I have to agree with Woody. If you are using your own fabric, and not the sheets made for printing you need to chemically treat the fabric with bubble jet set.
Also, make sure the ink in your printer is pigment not dye based. I found out the hard way that dye based inks are not color fast. I bought a Kodak printer and found out I can't use it for fabric. I've heard HP, Brother and Cannon are the three best companies for printers that work on fabrics.