Patent ID: 7278708

Claim:
An ink cartridge for an ink jet printing apparatus having a printhead which ejects ink droplets onto a recording medium, the printhead having an ink supply needle, and is mounted on a movable carriage, the ink cartridge comprising: a housing containing an ink therein and configured for removable mounting on the printhead, said housing having a first wall and a second wall, the second wall having both a first upper corner and a second upper corner; an ink supply port formed on said first wall for receiving the ink supply needle of the printhead and supplying the ink from said housing to the printhead, the ink supply port having an exit opening and a centerline; a memory device storing information about the ink disposed on said housing; and at least a first electrode having a first width and a second electrode having a second width, the first width being less than the second width, and wherein, viewing the ink cartridge in a direction perpendicular to a plane of the electrodes, both the first electrode and the second electrode are intersected by a plane passing through the centerline of the ink supply port, the first electrode being further from the exit opening of said ink supply port than the second electrode.