Accelerated development time-delayed message system
US5633836A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1995 |
| Grant date | May 27, 1997 |
| Priority date | — |
| Expiry date | Dec 4, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41M3/005
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A time-delayed message indicator system typically displays a printed message pattern on a contrasting viewing surface at a predetermined time after activation. One preferred indicator system employs a migrating message pattern and has a laminar, multilayer construction. The message is printed on a source layer using a migratable ink. An opaque layer overlies the source layer and a release layer protects the migratable message from contact with the opaque layer until the system is activated by removal of the release layer initiating migration of the message ink through the opaque layer. Arrival of the message agent at the viewing surface initiates development of a visible message pattern. To enhance the development process the invention includes a message development trigger, for example, a heating system. The heating system can consist of exothermic chemical reactants that are mixed to react and produce heat, for example by oxidizing iron filings or activated carbon. Other embodiments employ buffered pH indicators and a migrating acid or base.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.