7900 clogged green nozzles: ? head failure

[MarkJohnson]

My 2nd post here! My Stylus Pro 7900 is 4 years old & has made just 1192 prints. A few clogged nozzles in the green channel appeared recently which haven't cleared after several O/G pair cleans in normal mode, several SC1 cleans in Service mode and all 4 levels of O/G pair cleaning in Service mode. Along the way, I also cleaned the wiper blade, following Eric Gulbransen's video. I also tried printing to A3 an image of green foliage. The pattern of clogged green nozzles hasn't changed, despite all this. All other channels look 100% fine on the nozzle check print. I haven't yet tried the SS clean partly due to Eric's caution on this & partly because I would be surprised if it worked when all the above haven't.
Despite this, the 7900 seems still to be printing normally, so far.
Does the attached close-up of the green channel nozzle check look more like a head failure, or should I try an SS clean?

[BrianWJH]

Does the attached close-up of the green channel nozzle check look more like a head failure, or should I try an SS clean?

Not sure Mark, however it looks like there are many deflected nozzles, have you had any head strikes prior to the green channel dropping nozzles in the nozzle check?

Do all the nozzles checks since discovering the issue display the same pattern as the one you posted?

What media have you been using?

Brian.

[MarkJohnson]

Thanks Brian. No head strikes. The lower right defects appeared first, then the rest. The defect pattern has been the same for the last 4 nozzle checks. I use Ilford Gold Fibre Silk.

[Paul2660]

So far you have tried everything else so doing one SS cleaning is most likely is good idea.  You might try soaking the head in the inkjet solutions fluid first.  The is a post on this site started by Dan Berg that talks about it.

I don't think it's a damper issue based on the type of clog pattern you are showing.  I agree you have a lot of deflections so it may be actual material in the nozzle. 

Paul C

[BrianWJH]

I don't think it's a damper issue based on the type of clog pattern you are showing.  I agree you have a lot of deflections so it may be actual material in the nozzle. 

Yes I agree, if there is no physical damage then it may just be an accumulation of dried ink and paper dust, so a head soak would be a good idea.

Brian.

[MarkJohnson]

I don't know which inkjet cleaning solution available in the UK would be compatible but I'll investigate. I wouldn't want to worsen the problem especially as the 7900 isn't yet producing flawed prints.

[Paul2660]

You bring up a good point, if you are not seeing in banding at all even with the defected nozzles, you might be best to keep on printing until the issue becomes visible in prints. 

The green and orange use in these printers is very very very low, I am still on a 150mm set of carts from 1.5 years ago, and have gone several sets of 700ml on the other colors.  I guess if you have to develop this the green and orange are the best places for sure.

Paul C.

[davidh202]

You bring up a good point, if you are not seeing in banding at all even with the defected nozzles, you might be best to keep on printing until the issue becomes visible in prints.  

The green and orange use in these printers is very very very low, I am still on a 150mm set of carts from 1.5 years ago, and have gone several sets of 700ml on the other colors.  I guess if you have to develop this the green and orange are the best places for sure.

Paul C.

I agree with Paul.
I just replaced my green and orange carts -that were still indicating 1% and nearly two years past date. Figured I'd better not chance leaving them in any longer. Kind of sorry I purchased the 7900 but the 7890 was not yet offered. When I added the 44 inch, I got the 9890 instead of the 9900, since the Green and Orange were really not necessary for general photographic purposes.

   Let it be for a while, don't do any SS cleans, as it may actually do more harm.   Try raising the humidity. It may work it's way out on it's own  Don't use Windex
 If you have only cleaned the wiper it may be prudent to get a replacement and put it in .

David

 
  

[MarkJohnson]

Thank you David. I replaced the wiper blade assembly last year. No Windex or its UK equivalent, but maybe Dan Berg's idea of a soak with a compatible inkjet cleaning fluid could help without causing further problems?