| 摘要 |
A thermal ink-jet pen cartridge having a rigid external frame member is fabricated from a rigid engineering plastic and an interior frame structure is attached thereto, formed of a softer, more ductile plastic material than the engineering plastic. An ink reservoir is defined by the interior structure and a pair of flexible bag membranes formed of a plastic material impervious to the ink and compatible with the interior member material, allowing the membranes to be joined to the interior member to form a leak-proof joint. The external structure has locking features formed into an interior surface. When the interior member is injection molded to the external member, the molten material flows into and around the locking features, securing the interior member to the external member and resisting the shrinkage forces as the molten material cools. The ink reservoir is filled through a fill port passageway extending through the external frame member and the inner member. The passageway is lined with the softer material of the inner member, and is sealed by an oversized ball press fit into the passageway after the ink filling process. The external frame member comprises polysulfone, while the interior frame structure comprises a polymer blend composition comprising (A) a copolymer of ethylene and methyl acrylate and at least one of (B) a polyester copolymer and (C) either a styrene-ethylene/propylene or a styrene-ethylene/-butylene-styrene block copolymer. The present polymer compositions provide good chemical and heat stabilities and solvent resistance when subjected to inks used in printing. Further, the present polymer compositions are flexible and have excellent compatibility and adhesion to the various polymeric components used in the ink jet cartridge.
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