Printing error with exported TTFs

I have a non-widespread issue with some exported TTFs on a Xerox Phaser. Has anyone seen this before who might be able to shed some light on the issue? The suggestion is to use OTFs but I feel like TrueType should be more than adequate.

For anyone interested it seems to be an issue with Xerox and the driver:

This is a problem with hinting. Have you exported with autohinting?

Yes 100% sure.

I think that is a know problem with the ttfautohint library. If you need to use those printers, you need to manually hint the font.

Thanks for the insight Georg.