Oce-Technologies B.v.

Canon Production Printing Holding B.v.

Oce Holding B.v.

Johannes M M Simons

Cornelis W M Venner

Amol A Khalate

Marko Mihailovic

Hylke Veenstra

Aart Nijkamp

Tjerk E C Hummel

Ralph Van Der Heyden

Pierre A M Klerken

Erwin Schrijver

An electrical circuit for measuring the shape of a voltage waveform in a print head of a printer includes an integrated circuit for generating one or more voltage amplitude waveforms. The electrical circuit includes an inkjet drop forming unit including a plurality of inkjet chambers, wherein each of the plurality of inkjet chambers includes a piezoelectric actuator and an ink nozzle, and a connecting circuit between the integrated circuit and the inkjet drop forming unit suitable for applying one of the one or more voltage amplitude waveforms generated by the integrated circuit to the piezoelectric actuator in one of the plurality of inkjet chambers. In order to measure the shape of the one or more generated voltage amplitude waveforms via capacitive crosstalk, the electrical circuit also includes a conductor in physical proximity to the connecting circuit.

Circuit and method for measuring voltage amplitude waveforms in a printer

A method of operating a drop-on demand (DOD) jetting device having a nozzle, a pressure chamber filled with a liquid and connected to the nozzle and an actuator energized by a drive signal, wherein a periodic DOD signal determines whether or not a droplet is jetted out from the nozzle in a given DOD period, and the drive signal has a waveform configured to cause the actuator to excite a pressure wave in the liquid, the method further comprising the steps of a) energizing the actuator with a waveform that has a fixed pattern and extends over a time interval that is longer than the given DOD period; and b) ignoring the DOD signal in at least the first DOD period that follows after said period for which the step a) has been performed.

Method of operating a drop-on-demand jetting device

A droplet ejection device has a nozzle head with a plurality of ejection units, each of which includes a nozzle, a duct connected to the nozzle, and an electromechanical transducer arranged to create a pressure wave in a liquid in the duct so as to expel a droplet of the liquid from the nozzle. The device further includes an electronic control circuit arranged to apply control signals to the transducers and to receive detection signals that are generated in the transducers in response to the transducer being exposed to pressure fluctuations. The nozzle head includes a reference duct which has an electromechanical transducer serving as a reference transducer. The control circuit is arranged to subtract a detection signal of the reference transducer from a detection signal of at least one of the ejection units.

Droplet ejecting device

A method is provided for cancelling an electric crosstalk contribution in a monitoring signal from a monitored electro-mechanical transducer in a device including at least three electro-mechanical transducers. The crosstalk contribution results from an actuation of other transducers than the monitored transducer. The method includes selecting a second transducer, associated with the first, monitored transducer, wherein the electric crosstalk caused by an actuation of a third transducer is equal in the first and second transducer; actuating the first transducer and not acutating the second transducer; simultaneously measuring a monitoring signal from the first transducer and the second transducer; and subtracting the two monitoring signals to obtain a clean monitoring signal from the first transducer.

Method for cancelling electric crosstalk in a printhead

Fluid jetting device comprising: a nozzle plate, a fluid chamber terminating in an orifice in the nozzle plate, an actuator for generating a pressure wave in a fluid in the fluid chamber to jet fluid through the orifice from the chamber, a jetting waveform generating device connected to the actuator for generating an excitation waveform comprising two separated pulses, called a jetting pulse and a quenching pulse, for respectively generating a pressure wave in the fluid in the fluid chamber leading to a fluid droplet and for substantially cancelling a pressure wave in the fluid in the fluid chamber, wherein the jetting waveform generating device is adapted to make, when jetting two consecutive fluid droplets, a first and a second droplet, the jetting pulse of the second droplet at least partially overlap the quenching pulse directly following the jetting pulse of the first droplet.

Fluid jetting device, printing apparatus, and method therefor

An inkjet print head includes an ejection unit having a liquid chamber for holding an amount of liquid, a electromechanical transducer operatively coupled to the liquid chamber for generating a pressure wave in the amount of liquid and a nozzle in fluid communication with the liquid chamber for enabling a droplet of the amount of liquid to be ejected through the nozzle. A method for detecting an operating state of the ejection unit includes the consecutive steps of actuating the electromechanical transducer to generate a pressure wave in the liquid; actuating the electromechanical transducer to suppress a residual pressure wave in the liquid; sensing an amplitude of the residual pressure wave in the liquid; and based on the result of the sensing step determining that the ejection unit is (i) in an operative state if the amplitude of the residual pressure wave is below a threshold or (ii) in a malfunctioning state if the amplitude of the residual pressure wave is above the threshold.

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Venlo, Netherlands

Johannes M M Simons