http://www.pcworld.com/printable/article/id,152953/printable.html
PC World decided to do some real lab testing on this issue; and the results confirm what you may have suspected: Many manufacturer-branded (OEM) and third-party (aftermarket) vendor cartridges leave a startling amount of ink unused when they read empty. In fact, some inkjet printers force users to replace black ink cartridges when the cartridge is nearly half full, PC World has found.
PC World decided to do some real lab testing on this issue; and the results confirm what you may have suspected: Many manufacturer-branded (OEM) and third-party (aftermarket) vendor cartridges leave a startling amount of ink unused when they read empty. In fact, some inkjet printers force users to replace black ink cartridges when the cartridge is nearly half full, PC World has found.