Has my 7800 sung its last serenade?

[totowolff]

Hello!

Thank you all for your help, unknowingly, up to this point.  This forum is a frequent source of help for my printer woes.

To cut a long story short, I can't get the nozzles clear on my 7800, and whats even more maddening, my attempts to clean it made it even worse.

The process of cleaning went something like this

Line of nozzles on LK clog > clean head 3 times > power clean > supersonic clean > windex treatment.

Nothing worked.  So I thought what the hell, nothing to lose, found the service manual online, removed the head and gave it a clean with some amonnia solution and a paper towel.

Now looking back, I see that it may not have been the smartest thing to do, but hey, a printer that prints with permanent banding is as good as no printer at all right.

So my question is, how do print heads end up completely ruined?  What actually occurs?  Is it physical damage to the head, bits of paper towel blocking it, or what?  Its definitely not dried ink, but I have no idea.

The printer was second hand and wasn't expensive, and I have a 9700 now, so if it can't be fixed I won't cry, but it is rather annoying and would be great if there was a way to fix.  (aside from a new printhead, which costs £425/$700, more than the cost of the printer!)

Thank you in advance for any help anyone can give!

[BrianWJH]

Missing colours in a nozzle check can be caused by more than just the printhead, other items to check are:
Ink damper clogs, did you visually check these for clogging when you disassembled the printhead?
Ink cart(s) of the offending colour, check for pressurisation leak, low ink levels or cart valve issues, swap with known good or new cart to test.
Air or pigment clumping/settling in the Ink line, visually check with a torch.

Brian.

[totowolff]

Thanks for your advice,

I didn't check for damper clogs but the nozzle check went from having about 5-10 nozzles out before i took the head off, to having at least half in each channel missing afterwards.  The nozzle check is a mess, some of the lines aren't even printing all of the correct color.

I did an initial ink charge to eliminate air in the lines etc.  No such luck, nozzle check was identical afterwards.

[BrianWJH]

I did an initial ink charge to eliminate air in the lines etc.  No such luck, nozzle check was identical afterwards.

How much ink did the Initial Charge put into the waste tank and did you see a drop in the ink levels?

The best way to test the ink delivery from cartridge to damper outlet is to use a syringe inserted into the damper outlet where it mates to the printhead nipple and while manipulating the ink bay lever suck ink into the syringe.

This link with part 1 and part 2 videos shows the correct method although it's for an Epson 4880 modified for Direct to Garment printing, the process for priming ink from the cartridge to the ink dampers is the same for your 7800, note that moving the ink bay levers correctly is important for this to work.

Brian.

[totowolff]

Oh yeah, its put over 200ml in the maint. tank! Crazy stuff...

Ink depletion in the carts happened accordingly.

Do you think thats what it might be?  Like i said the major nozzle block only happened after i removed the head.  Everything was fine bar 5 nozzles prior to that.

I ran Super Sonic cleaning and all sorts.  If there was no ink in the head at the time is that likely to have fried it?

[BrianWJH]

Oh yeah, its put over 200ml in the maint. tank! Crazy stuff...

That, good.

I ran Super Sonic cleaning and all sorts.  If there was no ink in the head at the time is that likely to have fried it?

Not sure, first I would make sure that ink is flowing from the cart to the damper outlet for the missing colour(s), until you know the answer you can't rule out ink delivery problems.

The previously mentioned videos also show how to flush the printhead with flushing fluid, Jon Cone from InkjetMall sells the fluid (Piezoflush), American Inkjet Systems also sells flushing fluid.

Brian.