| abstract |
An ink jet printing mechanism includes an ink reservoir in which ink can be contained and can be subject to periodic pressure variation. A moveable shutter is provided which is displaceable between a closed position covering the nozzle chamber and an open position allowing the nozzle chamber to be in fluid communication with the ink reservoir, the shutter being activated by an actuator. The actuator comprises a coiled thermal actuator. The thermal actuation is via one of differing resistivities, differing cross-sectional areas, differing thermal expansion, and differing thermal conductivities of the actuator. |