Liquid ejecting apparatus and method of cleaning an ejection head

A liquid ejecting apparatus comprising:

• an ejection head including a nozzle opening capable of ejecting a liquid, a pressure generating chamber communicating to the nozzle opening, and a pressure generating element for changing a pressure in the liquid inside the pressure generating chamber;
• a drive signal generator for generating a drive signal including a drive pulse to be applied to the pressure generating element;
• an application controller for controlling an application of the drive signal to the pressure generating element;
• and
• a suction unit for sucking the liquid in the ejection head through the nozzle opening,
• wherein the drive signal generator is capable of generating a first drive signal which is used when the liquid is ejected toward an object of ejection and a second drive signal which is used at a time of a cleaning operation of the ejection head and whose frequency at which a drive pulse is generated is higher than that of the first drive signal,
• wherein the suction unit is actuated in association with an application of the second drive signal to the pressure generating element,
• wherein an elapsed-time measuring unit is provided for measuring the time elapsed from the time of previous actuation of the suction unit, and
• wherein the application controller applies the second drive signal to the pressure generating element on condition that the elapsed time measured by the elapsed-time measuring unit reaches a reference value for judgment.

A liquid ejecting apparatus comprising:

• an ejection head including a nozzle opening capable of ejecting a liquid, a pressure generating chamber communicating to the nozzle opening, and a pressure generating element for changing a pressure in the liquid inside the pressure generating chamber;
• a drive signal generator for generating a drive signal including a drive pulse to be applied to the pressure generating element;
• an application controller for controlling an application of the drive signal to the pressure generating element;
• and
• a suction unit for sucking the liquid in the ejection head through the nozzle opening,
• wherein the drive signal generator is capable of generating a first drive signal which is used when the liquid is ejected toward an object of ejection and a second drive signal which is used at a time of a cleaning operation of the ejection head and whose frequency at which a drive pulse is generated is higher than that of the first drive signal,
• wherein the suction unit is actuated in association with an application of the second drive signal to the pressure generating element,
• wherein an ejection-number counter is provided for counting the number of ejection of the liquid, and
• wherein the application controller applies the second drive signal to the pressure generating element on condition that the number of ejection counted by the ejection-number counter reaches a reference value for judgment.

A liquid ejecting apparatus comprising:

• an ejection head including a nozzle opening capable of ejecting a liquid, a pressure generating chamber communicating to the nozzle opening, and a pressure generating element for changing a pressure in the liquid inside the pressure generating chamber;
• a first drive signal generator for generating a first drive signal including a drive pulse to be applied to the pressure generating element and used when the liquid is ejected toward an object of ejection;
• a suction unit for sucking the liquid in the ejection head through the nozzle opening;
• a vibration applying element for applying vibration to the liquid inside the pressure generating chamber by vibrating in a period according to the applied drive signal;
• and
• a second drive signal generator for generating a second drive signal including a drive pulse to be applied to the pressure generating element, whose frequency at which a drive pulse is generated is higher than that of the first drive signal;
• and
• an application controller for controlling an application of the second drive signal to the pressure generating element;
• wherein the suction unit is actuated in association with an application of the second drive signal to the pressure generating element.

A method of cleaning an ejection head having a pressure generating chamber communicating to a nozzle opening for ejecting a liquid and a pressure generating element for changing a pressure in the liquid inside the pressure generating chamber, the method comprising the steps of:

• applying to the pressure generating element a second drive signal whose frequency at which a drive pulse is generated is higher than a first drive signal which is used when the liquid is ejected toward an object of ejection;
• sucking the liquid in the ejection head through the nozzle opening in association with the supply of the second drive signal;
• accumulating the liquid outside the ejection head;
• and
• bringing a nozzle surface side of the ejection head into contact with the accumulated liquid.

A method of cleaning an ejection head having a pressure generating chamber communicating to a nozzle opening for ejecting a liquid and a pressure generating element for changing a pressure in the liquid inside the pressure generating chamber, the method comprising the steps of:

• applying to the pressure generating element a second drive signal whose frequency at which a drive pulse is generated is higher than a first drive signal which is used when the liquid is ejected toward an object of ejection;
• and
• sucking the liquid in the ejection head through the nozzle opening in association with the supply of the second drive signal,
• wherein the second drive signal is applied in a state that the liquid flows out from the nozzle opening.