An ink jet printing system includes an ink jet printhead which has an n-bit code representing a unique characteristic of the printhead formed on a substrate forming a part of the printhead. An n-bit data code is sent from a remote source to the printhead. If the data code matches the code on the...http://www.google.com.tw/patents/US5831649?utm_source=gb-gplus-share專利 US5831649 - Thermal ink jet printing system including printhead with electronically encoded identification 
