Ink warnings--the final word...

[wlemann]

Epson 7900
How do I know what is really left in the cartridge?
What is the procedure to make sure I am not wasting precious ink, I mean, $$$.

[colinm]

Buy more ink when you get the warning (that's what it's there for), but don't change cartridges until it's empty.

[michael]

It's simple.

When you see a "ink low" warning, order a new cartridge right away. Some time in the next 20-40 prints it will run dry.

Replace it then, not before. Even if you're in the middle of a print. The printer will resume where it left off with no waste, and you'll be sure that you've used every drop of that expensive ink.

Michael

[Ernst Dinkla]

All good answers for practice.

If you want to go to the bottom of it then get the weight of a cartridge at 4 stages:
1/ a new cart
2/ first warning by the printer
3/ printer halts and declares the cartridge empty
4/ after pulling out remaining ink from the cart with a syringe

Consider 1 gram = 1 ML, good enough for this experiment.
Now you should know what you pay for.
 
There is ink wasted in the MK>PK>MK changes and in getting rid of clogs by (auto) cleanings. Not to mention prints that show the effect of clogs. That ink waste can not be measured with the above method but a driver log may tell.

--
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots

[Farmer]

Bear in mind that the carts are designed to NOT be completely empty - some is left to avoid trying to print on dry lines and to allow for cleaning etc.  i.e. if you buy a 700ml cart you'll find there's more than 700ml in there if you were to open it up and bleed it out from new.

Michael spelled out the correct operating practice, though - 100%.

[digitaldog]

Like Michael, I print until the damn thing stops in it's tracks and demands a new cart. I've never had an issue doing so. The warning light is the printer telling you, "have ink on hand", not "replace now".

[wlemann]

Thanks to all.
So takeaway, you know when its empty when the printing stops----

[Eric Myrvaagnes]

Thanks to all.
So takeaway, you know when its empty when the printing stops----

Yes. And I learned that the hard way on a Saturday evening several years ago. All the local photo stores were closed until Monday and I wanted to print. But when I did get a replacement cartridge, the printer just started up and finished the print it had been working on. There was no visible indication on the print where the old ink stopped and the new ink began.

So now I pay attention to the warning and keep spare carts on hand. Bu I never change the ink until the printer actually stops.

[Ernst Dinkla]

Bear in mind that the carts are designed to NOT be completely empty - some is left to avoid trying to print on dry lines and to allow for cleaning etc.  i.e. if you buy a 700ml cart you'll find there's more than 700ml in there if you were to open it up and bleed it out from new.

Michael spelled out the correct operating practice, though - 100%.

Very true. It just needs some users' verifications that can be done with the method I described.

--
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
January 2014, 600+ inkjet media white spectral plots.