Research on Dual-eye Color Code Photoelectric Sensor for Overprint Error Detection

During the gravure drum printing, some unexpected external factors have led to overprint error. Overprint error can be characterized by the deviation between the actual interval and the standard interval of the adjacent two color codes pressed on the edge of the printing material. Based on the photometry principle of optical reflectivity modulation and difference-plane properties of coating glass, we present a dual-eye color code photoelectric sensor (DECCPS) for detecting overprint color codes. Using difference-plane coating glass and photoelectric-detection techniques of photocell, optical system and photoelectric conversion is implemented. To amplify and digitize output signal of photocell, we design the signal-conditioning circuit. The results show that this DECCPS is better than traditional methods in independence on printing speed, installation requirements and cost, and has the advantages such as high detection precision, stability and reliability, simple and compact architecture, etc.