Somewhere recently I saw a discussion about banding on the Z6100. I have a similar problem, in that the banding starts part way thru the print, on both my Z6100 and Z3100. Diagnostic print shows no printhead fault, printheads are in warranty. This is a recurring problem and even happens with NEW printheads. Thewe printers are only a year old. HP doesn't have a solution, only to keep sending new printheads. Anybody have a REAL solution??? Please and Thanks!