Digital BW, The Print

I am not getting my image printed exactly in the centre (side to 
side) of the paper sheet. 
If for example I print an 8 x 8 inch image on 8.5 x 11 paper, instead 
of having exactly a 1/4 inch (.25 inch) on each side of the print 
area, one side is slightly more than a 1/4 inch and the other 
slightly less.

In the driver Properties> Paper tab > Printable area - I have the 
Standard button selected and the Centred Box checked On.

Is there another tweak I can perform to correct this misalignment ?
thanks
frank