Systems and method for determining presence of inks that are invisible to sensing devices
US6132024A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1999 |
| Grant date | Oct 17, 2000 |
| Priority date | — |
| Expiry date | Jul 27, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB41J2/2135
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
Nonoptical properties of inks can be brought to bear in locating ink that is invisible to an automatic sensor. Physical characteristics of inks as liquids can be exploited to reveal their locations with surprising precision. The system includes an optical sensor. Using ink that is visible to the sensor, a preferably fractional fill pattern is printed on a region of a printing medium. Using ink that is invisible to the sensor, calibration indicia or other patterns are printed on particular portions of the same region. Bleed (running together of the liquids of the two inks) tends to convert the fractional fill pattern into a solid fill, within the particular portions that were also printed with the "invisible" ink. Resulting optoelectronic signals provide amply high contrast between (1) fractional fill in the particular portions where the "invisible" ink is applied and (2) the original fractional fill elsewhere. The sensor responds to areas where bleed has converted the fractional fill pattern into a relatively more solid fill. Preferably, to enhance contrast, the visible-ink fractional pattern is printed as aggregations of multiple adjacent pixels, rather than individual, mutually s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.