In order to correctly position a printable character on a page, PCL uses a system of coordinates. The origin is the upper left corner of the logical page. All movements and positioning commands are taken with respect to this origin. X coordinates run from left to right and Y coordinates run from the top downwards.
The point (0,0) in the X,Y PCL coordinate system is defined at the left edge of the logical page at the current top margin position. Since the top margin can be modified using a printer command, the physical location of the point (0,0) may change.
PCL coordinates