More on The Canon Optical Sensor

[mikling]

More tests and experiments with the chip indicate that the optical sensor only will warn of low ink when the chips is within approx 20% of what the actual level is. What that band of tolerance is hard to determine...and it takes time to find it.

If you significantly underfill a cartridge, the cartridge will physically run out of ink before the optical sensor will warn of a low level. The underfill needs to be grossly off, my guess is 20%.

If you overfill a cartridge, intending to keep the chip level up, it will eventually run down to empty anyways. You cannot defeat the chip.

What the function of the optical sensor is really for is to re synchronize the chip ink level to what is in the sponge. The only accurate way to do that is when the reservoir is empty and the upper layer of the sponge is also empty. That way the accuracy of the chip ink level is better maintained all the way to Empty.

 

[Tigerman]

You mean when I got red X from printer when ink in under low (5%) even what chip count to printer (caution) so I must change cartridge ?

 

[The Hat]

I tried many time to defeat these pesky Canon chips, I used many methods both under-fills and over-fills and every time I lost, sometimes with dire consequences.

For instance, you might think that using a CLl-8 cartridge in a CLl-521 printer would cause problems, well the answer is no, it doesn’t because the EPROM chip seems to tolerate the extra ink after just one refill.

It takes much longer to reach the low ink warning with the bigger carts, and if you try to ignore that warning then the empty notice comes up far quicker that it should normally, you do get the benefits of the extra ink in the bigger reservoir, but lose out on the remaining ink left in the sponge area, it can’t be used up.

I have also reset a cartridge chip to full that had the low ink warning notice displayed on it, I reinserted the cart again and the printer acknowledged the full chip but choose to ignore it from that moment onwards, because I'd wilfully over ridden the sensor and so both the printer and chip happily kept on printing well after it had run out of ink, the results were, scratch one print head, O' and the cart chip remained at full.

Next if you try to top up a cart in an effort to defeat the chip, even by leaving the cart still in the printer, again the low ink warning comes up despite there being ink remaining in the reservoir, this is then followed up quickly by the out of ink notice.

Despite that I have never had an under filled cart run out of ink with any of my testing, I filled the reservoir with just ¼ of an inch of ink, to just barely cover the cart sensor, then reset the chip to full and the low warning came up as soon as the reservoir became void of ink and almost immediately the cart chip dropped from full to the yellow low ink warning.

All of these test can be done by anyone but please remember they can damage your print head, all in the name of science of course, but like @mikling and my tests, you too can get totally different results with your own tests, it just depends on which printer you use and how new the firmware is in that machine.

It’s good to try and I’d encourage you guys to have a go at beating the system but in the end it will be a total waste of time, ink and print heads, the house will win every time, because you cannot defeat the pesky cart Chip, but it’s bloody good fun to try anyway..

 

[stratman]

As @The Hat's tests have shown, the optical sensor seems to function as a fail safe for a loss or lack of ink despite a chip reset to "full". Quite useful if a catastrophic leak occurred.

In normal use and functioning of the cartridge and ink, the optical sensor may behave as corroboration of ink usage (ink remaining) to supplement whatever method Canon uses to determine ongoing ink usage, such as counting nozzle sprays or ink requirements based on the data of image to be printed. The precision of this count is unknown but appears to be adequate for the job.

It would seem based on The Hat's experiment with resetting a chip to full and then underfilling the cartridge, thereby triggering a low ink warning rapidly via the optical sensor, that the hardware optical sensor overrides the software ink counting method.

What is unknown, at least to me, is whether the optical sensor has its own routine that takes over ink counting until the cartridge is marked as empty. My gestalt is the optical sensor is a supplemental system as both fail safe and redundant system.

Didn't someone once report a test with an essentially empty or near empty cartridge with a reset chip to full? Did the cartridge report empty as anticipated or did the cartridge report low and kept printing beyond usable ink in the sponge?

