Hi.
I think that discovery rules for HP printers are not correct, because it looks at openports(631,9100).
What about print servers? They also have this ports :P

Would it be better if discovery rule is one (or combination of more) of the following:
osvendor HP
ostype printer
macvendor hewlet packard

Just mentioning this as a suggestion, so discovery for others will work better I have already modified my configuration..