Epson 4900: No ink Getting to Head

[EdRoberts]

I am trying to fix a faulty Epson 4900 printer I rashly acquired. The printer appeared completely clogged and shows no output on a nozzle test pattern. I removed the head and about half the colours were blocked. I tried de-clogging it gently using the foamed head cleaner-and-syringe technique which seemed to work judging by spraying distilled water through. When I replaced the head the test pattern was still completely blank.
Thinking that the previous owner must have fried the head with multiple cleaning cycles (the maintenance tank was 80% full but the printer hadn’t done many prints), I replaced the head with a new head ($ ouch!), performed a clean (level 2) as advised in the maintenance manual to charge the head with ink – still nothing at all. Looking at the ink lines from the capping station to the maintenance tank, they seemed suspiciously clean, and they were not blocked. I then weighed each of the ink cartridges in the left bay, and the maintenance tank, and did an ink charge on the left hand side. Still nothing, and there was no change in the weight of the ink cartridges or the maintenance cartridge (using electronic scales with 1 gm resolution), so no ink seems to be moving around at all.
I removed and looked at the damper assembly from the side, and the dampers I could see seemed clear (compared to damper clogging experiences with my 4880). So, my question is, what is the likely fault? Should I replace the capping station and its pump, or the damper assembly, or is it likely to be somewhere else, eg the decompression pump (whose function I don’t understand, given there also seem to be pumps in the head and the capping station, and the maintenance manual is sketchy).
Thanks,
Ed

[Mark D Segal]

If I remember correctly there is a way of doing a complete reset so that you can then recharge the printer as if it were a new machine. This way all the air is removed from the system and the ink flows through to where it belongs. But you need first to be sure that all the components in the ink delivery system are reassembled exactly right, otherwise you will have continuing problems.

[John Caldwell]

With the 4900, much of what I thought were clogs were not clogs, but were air entrainment that mimics all nozzles "clogged". In the end, we risked the expense of a capping station replacement, as an out of warranty expense, but it solved our problems. In retrospect, many episodes of "clogs" weren't clogs at all, with our machines, and in my opinion. Your description of "no ink getting to head" may be entirely correct, although I suspect air can be retained in the head itself. This point is my opinion.


Others may disagree, and others will know more than i do, but I've had too many experiences with our three 4900 machines to believe that *nozzle clogs* are as actually not prevalent as reported; and that capping station failures are in fact a leading cause of air entrainment that leaves the nozzle check full of holes, or blank altogether.

That the 4900 is crap. in terms of reliability, gets no argument from me.

John Caldwell

[Mark D Segal]

Mine was quite reliable for several years, then started to be cranky even under sustained usage (e.g. printing every other day or so); at that point I had both the capping station and damper replaced and a general cleaning done, and since then it is behaving quite well again - taking into consideration that to get trouble free printing from this machine the required operating mode is to make real prints at least every other day or so.

[EdRoberts]

Thanks for your comments and feedback. There didnt seem to be air in the lines leading to the damper assembly, and visually the capping station looks ok (ie the seals that face the underside of the head are visually clean and intact). The damper assembly seems to sit snugly onto the head and is locked down with its various screws, so hopefully this is airtight. The decompression pump rotates by hand, although that doesnt mean much by itself. It sounds like the next step is to get a new capping station. I have a spare set of refillable cartridges so I can use head cleaner rather than ink while trying to resolve the problem. Ed

[EdRoberts]

Update: I have put in a new capping station, run the initial fill for each side (I did the right side twice because of an error message glitch during the first attempt) and now I have ink in 7 of the 10 heads; cyan, magenta, Light black, orange, light light black, yellow (some blocked nozzles) and light magenta. Black and light cyan have no ink and green has a couple of lines visible. I suspect the almost complete absence of output from PK, Gr and LC indicates the dampers should also be replaced. Agreed? In the mean time, I have used up a new maintenance tank, so I am waiting for another to arrive.

[Mark D Segal]

Without actually being technically qualified and able to see the mechanism in your printer and knowing HOW you did what you did it's impossible to agree on what next step will completely resolve the issue. My experience on my 4900 is (said above) that I had to have the capping station AND the damper replaced, done by a very well qualified technician who knew exactly how to re-seat and re-seal the whole ink path so that air doesn't impede flow. Then it took a fair amount of cleaning (powerful cleans) and checking to bring all the channels into normal fill.

[EdRoberts]

Thanks for the helpful responses to my questions. I now have (for the moment?) a working 4900. The dampers, which I replaced, were probably OK, I had not fully removed the air from the bladders of a couple of the refillable cartridges although I had primed them. That probably caused the blank channels rather than blockages in the dampers, but regular replacement is suggested anyway. Now to get back to photography, rather than maintenance ....

[Wayne Fox]

indicates the dampers should also be replaced.

We always replace the dampers when we replace a head if the machine has seen normal usage.  We also usually replace the capping station ... doesn’t make sense to put in a brand new head and then leave in things that also guck up over time.