After recently installing a new colour cartridge in my printer (Lexmark) the indicated level shown in the system status display was only up to the third "rung" of eight in the display, so I presume the cartridge was under HALF full.  The suppiers have agreed to replace this, presumably faulty, cartridge.
My query is - how does the computer measure the INK capacity in the cartridge?  I know it's something to do with keeping track of usage, but would that not mean that it would presume a new cartridge was full?silkie, Ink level in a cartridge is determined by a "time of use factor'. Obviously prone to great deal of variables thus rarely accurate.If this is a new printer that came with it's original cartridges the cartridges that came with it are not of the same volume capacity as "new" replacements will be. Originals contain much less ink--after all they almost give you the printer so you will buy their ink cartridges--which is where they really make their money.I have never owned a Lexmark however if they are typical of most printers there are alternatives to buying the mfgr's cartridges even beyond other generic brands which are stated to work as well as OEM. It depends on your printing habits and willingness to go beyond just installing a "replacement" ink cartridge. Hope this helps.truenorth Ink cartridges are can of (ink) worms.
I have this HP 7200's printer, and FOREVER the message comes across "Low Level" or something, eventhough it is full after having it refilled. Thus my printer knows the cartridge was refilled. If the printer really runs out of ink, it will keep on printing.

The gossip goes that some Printer Software counts number of lines/characters printed, thus knows (assumes) how much ink is left.
Another gossip goes that some Software knows how many times a refill was done.
Some Software (HP I think)  will NOT allow a refill at all, therefor check that out before getting a refill done.
My favorite "Re filler" told me my luck will run out after 12X.

Thanks for replies -

The cartridge in question was not a new original Lexmark - it was a "compatible" refill, which the suppliers are replacing.  I made a similar enquiry about the ink measure of them and they have said that ink levels are not always shown correctly because the printer is reading the chip on the cartridge that shows (on original new ones) that it is full.  On refills this chip MAY be damaged or need resetting (?).  Anyhow, previous cartridges from them have been all ok so I have no real complaints.I never trust generic replacements or refills. Seen too many leak and ruin printers. Cartridge leaks, printer ruined, warranty void. It may not happen to everyone, but why take the risk?