Fixed - hopefully anyway. I don't know how I missed this post https://forum.support.xerox.com/t5/Hardware/New-Phaser-6510-DNI-feeding-paper-improperly/td-p/216044 but the rollers on mine were also down - rasing them both up has fixed the feeding issue.
I just received a 6510 printer but it will not complete a print. Every time it complains of a rear paper jam after nearly ejecting the page. I disabled the startup page print and tried to print via the network but no change. I did notice that if I grab the sheet as it is coming out and (gently!) make sure it actually comes right out the printer is happy.
The fault report is '010-106 Fuser exit SNR OFF Jam (Straight)'
I've looked at other similar posts in the forum but the only suggestions seem to be to ensure the paper is set right - it is, A4, plain. The 'jam' occurs regardless of if the paper is coming from tray 1 or the bypass tray. Paper is clean and runs fine through our HP laser.
I've tried some other better quality paper too just in case.
I've even checked again that I removed all the various bits of packing tape.