A droplet discharging apparatus includes: a droplet discharger including a pressure chamber, an actuator and a nozzle provided corresponding to the pressure chamber, and a discharge flow path coupled to the pressure chamber, the droplet discharger performing a recording process by discharging liquid in the pressure chamber from the nozzle in the form of droplets; and a return flow path coupled to the discharge flow path and forming a circulation path. The droplet discharging apparatus performs as a maintenance operation for the droplet discharger, a first discharge operation of causing the liquid in the pressure chamber to be discharged toward the return flow path via the discharge flow path when no droplets are discharged from the nozzle during the recording process.

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.

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 drop measurement pad is for measuring volumes and positions of inkjet drops that are sprayed and dropped in a constant volume from nozzles of a head of an inkjet device. The ink drop measurement pad includes a pattern part including a plurality of groove portions arranged at pitch intervals corresponding to those of a plurality of head nozzles and wall portions formed between the groove portions. The groove portions are uniformly formed so as to have the same cross-section throughout an entire longitudinal direction thereof.

A liquid ejection apparatus includes a nozzle, a pressure chamber, a piezoelectric element, a count processing portion, and a detection processing portion. The nozzle ejects a liquid. The pressure chamber communicates with the nozzle and contains the liquid. The piezoelectric element changes a pressure in the pressure chamber in response to an input of a drive signal. The count processing portion counts a number of times that an electric signal output from the piezoelectric element and corresponding to vibration generated in the pressure chamber in response to the input of the drive signal to the piezoelectric element exceeds a predetermined threshold value. The detection processing portion detects a viscosity of the liquid contained in the pressure chamber, based on a count result of the count processing portion.

A liquid droplet ejecting apparatus includes a liquid droplet ejecting head that includes a plurality of nozzles from which a liquid supplied from a liquid supply source through a liquid supply path is ejected as a liquid droplet, and ejects the liquid droplet from the nozzle to a recording medium to perform a recording process, a first detecting section that detects a vibration waveform of the pressure chamber, which is vibrated when an actuator is driven to cause the pressure chamber communicating with the nozzle to vibrate, to detect a state inside the pressure chamber, and a second detecting section that reads a pattern formed on the recording medium by ejecting the liquid droplet from the nozzle to detect an ejection state of the liquid droplet.

There is provided a liquid discharging apparatus including a liquid discharge head, a tank, and a controller configured to perform: estimating an amount of liquid remained in the tank; estimating a viscosity of the remained liquid; estimating an amount of the refilled liquid; estimating a viscosity of the refilled liquid; and estimating a viscosity of a mixed liquid of the remained liquid and the refilled liquid at a point of time of finishing a refill of the tank with the liquid, based on the estimated amount of the remained liquid, the estimated viscosity of the remained liquid, the estimated amount of the refilled liquid, and the estimated viscosity of the refilled liquid.

A liquid ejecting apparatus is provided with pressure generating units for pressure chambers one of which is provided for each of a plurality of nozzles and drives the pressure generating units corresponding to liquid ejection requests which request liquid ejection from the nozzles while achieving supplying of a liquid to the pressure chambers and collection of the liquid which has passed through the pressure chambers. Accordingly, the liquid is ejected from the nozzles. Meanwhile, an occurrence of a fault in the liquid ejection is determined using a vibration transition of a residual vibration which occurs in the liquid of the pressure chambers according to a pressure change accompanying driving of the pressure generating units, and driving of the pressure generating unit of an ejection fault pressure chamber in which it is determined that a fault occurs in the liquid ejection is stopped spanning at least a fixed stopping period.

A printing apparatus which includes a circulation route configured to supply ink stored in a storage unit to a print head via a supply passage and send back the ink collected from the print head to the storage unit via a collection passage and which performs printing on a print medium by ejecting the ink from the print head includes: a first detection unit which detects an ink concentration in the collection passage; an injection unit which injects a correcting liquid capable of correcting the ink concentration into a circulated ink flow downstream of a position where the first detection unit detects the concentration in the collection passage; and a control unit which obtains an injection amount of the correcting liquid based on the concentration detected by the first detection unit and controls the injection unit such that the correcting liquid is injected in the injection amount.

A liquid ejecting head includes: a first pressure chamber to which a first liquid is supplied; a first drive element that applies pressure to the first liquid in the first pressure chamber; a second pressure chamber to which a second liquid is supplied; a second drive element that applies pressure to the second liquid in the second pressure chamber; a nozzle channel which has one end communicating with the first pressure chamber and another end communicating with the second pressure chamber and in which the first liquid supplied from the first pressure chamber and the second liquid supplied from the second pressure chamber are mixed; and a nozzle that is provided in the nozzle channel and ejects a mixture of the first liquid and the second liquid.