The Canon Pro-1 Ink Empty sensor

[mikling]

A few years ago, Hat sent me a PGI-29 and I dissected it. We were stumped as to how the cartridge detected an out of ink condition. Well, recently after I re-energized my quest into the Pro-1, it dawned on me how this ink out sensor actually works. It is very clever and it is for this reason why it was not obvious at first.

Well here it is folks.....I figured out exactly what made the PGI-9 / PGI-72 tick and now the PGI-29.

If you look inside the cartridge bladder you will notice there is a clear paddle that just sits inside the bladder. This is supposed to be the sensor. It is not exactly a prism and it is not a "low" ink indicator either. This paddle senses when the cartridge has given up all the ink it is supposed to. It senses the out of ink condition because when the bladder is truly empty, the sides of the bladder will touch the side of this paddle due to the pressurized cartridge and the paddle will reflect light! So it is indeed powered by light as we knew before but we could not figure out how it did this. When the bladder has ink, the paddles sits in the middle of the bladder and the silvered sides of the bladder is kept away from the translucent paddle. Empty, the sides touch and voila!

Is this significant? Yes, it makes the printer operation failsafe. Without it, you can run the printer empty and do bad things to a large printhead on the Pro-1. And who wants to do that?

Apparently the aftermarket carts do not have this paddle. So if this is indeed true, another reason to always use genuine carts. Maybe the patent on this idea forbids aftermarket copies.

Also years ago, I did not possess a great refill adapter for these PGI-29s but now I have something essentially foolproof....and it is inexpensive too boot.

 

[stratman]

Very interesting tech. Thanks for the post and pics.

 

[The Hat]

I don’t want to undo all the good work that Mike is doing on his Pro 1 project, but I have to correct his assumption with aftermarket cartridges.

Both the OEM and aftermarket carts look very much the same on the inside of the bladder and they both function the same regards the low ink warning, but that’s where the similarities end.

click to enlarge.

The aftermarket carts do the job they were intended to do just as good as the OEM carts do, but the valve outlet on these carts will leak after only one refill, because they were never intended to be refilled in the first place.

2/ Aftermarket carts differ to OEM carts when it comes to installing them, while OEM’s are colour specific, the aftermarket carts are not. !

So it’s very easy to install an aftermarket cart in the wrong position, and if that happens then you’ll get the dreaded fatal error warning requiring some very serious intervention on your part or a trip to Canon Service. Ouch...

It would be advisable not to use aftermarket carts for refilling, stick with refilling the OEM’s and avoid many of the pitfalls that aftermarket carts can bring...

 

[stratman]

So it’s very easy to install an aftermarket cart in the wrong position, and if that happens then you’ll get the dreaded fatal error warning requiring some very serious intervention on your part or a trip to Canon Service.

More details please. Are you saying that just installing an aftermarket cartridge in the wrong slot in the print head that you will get a fatal error?

 

[The Hat]

More details please. Are you saying that just installing an aftermarket cartridge in the wrong slot in the print head that you will get a fatal error?

Yes that's correct, because this machine is full of little surprises, if a cart is installed in the wrong position, that’s a clear indication that the user is not using OEM carts, so for that infringement, your sent to the Service centre for your punishment.

If I can recall, it’s a B500 error...

 

[stratman]

Yes that's correct, because this machine is full of little surprises

Wow. That is dirty pool. I wonder if the same were to happen if an OEM cartridge were placed in the wrong position. Maybe this is the fault of the aftermarket cartridge and has nothing to do with Canon protecting their interests per se.

Any other surprises you'd care to share?

 

[jtoolman]

No. That could never happen as the OEM carts are keyed and only fit their specific slots!

To the hat.
I remember seeing a close up comparison between an OEM and a Chinese compatible cart and the little light pipe which connected to the internal paddle was not there and was indeed missing.
Do the Chinese cart now have this system incorporated?
Regardless, OEM is king and I have over 700 empties ready to accept single use chips and great inks from you know who!
Joe

 

[mikling]

There could be two or more manufacturers of these compatibles. However, the physical keying is also a perfect safeguard and reason enough to only use the OEMs.

I also thought of a hack to make each chip last longer. If you top off the cartridge even when it is not empty, I suspect you might be able to extend the life of the chip by maybe 20%..a guess. This would reduce your chip cost by 20%... again a guess. The printer will hang onto to "low" until it detects the out of ink condition or when the chip is run down normally. if it does not detect the optical sense then it will make sure it hangs in there until a limit is reached. By topping off, we can reach that state of the max reach. In the absence of a sensor, doing so is dangerous because the printer will stay low looking for the sensor trigger and still print. But if there is actually no ink...then trouble.

This is purely a guess at this point.

 

[jtoolman]

I could test that right now. I have 10 carts indicating LOW condition.
They all weigh about 50-54 grams.
Bone dry is 43 grams.
So am I at a good point to test this theory?

Joe

 

[The Hat]

@mikling, you have to get up early in the morning to try to fool the Pro 1, this printer is not your regular dumb Canon and you must also remember that it has a live EPROM chip at all times, even if it's unplugged from the power socket for a week, (3-year battery)

The chip and prism system can’t be tricked or fooled in any way, I tried topping up the cartridges and got nowhere using OEM chips and @jtoolman fills his cartridges to 84 gm, which is full.

But occasionally I filled mine to 95 gm and still the printer would report the cartridge empty with 20 ml left inside and it zapped the chip to X, this printer will not allow you to run your cartridges dry either, it just refused to continue till you put in another full cartridge, I have never been able to fool it regarding ink amounts.

Maybe someone else might have better luck than me...