I have changed the ink in my 9890 printer utilizing a set of inkjet mall cartridges. Prior to the change I replaced the ink selector unit. The ink change worked without a hitch but I am continually running into an issue with the Cyan and Vivid Magenta channels.
Each morning I have either the Cyan channel or the vivid magenta channel missing dots in the nozzle test. I perform a ink channel pair cleaning and it resolves itself for the rest of the day. The next morning I perform a nozzle check and either the Cyan channel or both the Cyan and Vivid Magenta channel are missing dots. I then do the cleaning and it is resolved.
I have removed the ink cartridges one at a time and this does not seem to help.
On two occasions I have done an powerful cleaning on the pair to see if that would have some long term results, but no.
I have not had issues with any of the other channels.
Any ideas on why this is occuring?
9890 and 9900s can be trouble-some for a whole host of often frustrating and compounding reasons. In this case you most likely have some debris in your head channels that is causing some very slight back-pressure when the head is resting. This is causing a slight contracting of the ink at rest and a few nozzles out in the morning.
PiezoFlush has a bunch of surfactants that get around debris like this (ideally it causes the medium and smaller debris to fully eject from the nozzles, but it can’t fix the larger debris) so it would show a good nozzle check while larger pigment inks would not.
I would simply continue to do 1 normal channel pair cleaning each morning. If permanence is not a consideration a dye ink like InkThrift Pro would get you a good nozzle check most likely as there are no pigment particles needing to work their way around the debris.
sorry for the bad news, I wish I could offer a full solution sans replacing the head/damper/cleaning assembly but I can not in this case.