Patent ID: 7530679

Claim:
An ink cartridge, comprising: an ink chamber comprising a wall; a translucent portion positioned at the wall, wherein the translucent portion has an inner space formed therein; and a movable member comprising: a first portion disposed within the inner space of the translucent member, wherein the first portion comprises at least one first protrusion portion formed on a first surface of the first portion; and a second portion disposed within the ink chamber, wherein at least a portion of the first portion of the movable member has a surface having a first surface roughness, and at least a portion of the second portion of the movable member has a surface with a second surface roughness, wherein the first surface roughness is greater than the second surface roughness, and the at least one first protrusion portion extends further towards a first interior surface of the translucent portion than the portion of the first portion having the first surface roughness.