Xaar Technology Limited

James Edward David Marchant

Stephen Mark Jeapes

Ian Anthony Hurst

Robert Errol McMullen

Subramanian Sivaramakrishnan

An inkjet printhead comprising a printhead die, the printhead die comprising: a plurality of actuators; a plurality of electrical connections in electrical communication with respective first electrodes of the plurality of actuators for providing drive signals thereto; a first electrical bus arranged in common electrical communication with second electrodes of a first group of the actuators for providing first signals thereto; and a second electrical bus arranged in common electrical communication with second electrodes of a second group of the actuators for providing second signals thereto.

Inkjet printhead

A printhead for a printer has actuating elements for ejecting fluid, and a drive circuit for selectively applying a drive waveform having several slopes, to an actuating element, according to a print signal. A resulting printhead has a lesser sensitivity to changes of slew rate in one slope of the drive waveform than a sensitivity to change in another. The drive circuit has a variable resistance circuit, and a control circuit to control the variable resistance circuit to adjust a slew rate of the slope of lesser sensitivity according to a trim signal. By making the adjustment less sensitive, the trim signal and trim control can have more relaxed tolerances, thus can employ simpler, cheaper circuitry.

Printhead drive circuit with variable resistance

A printhead provides actuation pulses for driving actuating elements from a common drive waveform via respective switching circuits, the waveform having a pre-charge ramp followed by a steeper slope. A start voltage of a leading edge of the actuation pulse is set by opening the switching circuit to decouple the common drive waveform from its actuating element part way along the pre-charge ramp. After the pre-charge ramp the actuating element is coupled again to the common drive waveform, so that the voltage across the actuating element follows the steeper slope to form the leading edge. Adjusting the timing of the decoupling adjusts the start voltage, enables trimming relative to other actuating elements. The gentle slope of the pre-charge ramp enables the precision of timing of switching to be more relaxed, so that trigger circuitry for controlling the switching circuit can be simpler, smaller, cheaper and thermally more efficient.

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Buckingham, United Kingdom

James Edward David Marchant