Probably not a good idea. If this unit is toner based, it will fuse the toner at a very high heat (did you know that Phaser stands for phased laser?), probably end up with vinyl wrapped around rollers inside. If it is a waxed based ink unit, I am not so sure as they run at lower temperatures than the toner units. Material would have to have melting point properties like whichever transparancy material is recommended by Xerox.
Like i said, I already tested this and it works with the phaser 850 printers,,, which is essentially the same as the other phaser printers..But you need to use vinyl used for INK JET printers, cut the sheets to the correct size,, I just haven't tried doing 50 pages at a time.