A video system including a circuit for automatically correcting reversed polarity in a polarity sensitive system. The two-phase heat exchange device includes a main body and a continuous wick structure. The sensor socket is disposed on the main shaft. The camera takes a thermal image across the width of the seam and transmits the data to a central processing unit. The waiting time and the return speed of the carriage can be manually selected or changed by using an operator’s control panel, so that the non-margin recording operation can be performed in a desired manner. The digital mask is created by laminating the negative image that is the by-product of a thermal proofer to a photosensitive printing plate.