A head unit includes an ejection section that ejects a liquid by a piezoelectric device displaced, a residual vibration detector that detects a residual vibration signal, a first switch that switches whether or not to feed a first drive signal, a second switch that switches whether or not to feed the residual vibration signal, and a controller that controls the first switch and the second switch. The controller acquires a detection start timing based on an extreme point of the residual vibration signal detected by the residual vibration detector, the first switch is switched such that the first drive signal is not fed to the piezoelectric device at the detection start timing, and the second switch is switched such that the residual vibration signal is fed to the residual vibration detector at the detection start timing.

A method for driving a liquid ejecting apparatus includes storing initial information on a residual vibration that occurs in the pressure chamber when the inspection signal is supplied at a first timing to the pressure generating element, storing determination target information on a residual vibration that occurs in the pressure chamber when the inspection signal is supplied at a second timing later than the first timing to the pressure generating element, and determining a property change in the pressure generating element based on the initial information, the determination target information, and correspondence information on, for each viscosity of the liquid in the pressure chamber, a correspondence between an amplitude of the residual vibration and a displacement amount of the pressure generating element.

In an inkjet printer, when an estimated viscosity of a first ink in a first nozzle is less than a threshold value, a power supply generates a first drive voltage, and when the estimated viscosity of the first ink is the threshold value or more, the power supply generates a second drive voltage higher than the first drive voltage. Moreover, at a time of vibrating a meniscus of a second ink in a second nozzle, when the first drive voltage is generated by the power supply, there is output to a drive element a first meniscus vibration signal, and when the second drive voltage is generated, there is output a second meniscus vibration signal by which energy imparted to the second ink by the drive element when applied to the drive element at an identical voltage level will be smaller compared to the first meniscus vibration signal.

An ink-jet recording apparatus includes: an ink-jet head provided with first and second nozzles for jetting a first ink and a second ink respectively, first and second drive elements which apply energy to the first and second inks respectively; a power supply circuit; and a controller. The controller estimates viscosity of the first ink in the first nozzle, controls the power supply circuit to generate a first drive voltage or a second drive voltage higher than the first drive voltage based on the viscosity of the first ink in the first nozzle estimated, drives the first and second drive elements by use of the drive voltage generated in the power supply circuit, and calculates a jetting amount of the first ink to be jetted from the first nozzle and a jetting amount of the second ink to be jetted from the second nozzle.

A jetting device includes an ejection unit arranged to eject a droplet of a liquid. The ejection unit includes a nozzle, a liquid duct connected to the nozzle, and an electro-mechanical transducer arranged to create an acoustic pressure wave in the liquid in the duct. The jetting device further includes a filter arranged to filter the liquid being supplied into the duct and a filter status detection system arranged to detect an obstruction status of the filter by measuring a property of the liquid in the duct. The filter status detection system includes a circuit configured for measuring the electric response of the transducer, for recording changes in the electric response that represent pressure fluctuations induced by the acoustic wave in the form of a time-dependent function, and for judging the obstruction status of the filter on the basis of that function.

A head unit control circuit controls a head unit. The head unit includes: an ejector, a determination circuit, and an ejection limit circuit. The injector includes a displaceable piezoelectric element. The piezoelectric element is displaced by changing a drive signal potential. The determination circuit determines whether the piezoelectric element has a predetermined electrical storage capability. The ejection limit circuit stops the drive signal to limit the ejection of the liquid based on the determination. The head unit control circuit supplies an instruction signal, a first designation signal, and a second designation signal to the head unit. The instruction signal instructs the head unit to execute the determination. The determination circuit executes the determination during a period in which the first designation signal is set to a high level, the second designation signal is set to a low level, and the instruction signal is supplied.

A connection cable electrically connects a head unit and a head unit control circuit. The head unit includes: an ejector, a determination circuit, and an ejection limit circuit. The ejector includes a displaceable piezoelectric element for controlling the liquid ejection. The piezoelectric element is displaced by changing a drive signal potential. The determination circuit determines whether the piezoelectric element has a predetermined electrical storage capability. The ejection limit circuit stops the drive signal to limit the ejection of the liquid based on the determination. The connection cable includes: a first connection supplying a determination instruction signal from the head unit control circuit to the head unit; a second connection supplying the drive signal from the head unit control circuit to the head unit; and a third connection between the first and second connections with a smaller potential change width than the second connection when the ejector ejects the liquid.

A method for managing the quality of an ink of an inkjet printer versus temperature resorting to the management of the viscosity of the ink versus temperature, the ink comprising a solvent or a mixture of solvents and the solvent or mixture of solvents representing at least 50% by mass of the total mass of the ink, wherein the viscosity of the ink at a temperature T is calculated from the following parameters: the viscosity of the ink at a single reference temperature T.sub.ref; the parameters K or Ln(K), and E/R of equation (1) giving the viscosity of the solvent or of the mixture of solvents: Ln (viscosity of the solvent)=Ln(K)E/RT (1) wherein E is the Arrhenius activation energy given in J/mol and R is the ideal gas constant.

An inkjet print head includes a droplet ejection unit having a pressure chamber; a first actuator configured for changing a volume of the pressure chamber; a second actuator configured for changing the volume of the pressure chamber; and a nozzle orifice. The inkjet print head further includes a control circuitry operatively connected to the first actuator and the second actuator. The control circuitry includes a drive circuitry for supplying a drive signal to at least one of the first and the second actuator; a sensing circuitry for receiving a sense signal from the first actuator; and a switch circuitry for switching a connection of the first actuator between a connection to the drive circuitry and a connection to the sensing circuitry.

A jet parameter generation system according to an embodiment of the present disclosure includes a data acquisition section, and a parameter generation section for generating a predetermined jet parameter, using a predetermined analytical method of taking a predetermined input parameter as an explanatory variable and taking a predetermined jet parameter as an objective variable. The parameter generation section determines which one of a first standard for setting a voltage value with which a drop volume of the liquid to be a reference is obtained and a second standard for setting a voltage value with which an ejection speed of the liquid to be a reference is obtained is to be selected, selects a first explanatory variable group when determining to select the first standard, while selecting a second explanatory variable group when determined to select the second standard, and uses the predetermined analytical method using just selected one of the first explanatory variable group and the second explanatory variable group to thereby generate the predetermined jet parameter.