Intermittent nozzle fallout

Have a K2-1000L CET flatbed printer that has intermittent nozzle fallout. I think that the issue is because the printer is exposed to too much fluctuation in temperature and humidity. It is basically in a small warehouse adjacent to a garage door that exposes it to the outside periodically through the day as shipments come and go.

The unit tends to have issues with banding when printing large areas of solid colors, and when shown to the lead tech he says it looks like the heads are losing nozzles. When we run a nozzle test, it sometimes shows all nozzles and sometimes shows nozzle loss of nearly all a specific head. Often these tend to be one or two heads in particular but not always. We have purged the the ink through the heads, checked for air in the lines, bled the lines that lead to the affected heads (at the time of specific failures) and adjusted the negative pressure numerous times.

It seems like the printer will work for a while without issue, then when we get a heavy workload in will start banding when it has to print a large area of solid colors.

I don't know for sure if I am approaching the problem correctly or not, as I have about 6 months or so experience with the machine, and no experience with other large format printers before that.

I would think though that if there was no blockage in the lines or heads that it would have to be the negative pressure not at the correct setting for there to be nozzle fallout. The machine has been calibrated numerous times by the technicians from CET, and when its not banding will print the quality check print seemingly to perfection on high quality setting.

I have photos of the banding and the various settings I used when it was banding, which I will post as soon as I get to work and have time to do it. I am hoping that someone here can at least point me in the right direction here as this problem has been a chronic issue since this brand new machine
was installed a year ago.

More to follow.

 

The picture on post two shows the banding I was talking about. This picture shows how I tested the negative pressure setting and compared the results. Unfortunately the banding is not showing up in the picture as well as I had hoped. The banding seems to go down as the negative pressure increases.



I just need to make sure that this is what is actually causing the issue (negative pressure). I don't want to be going through all this every time it starts to band when I can't prove that it is a change in temp and humidity is affecting the negative pressure equilibrium within the system. Also we have had no shortage of different explanations of what is causing the printer issues, and the owner wants to know and understand unequivocally what the problem is.

It would also be nice to come up with a solution so this is not such a problem. We have discussed humidifiers but really want to make sure it is necessary to get before spending more money.

 

The company is also looking for a humidity and temperature logger that can plug into pc for monitoring. I found this:

https://www.amazon.com/ECOWITT-Temp...ix=humidity+and+temperature+lo,aps,102&sr=8-9

I wanted to save money but don't want to go so cheap that we're buying junk.