Purging the PGI-9 cartridges

[ThrillaMozilla]

You can easily swamp the pad area with the syringe. This means that the surface area is not the bottleneck in the process but something else.

Toolman's video showed dribbling from the syringe. Used that way, the syringe is the bottleneck. If the pad is flooded, it will fill faster. Toolman says 2-3 minutes this way. If you want still faster, you must pressurize. Problem solved.

 

[jtoolman]

When I first attempted my first PGI-9 refill, and was told by mikling to drip the ink in I thought I would have to not apply ink at a faster rate than a few drops per second. It quickly became very evident that I could indeed expel ink out of my syringe at a much faster rate than what I originally thought was possible. So I started to stream the ink over the exit pad and though it was forming a small flood over it, it was entering the cart's inards quite readily.
Now, I was admitedly extremely naive of the actual internal engineering of this amazing cart, and I was exited about how easy this actually was so worrying about the actual physics of what was going on did not concern me at the time.

I am really enjoying what all you have been discovering, theorizing and sharing. That's was this group it TOPS.

 

[websnail]

Interesting how this topic went from purging to refilling instead so perhaps a review of the contents and a split is in order..

That aside, can I please note AGAIN that more than one proponent of the force-fill process has pointed out that (given the data provided prior to a lot of technical considerations) it's a good way to deal with two things:

1. Purging cartridges that have become dried out or, for whatever reason, need to be flooded, flushed and emptied in a patient manner.
2. For refilling the bulk of a cartridge refill before completing with the dribble method to ensure that the outlet sponge is liberally soaked, and ensure any air can escape.

As for air being trapped, etc... There are two things to consider here:
a) attaching a clip and then creating a reasonably hard vaccum (using a syringe or similar) can purge all but a tiny proportion of lingering air and/or ink from the cartridge. The effect, placement and/or potential for ingestion of any such air is still a point for debate so further research required here.
b) provided the cartridge is filled to the requisite level (or slightly beyond) and dribble filling is used at the end, any residual air remaining in the cartridge should (i) be removed thanks to the earlier vacuum pull.

I understand some of the potential for issues here but with a good set of instructions and some core rules on refilling pretty much all can be avoided.


As for the approach suggested with funnels, etc... fascinating approach that could work but a whole series of potential problems with ink contamination (dust, etc..) and mess (tipping out the tube at the end) so there would still be a host of issues to work out. In truth I'm not at all sure you would benefit from any speed improvements either because of the need to flush/clean the system between refills.


So, to summarise a few things...

First the original topic this thread was focused on... Flushing a cartridge:
1. Is greatly enhanced through the use of a modified clip to empty out any cleaning solution and/or old ink.
2. Need to focus on clearing any dried ink deposits in the sponge as much as, if not more than, the removal of old ink within the cartridge bellows/bag
3. Air removal required although to what extent this is possible and/or required is debated
4. Best practice for refilling of a flushed cartridge (to avoid potential air "contamintation" problems) would be to refill before the cartridge reads empty thus reducing potential printhead issues caused by air ingestion to virtually nill.


Secondly looking at the issues of refilling:
1. Refilling "in use" cartridges considered the best option due to (proposed) non-ingestion of air and optimal condition of sponge.
2. The dribble method provides the most "idiot proof" method for ensuring a distributed fill and soaking of the sponge (assuming of course the refiller actually dribbles over the whole sponge area)
3. For speed, a force fill approach is available to handle the bulk of refilling volume to say 80% and then complete using dribble fill to ensure good soak of all sponge area rather than in one specific area focused by clip adapter location
4. Care should be taken to avoid ingestion of air (remedial action being to use mod'd clip & syringe, etc.. to suck out).


.. and just to finish up a few other relevant bits..
1. Cartridge should be stored right way up (allowing any ink fluid to retain contact with the sponge and keep it moist)
2. Always cover cartridge with clip (unmodified) or, if clips are unavailable, something like alumin(i)um tape to avoid drying out the sponge.




Just to note something for follow up.
At some point I'm going to take a proper look at a cartridge where the bellows are fully viewable to see just how much air is actually trapped regardless of vacuum purging, etc... and report back. I suspect that nugget of information alone would help some folks rest a little easier but it seems the easy fix is to replace/refill the cartridge around the low ink mark, before empty to avoid any potential ingestion.

 

[mikling]

redispersion.......the forgotten issue that I have tried to stress. In the channels and settlement throughout the pad. This is something that we all omitted to think about until Hat maybe bumped into it and had my head scratchin for a bit.

3. For speed, a force fill approach is available to handle the bulk of refilling volume to say 80% and then complete using dribble fill to ensure good soak of all sponge area rather than in one specific area focused by clip adapter location

Let's look at the logic of this. The vacuum pressure of the bladder is greatest when it is empty. It is the least when it is nearly full. We've noted that the cartridge fills pretty quickly when it is initially being filled but slows down towards the end. This means that the velocity of the ink reentering through the pad and channels is very slow at the end of the fill. So if you choose to try and use the dribble/stream at the very end, you will be using it when it is least effective. This does not allow effective redispersion and flushing out as if the velocity was greater as if it was used at the start.

The contraptions I sketched indicated that the whole pad must be exposed. This will allow high flow at least at the start and will occur thoughout the pad. The turbo version will likely be the most effective.

