Liquid discharging apparatus
An ink jet printer is provided with a driving signal generating section which generates a driving signal for driving a piezoelectric element, a residual vibration detecting section, a control IC which includes the residual vibration detecting section, and a connection terminal which connects the piezoelectric element, an input terminal to which the driving signal is supplied and an output terminal from which an output signal of the residual vibration detecting section is supplied, a first external wiring which is connected to the input terminal and through which the driving signal is supplied, and a second external wiring which is connected to the output terminal and through which the output signal of the residual vibration detecting section is supplied. A resistance value per unit length of the second external wiring is larger than a resistance value per unit length of the first external wiring.
1. A liquid discharging apparatus comprising:
a nozzle which discharges liquid;
a pressure chamber which communicates with the nozzle;
a piezoelectric element which is provided in order to discharge liquid corresponding to the pressure chamber;
a driving signal generating section which generates a driving signal for driving the piezoelectric element;
a residual vibration detecting section which detects changes in electromotive force of the piezoelectric element in accordance with residual vibration inside the pressure chamber and generates an output signal;
a selection section which selects whether to supply the driving signal to the piezoelectric element or to supply electromotive force of the piezoelectric element to the residual vibration detecting section;
a semiconductor integrated circuit including the residual vibration detecting section, the selection section, a connecting section which connects the piezoelectric element, an input terminal to which the driving signal is supplied, and an output terminal from which an output signal of the residual vibration detecting section is output;
a first external wiring which is connected to the input terminal and through which the driving signal is supplied;
a second external wiring which is connected to the output terminal and through which an output signal of the residual vibration detecting section is supplied;
a first internal wiring provided between the input terminal and the selection section; and
a second internal wiring provided between the selection section and the residual vibration detecting section, wherein:
a resistance value per unit length of the second external wiring is larger than a resistance value per unit length of the first external wiring,
a line width of the second internal wiring is narrower than a line width of the first internal wiring,
the selection section includes:
a first switch that is disposed to be capable of switching between application and non-application of the driving signal to the piezoelectric element and includes a first transistor; and
a second switch that is disposed to be capable of switching between application and non-application of changes in the electromotive force to the residual vibration detecting section and includes a second transistor,
the first transistor and the second transistor have the same polarity,
the size of the second transistor is smaller than the size of the first transistor, and
when viewing from the second internal wiring side as seen from the second switch, an input impedance of the second internal wiring side is larger than the on-resistance of the second transistor.
2. A liquid discharging apparatus comprising:
a nozzle that discharges liquid;
a pressure chamber that communicates with the nozzle;
a piezoelectric element that is provided in order to discharge liquid corresponding to the pressure chamber;
a driving signal generating section that generates a driving signal for driving the piezoelectric element;
a residual vibration detecting section that detects changes in electromotive force of the piezoelectric element in accordance with residual vibration inside the pressure chamber and generates an output signal;
a selection section that selects whether to supply the driving signal to the piezoelectric element or to supply electromotive force of the piezoelectric element to the residual vibration detecting section;
a semiconductor integrated circuit including the residual vibration detecting section, the selection section, a connecting section that connects the piezoelectric element, an input terminal to which the driving signal is supplied, and an output terminal from which an output signal of the residual vibration detecting section is output;
a first external wiring that is connected to the input terminal and through which the driving signal is supplied;
a second external wiring that is connected to the output terminal and through which an output signal of the residual vibration detecting section is supplied, wherein a line width of the second external wiring is narrower than a line width of the first external wiring, and a resistance value per unit length of the second external wiring is larger than a resistance value per unit length of the first external wiring such that an impedance of the second external wiring is higher than an impedance of the first external wiring;
a first internal wiring provided between the input terminal and the selection section; and
a second internal wiring provided between the selection section and the residual vibration detecting section, wherein a line width of the second internal wiring is narrower than a line width of the first internal wiring, wherein:
the selection section includes:
a first switch that is disposed to be capable of switching between application and non-application of the driving signal to the piezoelectric element and includes a first transistor; and
a second switch that is disposed to be capable of switching between application and non-application of changes in the electromotive force to the residual vibration detecting section and includes a second transistor,
the first transistor and the second transistor have the same polarity,
the size of the second transistor is smaller than the size of the first transistor, and
when viewing from the second internal wiring side as seen from the second switch, an input impedance of the second internal wiring side is larger than the on-resistance of the second transistor.