A print head drive circuit drives a print head including an ejecting portion ejecting a liquid in response to a drive signal propagating through a drive signal line and a storage portion storing ejecting portion-related information changing in accordance with use of the ejecting portion, in which processing of reading the ejecting portion-related information changing in accordance with the use from the storage portion is performed before the drive signal for ejecting the liquid from the ejecting portion is supplied to the print head.

A liquid discharge head unit includes a liquid discharge head that has a first detection resistor that is provided to correspond to a first piezoelectric element group, a second detection resistor that is provided to correspond to a second piezoelectric element group, a power supply circuit that causes a current to flow through the first detection resistor and the second detection resistor, a voltage detection circuit that detects a voltage, and a switching circuit that is configured to switch between a first state in which the voltage detection circuit is configured to detect a voltage generated in the first detection resistor due to the current flowing from the power supply circuit and a second state in which the voltage detection circuit is configured to detect a voltage generated in the second detection resistor due to the current flowing from the power supply circuit.

A print element substrate comprises print elements generating thermal energy for ejecting liquid; and a temperature detection element circuit including temperature detection elements provided corresponding to each of the print elements, and reading temperature information by selectively energizing one of the temperature detection elements, wherein the temperature detection element circuit includes: a signal processing portion outputting a selection signal having a second voltage amplitude larger than a first voltage amplitude, based on an input signal having the first voltage amplitude; a selection switch provided for each of the plurality of temperature detection elements, selecting the temperature detection element; and a first read switch provided for each of the plurality of temperature detection elements, reading a voltage of a terminal of one of the temperature detection element selected by the selection switch, and wherein the selection switch and the first read switch are driven by using the selection signal.

There is disclosed a method of supplying an n-channel transistor, operating as a voltage regulator, with a supply voltage and providing a control voltage to the n-channel transistor. The n-channel transistor is controlled by the control voltage to output an operating voltage of a printhead at a predetermined voltage.

In some examples, a fluid dispensing device includes a reservoir containing a fluid, fluidic actuators, and an interface to receive a data packet comprising information to control activation of the fluidic actuators, the data packet comprising a random number generated by a random number generator.

A method for correcting an image includes: moving first and second ink jet heads and a medium relative to each other, each of the first and second ink jet heads including nozzles and drive elements corresponding to the nozzles respectively; discharging ink droplets from the nozzles of the first and second ink jet heads, by connecting each of the drive elements to one of power supply circuits and by applying voltage to each of the drive elements, the power supply circuits having different output voltage values each other; determining a density difference between a first image region and a second image region; and switching the voltage to be applied to first drive elements to a first voltage by switching the power supply circuits to be connected to the first drive elements based on the density difference.

There is provided a liquid discharging apparatus including: a liquid discharging head; an electrode; a voltage supplier configured to generate an electric potential difference between the liquid discharging head and the electrode; a first output part; and a voltage comparer connected to the voltage supplier. The voltage comparer includes a comparing signal output part configured to output a comparing signal. The voltage supplier is configured to: execute boosting to increase the magnitude of the voltage to be outputted from the voltage supplier in a case that the comparing signal indicates that a magnitude of the voltage outputted from the voltage supplier is not more than a magnitude of a predetermined voltage; and stop the boosting in a case that the comparing signal indicates that the magnitude of the voltage outputted from the voltage supplier is larger than the magnitude of the predetermined voltage.

There is provided a liquid discharge apparatus including: a liquid discharge head having a nozzle; an electrode facing the nozzle; a power supply which generates a potential difference between the liquid discharge head and the electrode; a first output unit which outputs a first signal in accordance with an electric change in a case that the liquid discharge head is caused to perform inspection driving; a low-pass filter; a second output unit; a high-pass filter; a third output unit; and a controller. The controller executes determination as to whether or not the liquid is normally discharged from the nozzle, based on the first signal; and determination as to whether or not a short circuit occurs between the liquid discharge head and the electrode, based on a second signal output from the second output unit and a third signal output from the third output unit.

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.

A printhead, comprises: a printing element; a first power supply wiring configured to be electrically connected to one terminal of the printing element and supply power to the printing element; a transistor configured to electrically connected to another terminal of the printing element, and drive the printing element; a first ground wiring configured to be electrically connected to a source of the transistor; a second ground wiring configured to be electrically connected to a back gate of the transistor; and a first capacitive element configured to be electrically connected, at one terminal thereof, to the first ground wiring and electrically connected at another terminal thereof, to the second ground wiring.