Liquid ejecting apparatus and maintenance method of liquid ejecting apparatus

1. A liquid ejecting apparatus comprising:

a liquid ejecting portion that has a supply port through which a liquid flows in, a discharge port through which the liquid flows out, a common flow path communicating with the supply port and the discharge port, an individual liquid chamber communicating with the common flow path, a nozzle communicating with the individual liquid chamber, a nozzle surface on which a plurality of the nozzles are open, and a discharge element, and that discharges the liquid in the individual liquid chamber from the nozzle toward a medium by driving the discharge element;

a liquid supply flow path coupled to the supply port so that the liquid is supplied to the liquid ejecting portion;

a liquid return flow path coupled to the discharge port so that the liquid supplied to the liquid ejecting portion is returned to the liquid supply flow path;

a pressurization mechanism that pressurizes the liquid in the liquid ejecting portion;

a return valve provided in the liquid return flow path and configured to take a valve-closed state blocking a flow of the liquid and a valve-opened state allowing the flow of the liquid; and

a control portion, wherein

the control portion performs a pressurization discharge operation of discharging the liquid from the nozzle by causing the pressurization mechanism to pressurize the liquid in the liquid ejecting portion and a pressure lowering operation of causing the pressurization mechanism to stop the pressurization in the liquid ejecting portion, and performs the pressure lowering operation in a state where the return valve is closed.

2. The liquid ejecting apparatus according to claim 1 , further comprising:

a wiping mechanism that performs a wiping operation of wiping the nozzle surface, wherein

the control portion drives the wiping mechanism to perform the wiping operation in a state where the return valve is closed after the pressure lowering operation.

3. The liquid ejecting apparatus according to claim 2 , wherein

the control portion drives the discharge element to perform a flushing operation of discharging the liquid from the nozzle, and performs the flushing operation in the state where the return valve is closed after the wiping operation.

4. The liquid ejecting apparatus according to claim 3 , wherein

the control portion performs the flushing operation during the pressure lowering operation.

5. The liquid ejecting apparatus according to claim 1 , wherein

when a pressure in the common flow path is defined as a common flow path internal pressure and the common flow path internal pressure when discharging the liquid from the nozzle toward the medium is defined as a discharge pressure, the common flow path internal pressure in the pressurization discharge operation is higher than the discharge pressure, and the common flow path internal pressure after the pressure lowering operation is lower than the common flow path internal pressure in the pressurization discharge operation and higher than the discharge pressure.

6. The liquid ejecting apparatus according to claim 1 , further comprising:

a liquid storage portion that stores the liquid supplied to the liquid ejecting portion and is coupled to the liquid supply flow path and the liquid return flow path; and

a supply valve provided between the liquid storage portion in the liquid supply flow path and the liquid ejecting portion and configured to take a valve-closed state blocking the flow of the liquid and a valve-opened state allowing the flow of the liquid, wherein

the pressurization mechanism is provided between the liquid storage portion in the liquid supply flow path and the supply valve, and

the control portion performs the pressurization discharge operation in a state where the supply valve is opened, and performs the pressure lowering operation in a state where the supply valve is closed.

7. The liquid ejecting apparatus according to claim 6 , further comprising:

a return-side flow mechanism provided between the return valve in the liquid return flow path and the liquid storage portion and discharging the liquid from the discharge port, wherein

the supply valve opens when a pressure in the common flow path is equal to or lower than a predetermined pressure, and

the control portion causes the return-side flow mechanism to discharge the liquid from the discharge port.

8. The liquid ejecting apparatus according to claim 1 , wherein

the control portion closes the return valve before performing the pressurization discharge operation.

9. The liquid ejecting apparatus according to claim 1 , further comprising:

a wiping mechanism that performs a wiping operation of wiping the nozzle surface, wherein

the control portion drives the wiping mechanism to perform the wiping operation in a state where the return valve is closed during the pressure lowering operation.

10. A maintenance method of a liquid ejecting apparatus which includes

a liquid ejecting portion that has a supply port through which a liquid flows in, a discharge port through which the liquid flows out, a common flow path communicating with the supply port and the discharge port, an individual liquid chamber communicating with the common flow path, a nozzle communicating with the individual liquid chamber, a nozzle surface on which a plurality of the nozzles are open, and a discharge element, and that discharges the liquid in the individual liquid chamber from the nozzle toward a medium by driving the discharge element,

a liquid supply flow path coupled to the supply port so that the liquid is supplied to the liquid ejecting portion, and

a liquid return flow path coupled to the discharge port so that the liquid supplied to the liquid ejecting portion is returned to the liquid supply flow path,

the maintenance method comprising:

performing a pressurization discharge operation of pressurizing the liquid in the liquid ejecting portion and discharging the liquid from the nozzle; and

performing a pressure lowering operation of lowering a pressure in the liquid ejecting portion in a state where a flow of the liquid in the liquid return flow path is blocked after the pressurization discharge operation.

11. The maintenance method of a liquid ejecting apparatus according to claim 10 , further comprising:

performing a wiping operation of wiping the nozzle surface in a state where the flow of the liquid in the liquid return flow path is blocked after the pressure lowering operation.

12. The maintenance method of a liquid ejecting apparatus according to claim 11 , further comprising:

performing a flushing operation of driving the discharge element to discharge the liquid from the nozzle in a state where the flow of the liquid in the liquid return flow path is blocked after the wiping operation.

13. The maintenance method of a liquid ejecting apparatus according to claim 12 , wherein

the flushing operation is performed during the pressure lowering operation.

14. The maintenance method of a liquid ejecting apparatus according to claim 10 , wherein

when a pressure in the common flow path is defined as a common flow path internal pressure and the common flow path internal pressure when discharging the liquid from the nozzle toward the medium is defined as a discharge pressure, the common flow path internal pressure in the pressurization discharge operation is higher than the discharge pressure, and the common flow path internal pressure after the pressure lowering operation is lower than the common flow path internal pressure in the pressurization discharge operation and higher than the discharge pressure.

15. The maintenance method of a liquid ejecting apparatus according to claim 10 , further comprising:

performing a wiping operation of wiping the nozzle surface in a state where the flow of the liquid in the liquid return flow path is blocked during the pressure lowering operation.