Ink-jet pen with near net size porous member

摘要

Disclosed is a novel inkjet print cartridge (pen) in which a body of polyurethane foam is inserted into an ink chamber of the pen for ink containment and backpressure. The ink chamber has a tall narrow aspect ratio. The body of polyurethane foam is felted in the width direction of the pen to have a width less than 20% of its pre-felted width. After felting, the body of foam is cut to have a "near net size" as the interior volume of the ink chamber. Specifically, the pre-insertion volume is less than about 130% of the interior volume of the ink chamber. The substantial felting in the width direction provides sufficient stiffness to the foam that it can be inserted into the tall, narrow aspect ratio ink chamber.