Print head drive circuit and printing apparatus

A printing apparatus comprising:

• a print head that includes 1500 or more ejection modules each having an ejection portion having a piezoelectric element driven by supplying a drive signal and ejecting a liquid on a medium as the piezoelectric element is driven, and a changeover switch switching whether or not to supply the drive signal to the piezoelectric element;
• and
• a print head drive circuit that outputs a selection signal including a first information block and a second information block for selecting whether or not to drive the piezoelectric element driving the print head, and a switching timing signal for changing a logic level to control a switching timing of the changeover switch, wherein
• the first information block includes drive data for controlling a drive of the piezoelectric element,
• the second information block includes drive pattern data that defines a drive pattern of the piezoelectric element, and
• the print head drive circuit
• outputs a clock signal that defines a propagation timing of the selection signal,
• outputs an entirety of the first information block in which a logic level of the selection signal changes without outputting the second information block and without changing a logic level of the switching timing signal in a first period,
• stops the output of the clock signal and changes the logic level of the switching timing signal, and does not change the logic level of the selection signal in a second period after the first period, and
• outputs an entirety of the second information block in which the logic level of the selection signal changes without outputting the first information block and without changing the logic level of the switching timing signal in a third period after the second period.