| abstract |
An ink jet printer uses an actuator and an oscillating pressured ink supply. A shutter is located between the ink supply and an ink ejection port, normally blocking the ink ejection port. An actuator is provided for moving the shutter mechanism on demand away from the ink ejection port so as to allow for the ejection of ink on demand from the ink ejection port. The actuator includes a thermal actuator in a coiled form constructed primarily from polytetrafluorethylene. The coil is uncoiled upon heating. The actuator includes a serpentine heater element encased in a material having a high coefficient of thermal expansion. The serpentine heater takes a concertina form upon heating and a thick return trace returns the actuator to its original position upon cooling. |