Need Help DesignJet z6810 printing light band at front head of each print

[KellyP12]

Title is my issue... I replaced the Magenta-Yellow print heads in my HP DesignJet z6810 on Tuesday, and it seems like since then, when I print anything from our normal Onyx RIP, no settings having been changed, the front 1" or so will be a lighter color than the rest of the print. In darker prints you can't see it very much, but in light colors it's like night and day.

It seems to do this on the 'leading edge' only, and my workaround has been setting Onyx to print 'Group Jobs Together,' and then let all the signs I need to print go in one 'batch' (i.e. turning the 'Print All Rows at a Time' setting on). And I will run a dark colored strip in front of the first print, so this issue messes up the bar, but doesn't encroach on my other prints. Aka if I queue up 12 signs it will only do this on the 'head' of the batch, but the other 11 behind it would be unaffected.

Any idea what's going on? These errors are not in my artwork. I am just thinking because it only started once I changed printheads that maybe the alignment is faulty or the heads aren't firing for the first few passes and need to be tossed/replaced.

 

[Steenland]

My Designjet Z6100 has been doing this for a while, though not as dramatically as yours. Mine shows up in light blues and reds mostly, and only happens at the leading edge, before all the nozzles are firing (before the media starts advancing.)

As you have discovered, it does not happen with subsequent prints if they are queued up and ready to print before the printer has a chance to rest after finishing the first print.

My machine is almost ten years old and has been doing this for a couple of years. I tried to resolve it for a while, but now I just do what you are doing, adding a 1" strip of any light color before the leading edge of the first print. I'm nearly positive that this is a mechanical/printhead issue, and not a software/RIP issue.

If anyone has an actual resolution to this, I want to know too!

 

[KellyP12]

[redacted, see below reply]

 

[KellyP12]

My Designjet Z6100 has been doing this for a while, though not as dramatically as yours. Mine shows up in light blues and reds mostly, and only happens at the leading edge, before all the nozzles are firing (before the media starts advancing.)

As you have discovered, it does not happen with subsequent prints if they are queued up and ready to print before the printer has a chance to rest after finishing the first print.

My machine is almost ten years old and has been doing this for a couple of years. I tried to resolve it for a while, but now I just do what you are doing, adding a 1" strip of any light color before the leading edge of the first print. I'm nearly positive that this is a mechanical/printhead issue, and not a software/RIP issue.

If anyone has an actual resolution to this, I want to know too!

Well, update! All it was was an over-used pair of Matte Black and Chromatic Red heads. I have been really busy lately and thus haven't been keeping up on checking the status of our heads. I usually replace them when they hit 100%, and this time the front panel of the printer told me 'printheads in slot 7 will need to be replaced soon before print quality degrades." or something like that. When I checked in the Embedded Web Server it showed they were both around 150% of their normal usage. So I replaced them with new ones and voila, the banding issues went away. That's as simple as that!