Liquid ejection device
A liquid ejection device has an element substrate having an ejection port; and a voltage application unit applying a voltage to the element substrate, wherein the element substrate has a first layer having the ejection port and a first channel communicating with the ejection port and a second layer fixed to a back face of the first layer and having a second channel communicating with the first channel, a heat element for ejecting the liquid, a first electrode covering a surface of the heat element on a side of the first layer and exposed to the first channel, and a second electrode exposed to the first channel at a position different from the first electrode and not overlapping the heat element on a plan view, and the voltage application unit is configured to apply the voltage so that the first electrode is at a negative potential.
1 . A liquid ejection device comprising:
an element substrate provided with an ejection port for ejecting a liquid; and
a voltage application unit configured to apply a voltage to the element substrate, wherein
the element substrate includes:
a first layer provided with the ejection port on a surface thereof, and
a second layer fixed to a back face of the first layer,
the first layer is provided with a first channel communicating with the ejection port,
the second layer is provided with a second channel communicating with the first channel, a heat element for ejecting the liquid from the ejection port, a first electrode covering a surface of the heat element on a side of the first layer, the first electrode being exposed to the first channel, and a second electrode exposed to the first channel at a position different from the first electrode, the second electrode not overlapping the heat element in a plan view,
the second layer is at a potential of 0 V,
the voltage application unit is configured to apply the voltage so that the first electrode is at a negative potential and the second electrode is at a positive potential, and
the voltage application unit is configured to apply the voltage to the first electrode continuously from before the heat element begins to generate heat for ejecting the liquid from the ejection port and while the heat element is generating the heat.
2 . The liquid ejection device according to claim 1 , wherein
the second layer is provided with a third channel communicating with the first channel, and
the first electrode is positioned between the second channel and the third channel in a flowing direction of the liquid in the first channel.
3 . The liquid ejection device according to claim 2 , wherein the liquid is fed to the first channel from the second channel, and the liquid in the first channel is collected from the third channel.
4 . The liquid ejection device according to claim 3 , wherein the liquid ejection device is configured so that the liquid can be circulated through the liquid ejection device and the outside of the liquid ejection device.
5 . The liquid ejection device according to claim 1 , wherein the first electrode and the second electrode are formed of a same material in a platinum group.
6 . The liquid ejection device according to claim 1 , wherein the first electrode contains Ir, Pt, or Ru.
7 . The liquid ejection device according to claim 1 , further comprising a protective layer between the heat element and the first electrode.
8 . The liquid ejection device according to claim 1 , wherein the voltage application unit is configured to apply the voltage so that a potential difference between the first electrode and the second layer is less than 2.5 V.
9 . The liquid ejection device according to claim 1 , wherein the voltage application unit is configured to apply the voltage so that the first electrode is at a potential of at least −2.0 V and not more than −0.1 V.
10 . The liquid ejection device according to claim 1 , wherein
the first electrode and the second electrode contain Ir, and
the voltage application unit is configured to apply the voltage so that a potential difference between the first electrode and the second electrode is smaller less than 2.5 V.
11 . The liquid ejection device according to claim 1 , wherein
the voltage application unit is configured to apply the voltage so that:
the first electrode is at a potential of at least −2.0 V and not more than −0.1 V, and
the second electrode is at a potential of at least 0.1 V and not more than 2.4 V.
12 . The liquid ejection device according to claim 1 , wherein
the voltage application unit is configured to apply the voltage so that:
the first electrode is at a potential of at least −0.5 V and not more than −0.1 V, and
the second electrode is at a potential of at least 1.0 V and not more than 2.4 V.