HP LaserJet 4100 HP PCL/PJL reference (PCL 5 Printer Language) - Technical Ref - Page 25

Pen Location Pen location refers to the X,Y coordinates of the current active position (CAP - the point at which the next HP-GL/2 command begins). Most commands, when completed, update the pen location. The next command then begins at that location. Some commands do not update the current pen location. The definition of each command tells you whether the current pen location is updated or restored. Use the Pen Up (PU) command with the desired X,Y coordinates to lift the pen and move it to a new location. The Default Values (DF) command does not reset the current pen location; the Initialize (IN) command moves it to the lower-left corner of the PCL Picture Frame. You should specify your beginning pen location for each HP-GL/2 drawing. EN Pen Status and Location 17-23