Hi Joe,
Please give us some more information.
Is you monitor calibrated/
Printer model, paper, source of ICC profile.
What are you driver settings for colour - show us a screen shot please.

My first reaction is that the white point of the image is out - maybe when not using a profile and the driver handling the colour, the driver corrects the white point.
Have you looked at the image in an editor and checked the levels?
In QU double click the thumb to open the editor and click the levels tab. If the right hand end of of the graph drops to nearly zero away from the max value of 255 then that would give grey whites I think.

Terry

Hi Joe,
Terry asked if I had any further ideas, so I am butting in with permission.
The above sentence has me confused.

You create the targets using the driver defaults?  What exactly does that mean.
If you asked Terry or me the same question, "How is your driver set when you make a target for Profile Prism," we would answer that it is set to the correct paper and NO COLOUR MANAGEMENT. (Color Management set to OFF)

Going by your explanation, white prints while with Profile turned OFF in Qimage, that sort of points me to your profile.  

Remember, the settings in the driver when you print, *Paper type, Quality setting, Color Management, and speed, * should be set the same when you create the target for Profile Prism.
Try this on a DARE.
Set the driver to ICM and set Qimage to Let Driver manage color. This will use Mike's internal print profile for Qimage.
Then tell us if the whites are gray in that configuration.
See screen snaps

Hope something helps.

Fred

Joe,
Sorry, but you must start again from the beginning    ....

First point , you should set your driver from within QU using the Printer setup icon  (next to the Print icon).

Secondly, Printer Properties is not the driver settings but a Windows thing. Driver settings are called "Printer Settings" but go there from QU as above.
In the context of full colour management for printing, the Windows Color Management is for devices connected to your computer and the printer profile is not relevant so remove that Profile Prism profile in that window.
You do not have a profile set for your monitor in Windows - that must be done too for good screen colours. I see from your 2nd post it's set to sRGB not the Spyder profile.

Finally, it seems you have not previously found your driver settings from within QU, it's likely your profile from PP is not correct.
Now you know where to set the driver from QU, use Fred's suggestion
Let us know how you get on