Cleaning method and ink ejection apparatus

An apparatus comprising:

• an inkjet head including an ejection port for ejecting ink, an electrothermal conversion unit disposed in an ink flow path communicating with the ejection port, an insulating protective layer for blocking contact between the electrothermal conversion unit and the ink in the ink flow path, and an upper protective layer that covers a portion of the insulating protective layer to be heated by the electrothermal conversion unit;
• a counting unit configured to count the number of pulse applications for driving the electrothermal conversion unit;
• and
• a determination unit configured to determine whether the number of the pulse applications is equal to or greater than a threshold value,
• wherein, in a state where the upper protective layer is used as an anode electrode and a portion that is conductive to the upper protective layer via the ink is used as a cathode electrode, a surface of the upper protective layer is configured to be dissolved by electrochemical reaction, and
• wherein the apparatus further comprises a change unit configured to switch a voltage to be applied for the electrochemical reaction from a first voltage to a second voltage greater than the first voltage in a case where a determination result by the determination unit is equal to or greater than a threshold value.