A determination method of determining a supply signal to be supplied to a first electrode and a second electrode includes an acquisition step of acquiring, when a predetermined condition is satisfied, first information regarding a liquid ejection characteristic when a first constant potential signal of a first potential is supplied to the second electrode, and second information regarding a liquid ejection characteristic when a second constant potential signal of a second potential different from the first potential is supplied to the second electrode, and a determination step of determining, based on the first information and the second information, the supply signal to be supplied to the first electrode and the second electrode after the predetermined condition is satisfied.

A liquid ejecting apparatus includes: a channel substrate having one or more pressure chambers, an absorbing chamber that absorbs vibration of a liquid; a vibration plate that is stacked on the channel substrate; a first piezoelectric element that is provided on a first surface of the vibration plate, which is on a side opposite to a side on which the pressure chamber is present, at a position overlapping the pressure chamber when viewed and that vibrates the vibration plate to apply pressure to the liquid; a second piezoelectric element that is provided on the first surface of the vibration plate at a position overlapping the absorbing chamber and that deforms to absorb the vibration of the liquid propagated from the pressure chamber; and a pressure detecting section that detects, based on an electromotive force of the second piezoelectric element, pressure of the liquid in the absorbing chamber.

A printing apparatus includes a first printing unit including a plurality of nozzles configured to eject ink onto a medium, a second printing unit configured to perform printing on the medium using a special liquid, a defective nozzle detector configured to detect a defective nozzle among the plurality of nozzles, and a control unit configured to control the first printing unit and the second printing unit. The special liquid is a liquid rendered invisible depending on an elapsed time after printing on the medium or an environment in which a printed result on the medium is visually recognized.

A liquid ejecting device includes: a liquid ejecting head configured to eject a liquid from a plurality of nozzles to perform printing; an imaging unit configured to image a nozzle surface at which the plurality of nozzles are provided; an ejection-failure detecting unit configured to detect whether the plurality of nozzles have an ejection failure; a maintenance unit configured to perform maintenance of the liquid ejecting head; a notification unit configured to perform notification; and a control unit, in which, when the ejection-failure detecting unit detects the ejection failure, the control unit causes the imaging unit to image a nozzle for which the ejection failure is detected, infers a cause of the ejection failure based on a result of the imaging, and performs at least one of the maintenance and the notification based on the inferred cause.

In some examples, a fluid dispensing device includes a plurality of fluidic actuators and a decoder to detect that a first fluidic actuator is to be activated, and detect that a sense measurement is to be performed. In response to detecting that the first fluidic actuator is to be activated and the sense measurement is to be performed, the decoder is to suppress activation of the first fluidic actuator at a first time, and activate the first fluidic actuator at a second time corresponding to a sense measurement interval to perform the sense measurement of the first fluidic actuator.

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 liquid ejecting apparatus includes: an acquisition unit that acquires first vibration information on an inspection target ejecting portion out of the ejecting portions concerning a vibration generated in a first detection period included in a first period in which the liquid ejecting apparatus forms a first printed image on the medium, and acquires second vibration information on the inspection target ejecting portion concerning a vibration generated in a second detection period corresponding to the first detection period, the second detection period being included in a second period that starts after completion of the first period, in which the liquid ejecting apparatus forms a second printed image related to the first printed image on the medium. The liquid ejecting apparatus also includes an inspection unit that inspects a ejection state of the liquid from the inspection target ejecting portion based on the first vibration information and the second vibration information.

A liquid ejecting apparatus includes an ejection section that includes a nozzle which ejects a liquid, a pressure chamber which communicates with the nozzle, and a piezoelectric actuator which imparts a pressure fluctuation to the liquid in the pressure chamber, a drive waveform generation section that generates a drive waveform including a non-ejection vibration pulse which, when supplied to the piezoelectric actuator, imparts the pressure fluctuation to the liquid in the pressure chamber such that the liquid is not ejected from the nozzle and a control section that controls supply of the non-ejection vibration pulse to the piezoelectric actuator in accordance with a temperature of the liquid in the pressure chamber.

A machine learning method includes: obtaining a discharge parameter on discharging performed by a liquid discharge head discharging liquid; obtaining an image quality determination result produced by determining a printed image quality; and learning the relationship between the discharge parameter and the image quality determination result. Also, the discharge parameter desirably includes a discharge state value indicating a discharge state of the liquid discharge head and a discharge result value indicating a discharge result of the liquid discharged on a print medium from the liquid discharge head. The machine learning method includes learning the relationship between the discharge state value and the discharge result value, and the image quality determination result.

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.