A jetting device configured to jet one or more droplets of a viscous medium through a nozzle may include an acoustic transducer configured to emit an acoustic signal that transfers acoustic waves into at least a portion of the viscous medium located in a viscous medium conduit a viscous medium conduit configured to direct a flow of the viscous medium to an outlet of the nozzle. The acoustic signal may be an ultrasonic signal. The acoustic signal may adjust one or more rheological properties of the viscous medium, based on acoustic actuation. The acoustic transducer may be implemented by an actuator of the device that is configured to move through an eject chamber to cause viscous medium to be jetted through the outlet of the nozzle as one or more droplets.

A print head includes ejecting portions ejecting liquid by being supplied with a high voltage signal, a switch group switching between whether or not to supply the high voltage signal to the first ejecting portion group in accordance with a low voltage logic signal, a memory, a high voltage signal input terminal, and a low voltage logic signal input terminal, the print head having a first mode in which the print head executes reading processing of reading information stored in the memory and does not execute ejection control processing of controlling whether or not to supply the high voltage signal to the first ejecting portion group by switching the switch group in accordance with an input signal input from the low voltage logic signal input terminal and a second mode in which the print head does not execute the reading processing and executes the ejection control processing.

In a method of controlling a liquid ejecting apparatus, where the liquid ejecting apparatus includes a pressure chamber that communicates with a nozzle that ejects a liquid, a drive element that changes a pressure of the liquid in the pressure chamber, and a drive circuit that supplies the drive element with an ejection pulse that generates a change in the pressure that ejects the liquid from the nozzle, the method includes specifying a viscosity of the liquid in the nozzle and a surface tension of the liquid in the nozzle from a residual vibration when the pressure of the liquid in the pressure chamber is changed, and controlling a waveform of the ejection pulse according to the viscosity and the surface tension.

A liquid ejection head includes a pressure chamber that allows a first liquid and a second liquid to flow inside, a pressure generation element that applies pressure to the first liquid and an ejection port that ejects the second liquid. The first liquid and the second liquid that flows on a side closer to the ejection port than the first liquid flow in contact with each other in the pressure chamber. The first liquid and the second liquid flowing in the pressure chamber satisfy
0.0<0.44(Q.sub.2/Q.sub.1).sup.−0.322(η.sub.2/η.sub.1).sup.−0.109<1.0,
where η.sub.1 is a viscosity of the first liquid, η.sub.2 is a viscosity of the second liquid, Q.sub.1 is a flow rate of the first liquid, and Q.sub.2 is a flow rate of the second liquid.

There are provided a liquid jet head and so on capable of ensuring the ejection stability of the liquid even when jetting the liquid high in viscosity irrespective of the structure of the liquid jet head. The liquid jet head according to an embodiment of the present disclosure includes a plurality of nozzles configured to jet liquid, an actuator having a plurality of pressure chambers communicated individually with the nozzles, and each filled with the liquid, and a drive section configured to apply a drive signal having a plurality of pulses in one cycle to the actuator to thereby expand and contract a volume of the pressure chamber to jet the liquid filling the pressure chamber from the nozzle. The plurality of pulses in the drive signal include a plurality of first pulses configured to expand the volume of the pressure chamber, and a plurality of second pulses configured to contract the volume of the pressure chamber. Further, with reference to an on-peak pulse (AP) in the pulses, a pulse width in at least one of the first pulses other than a final first pulse as last one of the first pulses out of the plurality of first pulses in the one cycle is set within a range of 0.2 AP through 1.0 AP, as well as, a pulse width in at least one of the second pulses other than a final second pulse as last one of the second pulses out of the plurality of second pulses in the one cycle is set within a range of 1.0 AP through 1.8 AP.

To provide an inkjet printing apparatus that improves the smoothness of the ink layer surface and improves the image quality. Provided is an inkjet printing apparatus that prints with a UV curable ink, the inkjet printing apparatus including: an ejection unit configured to eject the UV curable ink onto the surface of a print medium; and a control unit configured to control the ejection of the UV curable ink from the ejection unit, the UV curable ink containing a thixotropy-imparting agent, and the control unit setting the viscosity of the UV curable ink to 1 mPa.Math.s to 20 mPa.Math.s at the time of ejection and to at least 80 mPa.Math.s within five seconds of landing on the print medium.

An inkjet printing apparatus includes a printing unit having ejection parts, each configured to eject ink by using a piezoelectric element to be displaced in response to a change in electric potential. The inkjet printing apparatus also includes a circulation unit, a determination unit, and a control unit. The circulation unit executes ink circulation in a circulation path inclusive of the printing unit. The determination unit ejects the ink from each ejection part, detects residual vibration generated at an ejection part due to ink ejection, and determines an ejection state of ink ejection at the ejection part based on the detected residual vibration. The inkjet printing apparatus determines a printing state of ink ejection in the printing unit based on the ejection state. The control unit causes the determination unit not to make the ejection state determination in parallel with causing the circulation unit to execute the ink circulation.

A viscosity measurement device includes a measurement tool having a pump for feeding a printing liquid by pressure. The viscosity measurement device includes a passage part having a first passage part in which a flow path cross-sectional area for the printing liquid is set at a first area, and a second passage part in which a flow path cross-sectional area for the printing liquid is set at a second area smaller than the first area and which is arranged on an upstream side in a supply direction of the printing liquid with respect to the first passage part, the passage part being interposed in the supply path and arranged upward toward a downstream side in the supply direction of the printing liquid; and a sensor attached to the second passage part and measuring the fall time of the measurement tool in a prescribed vertical region in the second passage part.

A method for detecting an operating state of an ejection unit during the printing of an object of a print job the method comprising determining whether the ejection unit is in an operative state or in a malfunctioning state by analyzing a residual pressure wave generated in the liquid in a duct of the ejection unit by an actuation pulse. Further, the method comprises scanning the location of a recording medium onto which liquid has been ejected in order to perform an additional determination of whether the ejection unit is in an operative state or in a malfunctioning state. The method uses both determinations to build feedback information in the form of labeled data that is used in subsequent executions to improve the result of the determinations performed by analyzing a residual pressure wave generated in the liquid. Other aspects of the present invention relate to a droplet ejection device comprising a plurality of ejection units, as well as a printing system comprising the droplet ejection device, and a software product comprising program code on a machine-readable non transitory medium for executing the method in the printing system.

A liquid ejecting apparatus includes a discharge portion provided with a piezoelectric element that is driven by a driving signal and a compression chamber that discharges a liquid from a nozzle according to the driving of the piezoelectric element, a detection unit detecting residual vibration occurring in the discharge portion, in a detection period after the piezoelectric element is driven and outputting a residual vibration signal indicating a waveform of the residual vibration, a specification unit specifying an initial time from a start time when the detection period starts to a reference time when a residual vibration signal becomes a signal level of a center of an amplitude after the start time of the detection period, and an estimation unit estimating a viscosity of the liquid in the compression chamber, based on the initial time.