Digital BW, The Print

I'm been printing digital "positives" on transparency film to use in
making photo-polymer etching plates; similar to digital negatives, but
I'm printing positive images with black ink only at 720 or 1440 DPI,
because I want to get a dot/grain pattern that will become the "bite"
in the etching plate.  

I'm been doing this on my Epson R2400, using the Quadtone RIP
software, so I can print with black only ink. I have been using the
Matte Black ink cartridge because it seems to give better opacity and
coverage for this process (I read something similar about using this
ink for digital negatives as well). 

The problem is that on the transparency films I've been trying, the
matte black ink never seems to become permanent and I can smudge it
with my finger. I thought this might not be a problem if I handled the
sheets carefully, but under the pressure of the UV exposure unit
(similar to a big contact print frame but with much more pressure), it
seems the ink is getting smooshed against the plate and causing random
rings and marks to show up in the final image, especially in areas
with continuous tone.   

I'm wondering if people are having success with using the Photo black
ink to print digital negatives, or if anyone has found a transparency
film that will accept matte black ink? 

Any advice or suggestions would be helpful. 

Best, David.