hello.. i'd like to confirm if the printer function "printer_open()" without parameters opens the printer connected to the user/client computer? or does it look at all network connections including the web for the presence of a printer?
Without the parameter, the printer_open function attempts to find the default printer from your php.ini settings. If it can't find them it will then use the default printer of the machine running the script. It is always recommended to specify the printer name if known, or prompt the user for the printer if possible.
EDIT: Check out the printer_list() function, it might help you specify the printer if you have no other way of determining it.