A real stumper for me. Been printing k7 in 2 identical 7880’s for a long time. One is loaded with a Selenium ink set , the other a Carbon set. Both printers were acquired used, the selenium one had much less mileage than the carbon one but both are in excellent condition and currently appear to have perfect to virtually perfect nozzle checks. Attached sample does show the carbon one is missing a single nozzle line in shade 5 but otherwise perfect. Also sample shows both nozzle check prints show the exact same density
for each position , as far as i can tell. Both printers are used virtually everyday and almost never have any clogs. Any occasional clog gets cleared right up with a single head clean. The problem , recently being observed, that an identical image file sent to both printers, over a network from 2 different computers, are not matching very closely at all. Traditionally they both always did and outputs always match monitor display , with the correct soft proof profile enabled. The selenium is still an excellent match, in resolution, tone, contrast, etc. However the Carbon one is not even close anymore. As samples show Carbon output has what appears pixalation of some sort in midtones. Seems to be a dropout of density creating a blotchiness. I thought that maybe the computer sending over the network to the carbon host computer was losing data somehow so I temporarily changed the ip address of the carbon printer to that of the selenium and printed the same exact file with the same exact settings, curve as I had just printed to the selenium and the the output was still exactly the same as before. I’m pretty sure that I’m not dealing with incorrect curves or QTR driver corruption. I’ve since deleted and reinstalled QTR for the carbon printer. Also see sample 100 step tablet. Too me this also looks like identical density values, just different tone. Am I correct to assume that the carbon printer’s shade positions are all correct. All the tests are on type 5 and image files are from scanned b/w films. Print files are in greyscale , test outputs are scanned RGB to show tone color. Sample from larger format film is better resolution even in carbon sample than the other one from 35mm @8000dpi scan. I’ve always used your canned curves, with excellent results. Is it time to get custom curves for the carbon printer because the print head is starting to show it’s mileage compared to the other printer?
Both printers get about equal usage but at different times. Should I send the sample materials in for a closer examination? Or are the files have enough information.
Thanks for your thorough explanation. Makes it easier to trouble shoot and get right to the point of figuring it out.
I think it would benefit if you sent these into Technical Support at InkjetMall, 17 Powder Spring Road, Topsham, VT 05076
Please add to these,
Calibration Mode print out of the Inkseparation file for each printer.
21 step grayscale print on paper with correct Piezography curve for each printer
(please confirm the 21 step is at 5% increments before printing).
From above we can check integrity of your inks.
The blotchiness looks like to me that your carbon printer possibly has settled pigment as its printing darker in the mid-tones and 1/4 tones. Probably elsewhere, too. We would measure the density of the 60% patch for each of the inks.
If the inks are darker - then why? Age, contamination from mis-filling cartridge, mis-filled bottle (very very rare but possible), sitting in printer? Have you tried removing the carts and shaking them, reinserting and running the INITIAL FILL to freshen the ink lines and dampers with ink?
If the inks are okay in the cart (densities correct) - then it gets more difficult to trouble shoot. Perhaps your print head is decaying. Perhaps a re-linearization of your curves using the new QTR .quad linearization droplet will work, or a custom curve. Perhaps a fresh install of both the Epson printer driver and QTR will help. If the inks are correct, you may have to look in strange places for a fix. The 7880 is worth the rebuild. It has a significantly longer print head life than the newer Epsons. But that’s only after exhausting whether your ink system is confirmed.
Thanks Jon,
I did reinstall both QTR rips and even switched the host computer. All computers in network running OS 10.4.11 tiger. Never ran 7880 epson driver because it’s not supported. Do a cart shake periodically but not a INIT Fill. Will try and also send in the above mentioned items.
whew, INIT FILL did the trick. Virtual match to selenium printer, blotchiness all gone. It looks like If I want a closer match I’d probably would need a custom curve made to correct the older more used print head to bring it in alignment with the selenium printer. Important thing is I’m back to a high standard on the tone that was being requested for an upcoming exhibit. Without your quick input , late last night, come Monday I was going to tell clients that their work would be better on selenium, for “esthetic reasons”. I intended to upload the nozzle check yesterday but overlooked it. Sending now, looks like after the INIT FILL the carbon printer does have 2 dead nozzles in shade 5, oh well. Would it still be of value to send in samples to determine if any closer match could be accomplished with a custom curve build? Again thanks for your valuable and quick input. Wasn’t able to upload nozzle check for some reason.
Jon,
What threw me was the excellent nozzle check, always thought that was the best check for print head performance. Now I know that’s not the whole story.Words to the wise.
I’d have thought that trying Roy Harrington’s new “droplet” for relinearising curves would be worth trying first. If expect that if both curves for both printers were successfully relinearised, then the printers should be a close match.
Hi Mark~ I’m glad to hear your output from the two printers is matching again after charging your printer.
For the future, I recommend printing a 21 step strip and checking the linearization of your output from both printers. After confirming output from both printers is good and the same, print an Ink Separation chart thru Calibration Mode to have a reference chart of “known good” output. These two things will give you a solid base point for comparison if things ever look off again, you can simply reprint the two test files to determine where the problem lays. Regular agitation of ink carts and use of the printer will help maintain in-suspension pigment for consistent output. Instructions for printing the Ink Separation image can be found here: http://www.inkjetmall.com/tech/content.php?144-Print-Ink-Separation-Image-thru-QTR-Calibration-Mode
Thanks for your comment Brian, but if inks aren’t printing correct density due to settled pigment, then relinearizing using QTR droplet will only be a temporary solution by making a new curve to try linearizing the incorrect ink density, and not actually fix the cause of the problem.
Quite true, but I was responding to #5, my reading of which suggested that those density issues had been resolved, and the OP was after “an even closer match” between the two printers.
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