540v Banding & Dropping Ink

[thestickerman]

My 540v is banding magenta into the yellow. Cleaning will fix the problem but not for long. On the test print there is three lines of yellow at the back of the head that are being infected with magenta, so on both passes the infection is clearly at the back of the print head.
The problem is increased if I put registration marks down. When the registration marks are being printed, the magenta is dropped on the job as the carriage returns for the second pass, it's like the magenta is leaking and the quick movement of the head when it returns for the second pass makes the magenta drop onto the job. This doesn't happen when the carriage returns at the other end.
When this happens the magenta infects the yellow entirely and the banding is massive when the job is printing after the rego marks have printed.
I have tried everything with no success. I have cleaned the head area from hairs that may be catching ink, I have tried all manners of test prints with a number of cleans and nothing fixes the problem. Even the tech that has worked on the machine can't fix it.
I am desperate to find a solution to this as the machine can't be used in it's present state.. Help

 

[nsgraphics]

For start try to check if your cap tubes are clean and open. The usual problem is because of the common cap the pressure difference from yellow and magenta cartridges affects the balance between the two head colors. if the way to the waste is clear then usually no problem. it also happens some times when one cartridge is full and one is empty.