variation image and products constructed from such methods are generally disclosed. The variation in transparency creates a transparency variation image in the fibrous substrate in the form of a false watermark and/or a false shadow mark. In the method disclosed, a transfer sheet having a transfer coating is utilized. A portion of the transfer coating is removed from the transfer sheet by heat transfer with a printable sheet having a toner image applied thereon. The transfer coating of the transfer sheet includes a powdered thermoplastic polymer and a film-forming binder. The film-forming binder can have a melting point that is less than that of the powdered thermoplastic polymer. In the final step of the method, the remaining transfer coating is transferred to a fibrous substrate to form the transparency variation image in the fibrous substrate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.