CISS Ink expanding through tube and up to air filters!

[L4NE]

This may have been asked before, and if it has sorry, anyway...

I have a CISS for my Epson R1400 and I recently noticed that the ink keeps, what I can only assume is, expanding due to possibly heat variations in my house. The ink is expanding up the tube in the tanks and through my air filters, meaning my air filters are now full of ink!

Does anyones know how to stop this from happening, and do I need to buy yet more air filters?

 

[L4NE]

Ok, I think I have realised what the problem is. I think the tanks are slightly lower than the cartridges, at the base of the printer, so the ink is flowing back up the tubes. Just incase anyone is having the same problem.

 

[crexas]

Those air filter tubes in a ciss are a real headache for me. And I don't understand what's wrong with them or why are they there in the first place. The problem is that I cannot fully fill my ciss with ink. Every time I fill my ciss, I cannot fill too much. This is the example:



If I fill above the red lines, I begin experiencing a sh*tload of problems with my ciss and printing. First of all, ink flows up the air filter tube and floods the air filter and sometimes even comes out of it. This happens as soon as I close the refill cap. While closing it, the pressure inside ciss builds up, and ink is pushed through the air filter tube. It's pure physics, nothing weird here.

Example below. When I close the refill cap (1) the pressure pushes ink up in the air tube (2) and my ciss gets flooded. This obviously happens only when my ciss is filled with ink above the red lines and covers the bottom of the air filter tube.




That is why I NEVER fill above the red lines in the first picture. I have another CISS and it came from CityInkExpress. It looks a lot like Rihac ciss.




But the problem is that the air tube goes all the way down the whole reservoir and because of that, no matter how much ink I fill, when I close the refill cap, ink is always pushed through the air tube and comes out from the top. Hence my air filters - they are all colorful. It's really frustrating and I still don't understand what are those tubes for if they cause so much trouble when refilling.

 

[The Hat]

I have got the total opposite with my CISS which was purchased from cityexpress as well.
When my ink bottles go below full I just fill them back up to the very top of the refill plugs (See Pic).

I do this while print is in progress and have never got any ink straying into my air filters at all.
I have filled the bottles many times and can safely say that I have never experienced
any of these back flow problems at all with any of my CISS units.

I refill my CISS bottles using a syringe and just squirt ink into the bottles till full and replace the refill plug.
One other explanation maybe that the air filters could be fitted upside down..

 

[mikling]

Interesting that these CISS sellers do not even comprehend how the ink tanks are theoretically supposed to work and what potential problems they can cause.

Listen up. "Everything your mother never told you about CISS systems."

The basic principle of these constant pressure system is the mariotte bottle principle. http://en.wikipedia.org/wiki/Mariotte's_bottle

That is why the tube is dipped into the tank. All constant pressure system depend on this principle. They can shroud it in all kinds of markets talk etc. BUT in the end it is the mariotte bottle when the design is reduced to its basics.

This works well in theory when everything is constant.

Now let's get to the real world for a second.

The room temeperature fluctuates. What happens? The air that is trapped inside the tank expands and contracts. So now think what happens when that occurs. If the printhead parking pad/purge unit is sealed properly, the expansion of air will create pressure and this pressure will have to go somewhere. The air inside the tank will expand and push ink up the tube. Cute eh! Now the bigger the air space inside the tank, the more ink will be pushed up. Suprised? Now think of the cycle of cooling and expanding. Well, when the air cools it contracts, what happens? air is sucked into the tank. ( In operation the air inside the tank is under a vacuum) so we lose this small vacuum and then when we expand it later , ink shoots up.
Ok we want to stop that right? so we plug the vent to stop all this nonsense. Well, now we how have pressurised printheads when the pressure build us and then then ink is pushed out of the nozzles. If we have a cooling cycle with the vent cap on, we now suck air into the nozzles and we then have "clogging" the next time we start up and have to do some head cleaning.

Now we haven't left real world yet. What else can happen? Barometric pressure differences. Remember that the tank is sealed and the exit point and entry points present relative pressure differentials. The atmospheric pressure variances can affect this as well.

What else? If the ink is emitting gases as it ages, then it can potentially build up pressure as well. I don't know if this is in happening in your case or what but it could be a factor.

So are these systems "bad" no for the majority of people who use dye inks, NO not really, but when you see certain sympotoms, you need to understand what is happening. The worse thing is that these CISS systems are shrouded in all kind of technical mumbo jumbo with all kinds of features that mean "sq_at" in the end.

Now one type that has not been discussed is the open to the air "dip tube" system or what I can siphon. These systems are NOT subject to these real world issues. In fact they offer something that these closed bottles cannot. Serviceability. Typically the tubes are just hung through a bottle cover and a bottle is used as a tank. When you need to service them, you remove the cover and clean the bottle. This is CRITICAL for Epson based CISS systems that use pigment ink. Sedimentation will always occur over time and you need to remove it.

The open bottle system does NOT feature constant pressure. Is this necessary? In an Epson printhead, the window of pressure the head can tolerate is wide enough that normally this is not necessary. In fact, the standard cartridge presents a slight negative pressure. So you ideally want an ink level that around or below the bottom of the printhead. This means that for larger sized tanks you want to present bottles that are wider rather than skinny and tall.

Here is an example of a dip tube system:

Simple reliable and as many have discovered. In normal homes that air filter presents something that is really not necessary and potentially can create more problems than it solves.

How do you convert the closed bottle to an open bottle? open up the top cover and leave a crack open. Now only fill the tank around the relative height of the cartridge in the printer and no more. Less if allowable.

Pigment ink users. Pay attention to the heavily saturated dark color inks. Beware of deposits.

You problems are gone.

Each time I hear of this constant pressure biz and blah blah, I cringe.

 

[mikling]

As an addendum, the owners of aftermarket large format cartridges will observe that the same principles are utilized for the cartridges.

discussed before:

http://www.nifty-stuff.com/forum/viewtopic.php?id=4718

AND the Canon type ink tanks at their core rely on the same principle plus one more.. a hybrid to two principles.

Break down how the Canon cartridges works and you will see that it is a marriage between a normal sponge cartridge and a mariotte bottle.

 

[gigigogu]

Hi everybody

To avoid said problems with ink pushed out by atmospheric pressure and temperature variations I made myself a CIS with overflow drain from air tube into another bottle placed below ink tank.

It complicates a bit the refilling but at least I am sure no ink will flow on my desk.

 

[mikling]

You're creating more complications than required. Good luck.

 

[aaa]

The Hat CISS bootles are improperly constructed.

 

[The Hat]

aaa The Hat CISS bootles are improperly constructed.

Would you please enlighten me then? :|