Again, not all USB printers are compatible with AirPort base stations. In addition, the AirPort's USB port does not support the "advanced" printer functions, like scanning, copying or faxing, of multi-function printers.
To see if your printer is compatible, take a look at this
iFelix Unofficial AirPort Printer Compatibility link.
If your printer isn't listed, it doesn't necessarily mean it won't work, but simply that it has not been verified. iFelix also provides the following
workaround for printers not on the list that would certainly be worth a try.
Also you can try this Apple Tech Support article to see if it will help:
o
Printer troubleshooting for AirPort Base Stations and Time Capsule
Finally, check out this
IBM support article to see if the printer you are interested in is listed as having a Postscript or PCL3 interface. If it does, then it will most likely work with the AirPort's USB port. Printers that use the "HP LIDIL" interface must be connected to a computer directly and will not work.