Ink jet pen having improved ink storage and distribution capabilities

Abstract From the Canadian patent

An ink jet pen (or other similar fluid delivery system) wherein primary and secondary ink reservoirs and an ink jet printhead are all interconnected by way of a porous ink-transfer member. The ink will pass directly from the primary ink reservoir to the printhead under a normal or predetermined range of temperatures and pressures. However, for temperatures and pressures outside this range, the secondary reservoir will be brought into operation to give or receive ink to or from the porous ink transfer member and thereby serve to maintain a substantially constant backpressure at the printhead.