Techniques for removing a substrate from a polishing pad are described. Further, it receives designation of the number of letters, letter size, or the number of lines as a threshold value for determining whether the title information input to be printed on the tab should be converted into an index or not. The rate of change is compared to a change threshold value. The power supply may be a cell or battery and may be combined with the sacrificial anode to form a single unit. Under this circumstance, like the Schottky diode, the low gate charging rectifier has low forward voltage drop and rapid switching speed.