| 摘要 |
Method and apparatus are disclosed for detecting and measuring the quantity of particulate matter on a substrate without contacting the sheet or disturbing the particulate matter. Directed, non-visible light energy interacts with particulate matter on the surface of the sheet; and a portion of such incident light energy is redirected at an acute angle that is significantly different from the angle of reflection of such light energy by the surface of the sheet. Infrared energy, particularly that having a wave length of about 940 nanometers, is particularly effective in the detection and measurement of clear epoxy powder; and the portion of such infrared energy effected by the particulate material may be related to the quantity of particulate material on the substrate. In the system for effecting the method and apparatus, a detector generates a voltage signal that may be related to the weight of coating material on the surface of the sheet by the relationship: <IMAGE> where W is the density of coating material on one surface of the substrate, VR is the level of the amplified voltage signal, and k1 and k2 are constants of the system. |
