A print head control circuit includes a first diagnosis signal propagation wiring for propagating a first diagnosis signal, a fifth diagnosis signal propagation wiring for propagating a fifth diagnosis signal indicating a diagnosis result, and a second voltage signal propagation wiring for propagating a second voltage signal. The fifth diagnosis signal propagation wiring and the second voltage signal propagation wiring are electrically coupled to each other via a fifth terminal and a seventh terminal, and the first diagnosis signal propagation wiring and the second diagnosis signal propagation wiring are located to be aligned. The first diagnosis signal propagation wiring and the second voltage signal propagation wiring are located to be adjacent to each other in a direction in which the first diagnosis signal propagation wiring and the second diagnosis signal propagation wiring are aligned.

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.

In a method of nozzle failure detection in an ink jet printer having a plurality of ejection units including a nozzle and an associated liquid chamber with an electromechanical transducer, nozzle failure detection is performed, for each ejection unit, with a given minimum detection frequency. Each nozzle failure detection includes energizing the transducer with a waveform that does not lead to the ejection of a droplet but creates a pressure fluctuation that is sensitive to whether or not the ejection unit is in a malfunction state; measuring the pressure fluctuation in order to detect the malfunction state; defining a mask pattern that is independent of image contents to be printed; and when an image is being printed, performing the nozzle failure detection steps for each ejection unit at timings at which the respective nozzles are in pixel positions that belong to the mask pattern.

A digital printing system includes a print head and a processor. The print head is configured to jet droplets of ink. The a processor is further configured to translate a required shade of a color, to be printed at a given location on a substrate by the print head, into a sequence of pulses, the sequence including: (a) up to a predefined maximum number of driving pulses that cause the print head to jet respective droplets, and (b) a tickling pulse, which has a smaller amplitude than the driving pulses and which causes the print head to jet a droplet smaller than the droplets jetted in response to the driving pulses. The processor is additionally configured to apply the sequence of pulses to the print head.

An inkjet recording device includes a nozzle, a pressure generator and a driver. The nozzle ejects ink. The pressure generator changes pressure on ink in an ink flow path that communicates with the nozzle by a predetermined drive operation. The driver makes the pressure generator perform the drive operation predetermined limes of at least twice at time points on a predetermined cycle, and makes the nozzle eject an ink droplet of an amount corresponding to a number of drive operations included in a set of drive operations. In a case in which the number of drive operations is two, the driver makes the pressure generator perform the drive operation twice with an interval twice as long as the cycle.

To provide a head device, a liquid jetting apparatus, and a head maintenance method with which it is possible to suppress a decrease in performance of a liquid-repellent film on a nozzle surface that is caused by a wiping process with respect to the nozzle surface. Provided is a head device including an ink jet head (10) in which a liquid-repellent film (10B) is formed on a nozzle surface (10A) and a head control unit. The head control unit applies a negative pressure to liquid in a nozzle, performs a non-jetting driving operation of causing the liquid in the nozzle to vibrate without being jetted, and stops the non-jetting driving operation for a wiping target nozzle (12A) with which a wiping member (22) to be used in a wiping process comes into contact in a case where the wiping process with respect to the nozzle surface is to be performed.

In a liquid discharging apparatus, a head control unit, which controls an operation of a head unit, includes a first conversion circuit that converts an image signal input from an outside into a first electric signal, a first photoelectric conversion circuit that converts the first electric signal into an optical signal, the head unit, which discharges a liquid, includes a second photoelectric conversion circuit that converts the optical signal into a second electric signal, a second conversion circuit that converts the second electric signal into a discharge control signal for controlling discharge of a liquid. The first conversion circuit performs a first conversion process of converting the image signal into the first electric signal without depending on a discharge information, and the second conversion circuit performs a second conversion process of converting the second electric signal into the discharge control signal by using the discharge information.

A print head drive circuit outputs an output signal from a terminal electrically coupled to a low voltage logic signal input terminal to which a low voltage logic signal is input and has a first mode in which the print head drive circuit controls a print head to execute reading processing of reading information stored in a memory and not to execute ejection control processing of controlling whether or not to supply a high voltage signal to an ejecting portion group by switching a switch group in accordance with the output signal and a second mode in which the print head drive circuit controls the print head not to execute the reading processing and to execute the ejection control processing in accordance with the output signal.

According to one embodiment, an actuator of a liquid ejection head is supplied with a drive signal including a first waveform and at least one second waveform. First waveform includes a first change from a first voltage to a second voltage, and a second change from the second voltage to a third voltage less than the first voltage. A second waveform begins after a time equal to one half of the natural oscillation period of liquid in a pressure chamber of the liquid ejection head. The second waveform includes a change from the third voltage to the second voltage and a change from second voltage to the third voltage after a time less than one half of the natural oscillation period.

A width in a second direction of the first portion disposed in a position corresponding to the first piezoelectric body in the third electrode which intersects with the first direction is a first width. A width in a second direction of the second portion in the third electrode disposed in a position corresponding to the second piezoelectric body is a second width. A width in the second direction of the third portion in the third electrode disposed in a position between the first piezoelectric body and the second piezoelectric body in the first direction is a third width which is smaller than the first width and the second width.