I've got a 7760, and it took me a while to figure out how to get the best results.
First up - grab the ICC file for your printer - http://www.support.xerox.com/support/phaser-7760/file-download/enus.html?contentId=54918
I've a Mac, so I stuck my ICC in the following directories:
Hard Drive -> Library -> ColorSync -> Profiles -> Phaser7760_Paper.icc
Hard Drive -> Library -> Application Support -> Adobe -> Color -> Profiles -> Phaser7760_Paper.icc
Andrew (my username) -> Library -> ColorSync -> Profiles -> Phaser7760_Paper.icc
...obviously your username may be different, as regards the last path.
After that, when printing from Acrobat I do the following:
In Copies & Pages, there is an "ADVANCED..." button.
I click ADVANCED...
This shows a dialogue box for Output, Marks & Bleeds, and PostScript Options.
I stay on the default Output page.
Where it says Color Profile, I select Phaser 7760 from the drop down menu.
Clicking okay, takes me back to Copies & Pages.
I then go to Color Matching.
It gives you a choice between ColorSync or In Printer.
Select "In printer".
Then go to Image Quality.
For Print Quality, select PHOTO
For Color Correction, select NONE.
That's about it.
The trick is, to only have your ICC file specified at one point. If using ColorSync in both the Color Matching option, and under the advanced button, the colour profile would be messed up, as it would try to correct colours twice, =P.
There are basically three places to select the colour profile - Advanced Print Setup, Color Matching, and Image Quality. Only set it under Advanced Print Setup, and leave Color Matching and Image Quality at In Printer, and None, respectively, else everything will get confused.
I typically only print from Acrobat.
When in other programs, I use OSX's option to Save as PDF, and then I'll open the PDF in Acrobat and print using the above settings.
I find that always gives the best output. But let us know, how you get on.