Digital BW, The Print

I'm using an epson 1400 with ut-14 ink set. 
I'm very happy of this choice!

I have a problem that I can't solve if I try to print with icc solution (eveithing is OK if I use QTR or curve).

If I print with an icc file created with qtr the 21 step image is cut exactly on 70%.
The print is ok from 0 to 70%, total white from 70 to 100.
Why my printer don't print nothing from 70 to 100?

I try to use the icc file downloaded from paul roark site and the result is the some.
Any idea?

CS4 with windows vista 64 bit

Thank you

Marco