Intake seal wear issues?

[mikling]

Over the years I have come across an issue that I could not figure out but something has come to light.
Here it is. I have used printers and then put them away for a period and then brought them back out for reuse again.
When brought back out, sometimes a printer will give some trouble in the nozzle check pattern. The same printer when used regularly does not give trouble.

One time, after servicing a printhead, I reinstalled the cartridges WITHOUT those inlet seals and the printer worked perfectly. I did not notice that the seals were missing until I found them in a little cup I had placed them in. This was on my Pro9000.
This tells me that the printer can work WITHOUT the seal sealing.

Then one day I brought out a printer and noticed that ink had dried up on the outlet felt area.

So this is what I think could be happening to those printers that are put away perfectly fine but when starting again after a period of rest, gives trouble. The rubber seals that the cartridge sits on are actually letting air in and allowing ink to dry in the outlet of the cartridge. This impedes flow of ink into the printer...giving bad nozzle checks or banding. I'm even wondering if by purging, we are actually washing out the outlet filter at the same time and if in fact this might the cause of the flow issue.
On new printers, I can put them away for weeks and months and not have a problem at all. On older printers is where I was hit with occurrences....the older printers had worn or weak seals....that is my theory.

On a regularly used printer, the flow of ink prevents drying to cause issues, so even if the seal is worn, you won't experience problems. However, when it is not used, the dried ink will become concentrated in the outlet sponge AND possibly in the inlet of the printhead. The inlet of the printhead has a very fine porous filter material and clogging can actually occur there as well.

Rodbam, this could be what happened to your old printhead on your Pro9000. I got hit with the same thing a earlier this year.

These are my thoughts anyway and I could be wrong but it is worthy of consideration and could explain issues that some have faced.

 

[turbguy]

...good theory. Ink will dry and impede flow at that critical juction between cart and printhead.

 

[rodbam]

There could be something in your theory Mike because I remember the cart on the problem nozzle having dark gungy bits on the outlet sponge that I picked off with a needle. I installed a new refilled cart but the poor nozzle check continued. I wish I hadn't destroyed the old head now because the stray ink I found on around the print screens that I put down to blowing the gaskets when cleaning is normal as my new printhead has the same stray ink, I think it is from where the head is cleaned or from when it sits in the parked position.
I possibly could have left the old head soaking for weeks after buying a new one & maybe it may have come good. There's a Vaseline like grease called potable grease they use in plumbing & I reckon that a smear of that around the seals would stop any air getting in.

 

[mikling]

I thought of using white lithium grease as well but once you get that stuff on the inlet screen by accident it would be hard to come off, if at all. Too dangerous I think.

 

[ThrillaMozilla]

Sounds like death to print heads to me. Grease is likely soluble in one or more of the organic solvents in the ink.

 

[barfl2]

Perhaps if intending to store a printer for an extended period would it be worthwhile 1. putting storage clips on all carts then wrapping in cling film and putting the lot into a zip locked bag. 2. remove print head and put it on paper towels and run some windex or similar to clear out any ink left in the channels repeat with the cling film and zip lock bag.

With regard to seals I notice that you only need a very small amount of pressure to click in a Canon cart whereas the HP 5360 I previously owned required a really firm pressure to insert the cart. Harder rubber? the output filter on the HP 364 is also very firm I checked one with a micrometer. I have not taken a CL521 cart apart to compare but I believe a lot of the problems with CISS and Canon printers was adjudged to be leaky seals.

The observation about purging is also very interesting because I have had problems recently with poor feeding/banding after using purged/refilled carts

 

[Smile]

OCP makes some print head preservation liquid that can be used to store wash the head and store it in a bag. I have used this and can report that it works, I stored the head for my older printer and after opening it worked fine. The storage period was 6 months. Head was stored in a vacuum seal bag.

 

[Ron350]

Smile could you please supply a link to the OCP preservation liquid.

Thanks Ron.

 

[websnail]

When I was playing with homebrew CIS systems for Canon printers I found the rubber seals around the printhead inlets were a major source of pain and problems and doubtless because of the sensitivity of CIS systems to air leaks the issues of these seals were effectively magnified.

As ways to resolve the issue I tried various approaches including:
- Thin silicon shims (the preferred solution for Canon CISs)
- Replacement Silicon gaskets (replacing the whole rubber seal)
- Silicon grease


The silicon grease was a complete disaster for reasons already noted so I would, as per others, recommend avoiding this like bubonic boils... Shims do work to a point but the design of the rubber seals is that of a disk with a skirt. When cartridges are inserted the bulk of the seal can depress and force this skirt outwards resulting in reduced pressure to maintain the seal and ultimately the skirt cracks/fails over time so with a shim you're adding additional pressure and exacerbating the process.

The silicon replacement may well have worked properly if I had taken the time to pursue it properly but the problem here is that cartridge internal sponge needs to make contact with the receiver in the printhead so your seal needs to be spot on in terms of height and also requires a certain amount of flexibility (or 'give') to allow the sponge to make contact without breaking the seal around the cartridge rim. My ham-fisted testing showed silicon wasn't an ideal material for this and actually the OEM rubber seal is probably the best bet given the design.

 

[The Hat]

Would it not be better then when adding any washers to accomplish a better seal,
to actually put them underneath the excising OEM rubber seal itself,
height restrictions would apply of course ?