There are many HP 4280, so please say exactly which one, see here:
http://openprinting.org/printer_list.cgi?make=HP
Make sure you have HPLIP installed.
You should also try to configure the printer using the CUPS interface:
http://localhost:631/
If the printer exists try to print a test page, and if you want lpr to work you will need to set the printer to be the 'default printer'.
If you decide to reconfigure it, just remove the old printer, and click 'add printer', at one point you will need to select the option with printer serial number in it, and later it should automatically choose the right driver.