Patent ID: 6981753

Claim:
A controller for a print head comprised of: a. a series of multi-terminal latching current sources, each current source having first, second and third inputs and first and second outputs said series of multi-terminal latching current source configured to have: 1) the first current source having its first and second inputs coupled to a first signal source and the third input coupled to a second signal source, said first output of said first current source coupled to a heater resistor for said print head; 2) each of the other N-number of multi-terminal latching current sources coupled in series behind said first current source whereby the N th multi-terminal latching current source has its first input coupled to said first signal source, its second input coupled to said second output of the N-1 th multi-terminal latching current source and the third input of the N th multi-terminal latching current source coupled to said second signal source, said first output of said N th current source being coupled to an N th heater resistor for said print head; whereby said multi-terminal latching current sources are sequentially latched to a conductive state by a sequence of synchronous voltage pulses on both said first and second signal sources.