consumeraffairs.com/news04/2007/02/ink_cartridges.html
>Some HP, Lexmark Cartridges Shut Down after a Predetermined time
>Many Hewlett Packard and Lexmark consumers with inkjet printers may find that their ink cartridges are no longer working -- not because they are out of ink or because they're broken, but rather, because the manufacturers designed them to shut down after a certain amount of time.
>ConsumerAffairs.com has received a few complaints from consumers who say their ink cartridges, although full of ink, just stopped working.
"I bought my HP ink 3 months ago, used it only twice and now my printer 'doesn't detect a cartridge!'" wrote Helga of Clearwater, Fla. "This is downright crooked. It should last for as long as there is ink in it."
>The majority of ink cartridges with timers are manufactured by Hewlett Packard (HP) and Lexmark, said Alwin Morgenstern, chief operating officer of freerecycling.com, a company that recycles ink cartridges.
>A letter from "Beebo" to TheInquirer.net, a news website, reported that when he purchased discounted and expired HP ink cartridges, they wouldn't work. When he tried to use them, a warning would pop up saying the cartridges had expired.
>Beebo examined the copper connector pins on his old cartridge and the new ones and found that the new ones had one extra pin. He removed that pin and sure enough, the cartridge printed fine.
>For years, the cartridges have had suggested "sell by dates," said HP's senior ink and media scientist, Nils Miller. But in 1999, HP installed chips on some cartridges that communicate with the printer to tell it how long it has been since the cartridge was manufactured and installed in the printer. After a certain time, the printer will discontinue use of the cartridge....