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.

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.

In a method of controlling a property of liquid droplets, the droplets are ejected from a jetting device having an array of ejection units, each of which comprises a cavity connected to a nozzle and an actuator associated with the cavity for exciting a pressure wave in the liquid in the cavity. The method includes monitoring a sub-threshold pressure wave oscillating in the cavity, but having an amplitude not large enough for jetting-out a droplet, deriving an indicator for the viscosity of the liquid from the behavior of the sub-threshold pressure wave, and adjusting a setting of the jetting device on the basis of the indicator. The method also includes keeping the array of ejection units at a reference temperature, establishing a reference profile, and establishing an operation profile of the indicator. The setting is adjusted on the basis of a difference between the operation profile and the reference profile, thus eliminating non-temperature related differences between the ejection units.

A control device controls an image printing by a printing execution unit. The control device performs: determination processing of determining whether a first condition indicating that a supply of ink from an ink supply unit to a printing head is possibly delayed at a partial printing is satisfied, for each of a plurality of band images included in an image to be printed and aligned in a sub-scanning direction; first printing processing of, in a case where the first condition is not satisfied, causing the printing execution unit to print the band image by single time partial printing; and second printing processing of, in a case where the first condition is satisfied, causing the printing execution unit to print each of N partial images included in the band image and aligned in the sub-scanning direction by single time partial printing, to print the band image by N times partial printings.

According to one embodiment, a liquid ejection device includes a nozzle plate in which nozzles for ejecting liquid are arranged, an actuator, a liquid supply unit, and a drive control unit. The actuator is provided in each of the nozzles. The liquid supply unit communicates with the nozzles. When one of a plurality of nozzles is given attention, the drive control unit gives drive signals to actuators of nozzles adjacent in an X direction and a Y direction, to drive the actuators at a timing shifted by a predetermined amount, such as half of a drive period, from a timing of an actuator of the nozzle given attention.

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.

An ink-jet recording apparatus, including: a recording head including a first nozzle communicating with a first chamber storing a first ink and a second nozzle communicating with a second chamber storing a second ink whose viscosity change rate differs from the first ink; and a controller configured to determine a drive voltage to be a first voltage and determine voltage application timings for the respective first and second nozzles to be a first timing when estimated viscosity of the first ink is lower than a first viscosity and to determine the drive voltage to be a second voltage higher than the first voltage, determine the voltage application timing for the first nozzle to be the first timing, and determine the voltage application timing for the second nozzle to be a second timing different from the first timing when the estimated viscosity is equal to or higher than the first viscosity.

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(.sub.2/.sub.1).sup.0.109<1.0,

where .sub.1 is a viscosity of the first liquid, .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.

A liquid ejecting apparatus is configured to record a pattern group including a first pattern and a second pattern by driving a moving mechanism to perform a relative movement between a head and a recording medium and by driving the head to eject liquid towards the recording medium. The first pattern and the second pattern are recorded at different timings. Further, recording of the second pattern is performed when a temperature of the liquid in the head is temperature T2 which is different, by a target temperature difference or more, from temperature T1 which is a temperature of the liquid when the first pattern is recorded.

A liquid ejecting head includes a nozzle from which liquid is ejected, a pressure compartment that is in communication with the nozzle, a flow passage configured to lead the liquid between the nozzle and pressure compartment, and an air discharge mechanism configured to discharge air to outside from inside of the flow passage.