| 摘要 |
An edge detection system that locates the edge of a printing plate on a platesetter includes: first scratches aligned in a first direction on a support surface; a groove machined into the support surface where the groove includes two surfaces. One surface is reflective and has second scratches aligned in a second direction perpendicular to the first direction of the first scratches. The system also includes: an edge detection light source to provide a beam for scanning along a length of the support surface on a path coincident with the groove; a sensor to sense a reflected edge detection beam from the support surface; and a controller to analyze the reflected beam, where the beam reflected from the first scratches is 90 degrees out of phase with the beam reflected from the second scratches and where the beam reflected from the first scratches is high in intensity relative to the beam reflected from the second scratches.
|
