When evaluating a printing inspection machine, the most critical factor is the detection accuracy and speed. You should look for systems equipped with high-resolution linear CCD or CMOS cameras (typically 4K or 8K resolution) capable of detecting defects as small as 0.1mm². Ensure the machine supports your specific maximum web width and operates at a production speed that matches or exceeds your printing press (e.g., 300-500m/min). Additionally, verify the software algorithms for their ability to detect specific defects like color variation (ΔE), misregistration, ink splashes, and broken text.