HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part II

EN IR, Input Relative P1 and P2 19-27
Sending the command IR25,25,75,75 establishes new locations for
P1 and P2 that create an area half as high and half as wide as the
PCL Picture Frame, in the center of the picture frame. Refer to the
following illustration.
Figure 19-10Example: P1 and P2 command
P1 or P2 can also be set outside the PCL Picture Frame by specifying
parameters less than zero and greater than 100. For example,
sending (IR-50,0,200,100) would set P1 and P2 as shown in the
following illustration.
Figure 19-11Example: P1 and P2 command