PJL stands for "Printer Job Language". This is a set of commands that are used to set the printer up for specific printing functions, before the actual job is sent. Examples are duplexing, stapling, etc. The PJL commands are added to the beginning of the job by the driver.
PJL is normally used by printers with high-level printer languages like PostScript or PCL. It is not used by printers with low-cost, host-based printers.
I have not been able to find out what languages (if any) your printer understands. Neither the data sheet nor the manual mention it, which makes me think your printer is host-based.
However, the fact that it prints the PJL commands implies that you are not using the correct driver. Try re-installing the printer. Go to Devices and Printers. First delete the printer. The click on any other printer and select Print Server Properties from the menu that appears at the top. Click The Drivers tab and remove any instances of your printer. Now install from CD or from a downloaded driver. Click the Download button on that page.
Note that the link @harrymc gave is not an Epson Support link, although that driver may well be the same.