DSF

If you only want to print greyscale and there's no colour in your design, forget all your profiles and just print via the printer driver, selecting "Greyscale" or "Black Ink Only" (depending on which printer you have). So long as you're set to print on plain paper, the printer should print with just the black ink. Try it and see.

It's the profile that forces the printer to use all the inks to create a composite black/grey. And it's the rendering intent which shuffles it away from actually being a good composite black/grey. Trying to get a neutral greyscale out of composite inks from an inkjet printer is the photographer's nirvana - that's why photographic inks are available in three or four shades of grey (such as Epson K3, or the Lyson Quad-black). In the relatively tiny gamut of dye-sub ink, it's a tough task to get even remotely close.

I had a design to print on lots of mugs awhile back which featured a photo on the front and black/white on the back. I actually ran the paper through the printer twice (once using the profile to get the colour photo, and then again using no profile and "greyscale" to get the b&w). Results were far better than sending it through once and ending up with a composite black/grey.

The next question will be - is Sawgrass black ink actually black? Well...

Very informative

Ok next question:

I suspect that the yellow ink I'm currently using is too "strong" (can't think of a better word) whereas previously the magenta was slightly dominant. Is there a way of manually adjusting the four colour levels to get the desired output using Coreldraw?

Fresh ink arrived today, drained out the old stuff, powerflush and head clean and it's back to printing normally

Thanks for all the help guys.