Digital BW, The Print

I am using QTR and Epson 2200 and ultrachrome inks with photo black
on Epson Enhanced Matte Paper.  Tried printing test strip with QTR and
my DMax is low, only about 1.55. It is slightly higher if I just use 
the epson driver, about 1.6.  These are still quite low.  Is there any
way to increase the Dmax to get it in the 1.78 range that I get when
using Piezo inks?  Thanks.

Matthew Kraus