Assuming the raster data is in PCL format, simply locate the cursor to the desired position on the page and let the raster flow.
Very often it is more convenient to set up the raster image as a PCL macro, and call the macro at the appropriate moment, or enable the macro for automatic overlay whereby the printer will put the image on every page without further intervention from the application.
I would suggest that you study the chapter in the PCL5 Reference on raster images. There was a pointer to the PDF file in a previous thread here "Electronic Documentation".
There was also another thread "Embedding a Graphic..." that may be of some use.
Jim Asman
jlasman@telus.net