Abstract: A liquid ejection apparatus includes a nozzle, a pressure chamber, a piezoelectric element, a count processing portion, and a detection processing portion. The nozzle ejects a liquid. The pressure chamber communicates with the nozzle and contains the liquid. The piezoelectric element changes a pressure in the pressure chamber in response to an input of a drive signal. The count processing portion counts a number of times that an electric signal output from the piezoelectric element and corresponding to vibration generated in the pressure chamber in response to the input of the drive signal to the piezoelectric element exceeds a predetermined threshold value. The detection processing portion detects a viscosity of the liquid contained in the pressure chamber, based on a count result of the count processing portion.

Abstract: A liquid ejection apparatus includes a nozzle, a pressure chamber, a piezoelectric element, an acquisition processing portion, and a restriction processing portion. The nozzle ejects a liquid. The pressure chamber communicates with the nozzle and contains the liquid. The piezoelectric element changes a pressure in the pressure chamber in response to an input of a drive signal. When image formation processing for ejecting the liquid from the nozzle is executed based on image data, the acquisition processing portion acquires a length of a non-ejection period in which the liquid is not ejected from the nozzle, the non-ejection period being included in an execution period of the image formation processing. When the length of the non-ejection period acquired by the acquisition processing portion is less than a predetermined first threshold value, the restriction processing portion restricts abnormality detection processing for detecting an abnormality of the nozzle using the piezoelectric element.

Abstract: A liquid ejection apparatus includes a nozzle, a pressure chamber, a piezoelectric element, an output processing portion, and a determination processing portion. The nozzle ejects a liquid. The pressure chamber communicates with the nozzle and contains the liquid. The piezoelectric element changes a pressure in the pressure chamber in response to an input of a drive signal. The output processing portion causes the piezoelectric element to output a first electric signal corresponding to vibration generated in the pressure chamber in response to the input of the drive signal to the piezoelectric element. The determination processing portion determines whether or not the pressure chamber is in a filled state in which the pressure chamber is filled with the liquid, based on a frequency of the first electric signal output by the output processing portion.

Abstract: A signal generation device includes a first signal generation portion and a second signal generation portion. The first signal generation portion, based on a reference signal that includes a plurality of rectangular single-wave signals, generates an original common signal in which the rise times of the two or more of the single-wave signals are extended so that they are different from each other, and the fall timing of one or more of the single-wave signals is shifted. The second signal generating portion generates a drive signal to be input to a piezoelectric element by extracting a rising edge of any one of the single-wave signals, the rise time of which is extended, from the original common signal amplified by the amplifying portion, maintaining a signal level changed by extracting the rising edge of the single-wave signal, and extracting a falling edge of a single-wave signal after the single-wave signal.