Patent ID: 7077064
Filing Date: 2006-07-18
Classification: B41F,G01N

Abstract:
1. A method of measuring printed ink concentration on an opaque substrate on-line comprising: (a) projecting a light over the ink printed on the substrate measuring light reflectance as a camera response R, G or B, wherein R is the camera response for a red sensor, G is the camera response for a green sensor and B is the camera response for a Blue sensor; (b) Substituting the camera response R, G or B for reflectance (ρ) of the printed ink over the opaque substrate in order to calculate the ratio of absorption to scattering (K/S) as indicated in the following formula (c) calculating printed ink concentration (c) based on the following formula: wherein (K/S) is as calculated in step (b), (k/s) is the relative (relative to the scattering of the substrate) unit absorption coefficient, a predetermined measurement of the pre-printed ink per unit concentration per unit thickness and (t) is the thickness of the printed ink either predetermined prior to or measured after printing.