Energy efficient heater stack using DLC island

An apparatus for expelling droplets of ink onto a printing surface, said apparatus comprising:

• a semiconductor substrate;
• a first insulating layer deposited over said semiconductor substrate;
• a thin resistive heating layer deposited over said first insulating layer;
• a metal conductor layer deposited over said thin resistive heating layer wherein a portion of said metal conductor is removed to expose a portion of said thin resistive heating layer;
• a diamond-like-carbon island deposited over said exposed portion of said thin resistive heating layer such that an outside perimeter of said diamond-like-carbon island partially overlaps said metal conductor layer;
• and
• a second insulating layer deposited over said metal conductor layer wherein a portion of said second insulating layer is removed such that all of said metal conductor layer and said outside perimeter of said diamond-like-carbon island are covered by said second insulating layer and wherein said second insulating layer is effective to reduce heat dissipation to an area surrounding the resistive heating layer.

A printhead for an ink jet printer wherein said printhead expels droplets of ink from a nozzle in a nozzle plate attached to a heater chip containing heating elements by nucleating a volume of ink that is in contact with a surface of said heating element, said printhead comprising:

• a resistive heating element wherein said resistive heating element rises in temperature in response to a voltage;
• a diamond-like-carbon coating positioned on said resistive heating element;
• and
• a smoothing layer deposited on said diamond-like-carbon coating such that said surface of said heating element that is in contact with said ink has a surface roughness less than 75 angstroms.