Using thermally transferred invisible ink detectable by exposure to invisible light of specific wavelength
US5212558A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 26, 1991 |
| Grant date | May 18, 1993 |
| Priority date | — |
| Expiry date | Feb 26, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41M3/14
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a facsimile machine which receives transmit data based on an original that is transmitted from a facsimile transmit machine through a telephone line at its data scrambler and which records an image of the original that is transmitted by decoding the received transmit data on recording paper at its thermal transfer printer portion, in order to maintain the secrecy of the original until the recording paper is delivered to an intended receiver by making it impossible to read the recording paper itself on which the transmit data is recorded and outputted, an image by invisible ink is recorded on the recording paper. Also, the image by the invisible ink which is recorded on the recording paper is displayed by converting it to a visible image by means of a visual observation apparatus, so that only a predetermined person can read the recording paper.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.