QTR-Quadtone RIP

I am an artist in NM. I am new to this forum.  I have been printing with QTR for the past four years using the Epson 4000. 

I have converted an Epson 7600 to use K7 Piezography inks and have encountered vertical cockling in the paper traveling direction.  What I mean by cockling is that the paper is getting more ink and solvent that causes the paper to swell (it is wavy) that repeats itself throughout the print.  This problem doesn't seem to be density dependent.

This problem seems to be that too much ink is applied by the printer in spite of the tonal qualities of the print. 

In the past the same files were printed in an Epson 4000, using the same inks and paper, with no problems.

Any ideas, words of wisdom or solutions are very much welcomed.

Cecilia