A program called printopia will work with your issuse it makes the printer airprint through the time capsule. It is free and very easy to use. All the instructions are on the website http://www.ecamm.com/mac/printopia/
Quite a number of "AirPrint" compatible printers need a software update from the manufacturer to work correctly.
Have you downloaded the latest software updates from your printer manufacturer?
Have you verified that your printer is actually "AirPrint" compatible? Use the support document below to check your model:
If your printer is not on the list of compatible models, the only way that you will be able to print from an iOS device is install an App like Printopia or Print Central.
In other words, it is not up to Apple to make your printer AirPrint compatible. That has to come from the printer manufacturer.
My printer worked fine via AirPrint while using the Airport Extreme, before I upgraded to the Time Capsule. I've since determined that the problem only occurs when I put the printer on the Time Capsule's Guest Network. If I put it on the main wireless network (whether hidden or not) it functions properly.
So if I want guests to be able to print to my printer, I either have to give them access to my private (and hidden) network, or I get rid of the private/guest networks altogether and set up a basic network with password.
Apple technology is great and one has lots of choices, the problem is they never quite work in conjunction with each other in exactly the way I need them to. This reminds me of a time when I wanted to use Time Machine but couldn't because it was incompatible with FileVault. At least now that mostly works.
I've since determined that the problem only occurs when I put the printer on the Time Capsule's Guest Network.
Did you enable the option to allow guest network clients to communicate with each other? This would allow anyone on an iPhone, iPad, etc to print to an AirPrint compatible printer that is also a client on the Guest Network.
I have no problem at all with "guests" who want to print to the AirPrint printer that is used only on the Guest Network.
If you have already set things up this way, and it does not work, then I am out of ideas