Top filling mod for 3800 & 3880 refillable carts.

[jtoolman]

OK so just a while ago I drilled a 5/32 diameter hole centered on the front top corner of one of my old 3800 refillable carts all the way into the chamber.

The corner I am speaking of is the flattened portion where the top edge and front edges join. That's the only surface you could drill for a plug and still have it be accessible for top filling without removing the cart. After carefully deburring of the hole I pressed in a white silicone plug exactly like the ones that cover the priming hole of the refillable carts.

I attached a length of tubing to the pressurizing post on the cart. The one that comes with a large yellow plug. Using a larger 60 ml syringe I pressurized the cart under water. Waited for about 20 minutes, no bubbles. Waited another 5 mins. Still no bubbles. Removed tubing from port. Lots of bubbles came out as the pressure was released.

The hole I drilled enters into the general internal space of the ink compartment so there really is no difference as far as the " Ink in the Chamber " if it enters through the original intended port or the one I propose to use. The top flat portion of the upper and front edges.

Structurally is appears to be just as suitable.

So this may definitely work.

I can envision top filling my 80ml refillable carts just like the Large Ones that protrude out of the ink compartment.
My carts only use the MK & PK OEM chip. They do monitor ink usage.
So I can open my ink compartment top off each cart. Close the door, Turn printer OFF and then back ON and all the colors are reset including the maintenance tank.
Not having to remove the carts, will preserve the ink exit port and likely extend the life of the seals greatly

Again, this is SO simple it boggles my mind why CHINA has not adapted this method in design. One possible reason is that tons of money was spent on the main Injection Mold Design and any new modification or change would cost a ton more money!

OR there is something else, some reason I am totally missing as to why this will not work in practice.
Any one?

pharmacist, you are our resident expert and pioneer on the 3800 and 3880. I look forward to reading any comments and or suggestions you may have.

I will be receiving a second set of carts for my 2nd 3800 next week and will very likely mod them for top fill.
Unless I hear NOOOOOOOOO from you or someone else.

 

[pharmacist]

Hi Jtoolman,

Whow: that is the place of the refill hole I was expecting to be. I never understand that strange place of the original refill port. It doesn't make sense to me, also from point of safety (leakage when the cartridge is unintentionally not well sealed and the cartridge is put under pressure....). This is the way it should be. Easy refilling, without the need of removing from the printer, much less wear on the ink outlet valve. This is the way to go !!!. I have always complain about the position of the refill hole and you have done a great job.

 

[mikling]

You guys need to be cautious. The 3800/3880 uses a pressurised cartridge system. The air inlet plug (yellow when on as you described) pumps air into the cartridge via a pump inside the printer and this is regulated by a valve inside the printer. There is one common pump. Please check the service manual for details.

On the original OEM carts the ink is held in a bladder. The pump system to the cartridge is always separated from the printer securely by this bladder bag....similar to the Canon Pro-1 and the larger wide format printers. On these refillable carts, the pressure and pump path is directly linked to the ink. There is NO physical barrier of a bladder wall. If for some reason the ink were to leak back into the pressure path, then it is possible to have the ink leak back into the printer pump or even cross contaminate to the other colors when the pump reinitiates.

I would not want ink leaking back into the printer where the original would never allow this. Could be big trouble if it happened.

If it were me, I wouldn't do this on a 3800/3880. It's not a sub $100 desktop. This is one reason why I like the R3000 over the 3800/3880 if I did not have the need for wider prints than 13". There is more complexity in these 38XX printers than even the Pro line of the 4880 that prints a similar width and built more ruggedly and provides superior media handling and can use clear carts that do not have the pressure system.

 

[jtoolman]

Of course we would LOVE to have a refillable for the 3800 and 3880 with the same ink bladder, and as far as I know there are not any examples of refillable carts for the 3800 currently using an ink bag design although I know at one time there were some. Don't really know why they are no longer around.

But Mike, all I have done is to relocate the hole from its illogical original factory location ( Refillable carts ) to the top which would be ABOVE the ink surface level. I Pressurized the cart with a 60ml syringe with a one way valve until the syringe was being forced back because of the pressure I built in the cart, placed it under water and left it for over an hour and not a single bubble escaped. I do not see any structural difference between the wall were the original hole is located and were I placed the new hole. I have not compromised the membrane that seals the ink compartment in any way simply because I moved the location of the hole. The original hole is actually located in a more "Dangerous" location if you think about it. So if during pressurization, other than the membrane rupturing, which can happen regardless of where the ink hole is located, the other possible way for a leak is out of the fill hole, if say, your plug is not fitting well and leaks or literally pops out. Ink would readily flow all over the place. With the hole where I propose, located well above the ink surface level, you would just get pressurized air, instead of ink escaping! Membrane rupturing is always a concern specially with these refillable carts. But I don't see where the location of the hole would increase the possibility of membrane failure.

