In my experience the Phaser line (we have had 4 7500s, 2 currently) is not capable of "critical" registration tasks, such as business cards. The Phaser is not a good fit for most production print environments, I would suggest a more robust production level printer. The Phasers are really just a glorified office printer, for printing presentations and envelopes and such. We only use the Phasers for special applications, the registration spec is + or - 2 mm per side of an 8.5x11 (this spec increases the larger the sheet size, for SRA3 it would be + or - 4mm or so). So your machine is likely in spec, the hardware itself is just not capable of what you are expecting.
we bought a phaser 7800 printer about one month ago.
We are a digital print center established in Greece and one of our main jobs is printing business cards.
For printing business cards I specifically bought the Phaser 7800.
To print the business cards I impose the card on a professional s/w and export to PDF.
So I have a 20up SRA3 image ready to print at a velvet paper at 350 gr. The problem is that when I print 20 copies of this image I constantly have different distances from the end of the paper to the crop marks. For example the first copy has a distance of 1,5 cm from the end of the paper to the crop marks, the third copy has a distance of 1,3cm, the 5th copy 1,1cm and so on.
From that you can understand that it is impossible to cut the print outs all together into business cards and obviously I can't deliver to my customers a correct product.
I need your help on this, since I have already done everything that the troubleshooter describes but without success.
Thank you in advance and I will be expecting for your help and support