Method and apparatus for compensating for printhead damage

Abstract

Micromechanical pagewidth printheads include a very large number of separately addressable thermal ink ejection actuators. Failure, or degraded performance, of actuators typically leads to white lines occurring down printed media. A method for addressing this problem is described. The method involves monitoring for degraded actuator performance and in response altering the dot size associated with properly functioning actuators neighboring the failed actuator. Typically the dot size is increased to 50% of the standard size by increasing the duration of heating current pulses to the neighboring actuators. Although the method is particularly described in the context of thermal micromechanical printheads it is also applicable to piezoelectric and optical printers.

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