US Patent 7841688 Liquid ejecting apparatus

A liquid ejecting apparatus including a liquid ejecting head, a liquid supply passage, a gas discharge passage, a gas-permeable film, a switching device, and a differential pressure valve. The gas-permeable film allows only gases to pass therethrough and provides a partition separating the gas discharge passage and the liquid supply passage. The switching device selectively connects a sucking device with one of the gas discharge passage and a liquid suction cap. The differential pressure valve is disposed in a portion of the gas discharge passage between the gas permeable film and the switching device and opens by a suction pressure from the sucking device to communicate the gas permeable film with the switching device when the sucking device is operating, and prevents communication between the gas permeable film and the switching device when the sucking device is not operating.