It would be interesting to have someone do a video of what websnail recommends. Just from a timing standpoint, just how time is saved when you need to attach the jig, partially fill it, detach it, dribble at the end and then wash the jig....compared to the standard dribble stream. Me, I'm lazy, I'd just stick it out with an easy syringe or squeeze bottle from the start, do it a bit longer and be done with it. Music is in the background I can still enjoy my time.

 

[ThrillaMozilla]

And as for removing air, unless the pad is wet, the cartridge will not hold a vacuum. That means the air will get sucked back in immediately as soon as the syringe is removed. Keep that in mind when attempting to "vacuum" a dry cartridge.

 

[websnail]

And as for removing air, unless the pad is wet, the cartridge will not hold a vacuum. That means the air will get sucked back in immediately as soon as the syringe is removed. Keep that in mind when attempting to "vacuum" a dry cartridge.

Already done this aspect of things and noticed something interesting... the bag inlets/holes are designed in such a way that if you empty the bag, the bag material closes over the inlet holes in such a way so as provide a quite effective sort of lid. The spring doesn't appear to have the necessary power to peel this lid back because it's not close enough to the inlets to overcome the negative pressure and lift the lid.

I expected the exact same issue but found that it wasn't doing this at all and found the above and had to marvel at the way the thing has been designed..


As for a speed comparison... I'm intending to do that in the next couple of days now that I have all my new work surfaces painted protected and available. I'm aware from thinking through the funnel alternative that it's all well and good hypothesising but facts tend to work better... Likewise all this back and forth on dispersion...

Perhaps the half way house here is to recommend that dribble filling be done every so often to ensure the sponge is flushed with new ink?

From a "perfect solution" point of view, some kind of clip on dispersion sprayer would be an ideal solution but from a pragmatic viewpoint would be costly in terms of development and production... If nought else we may well discover that the mod'd clips provide the best flushing solution for older cartridges and dribbling best for refilling... We shall see.

 

[ThrillaMozilla]

Already done this aspect of things and noticed something interesting... the bag inlets/holes are designed in such a way that if you empty the bag, the bag material closes over the inlet holes in such a way so as provide a quite effective sort of lid.

In other words, it's a crude check valve. No, that can't be what's doing it, because it works in the wrong direction. It might slow removing air from the cartridge, but it won't prevent air from going back into the cartridge. I suspect that you had enough moisture in the pad to retard the return of air. From the description of the pad, I doubt that a really dry cartridge could hold a vacuum for more than a second or two. I just thought it might be something to keep in mind. Hopefully it won't happen often.

 

[websnail]

Already done this aspect of things and noticed something interesting... the bag inlets/holes are designed in such a way that if you empty the bag, the bag material closes over the inlet holes in such a way so as provide a quite effective sort of lid.

In other words, it's a crude check valve. No, that can't be what's doing it, because it works in the wrong direction. It might slow removing air from the cartridge, but it won't prevent air from going back into the cartridge. I suspect that you had enough moisture in the pad to retard the return of air. From the description of the pad, I doubt that a really dry cartridge could hold a vacuum for more than a second or two. I just thought it might be something to keep in mind. Hopefully it won't happen often.

Ok, perhaps I should have indicated that this is not one single cartridge. When I tested the same theory I assumed, like you, that the cartridge would re-inflate promptly and that there was no means of keeping it empty of air. To that end when I saw it stayed voided, I assumed an anomaly so I grabbed a bunch more empty, old cartridges. Most had sponges that were dry to touch and any ink left inside the cartridge appeared dried or, at best, slightly moist. Around half had caked pigment in the sponge. As an aside, most of the cartridges had collapsed bellows/bags that appeared to have stuck in the empty position with. As an aside, out of around 100 cartridges a quick scan showed only two or three re-inflated with air.

Granted I didn't test any over extended periods of time but I did pull vacuums on more than five different cartridges to check my findings. Same thing with each. They didn't, even after 5 minutes show any re-inflation or movement in the plate. So from a refilling point of view it seems if you pull a vacuum to empty the cartridge you have plenty of time to refill.

So all that aside, I should also point out that you wouldn't want to refill a dried out cartridge anyway. So, assuming the accuracy of sponge moisture content equals avoidance of new air ingestion, as soon as you start the process of flushing and purging, you would be re-saturating the sponge and thus when it came to purging any fluid/air ready for refilling the sponge would be working as the moisture barrier to further air ingestion, as suggested.

 

[rodbam]

If we take it that we want to have the whole sponge saturated with ink during refilling can't we cut the silicone seal on a modified clip used for the force fill so it forces ink in through the whole pad. If this works we could also use the modified modified clip & just dribble ink down the glued on thingy which will make the dribble method a lot easier for those that don't fancy force filling.
Just cut along the white line.

 

[The Hat]

No sorry rodbam that doesnt work tried that and I didnt get the cigar.

http://www.nifty-stuff.com/forum/viewtopic.php?pid=58719#p58719

Youre either stick with the dribble method or go with the pump action method and if it doesnt work out right just blame the wife; she always said you had a terrible aim anyway

If you want to make something that is guaranteed to work then try making something like this,or get some from websnail when youre ordering your resetter.