Time Capsule and printer problems

I had set up my time capsule and home network and all was working but the printer. I managed to get it to print from my MBP but not from my PC desktop. I thought it was because I had installed the airport software after the time capsule so i deleted the software, unplugged the time capsule, reinstalled the software and switched on the time capsule. The result is that the time capsule now does not recognise the printer and it does not show up in a list of printers. As a result I now cannot print from either the MBP or the PC unless I unplug the printer from the time capsule and plug it directly into the USB port on either computer. What has happened and why can't the time capsule see a printer plugged into its USB port???