Recording apparatus and control method

A control method of a recording apparatus, the recording apparatus including a liquid ejection head including (1) a heating element that generates thermal energy required to eject liquid, the liquid including pigment charged to a negative potential, (2) a first protection layer that blocks contact between the heating element and the liquid, (3) a second protection layer that covers at least a portion of the first protection layer to be heated by the heating element and that functions as a first electrode, (4) a second electrode that is electrically connected to the first electrode through the liquid, (5) an ejection port that ejects the liquid, and (6) a temperature detection element that corresponds to the heating element, the control method comprising:

• detecting a feature point in a temperature curve that is obtained by the temperature detection element and that indicates a relationship between time and temperature,
• wherein the recording apparatus has (1) a non-ejection determination mode in which a determination as to whether or not the liquid is normally ejected from the ejection port is made, based on whether or not the detecting has detected the feature point in the temperature curve, and (2) a printing mode in which printing is performed without making the determination,
• wherein in the printing mode, a potential set for the first electrode and a potential set for the second electrode are controlled so that an electric field that reduces a presence ratio of the pigment near a surface of the second protection layer is formed between the first electrode and the second electrode, and
• wherein in the non-ejection determination mode, the potential set for the first electrode and the potential set for the second electrode are made different from that under potential control in the printing mode.