Patent ID: 7159974

Claim:
An inkjet assembly comprising: a vented ink reservoir for containing a liquid ink therein, the vented ink reservoir defining an internal volume occupied at least in part by a semipermeable membrane in fluid communication with a vent that automatically adjusts for pressure differentials by enabling gaseous diffusion between an environment external to the vented ink reservoir and the internal volume of the vented ink reservoir and concurrently inhibiting liquid diffusion therethrough, wherein at least a portion of the semipermeable membrane is angled other than parallel with respect to an operating level of the liquid ink within the vented ink reservoir; wherein: the vented ink reservoir includes a cap mounted to a tank; the semipermeable membrane is mounted to the cap; the cap includes a raised hump providing a space adapted to trap gas therein above a highest level of liquid ink within the vented ink reservoir; and at least a portion of the semipermeable membrane extends into the space provided by the raised hump.