I use to print fabric for piecing and what works for me is:
a) let the ink dry and then set it by ironing before washing ,
b) to adhere fabric to freezer paper the iron has to be very very hot - cotton setting, press front and back on a hard surface,
c) cut the fabric 1/8" smaller than the freezer paper at the edge the printer pulls the paper
d) make sure there is not any piece of thread hanging from the fabric
e) set the printer to "photo paper" - thicker than regular paper since I´m feeding it with thick material.