Patent ID: 6655770
Filing Date: 2003-12-02
Classification: B41J

Abstract:
A printhead comprising:a substrate having a first and second groups of ink firing chambers; an N-bit print data register having a serial input and N data outputs; a first group of N ink energizing elements, each element having: a print data input coupled to a corresponding one of said N data outputs, a first control input; and a resistive element in thermal contact with fluid in a corresponding ink firing chamber; a second group of N ink energizing elements redundant of the first group of N ink energizing elements, each element having: a print data input coupled to a corresponding one of said N data outputs and redundant of a corresponding one or said print data inputs of the first group, a second control input; and a resistive element in thermal contact with fluid in a corresponding ink firing chamber; and a nozzle firing controller having a first output coupled to said first control inputs and a second output coupled to said second control inputs wherein the nozzle firing controller first enables activation of the resistive elements in the first group of N ink energizing elements and then sequentially enables activation of the resistive elements in the second group of N ink energizing elements for redundant printing of each bit of print data in an N-bit print data input.