This is all experimental at this time, but do you really think this will absolutely not work, or would the possibility of membrane would increase solely due to this mod?

 

[mikling]

I say be cautious because technically it looks not to be a good idea because of the design of the refillable. I think you're misunderstanding my explanation. The original OEM cartridge has a bag of ink inside a sealed chamber. No matter how hard you squeeze back on the bag, there is never any ink that will come back through the pressure inlet because the bag is inside a separate chamber into which the pressure is applied. This is like the Canon Pro-1. On these refillable carts there might/should exist a flapper valve inside which is simply a rubber disc over a hole to make sure that there is a check valve function. Sometimes these flapper valves don't seat well and ink seeps back out like your toilet tank flapper valve and ink can come out the pressure inlet just like how your toilet tank leaks. It's not the membrane leaking on the refillable or the plug, it is the design itself that has a level of risk if not managed.

Let me explain further in the OEM design, the air from the printer pump NEVER comes into DIRECT contact with the ink. It is separated by the bag. In the refillable cart you have, the air from the pump comes into direct contact with the ink. Therein lies the risk. You need to take steps that ink will not go back. I think out of printer refilling and replacing the yellow cap when refilling is one such step.

Your method can work but if Murphy is around your neighborhood it can get nasty. I take a view that if things can happen, one day it will.

 

[jtoolman]

Mike. I do appreciate your expertize which is well beyond mine.

My main point I need clarification on is whether the refillable carts by themselves are a potentially dangerous system to use on a 3800 in it's original unaltered factory form OR will the addition of a secondary ink port such as I have proposed, increase the ever existing possibility of a membrane rupture due to normal internal pressures normally produces during printing.

The way I am understanding you, is that you are, understandably, not too thrilled about the current state of design of refillable 3800 and 3880 carts as they stand today.

I agree as well, but other than the huge carts that require the ink compartment door to be removed which also fill from the top, we just do not have too many other choices.

So I guess the bottom line question is, does this mod weaken the membrane to cart weld? I can't see how this would weaken the integrity of the membrane to cart body weld.

 

[mikling]

I am just pointing out that there is a limitation to using these type of refillables which have taken a design shortcut.. They can and DO work, just don't push the boundaries too hard or do so with caution knowing what could happen. Used as intended with out of printer refilling, they will work fine.

It's not the integrity of the cart or plug. It is the basic design as compared to the OEM.

 

[mikling]

In case anyone thinks I am pumping "hot air".

 

[mikling]

In the refillable, the pressure does not squash an ink pack but pressurizes the ink directly. The ability to prevent reverse flow will depend on whether Epson provided a check valve and they did not because they allow the release of pressure during standby and power off. None is shown or mentioned. The fail safe aspect is in the ink pack bag, which if anyone has taken a cart apart is of high quality and not likely to leak. When you open the top plug, and refill, the now open to the atmosphere static pressure force of the ink could force ink in the air path ink into a reverse path back to the printer?? It is anyone's guess unless you experimented with all sorts of ways or take everything apart and look at the engineering. You can experiment and see. If you thoroughly investigate this aspect and it is OK then by all means proceed.

Remember I said to be cautious that does not mean it doesn't work....it could just do the homework first.

 

[jtoolman]

Question for you and by the way WE ALL KNOW you are not blowing hot air. I really do admire and appreciate your vast overall inkhet printer knowledge!

Is the pressure in the carts allowed to slowly dissipate when you hit the ink compartment button and open the door? If so, does it allow pressure to escape through the same port it is originally pressurized through?

The instructions that are given for the large protruding 3800 and 3880 carts are to wait a few seconds before twisting off the keyed upper fill plug.
I know that when I open the door I can immediately pull out a cart and no air is heard escaping fromt the air port.

I did not take into account whether simple atmospheric pressure from having removed the top refill plug while the cart is still connected to the printer.

Are the larger top filled carts from Ink republic and inkjetcarts for example, are not removed and are designed to be refilled in situ. Are they specifically disigned ti allow such a feat?

Thanks for all you help Mike. I will have to think this out a bit longer.

Pharmacist, you have done extensive work on your printers with just about every type of refillable cart for these printers.
What are you views on whether it is safe to open a top fill plug on a small 80ML refillable while it is still connected to the prnter?