A method of controlling a liquid ejecting apparatus that includes a liquid ejecting head having nozzles configured to eject a liquid, pressure chambers communicating with the nozzles, and drive elements configured to change the volume in the pressure chambers, and a drive-waveform generating circuit configured to generate a drive waveform for driving the drive elements to vibrate the liquid in the nozzles is provided. The method includes detecting a power-off operation for issuing an instruction for turning off an electric power of the liquid ejecting apparatus and vibrating the liquid by driving piezoelectric elements by the drive waveform in response to detecting the power-off operation by the detecting.

There is provided a liquid discharge head including a drive IC that outputs the first signal and the second signal, and a wiring substrate having a first side and a second side longer than the first side, electrically connected to the drive IC, and propagating the first signal and the second signal, in which the wiring substrate includes a first electrode to which the first signal is input, a second electrode to which the second signal is input, a third electrode electrically connected to the first electrode, and a fourth electrode electrically connected to the second electrode, and in a direction along the second side, the second electrode is positioned between the first electrode and the third electrode, and the third electrode is positioned between the second electrode and the fourth electrode.

To provide an adjusting method for a printing apparatus, and the printing apparatus, capable of appropriately adjusting drive voltages of heads even when printing conditions are changed, this invention can appropriately acquire adjusted voltages of the heads even when printing conditions are changed. That is, according to this invention, a construction is configured to change an adjustable range of head drive voltages with a printing mode. This invention acquires the adjustable range corresponding to the printing mode set by referring to a table Ti. Consequently, the adjusted voltages of the heads can be determined within the adjustable range suited to each printing mode.

A power supply control apparatus comprises a first power supply supplying power to a controller and a second power supply supplying power to an operation unit and a power controller. The operation unit receives an operation for switching the first power supply on and off. The power controller is operable to turn on the first power supply according to the signal from a timer or the operation by the operation unit, and to turn off the first power supply according to a state of the controller. The controller, upon at least either of the operation by the operation unit or the signal from the timer, performs a setting to the timer of a time at which to turn on the power from the first power supply or a time at which to turn off the power from the first power supply.

A liquid ejection system includes a first head unit and a second head unit. The first head unit includes a first determining circuit that determines whether a first power supply voltage is normal, a first drive circuit that outputs a first drive signal based on the first power supply voltage, and a first ejecting head that ejects liquid The second head unit includes a second determining circuit that determines whether a second power supply voltage is normal, a second drive circuit that outputs a second drive signal based on the second power supply voltage, and a second ejecting head that ejects liquid When the first determining circuit determines that the first power supply voltage is not normal, or when the second determining circuit determines that the second power supply voltage is not normal, the first ejecting head and the second ejecting head stop ejecting the liquid.

In some examples, a controller includes an interface to receive an indication based on an electrical current through a device, and a processor to send control data to the device to operate the device, detect a measurement based on the indication that is responsive to an operation of the device according to the control data, and determine whether an issue exists in the device responsive to determining whether the measurement satisfies an expected property based on the control data.

A liquid-droplet ejecting apparatus includes: N nozzles; N driving elements; M power supply circuits that create a driving signal to be selectively supplied to the N driving elements; and N selecting circuits that selectively connect one of the M power supply circuits to a corresponding one of the N driving elements. The N driving elements are connected to the M power supply circuits in a first combination until a particular condition is satisfied. The first combination is a combination between the M power supply circuits and an M driving element groups, into which the N driving elements are divided based on a voltage of the supplied driving signal. The N driving elements are connected to the M power supply circuits in a second combination after the particular condition is satisfied. The second combination is another combination between the M driving element groups and the M power supply circuits.

A printing apparatus that performs printing by using a print head includes a first power supply, a second power supply, and a control unit. The first power supply supplies a first voltage to the print head through a first supply line. The second power supply supplies a second voltage to the print head through a second supply line. The control unit supplies the first voltage from the first power supply without supplying a voltage from the second power supply at the time of an inspection of the print head, and executes a process action concerning a current leakage when a voltage exceeding a predetermined first threshold is generated on the second supply line.

The power supply unit includes a circuit substrate including a first layer that is a surface layer being conductive, a first wiring pattern formed of the first layer, a second layer that is conductive, and a second wiring pattern formed of the second layer, and first and second capacitors formed on the first layer. The first capacitor includes a first terminal and a second terminal. The second capacitor includes a third terminal and a fourth terminal. The circuit substrate includes a first electrode connecting the first terminal of the first capacitor to the first wiring pattern, a second electrode connecting the second terminal of the first capacitor to the second wiring pattern, a third electrode connecting the third terminal of the second capacitor to the second wiring pattern, and a fourth electrode connecting the fourth terminal of the second capacitor to the first wiring pattern.

A liquid jetting apparatus includes: a liquid jetting head having individual channels, first and second common channels connected to the individual channels, the individual channels having nozzles respectively; a pump which circulates liquid inside the liquid jetting head; and a controller. The controller is configured to: reduce a unit circulation amount of the liquid in stages as standby time becomes longer, the unit circulation amount being a circulation amount of the liquid per unit time by the pump, the standby time being a length of time during which a standby state is continued, the standby state being a state in which the liquid jetting head is ready without jetting the liquid; and in a case of shifting the liquid jetting head from the standby state to a jetting operation, determine a type of recovery operations in accordance with the standby time.