A printhead control circuit outputs a first signal to a second wire while a first wire coupled to a first terminal is being supplied with a first voltage signal; outputs a second signal to the second wire coupled to a second terminal while the first wire is being supplied with a second voltage signal; outputs a third signal to the second wire while a third wire coupled to a third terminal is being supplied with a third voltage signal; outputs a fourth signal to the second wire while the third wire is being supplied with a fourth voltage signal; and thereby causes the printhead to perform abnormality detection in response to the first to fourth signals and the first to fourth voltage signals.

A liquid discharge apparatus includes a print head discharging a liquid and a control circuit controlling an operation of the print head. the print head includes a connector having a first terminal, a second terminal, a third terminal, and a fourth terminal, a first integrated circuit, a circuit substrate on which the connector and the first integrated circuit are provided and which has first wiring, second wiring, third wiring, fourth wiring, fifth wiring, and sixth wiring, and a first wiring substrate, in which the first wiring electrically couples the first terminal and the first integrated circuit to each other, the fifth wiring electrically couples the first terminal and the first integrated circuit to each other, and the sixth wiring electrically couples the first integrated circuit and the first wiring substrate to each other.

A liquid ejecting apparatus executing a print operation of ejecting liquid to a medium when a print job is input includes nozzles configured to eject liquid, piezoelectric elements corresponding to the nozzles, and driving circuits configured to supply a micro vibration pulse for generating micro vibration in the liquid included in the nozzles without ejection of the liquid from the nozzles to the piezoelectric elements. Strength of the micro vibration generated by the micro vibration pulse varies based on the print job.

A droplet discharging apparatus that discharges liquid droplets from one or more nozzles based on drive waveforms, includes a memory and a processor configured to execute generating, as the drive waveforms, a first drive waveform, and a second drive waveform to change a drive voltage without discharging the liquid droplets; and controlling to output one set of drive waveforms including a predetermined number of instances of the first drive waveform and one instance of the second drive waveform.

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.

A controller for a print head of an inkjet printing device is described that is configured to generate a virtual timing signal during a printing pause of the printing device, and to use the virtual timing signal for the generation of pre-ejection pulses in order to produce a reliable regeneration of the nozzles of the print head during the printing pause.

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.

A digital printing system (10) includes a print head (622) and a processor (20). The print head is configured to jet droplets of ink. The processor is further configured to translate a required shade of a color, to be printed at a given location on a substrate by tire print head, into a sequence of pulses (625, 630), the sequence including: (a) up to a predefined maximum number of driving pulses (625) that cause the print head to jet respective droplets, and (b) a tickling pulse (630), 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.

A drive circuit includes a drive signal output circuit that outputs a drive signal supplied to the piezoelectric element and a first constant voltage signal that is constant at a first voltage value; a switch circuit having one end electrically coupled to an output terminal of the drive signal output circuit and the other end electrically coupled to the first terminal of the piezoelectric element, and a reference voltage signal output circuit that is electrically coupled to the second terminal of the piezoelectric element and outputs a second constant voltage signal which is constant at a second voltage value, in which before the reference voltage signal output circuit starts to output the second constant voltage signal, the one end and the other end of the switch circuit are controlled to be non-conductive, and the drive signal output circuit outputs the first constant voltage signal.

A liquid ejecting apparatus includes a head unit, and a drive signal output unit that outputs a drive signal. The head unit includes a first rigid substrate, and a first connector to which the drive signal is input, the drive signal output unit includes a second rigid substrate, and a second connector from which the drive signal is output, the first connector includes a first fixing portion, and a first terminal, the second connector includes a second fixing portion, and a second terminal, one of the first connector and the second connector has a receptacle shape, the other has a plug shape, the first connector and the second connector are fitted so that the first terminal and the second terminal are in direct contact with each other, and at least one of the first fixing portion and the second fixing portion is tin-plated.