| CPC B41J 2/14112 (2013.01) | 8 Claims |

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1. A liquid ejection head substrate comprising:
electrothermal conversion elements that apply heat to a liquid;
an upper electrode part in which a plurality of upper electrodes that protect the electrothermal conversion elements are formed at positions where the upper electrodes come into contact with the liquid;
a counter electrode part which is provided to correspond to the upper electrode part and in which a plurality of counter electrodes are formed to be electrically connectable to the upper electrodes via the liquid; and
a generation unit that generates a voltage to be applied to the upper electrode part and the counter electrode part,
wherein a plurality of the upper electrode parts and a plurality of the counter electrode parts are provided,
wherein the generation unit comprises a plurality of digital-analog converters which set a voltage to output based on an input signal and applies the voltage to each combination of the upper electrode part and the counter electrode part corresponding to the upper electrode part by using a different one of the digital-analog converters, and
wherein the plurality of digital-analog converters selectively apply a voltage to the upper electrode part and the counter electrode part corresponding to each other via a switch unit.
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