Designjet Z3100ps - Light Cyan & Gray problem

... and sometimes Light Gray also.
We are not heavy users, but have had it since 2008 when it was a new model. This printer was overhauled within the last year. They changed a whole lotta stuff including all the heads, the drive belt and some part/unit that came in a box the size of a small microwave . All was well ... it was like a new printer !
Anyway, lately I am getting/canceling a bad print job because I could see it was coming out bad ... and after printing the diagnostic print finding that Light Cyan and Gray, and sometimes Light Gray were suddenly blank for very weak/streaky.

I would run the head clean function for those colors and then print another diagnostic print. I was finding that it would sometimes be better, sometimes not. After a second round of cleaning and printing the diagnostic, I fount that LEAVING IT OVERNIGHT and then printing the diagnostic the next morning resulted in A PERFECT PRINT.

However, after printing a single glossy print (A2 size), it was again giving the same problems with Light Cyan, Gray, sometimes Light Gray (as shown in a diagnostic print.

There are no error messages.

What does this sound like?

Thanks.

 

It sounds like an intermittent head/nozzle problem, or a pressure issue in the hoses that deliver ink. I've never been extremely satisfied with HP wide format (at least not at the lower end) - however they do come at great print, and offer decent print quality for it.

It's peculiar that leaving it overnight makes the issue better. Usually idle wide formats are a recipe for disaster.

If color was completely absent on the head cleaning and/or calibration test, there's something not quite right with the print head.
If you have a new head available (i know they're quite costly) or even perhaps a used one, to briefly swap them out and see if the issue becomes resolved.
Also, carefully try reseating the existing print head, perhaps it's not mounted properly, or maybe a previous jam or disheveled media knocked it out of place.

Also HPs tend to have issues when the ink cartridges are very low. Or, perhaps even defective (it happens).
If the grey cartridge is near empty, try replacing it. Or, replace it anyway to see if the cartridge itself it not depositing ink properly.

That aside, if the printer is not in use on a daily basis, I would run the calibration on the days it may be idle. just to keep ink flowing.
I recently switched the Canon Pro4000s devices, and they have a neat feature that drains the print head, and purges the hoses and nozzles. I have yet to have any issue with the device since purchase. Plus, it's prints absolutely beautifully.