Liquid discharge apparatus and cleaning method that remove an adhered substance from an electrode in first and second operations
A liquid discharge apparatus including a liquid chamber for a liquid, a liquid discharge unit including a heat-generating resistor imparting discharge energy to the liquid, first and second electrodes in the chamber, a first voltage application unit for applying a voltage to the heat-generating resistor, a second voltage application unit for applying a voltage between the first and second electrodes, and a controller controlling the voltage application units. The controller performs, to remove a substance on the first electrode, a first voltage application by the second voltage application unit between the first and second electrodes, in a first voltage application where the first electrode is an anode and a second voltage application where the first electrode is a cathode are alternatingly repeated, to partially dislodge the substance, and a second voltage application by the first voltage application unit to the heat-generating resistor, to remove the substance from the first electrode.
1 . A liquid discharge apparatus comprising:
a liquid chamber that has a discharge orifice for a liquid;
a liquid discharge unit including:
a heat-generating resistor for imparting discharge energy to a liquid in the liquid chamber;
a first electrode that is provided in the liquid chamber so as to cover the heat-generating resistor; and
a second electrode that is provided at a different position from the first electrode in the liquid chamber;
a first voltage application unit capable of applying a voltage to the heat-generating resistor;
a second voltage application unit capable of applying a voltage between the first electrode and the second electrode; and
a control portion that controls the first voltage application unit and the second voltage application unit,
wherein the control portion performs, as operations to remove an adhered substance on the first electrode,
a first operation that is a voltage application by the second voltage application unit between the first electrode and the second electrode, in which a first voltage application where the first electrode is an anode and a second voltage application where the first electrode is a cathode are alternatingly repeated, in order to partially dislodge the adhered substance, and
a second operation that is a voltage application by the first voltage application unit to the heat-generating resistor, the second operation being an operation for separating the adhered substance from the first electrode by applying a discharge energy thereto, in order to remove the adhered substance.
2 . The liquid discharge apparatus according to claim 1 , wherein the second operation is performed after the first operation.
3 . The liquid discharge apparatus according to claim 1 , wherein the second operation is performed in the middle of the first operation.
4 . The liquid discharge apparatus according to claim 1 , further comprising a circulation unit for circulating the liquid in the liquid chamber,
wherein the first operation and the second operation are performed as the circulation unit circulates the liquid in the liquid chamber.
5 . The liquid discharge apparatus according to claim 1 , wherein the voltage that the first voltage application unit applies to the heat-generating resistor in the second operation is pulse voltage.
6 . The liquid discharge apparatus according to claim 5 , wherein the pulse voltage is applied a plurality of times.
7 . The liquid discharge apparatus according to claim 1 , wherein the first operation is an operation for reducing an adherence area of the adhered substance on the first electrode.
8 . The liquid discharge apparatus according to claim 7 , wherein, in the first operation, the first voltage application and the second voltage application are performed at a magnitude of voltage that causes elution of the first electrode into the liquid, but not enough to cause the adhered substance to separate from the first electrode.
9 . The liquid discharge apparatus according to claim 7 , wherein, in the first operation, the first voltage application and the second voltage application are performed for a count of times that causes elution of the first electrode into the liquid, but not enough to cause the adhered substance to separate from the first electrode.
10 . The liquid discharge apparatus according to claim 1 , wherein the voltage that the first voltage application unit applies to the heat-generating resistor in the second operation is of a magnitude to cause film-boiling of ink serving as the liquid.
11 . The liquid discharge apparatus according to claim 1 , wherein the second operation is also an operation for discharging liquid to a recording medium.
12 . The liquid discharge apparatus according to claim 1 , wherein the second operation is also an operation for preliminary discharging liquid.
13 . The liquid discharge apparatus according to claim 1 , wherein the second operation is also an operation for discharging liquid in a state in which a cap is attached to a nozzle into which the discharge orifice opens.
14 . The liquid discharge apparatus according to claim 1 , wherein—the first electrode is made of a material including iridium, ruthenium, or platinum.
15 . A cleaning method for cleaning a liquid discharge apparatus that includes a liquid chamber that has a discharge orifice for a liquid, a liquid discharge unit including a heat-generating resistor for imparting discharge energy to a liquid in the liquid chamber, a first electrode that is provided in the liquid chamber so as to cover the heat-generating resistor, and a second electrode that is provided at a different position from the first electrode in the liquid chamber, a first voltage application unit capable of applying a voltage to the heat-generating resistor, and a second voltage application unit capable of applying a voltage across the first electrode and the second electrode, the cleaning method comprising:
performing operations for removing an adhered substance on the first electrode by:
performing a first operation that is a voltage application by the second voltage application unit between the first electrode and the second electrode, in which a first voltage application where the first electrode is an anode and a second voltage application where the first electrode is a cathode are alternatingly repeated, in order to partially dislodge the adhered substance; and
performing a second operation that is a voltage application by the first voltage application unit to the heat-generating resistor, the second operation being an operation for separating the adhered substance from the first electrode by applying a discharge energy thereto, in order to remove the adhered substance.
16 . The liquid discharge apparatus according to claim 1 , wherein the adhered substance is scorching.
17 . The cleaning method for cleaning a liquid discharge apparatus according to claim 15 , wherein the first operation is an operation to reduce an adherence area of the adhered substance on the first electrode.
18 . The cleaning method for cleaning a liquid discharge apparatus according to claim 15 , wherein the adhered substance is scorching.