Patent ID: 7448742

Claim:
A reusable cartridge for an ink jet printing apparatus comprising, in combination: a) a case; b) said case comprising mutually orthogonal pairs of parallel planar walls defining the sides of an ink reservoir; c) a substantially planar cover forming the top of said case; d) a planar floor and a downwardly-projecting nose section comprising the bottom of said case; e) an aperture in the bottom of said nose section; f) an upright stand pipe interior to said nose section surrounding said aperture; g) a removable insert for selective affixation to said stand pipe; h) said insert including a tube section for insertion into the stand pipe, said tube section having upper and lower ends, and an upper peripheral flange; g) a filter being fixed within said peripheral flange; h) a plurality of annular ridges arranged along and surrounding the exterior of said tube section; i) each of said ridges being substantially orthogonal to the axis of symmetry of said tube section; j) said ridges being substantially parallel to one another; and k) the outer diameters of said annular ridges being of decreased sizes from said upper end toward said lower end of said tube section.