Method and system for verifying correct mounting of a printing plate on an external drum imaging machine

摘要

A printing plate mounted on an external drum platesetter is verified to be securely fastened to the drum using an autofocus system prior to spinning the drum to maximum operating speed. An autofocus mode is employed to set a reference signal using a light beam and light sensor. After establishing the reference signal at one end of the plate, the system switches to a second mode of operation where the autofocus system is fixed, and the reference signal is monitored as the drum and plate are rotated. If the reference signal deviates from the initial value, the rotation of the drum is stopped and an operator is alerted.