Diluted ink darker than undiluted ink

[Guilherme Maranhao]

My first post was about getting the T511 cart open.
I was able to collect all "Epson Archival Ink" Black Ink from within. This is a beautiful warm tone ink, mostly carbon, enough to print for a long time.

I'm converting an Epson 4900 that was headed to the dump to a B&W printer. K channel seems dead.
I ordered refillable ARC carts, made up C6a base and diluted this ink into 2%, 6%, 9%, 18% and 30%.
I decided to use the left side of the printer (6 carts) for the entire inkset and undiluted ink was placed into the OR cart.

1 initial charge down the road (for the left side only) and I had all diluted inks working properly, but the undiluted ink was brighter than 30%, it has some dark spots, but it is mostly banding throughout the entire %s - using QTR's inkseparation file. Beautiful nozzle check nonetheless.

I introduced 5% base into the 100% cart, turned it over a couple times and did one more initial charge. No change.

Introduced another 15%, making it 20% C6a base, then I didn't have space for another initial charge (resetter is somewhere between China and Brazil), so I printed around 20 A4 full area purging OR channel using the appropriate file from QTR. One manual clean of both GR and OR. 7 or 8 nozzle checks all perfect. Still no change in banding.

Air bubbles in OR nozzle?
OR nozzle bad for K ink?
Bad damper? Should change the channel?

 

[Ink stained Fingers]

You state that you get a clean nozzle check but prints show banding, this could be a sign of a restricted ink flow e.g. by a clogged damper. How does a print look if you print just a gray scale ramp - from white to black - or a step wedge with 5% lightness difference, with basic driver settings - no QTR adjustments in between. Please post the nozzle check and such a print for comparison

 

[Guilherme Maranhao]

First the entire inkseparation10.tif

The printer is missing Black Ink, so I made notations by hand for each channel. The next column is whatever ink is installed in the channel. Cyan, Magenta and LK have leftovers inside the hoses, so this is why they are printing.
On the left side you can see the nozzle check on the this same piece of paper.

This is a detail of the above sheet of paper showing how the OR channel is printing. It shows this same problem from 0% to 100%.

(On a side note, comparing to LK, you can see the warm tone given by this ink. I love it!)

I have been thinking that once my resetter arrives, I hope in a week or so, I could flush the entire right side and then install 50%, 60% and 70% on C, M and LK to see if it works better. It could be simple incompatibility of ink.

 

[Guilherme Maranhao]

BTW this green and magenta mess in the LLK channel is mostly Flickr compression, the actual print has nothing of that sort.
After the first initial charge, the 9% channel was kind of Yellow still, but that was gone on the second initial charge.

 

[Ink stained Fingers]

I'm not that familiar with the Pro 4900 , I was running a Pro 4000 long time ago.
You are missing the black channel altogether, I guess you googled already for something like this ' Pro 4900 clogging' or similar
and got here
http://www.photodady.com/blog/2014/11/18/epson-stylus-pro-4900-fixed-print-head-clog/
or here
http://www.nwpphotoforum.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=40109
Your orange channel seems to suffer from another problem - most or all nozzles are printing but the droplets are deflected somehow sideways, this should be visible as well when looking to the nozzle check print.
It seems that there is some deposit along the rim of the nozzle opening causing this effect, this happens as well with
other Epson inkjet printers, longer print cycles with a cleaning fluid reduces or fixes that in most cases, as well the soaking
of the printhead from underneath with a cleaner for a while, but it is coming back after some time.
If all that will not get your nozzles working o.k., you might go the next step and get a service manual to see how to get to
the printhead , removing and replacing the dampers and cleaning the individual ink channels with a syringe and a short piece of
tube pulling and pushing a cleaner into every affected ink channel.

 

[Guilherme Maranhao]

This second link is crazy, a lot of things you shouldn't do to a X900 head and on his last update he says he placed the printer next to the heater. No no
I know of people who cover them in plastic everyday and leave a tray with water inside, just to keep the printer in a humid environment.

 

[Guilherme Maranhao]