US 12,257,845 B2
Ink replacement method in ink-jet recording apparatus
Noriaki Furukawa, Osaka (JP); Shunsuke Yamasaki, Osaka (JP); and Kaori Kitayama, Osaka (JP)
Assigned to KYOCERA DOCUMENT SOLUTIONS INC., Osaka (JP)
Filed by KYOCERA Document Solutions Inc., Osaka (JP)
Filed on Mar. 16, 2023, as Appl. No. 18/185,308.
Claims priority of application No. 2022-049053 (JP), filed on Mar. 24, 2022.
Prior Publication US 2023/0302808 A1, Sep. 28, 2023
Int. Cl. B41J 2/175 (2006.01)
CPC B41J 2/17523 (2013.01) [B41J 2/175 (2013.01); B41J 2/17596 (2013.01)] 4 Claims
OG exemplary drawing
 
1. An ink replacement method in an ink-jet recording apparatus including
a recording head having an ink ejection face in which a plurality of nozzles for ejecting ink onto a recording medium are arranged,
a sub-tank that temporarily stores the ink fed from an ink container, and
an ink flow passage through which the ink circulates from the sub-tank via the recording head to the sub-tank,
wherein
gas is inserted between a first ink present in the ink flow passage and a second ink newly supplied to the recording head via the ink flow passage to form a gas-liquid interface between the first and second ink and the gas, and then the first ink is replaced with the second ink,
the method comprising;
an ink discharging process in which the first ink in the ink flow passage is discharged out of the recording head until the sub-tank becomes empty;
a gas filling process in which the gas is circulated from the empty sub-tank through the ink flow passage into the recording head; and
an ink injecting process in which the second ink is ejected from the sub-tank through the ink flow passage into the recording head.