Today I looked at this HP M775dn in North East London near Walthamstow. Customer reported a fault regarding poor quality printing, on inspection I noticed that the image transfer belt was damaged and causing banding marks on the paper. So recommended that we change the transfer belt which resolved this issue. If banding marks appear cross all colour prints of your machine it is more likely to be either the transfer belt or fuser unit. It can also be the transfer roller. This HP M775dn printer is a great eliable business printers with the majority of faults coming as result of faulty consumables. For this reason we always recomended using HP original drums and good quality compatible toners not the cheapest you can buy online. These will minimise printer repair callouts.