System and method for ink drop acceleration with time varying electrostatic fields

摘要

An inkjet printer includes an electrode in either a printhead or an image receiving member that is operatively connected to a waveform generator. During operation, a controller operates the waveform generator to generate an electrostatic field between the printhead and the image receiving member during operation of inkjets in the printhead to eject ink drops. The controller operates the waveform generator to reduce an amplitude of the electrostatic field while the ink drops travel toward the image receiving member during a time when satellite ink drops can be formed from the ejected ink drops. The controller subsequently operates the waveform generator to generate the electrostatic field while the ink drops are in flight after formation of the satellite to accelerate the ink drops and satellites towards the image receiving member.

主权项

1. An inkjet printer comprising:
a printhead having at least one inkjet with an actuator configured to eject ink drops through a nozzle in the printhead towards a surface of an image receiving member in response to receiving an electrical firing signal; a waveform generator configured to generate a time-varying output signal; an electrode operatively connected to the waveform generator to generate an electrostatic field in response to the time-varying output signal; and a controller operatively connected to the printhead and the waveform generator, the controller being configured to:
generate the electrical firing signal to operate the actuator and eject an ink drop from the inkjet toward the image receiving member;operate the waveform generator to generate an electrostatic field from the electrode for a first predetermined period of time of approximately 20 microseconds to generate a first charge on the ink drop and a second charge at the image receiving member, the first charge having opposite polarity from the second charge;operate the waveform generator to reduce an amplitude the electrostatic field for a second predetermined time of approximately 40 microseconds after the first predetermined time and prior to the ink drop reaching the image receiving member; andoperate the waveform generator to generate the electrostatic field through the electrode for a third predetermined time of approximately 120 microseconds after the second predetermined time and before the ink drop reaches the image receiving member to accelerate the ink drop and a satellite ink drop toward the image receiving member, the satellite ink drop separating from the ink drop during the second predetermined time.