Whatever the purpose(s) of the optical sensor, it must be considered by Canon to save them money.

 

[palombian]

I once tested resetting a cartridge with an empty reservoir (with enough ink in the sponge to not risk the printhead).
The level stayed full.
This could suggest the optical sensor needs to record a change.

But as said, why worry ?

 

[mikling]

I once tested resetting a cartridge with an empty reservoir (with enough ink in the sponge to not risk the printhead).
The level stayed full.
This could suggest the optical sensor needs to record a change.

But as said, why worry ?

If you perform the above the sensor will not detect the low ink because the chip level is high or full. When the chip level is full, the optical sensor is turned off or will not work.

Only when the chip gets down to a certain level, the optical sensor will kick in. So if you grossly underfill, it is possible to run out of ink before that level is reached by the chip.

If you grossly ovefill it or top it off midway without resetting the chip, the chip countdown will predominate and the sensor will be ignored all the way to "chip" empty level.

Now when the countdown of the chip runs normal and the refill is proper, the optical sensor and chip levels might be within say 10%.
So suppose in a perfect situation, the optical sensor and chip will be the same say at 25% remaining when the optical sensor is supposed to detect no ink in the reservoir.
If the reservoir is detected at empty by the optical sensor when the chip says there is 30% left, the printer will pull the chip count down to 25% left. This will re synchronize the chip and physical ink to match. I have not been able to determine at exactly what point the optical sensor is turned on. It might be 60% or 50% empty.

The key takeaway is that the optical sensor is ignored when the chip reading is high.

 

[stratman]

If you perform the above the sensor will not detect the low ink because the chip level is high or full. When the chip level is full, the optical sensor is turned off or will not work.

Only when the chip gets down to a certain level, the optical sensor will kick in. So if you grossly underfill, it is possible to run out of ink before that level is reached by the chip.

This seems to be discordant with what The Hat posted:

Despite that I have never had an under filled cart run out of ink with any of my testing, I filled the reservoir with just ¼ of an inch of ink, to just barely cover the cart sensor, then reset the chip to full and the low warning came up as soon as the reservoir became void of ink and almost immediately the cart chip dropped from full to the yellow low ink warning.

 

[mikling]

have verfied results twice with an iP3300 and PGI-5 and once with an iP4500. Each time watching to see what happens.

Now for something more interesting.
With previously overridden chips on a Pro-100 and then reset, something more interesting happens. As long as you keep the ink levels up, the chip will never go to empty. It indicates that the chip level count behaves such that it is full, then drops in one or two distinct drops . However, the optical sensor is already activated at the lowest point....looking for resync with the chip. If the ink does not drop further to the point the optical sensor sees an out of ink, the sync point is never reached. Remember this is for previously overridden chips on the Pro-100. Something happens on the chip count once the chip has been overriden. This aspect has been verifed three times.

 

[The Hat]

This seems to be discordant with what The Hat posted:

It’s just not worth disputing..

 

[Roy Sletcher]

have verfied results twice with an iP3300 and PGI-5 and once with an iP4500. Each time watching to see what happens.

Now for something more interesting.
With previously overridden chips on a Pro-100 and then reset, something more interesting happens. As long as you keep the ink levels up, the chip will never go to empty. It indicates that the chip level count behaves such that it is full, then drops in one or two distinct drops . However, the optical sensor is already activated at the lowest point....looking for resync with the chip. If the ink does not drop further to the point the optical sensor sees an out of ink, the sync point is never reached. Remember this is for previously overridden chips on the Pro-100. Something happens on the chip count once the chip has been overriden. This aspect has been verifed three times.

I had exactly this problem when I started refilling my pro 100. Because at that time the resetter was not available and I had to override the Canon detection system. When I eventually got hold a a resetter this set of Carts, always displayed incorrectly.

I wrote many message on this board seeking some sort of guidance, but it seems nobody else had the problem. This was a few years back.

rs