Ir5020 add to network

I am trying to add a iR5020 Canon printer to a network.
Here is what happened:
The computer finds the printer i installed the printer(Printer has an ip)
i used the ping command to ping the printer(found, no errors) i am also able to access to the printer web interface to change settings.
what could it be the problem?
Additionally, i tried to ping from the printer to the computer that i want to be able to print, but it does not find.
I tried to another one that is not hooked in the same switch and it responds.
.....
my network does not have a server, i have vista and XP computers
Can any one help figure out what the problem might be?