You cannot print directly to QTR through the LR Print Module and it wouldn't make much sense anyway, as the image needs to be in Grey Gamma 2.2 profile in order to print correctly with K7.
There is no way to convert to GG 2.2 in LR, not even for Mac users
My workaround: (I'm on Mac but this should work on PC too)
I edit my image (after final retouching, etc.) in Photoshop and convert the image to GG 2.2 - save and return to LR. It now keeps the correct profile for K7 as long as you only edit the 'original'.
In LR preferences, add a new custom external editor, in your case QTR (you have to browse to the exact location of 'QTRgui.exe' in you Program Files folder).
Back in the Library Module, choose your image that has been converted to GG 2.2 and that you wish to print. Using the edit command, EDIT THE ORIGINAL with the external editor that you had just added.
This should open your image in QTR.
Obviously, you cannot take any advantage of the LR Print Module functions, like layout, duplicating, etc.
Let me know if this works.