Thank you for your quick reply. Actually, the printer is still under warranty, so I'll wait for the guy in charge to take care of the problem, but from what I've seen by opening by hand the ink compartment is that the ink cartridge has leaked a bit. I cleaned it from the cartridge, put it back...
I came here quite often since this forum provides great and valuable information on Canon printers. Since I got a Pro-1, and now have a B500 error, I'm back, registering, and trying to figure out what's the big deal since I did everything by the book and only printed a full set of ink...