Abstract: A ink printer cartridge is described that is compatible with a particular type of printhead. The printhead has a camming shoe having a horizontal pressing mechanism for pressing another type of ink cartridge and thereby mechanically holding the ink cartridge in place. The cartridge according to the present invention has a shape and size that it does not engage the camming shoe, rather the cartridge engages an interior surface of the top of the printhead. In this way, a cartridge can be constructed to be used in a printer having a printhead with a camming shoe, which does not use the camming shoe in any way whatsoever.

Abstract: An ink printer cartridge is provided wherein ink is stored in a foam reservoir situated within an ink chamber. The foam reservoir does not substantially fill the interior space of the ink chamber, and in particular does not contact the lid of the cartridge. The foam reservoir is retained in place by means of a clip which abuts the top of the foam reservoir. In an embodiment, the clip may compress the foam. A number of features of clip are disclosed, including particular arrangements for fitting into the cartridge, and adjustments as to height and width.