K7 MPS prints suddenly too dark


#1

I’m somewhat stumped. My 9890 K7 MPS printer with selenium inkset is printing too dark. Prints were fine and now suddenly print about a stop too dark. Printing from dedicated Win 7 laptop using QTR.

I have agitated all the ink carts and reinstalled. I’ve run several power cleans, followed by nozzle check and a test print----in thinking that the issue was pigment settling causing dark prints. It might be my eyes playing tricks on me that subsequent prints appear ever so slightly lighter, but hard to say. Not sure where/what else to check. Files being printed are not new so it is not an issue with files with conversion error.

I moved the gamma slider within the QTR interface to -4 and print looks much better—about right.

Any ideas or suggestions?

ken


#2

Hi Ken~

If your prints were fine, then suddenly started coming out too dark, then I also suspect settled pigment, but have a few questions to help troubleshoot.
When were any carts last refilled?
Do you know which carts were last refilled?
How often have you been agitating the ink carts?
How often is the printer used?
What are the humidity and temperature levels in your printing environment?
Have any updates been done to your computer between when output was good then dark, such as OS, Photoshop, print driver, etc?
Have you shut down both the computer and printer at the same time, then restarted to refresh your system?
After agitating the ink carts, about how many power clean cycles did you do (how many is “several”)?
What paper(s) are you printing on?
Are you using paper from an existing box/batch, or did the problem start after opening a new box/batch of paper?

Please let me know so I can help you get back to happily printing.
Thanks~ Dana :slight_smile:


#3

Hi Dana,

My sense is that it is from pigment settling, but I really don’t see much or rather no difference after agitating all cartridges and at least four power cleans, with nozzle checks in between.

I had not been using the printer as much as normal, but still checked on it regularly. Carts were refilled probably about two months prior. Humidity levels are pretty constant in the 50-60% range, and temps around 65F. No updates to o/s or drivers. I use a dedicated laptop Win 7, and print directly from QTR. Both printer and computer have been shut down and restarted several times over the course of this printing issue. Paper used is Cone 5—same roll.

It just seems a shade too dark----comparing the same prints, same files. Otherwise print quality remains excellent… Nudging the gamma slider in QTR to lighten midtones seems to do the trick, but not so sure I should be playing with that slider!


#4

Hi Ken~

Sorry for not getting back to you sooner, somehow your last message got lost in my email…

Power clean cycles don’t move much ink thru the lines with the 7890/9890 and 7900/9900 printers, compared to previous models. For example, with the 7880/9880 and 7800/9800 2-3 power clean cycles is enough to move ink from cartridges to the print head, but you would have to do dozens with the newer models to move ink the same distance (so, power clean cycles are less powerful with the newer models).

What is your current status- is your output back to normal, or are you still struggling with dark output?

Please let me know, thanks and best regards~ Dana :slight_smile:


#5

I think I’ve got a handle on the dark prints, and all is headed in the right direction-----except still having to deal with that frustrating at times----GO issue on the 9890. The only thing I’ve found to is try and load the darkest portion of the image into the printer first and cross my fingers when applying the GO. Not exactly satisfying. I hope you have good news for us soon on that RIP…

ken


#6

I’m glad to hear you’ve got a handle on the dark prints. We will certainly make an announcement if all goes well with this new RIP testing- keep your finders crossed! :slight_smile:

Warmly~ Dana