When I send a request to print to a HP4si networked printer, It prints an extra page with User, Host, Class & job info.
Is it possible to eliminate this page?
Assuming you are using jetadmin to setup and manage your network printer, go into jetadmin screen and change the spooler queue options not to include the banner page etc.
Some versions of lp[r] allow you to switch that off with a flag. On many Linux systems, the flag is -h.
lpr -P myprinter -h myfile
Check your manual page for details.