There are multiple issues with your printer. For the 49mm banding you must replace the drum cartridges. For the defect like staples you will need a tech to clean the transfer module ( IBT assy ).
For upgrading the machine software to the latest, also you need a tech because this involve a special procedure ( AltBoot method ) to go trough a bridge software which is not public available and finally to upgrade to the latest.
I have got last week second hand Xerox Phaser 7800DN printer what was manufactured on December 2013 y. Printer page count about 85.000.
When I tried to test the printer I figured out that it`s printout contains very visible vertical lines all over the page. Distance between the lines are about 49 mm.
I took some photos of my printer printout.
I looked the fuser unit carefully, it looks visually very good. I cleaned the LED-printheads, no changes.
Printer firmware is 081.150.103.05600
Is it possible to upgrade the firmware through USB connection?
Maybe someone have a clue what may cause such a print quality problems?
Thank you very much!
Best regards from Estonia,