Pixma IX6820 settings for dark blacks on transparencies

[jasons123]

I'm trying out this printer for making positives on transparencies for screen printing. This is aimed at replacing my Epson Artisan 1430 that died.

I've been playing around with the settings quite a bit and can't seem to get the ink very dark. Here is what I have tried.

1. My art is all 100% CMYK Registration Black
2. I export to PDF file and print from there
3. Print properties are:
   
   1. Photo printing
   2. Grayscale printing
   3. Photo paper Plus Glossy II (I tried plain paper as well and no difference)
4. Advanced properties
   1. Treat Gray as K-only grays
   2. Preserve Blacks
   3. Ink Manager set ink density to 10.0 for everything
   4. Color: Composite
   5. 600 DPI

Let me know what options I should tweak or if this printer is not going to work for screen printing transparencies and I should return it.

Thanks