Try using a High Rez image and substituting that for the Zoom Destination.
Give the Zoom Destination focus and look at the Properties Panel. In the Fill & Stroke section is a small folder icon.
Click that icon and you may then browse to and choose the higher resolution image. Note that you may wish to note the actual image dimensions and configure the Zoom Destination so there is no scaling. Otherwise, you will be back to needing the screen razor to shave off the fuzzy stuff because of scaling!
Cheers... Rick 