See CUPS user guide ->http://www.cups.org/doc-1.1/sam.html
Similarly, a HP LaserJet printer using a JetDirect network interface at IP address 184.108.40.206 would be added with the command:
/usr/sbin/lpadmin -p LaserJet -E -v socket://220.127.116.11 -m laserjet.ppd ENTER
As you can see, deskjet.ppd and laserjet.ppd are the PPD files for the HP DeskJet and HP LaserJet drivers included with CUPS. You'll find a complete list of PPD files and the printers they will work with in Appendix C, "Printer Drivers"