Ink jet printer nozzle clogging-preventive device

Claim 1

An ink jet printer clogging-preventive device for position­ing a carriage at a non-travel part when non-printing is performed and for covering a printing head installed on the carriage with a cap member at the non-travel part, said device comprising: a moving mechanism including a cap member placed oppositely to the printing head of the carriage at said non-travel part and located movably in the direction away from or near to said printing head and a drive source to move said cap member toward the printing head; a first opening/closing means to open and close an ink passage connected from said printing head to an ink supply tank when the printing head is covered with said cap member; a switching means to switch the inside to the cap member to closed condition or to atmospherically open condition when the printing head is covered with said cap member, a pump means connected to the inside of said cap member in order to lead the internal pressure of said cap member to a negative value when the printing head is covered with said cap member; a maintenance liquid supply means to supply a maintenance liquid into said cap member; a second opening/closing means to open and close said maintenance liquid supply means; a control means to control said moving mechanism, said first opening/closing means, said switching means, said pump means; said maintenance liquid supply means and second opening/­closing means and a directing means to direct a recovery operation of a nozzle in the printing head if air enters said nozzle; characterized in that said control means allows the first motion by which the moving mechanism is drived according to the non-printing condition with the printer power on and to the normal power-off condition to cause the printing head to be covered with said cap member, allows the second motion by which the moving mechanism is drived according to the printer power-off conditions such as the printer transportation and long-period printer stoppage conditions to cause the printing head to be covered with the cap member, and the maintenance liquid supply means if actuated to cause the cap member to be filled with the maintenance liquid, and allows the third motion by which following said second motion and according to the nozzle recovery direction the internal pressure of the cap member is reduced (to a negative value) by the pump means to cause the bubbles in the nozzle to be discharged.