Print Registration Control — Closed-Loop Color Alignment

A web offset press has to keep four separate print units — cyan, magenta, yellow and key — landing on the exact same spot on a paper web moving at hundreds of meters per minute, or the printed image shows visible color fringing. This simulator animates the real feedback loop that holds that alignment: optical registration-mark sensors report each color's phase error against the black reference, and a servo controller advances or retards that unit's plate-cylinder rotation to cancel the drift. Drive the web faster, inject more tension disturbance, tune the controller gain, and flip closed-loop control on or off to watch the printed dot trail snap into alignment — or drift apart — in real time.