I don't have any printable ones, but there are a few different sources for their coupons.
!. Newspaper ad. This week is coupon commotion week, so you should be able to have TONS of coupons.
2. Join their mailing list. They send you the sales flyer AND at least one coupon in each one. The only thing you need to watch with this is to make sure you have the flyer scanned each time you shop there to keep yourself on the mailing list. You can get it in the mail or via email. I think there's also a way to do both.
3. Michaels coupons. The only stipulation with this one is that the item MUST be sold by Michaels in order for you to use it at Joann's. Basically, you can use it on anything in crafts or floral. The fabric areas are what will almost definitely be excluded.
One thing to bear in mind though, is that the item cannot be on sale for you to use a coupon.