A liquid circulation device comprises a liquid chamber connected with a liquid discharge section that discharges liquid, a circulation section which circulates the liquid in a flow path containing the liquid chamber and the liquid discharge section, a liquid supply section, a pressure adjustment section and a control section that, according to fluctuation velocity of the pressure, replenishes the liquid through the liquid supply section if the detected pressure is equal to or smaller than a predetermined pressure value or lower than the predetermined pressure value and the pressure fluctuation velocity is equal to or greater than a predetermined speed or faster than the predetermined speed and adjusts the pressure of the liquid discharge section through the pressure adjustment section and the pressure fluctuation velocity is slower than the predetermined speed or equal to or smaller than the predetermined speed.

A maintenance method for a liquid discharging apparatus including a discharging portion that discharges liquid, the maintenance method includes acquiring first viscosity information related to viscosity of the liquid inside the discharging portion, discharging a first amount of the liquid from the discharging portion, acquiring second viscosity information related to viscosity of the liquid inside the discharging portion, and discharging a second amount of the liquid based on the first viscosity information and the second viscosity information, from the discharging portion.

A print head includes ejecting portions ejecting liquid by being supplied with a high voltage signal, a switch group switching between whether or not to supply the high voltage signal to the first ejecting portion group in accordance with a low voltage logic signal, a memory, a high voltage signal input terminal, and a low voltage logic signal input terminal, the print head having a first mode in which the print head executes reading processing of reading information stored in the memory and does not execute ejection control processing of controlling whether or not to supply the high voltage signal to the first ejecting portion group by switching the switch group in accordance with an input signal input from the low voltage logic signal input terminal and a second mode in which the print head does not execute the reading processing and executes the ejection control processing.

There is provided a print apparatus including: a piezoelectric member; an individual electrode formed in the piezoelectric member; a first common electrode formed in the piezoelectric member so that the first common electrode is opposed to the individual electrode; a second common electrode formed in the piezoelectric member so that the second common electrode is opposed to the individual electrode, a voltage to be applied to the second common electrode being different from a voltage to be applied to the first common electrode; and a detection circuit configured to detect a capacitance of a first capacitor configured by the piezoelectric member, the individual electrode, and the first common electrode and a second capacitor configured by the piezoelectric member, the individual electrode, and the second common electrode. The detection circuit includes an oscillation circuit configured to be connected to the individual electrode.

The invention relates to a method for detecting a failing ejection unit in an array of ejection units during printing of a digital image with liquid ink in a printer wherein a medium is transported relative to the array. The printed image is captured to density values on print positions of the printed image. The invented method comprises a step of adapting a halftone mask that is used in preparation of the digital image, such that from a variation in the image density around the line shaped defect the exact nozzle number associated with the failing ejection unit can be determined.

In a device for regenerating a print head of an inkjet printing device, a fluid is applied onto the nozzle plate of the print head. The one or more nozzles of the print head can be subsequently operated with one or more no-ejection pulses to produce the effect that fluid is drawn from the nozzle plate into the one or more nozzles and mixes with the ink in the one or more nozzles that the viscosity of the ink in the one or more nozzles is reduced.

A printing apparatus, which uses a printhead including a circuit configured to inspect an ink discharge status of a selected nozzle using a temperature detection element, causes the printhead to inspect the ink discharge status by changing a threshold value for judging a detection result of the temperature detection element, in order to judge the ink discharge status in a state in which a heater in the selected nozzle is driven by each of a first pulse and a second pulse whose waveform is different from that of the first pulse, obtains first information about a change point where a judgment result obtained by the first pulse changes, and second information about a change point where a judgment result obtained by the second pulse changes, and sets the threshold value, based on the first and second information.

A liquid ejecting apparatus includes a head unit that ejects liquid, in which the head unit includes an integrated circuit and an ejector, the integrated circuit includes a drive signal input terminal that inputs a first drive signal, a first signal input terminal that inputs a first signal, a second signal input terminal that inputs a second signal, a first reference voltage signal input terminal that inputs a first reference voltage signal, a differential signal receiving circuit that converts a pair of first differential signals into a control signal and outputs the control signal, a drive signal selection circuit that outputs a second drive signal based on the control signal and the first drive signal, and a drive signal output terminal that outputs the second drive signal to the ejector, and the first signal input terminal and the first reference voltage signal input terminal are located adjacent to each other.

An liquid ejecting apparatus includes a drive signal output circuit, a control signal output circuit, a differential signal output circuit, a residual vibration signal input circuit, and a head unit, in which the head unit includes an integrated circuit and an ejector, and the integrated circuit includes a drive signal input terminal that inputs a first drive signal, a residual vibration signal output terminal that outputs a residual vibration signal, a differential signal receiving circuit that converts a pair of differential signals into a control signal and outputs the control signal, a drive signal selection circuit that outputs a second drive signal based on the control signal and the first drive signal, a drive signal output terminal that outputs the second drive signal to the ejector, and a residual vibration signal output circuit that outputs a residual vibration signal based on the residual vibration generated by driving the piezoelectric element.

A printing apparatus includes a head including a plurality of nozzles configured to discharge liquid to a medium, an abnormal nozzle detection unit configured to detect an abnormal nozzle having a discharging defect among the plurality of nozzles, a contact detection unit configured to detect contact between the head and the medium, a suction unit configured to perform an ejection operation of ejecting the liquid from the plurality of nozzles, and a control unit. The control unit executes a suction operation when the abnormal nozzle is detected and the contact between the head and the medium is detected, and the control unit executes a printing of complementing the abnormal nozzle when the abnormal nozzle is detected and the contact between the head and the medium is not detected.