Monitoring ink by weighing

[ThrillaMozilla]

There's no way to reset the cartridges on my HP C309a, so the printer cannot monitor ink after refilling. Fortunately, there are now some very inexpensive, precision balances (aka "scales") on the market, which make it it easy to check ink levels periodically by weighing the cartridges.

It takes only a few seconds to weigh a cartridge, record the weight, and get it back into the printer. You need to work quickly, since you want to finish before the print head parks itself, but I didn't have any trouble in accomplishing the task. Be careful not to let it park with a cartridge half out, because it could jam the print head. You probably won't want to pull the plug to keep the printhead accessible, since this will probably cause a purge cycle.

I wondered whether the printer would exact a penalty by forcing a purge cycle after weighing the cartridges. I did a test in which I opened the printer, weighed the cartridges, and then closed the printer, allowing it to do whatever it was going to do, then repeated the weighings. The printer did go through a brief cycle of its usual clunks and other noises, but maybe less than it would do to print the first page. The maximum loss in any cartridge was 0.01 g; the mean of 6 pairs of weighings was 0.0017 g loss. This is within the error of measurement. In other words, ink consumption by purging was undetectable.

The bad news is that you need to know the weights for empty and full cartridges, and you need to keep records. The best time to start is with new OEM cartridges. The information is also most useful if you combine it with a log of page counts vs. weights.

As for equipment, there are now some extraordinarily cheap balances (aka "scales") on the market for under $20. Be sure to buy a 100-g calibration weight if it's not included. It was also dirt-cheap. I just bought a balance with 100 g capacity and 0.01 g precision from Amazon. It's a fantastic device, with unbelievable performance for the price. I checked it against a Mettler. The calibration weight weighed 100.0024 g. The balance was accurate usually to +/- 0.01 g over the whole scale, or +/- 0.02 g at worst.

 

[The Hat]

ThrillaMozilla
There's no way to reset the cartridges on my HP C309a, so the printer cannot monitor ink after refilling.
Fortunately, there are now some very inexpensive, precision balances (aka "scales") on the market,
which make it it easy to check ink levels periodically by weighing the cartridges.

Just as long as you remember that each colour cartridge could weigh different,
because not all of the inks and cartridges actually weight the same when purchased new..

 

[ThrillaMozilla]

You need to keep records. Although I don't have weights for new, filled cartridges (which is the one weight you really need), but they seem fairly similar in either empty or full state.

 

[ThrillaMozilla]

Ink purged during cartridge change

I checked cartridge weights before and after changing cartridges. This shows the difference, i.e., the ink consumed. HP C309a printer with HP 564XL and HP 564 cartridges.

C XL 0.61 g
M XL 0.81
Y XL 0.71
K XL 1.20
PK (not XL) 0.50 g

 

[The Hat]

Ink purged during cartridge change

I checked cartridge weights before and after changing cartridges. HP C309a printer with HP 564XL and HP 564 cartridges. This operation uses a lot of ink.

C XL 0.61 g
M XL 0.81
Y XL 0.71
K XL 1.20
PK (not XL) 0.50 g

Is that the weight of the ink, the cartridge, or both which.
It seems very little..

 

[PeterBJ]

ThrillaMozilla wrote:
Ink purged during cartridge change

As I read it, it is the amount of ink spent by cleaning after removal and reinsertion of the cartridges. If the capacity of the cartridges is something like 10 ml or grams, it is a significant percentage of the total amount of ink in the cartridge.

 

[ThrillaMozilla]

Yes, that's the ink consumed. The capacity of the XL cartridges is nominally 8 mL or according to most reports. I usually fill to between 9 and 12 g. Black is at least 20 mL; I fill to 30 g. The non-XL cartridges (PK in this case) hold about 4 mL.

 

[PeterBJ]

So for magenta 10% ink is lost before even starting to print?

 

[macbroom]

I would be curious to see what the numbers are for the newer Canon printers with the 225/226 carts! If nobody knows I might try it later tonight just to see. I would guess it's in the same ballpark as I have seen color carts drop levels after only a PGI 225 fill.

 

[ThrillaMozilla]

PeterBJ, that's right. This is just one measurement, but it's even worse for non-XL cartridges (PK). (Look again. I added some detail to the post. XL and non-Xl cartridges are interchangeable, the difference being capacity.)

There's a little more to it, though. The amount consumed depends somewhat on the fill level of the cartridge. As it turns out, for the three color cartridges, the higher the fill level, the more was consumed, so it must be harder to get ink out of a nearly empty cartridge. Makes sense. The three color cartridges were filled to between 11 and 12.5 g. Overfilled by some measures, but they print well and don't leak. But PK represents a lower limit. As it turns out, I put in the wrong PK cartridge by mistake, and that one was almost empty. So you can expect to use at least 0.5 g per color cartridge, and possibly up to 0.8 g!

I thought that was too much detail for this thread, but since it came up....