Inkjet printer printhead interface circuit
View Patent ↗An inkjet printer includes a processor that communicates, via a printhead interface circuit, with an electromechanical printhead having a plurality of ink ejection nozzles. The printhead interface circuit transfers data from the processor to the printhead using a double buffering scheme built on first and second buffers that are alternatively loaded with nozzle fire enablement data. Output sides of the first and second buffers are connected to a multiplexor that is in turn coupled to a printhead interface circuit. In order to increase data throughput, while one of the buffers is loaded with the data, data from the other is transferred to the printhead interface circuit.
1. An inkjet printer including a processor in communication with an microelectromechanical printhead having a plurality of ink ejection nozzles, the printer including:
a printhead interface circuit responsive to the processor and arranged to transfer data from the processor to the printhead, said printhead interface circuit including:
a line format circuit arranged to generate nozzle enablement data indicating nozzles to be fired; and
a printhead interface circuit responsive to the nozzle enablement data and arranged sequence firing of said ink ejection nozzles;
wherein the line format circuit is arranged to implement a double buffering scheme.
2. An inkjet printer according to claim 1 , wherein the line format circuit includes first and second buffers.
3. An inkjet printer according to claim 1 including a multiplexor coupled to output sides of the first and second buffers, wherein the line format circuit is arranged to deliver nozzle enablement data from one of said buffers to the printhead interface circuit while the other of said buffers is being loaded.
4. An inkjet printer according to claim 2 , wherein the first and second buffers are arranged to be loaded with nozzle addresses from a data bus coupled to the processor.
5. An inkjet printer according to claim 4 , wherein the first and second buffers are loaded with nozzle addresses from the data bus in accordance with signals generated by a portion of the line format circuit that implements a state machine.
6. An inkjet printer according to claim 5 , wherein the state machine is responsive to signals from the printhead interface circuit.
7. An inkjet printer according to claim 5 , wherein the state machine communicates with a DMA controller associated with the processor.
8. An inkjet printer according to claim 2 , wherein the first and second buffers are each broken into four sub buffers dedicated to storing data to enable firing of nozzles containing ink of each of four respective colors.
9. An inkjet printer according to claim 8 , wherein each of the first and second buffers is connected to a write enable line controlled by a portion of the line format circuit implementing a state machine.