The Internals of the Canon Pigment Ink Cartridge PGI-9

[mikling]

The following are the internals of the PGI-9 Cartridge. The viewer will come to realize that while simple to refill, there are a number of refinements built into the cartridge which many will never realize are there. Furthermore, these refinements are there for a purpose and ignoring the issues that Canon engineers knew about and how they came about their solutions will possibly lead to faulty refill processes and procedures with eventual detriment to the printer.
View for your own pleasure.

Finally, did you notice the small serrations in the paddles !!??? They are there for a reason. The number of details that you simply will never see.

 

[mikling]

Did you notice the canopy that extends over the exit holes inside the bladder? They do not want settled pigment to unnecessarily settle underneath. Significant effort is evident to mix the ink internally during use and then evenly distribute the ink onto the pad.
The bellows appear to be a single fold which can trap liquid within that fold sometimes.

 

[turbguy]

Interesting Construction.

The internal spring appears to impose a light vacuum on the internal bladder. I would guess that it is about 5" of water vacuum, or so.

I wonder what physical mechanism prevent air from entering the cart upon unpackaging, expanding the piston/bladder, and disabling the cart. Surface Tension of the ink in the screen and the "sponge"?

Wayne

 

[mikling]

http://www.nifty-stuff.com/forum/viewtopic.php?id=8132&p=4

My rough measurements indicate around 2-3 inches of water actually.

You have the idea on the functioning of the cart and the air aspiration when dry. The surface tension in the mesh and screen will essentially create a liquid block. What is also interesting is why there are two cut lines in the pad. Why have the cuts? I am still trying to reverse engineer the thinking behind that aspect of the pad.

From what I see, the cut lines on the pad are not cuts but is molten polyester. From this, it looks like the cut lines essentially form a line that is resistant to flow. This will equalize the flow across the pad because the the three exit holes are not placed symmetrically along the pad. It is easy to see why. You have to accommodate the piston will be flat on one side of the cartridge and still be able to let ink exit, so the holes have to be at that side. Why place it to one side of the length? Simple again. The two mixing paddles above. The exit holes are as close as possible to the center between them, yet still leading to the bottom mesh/pad chamber.

The other detail that I am seeing are the two small rectangular cutouts that appear to have no purpose, except that I have seen something similar internally inside the printheads before. It helps establish a ribbon of ink across the pad/mesh layer.

 

[turbguy]

I wonder how Canon fills them during manufacture?

Is the Piston magnetic? Can they "collapse" the piston and bladder otherwise? and let it "drink it up"?

Wayne

 

[turbguy]

http://www.nifty-stuff.com/forum/viewtopic.php?id=8132&p=4

My rough measurements indicate around 2-3 inches of water actually.

You have the idea on the functioning of the cart and the air aspiration when dry. The surface tension in the mesh if you want to be perfectly accurate. What is also interesting is why there are two cut lines in the pad. Why have the cuts? I am still trying to reverse engineer the thinking behind that aspect of the pad.

What is the shape of the contact area in the print head? Are there matching features?

W

 

[mikling]

As indicated the piston is aluminum. Based on the construction, the side holding the piston down is put on before the pad ring/frame is attached. I suspect the sequence is this. Of the three holes, two are used to inject ink into the bladder. The third hole is used to allow air to exit. The bladder is not filled to the top. After the fill, the mesh is welded on, then the pad and its frame is attached. After this, there is a short duration vacuum placed over the entire pad that will slightly collapse the diaphragm and remove the air and allow ink to saturate the pad and mesh. Once the pad and mesh is saturated, there will be no possibility of air re- entering the bladder. The orange clip is then attached.

This will fully explain why on refilling we can get higher weights than when the cartridge is new.....because the diaphragm/bladder is already partially collapsed a bit when new. When we refill, we can get the diaphragm to fully extend because we do not need the step of air withdrawal that was intially required. Thus we can get higher weights and hold more ink .

 

[mikling]

http://www.nifty-stuff.com/forum/viewtopic.php?id=8132&p=4

My rough measurements indicate around 2-3 inches of water actually.

You have the idea on the functioning of the cart and the air aspiration when dry. The surface tension in the mesh if you want to be perfectly accurate. What is also interesting is why there are two cut lines in the pad. Why have the cuts? I am still trying to reverse engineer the thinking behind that aspect of the pad.

What is the shape of the contact area in the print head? Are there matching features?

W

The printhead has matching shaped intakes.

 

[The Hat]

Thanks for the lovely clear pictures Mike..

 

[Emulator]

Fascinating detective work and reasoning. I can imagine Canon engineers visiting this site to see how long it takes and how well the design is analysed!