Counting dots and counting dots for determining ink level are two different
statements. If it uses dot counts to determin ink levels then the printer
shouldn't know when a 1/2 or 3/4 filled cartridge was installed and would
therefor not indicate levels accurately when a cartridge is empty since it
hadn't sprayed the prerequisit number of dots. It seems to me that the Canon
printers rely on the prism reading to determin ink levels.
It actually does both. If you look at the cartridge you will see a foam area
and a free ink area. The prism monitors the ink in the free ink area. When
this area gets empty the foam still will have ink. It is this ink that is then
drop-counted. At least that is what I would do if I had their system....
- Bob Headrick, not speaking for my employer HP
