A printhead may include a nozzle, a firing chamber fluidly coupled to the nozzle, a printing fluid slot fluidly coupled to the firing chamber, and a sensor to detect a plurality of complex impedance values of a printing fluid at the printhead over a plurality of frequencies and create a printing fluid signature of the printing fluid. A method of determining at least one characteristic of a printing fluid provided to a printhead ma include, with a number of sensors, applying an alternating current at a plurality of frequencies over time to the printing fluid to receive a plurality of complex impedance values and comparing the plurality of complex impedance signals to a number of stored signals.

A print element substrate comprises: a plurality of heaters configured to cause discharge of droplets; a pad array in which a plurality of pads configured to do electrical connection from an outside are arranged; and a plurality of resistance monitor elements configured to measure resistance values of the plurality of heaters, wherein the plurality of resistance monitor elements are arranged along a direction of the pad array.

A printing apparatus for printing using a printhead including a plurality of nozzles each configured to discharge ink and a plurality of sensors, corresponding to the plurality of nozzles, for detecting a discharge state of ink from the plurality of nozzles, judges a discharge state. More specifically, the apparatus prints, based on print data, an image by driving the printhead under a first drive condition to discharge the ink from the printhead to a first area, discharges ink to a second area different from the first area by driving the printhead, based on inspection data, under a second drive condition different from the first drive condition, and judges a discharge state of each nozzle by monitoring an output from each sensor at a timing of driving the printhead under the second drive condition.

A semiconductor device used for a liquid discharge head includes first heaters configured to apply energy to a liquid, second heaters whose resistance values are to be measured, switch elements, and first and second lines. Each of the second heaters is connected in series with a corresponding one of the switch elements between the first line and the second line. The second heaters have shapes different in at least one of length or width. A connection destination of at least one of two terminals of each of the first heaters is different from connection destinations of two terminals of each of the second heaters.

Provided is a technique which can inspect liquid ejection energy without changing electric wiring on an ejection element substrate of a liquid ejection head or ejecting liquid from the liquid ejection head. A liquid ejection head as an ejection-energy inspection target includes an ejection element substrate having a substrate, a heat generation portion having an electrothermal converter on the substrate, a protective film covering the electrothermal converter, and an organic layer covering the electrothermal converter and the protective film. For this liquid ejection head, an electrical resistance value of the electrothermal converter is acquired as a first measurement result, and the film thickness of a film thickness measurement portion of the ejection element substrate where the protective film is exposed is acquired as a second measurement result. Further, information on ejection energy needed to eject liquid from the ejection port is obtained based on the first and second measurement results.

A distance between the first circuit and the second circuit is a first distance, a distance between the first circuit and the temperature detection circuit is a second distance longer than the first distance, and a distance between the second circuit and the temperature detection circuit is a third distance longer than the first distance.

A printhead comprises a printing element, a driving circuit configured to drive the printing element, an analog signal processing circuit configured to process one or more analog signals, a bias circuit configured to supply a bias voltage to the analog signal processing circuit, and a control terminal to which a control signal is inputted. In a state in which the analog signal processing circuit and the bias circuit are receiving a supply of power, it is possible to switch starting and stopping of at least one of the analog signal processing circuit and the bias circuit based on the control signal.

There is provided a drive method of a liquid discharge apparatus including a liquid discharge head that includes a nozzle, a pressure chamber, a piezoelectric element, a drive line, and a resistor that is made of the same material as any of the first electrode, the second electrode, and the drive line. The method includes: executing a non-printing process of preventing a liquid from being discharged toward a recording medium after executing a first printing process of printing a first image on the recording medium and before executing a second printing process of printing a second image on the recording medium; and detecting a potential of the resistor when a state of a potential applied to the drive line is in a state of causing no liquid to be discharged from the nozzle during an execution period of the non-printing process.

A print element substrate comprises: a plurality of heaters configured to cause discharge of droplets; a pad array in which a plurality of pads configured to do electrical connection from an outside are arranged; and a plurality of resistance monitor elements configured to measure resistance values of the plurality of heaters, wherein the plurality of resistance monitor elements are arranged along a direction of the pad array.

A semiconductor device used for a liquid discharge head is provided. The device includes first heaters configured to give energy to a liquid, second heaters resistance values of which are to be measured, switch elements, and first and lines. Each of the second heaters is connected in series with a corresponding one of the switch elements between the first line and the second line. The second heaters have shapes different in at least one of length or width. A connection destination of at least one of two terminals of each of the first heaters is different from connection destinations of two terminals of each of the second heaters.