How Does Air and Liquid Displacement Work in an Ink Cartridge?

[simonrepro]

I am trying to re-manufacture an ink cartridge and need to understand the physics of how this thing is working.

The Cartridge

1. Ink in tube
2. Ball bearing on top of cartridge which I can push into the cartridge to allow me to get liquid into clean
3. Adaptor on top of cartridge which links through to an expandible plastic bag inside the cartridge, the bag fills up with air when I blow in the top adaptor. This adaptor is not 100% air tight so the air can slowly come out of the bag through the adaptor.
4. 520 45micron nozzles on bottom of cartridge which spray out ink.

I fill the cartridge with ink by removing (2.) then attaching a syringe to (1.) then as I blow into (3.) this allows the syringe to be pushed to enter ink into the cartridge but it inflates the air bag on the end of (3.).

What I need to be able to do:
Fill the cartridge with ink, then put some force on the ink to force the ink into the bottom nozzles, this is called priming. After doing this I then need to be able to deflate the plastic blow up bag leaving normal atmospheric pressure within the cartridge, there must be no air in the cartridge and it must be completely filled with ink.

My Problem:
If I blow in the bag and pump ink in, when I deflate the bag it pushes the ink back into the syringe.

Can anyone help with this please?

 

[Aaron Barnard]

What I am missing here? Is there a way to pressure seal the ink so it does not move back into the syringe when the bag is deflated? Is there a way to prime the cartridge without using the air bag? Is there a physics principle I am missing here?

Thank you.

 

[quicknote]

I can provide some insights into the physics behind liquid and air displacement in this ink cartridge. First, let's start with the basic principle of displacement - when an object (in this case, the ink) is placed in a container, it will displace a volume of liquid or air equal to its own volume.

In this cartridge, the ink in the tube (1.) is the main source of displacement. When you push the ball bearing (2.) into the cartridge, it creates a space for the ink to flow into and fills up the remaining volume. This is similar to how a syringe works, where pushing the plunger creates a vacuum that allows liquid to be drawn in.

The adaptor (3.) on top of the cartridge is the key component for displacing air. When you blow into it, you are increasing the air pressure inside the cartridge, which pushes the ink out of the nozzles (4.). This is known as pneumatic displacement, where air pressure is used to move a liquid.

Now, for the priming process, you need to create enough force to push the ink into the nozzles. This can be achieved by applying pressure to the ink using the syringe while simultaneously blowing into the adaptor. This will create a balance of forces, with the pressure from the syringe pushing the ink down and the air pressure from the adaptor pushing it out of the nozzles.

To prevent the ink from being pushed back into the syringe when you deflate the plastic bag, you need to make sure that the pressure inside the cartridge is equal to the atmospheric pressure outside. This can be achieved by slowly releasing the air from the bag while keeping the adaptor open until the pressure inside the cartridge equalizes with the outside pressure.

Overall, understanding the principles of displacement and pressure can help you successfully remanufacture the ink cartridge. Good luck with your project!