Patent ID: 8837992

Claim:
A powder feeding device comprising: a powder container configured to contain powder; a feeding tank including an input port through which the powder is supplied from the powder container, an output port through which the powder is discharged to outside, and a suction port through which air in the feeding tank is suctioned; a negative pressure room configured to be in communication with the feeding tank via a suction port communicating tube connected to the suction port; an air suction device configured to be in communication with the negative pressure room via a negative pressure room communication tube connected to a negative pressure room suction port formed on the negative pressure room; a suction port opening and closing unit configured to open and close an inside of the suction port communicating tube; a negative pressure room opening and closing unit configured to open and close an inside of the negative pressure room communication tube; an output port opening and closing unit configured to open and close the output port; and a controller configured to perform a negative pressure generation control, a powder supply control, and a powder discharge control; wherein, in the negative pressure generation control, after causing the suction port opening and closing unit to close the inside of the suction port communicating tube and causing the negative pressure room opening and closing unit to open the inside of the negative pressure room communication tube, the controller is configured to drive the air suction device so as to suction air in the negative pressure room, and after that, when a pressure in the negative pressure room is equal to a negative pressure state, the controller is configured to stop the air suction device and cause the negative pressure room opening and closing unit to close the inside of the negative pressure room communication tube, wherein, in the powder supply control, after causing the output port opening and closing unit to close the output port and causing the suction port opening and closing unit to open the inside of the suction port communicating tube, the controller is configured to cause the suction port opening and closing unit to open the inside of the suction port communicating tube so as to supply the powder from the powder container to the feeding tank, and after that, when determining that an amount of powder is supplied to the feeding tank, the controller is configured to cause the suction port opening and closing unit to close the inside of the suction port communicating tube, wherein, in the powder discharge control, the controller is configured to cause the output port opening and closing unit to open the output port so as to discharge the powder from the output port, the powder having been supplied into the feeding tank, and wherein the controller is configured to simultaneously start the negative pressure generation control and the powder discharge control.