US 12,275,254 B2
Inkjet printing method and inkjet printing apparatus
Kenta Hagiwara, Kanagawa (JP); Shunsuke Horie, Kanagawa (JP); and Hiroki Kobayashi, Kanagawa (JP)
Assigned to Ricoh Company, Ltd., Tokyo (JP)
Filed by Kenta Hagiwara, Kanagawa (JP); Shunsuke Horie, Kanagawa (JP); and Hiroki Kobayashi, Kanagawa (JP)
Filed on May 25, 2023, as Appl. No. 18/323,759.
Claims priority of application No. 2022-086531 (JP), filed on May 27, 2022; and application No. 2023-067899 (JP), filed on Apr. 18, 2023.
Prior Publication US 2023/0382122 A1, Nov. 30, 2023
Int. Cl. B41J 2/175 (2006.01); B41J 2/17 (2006.01)
CPC B41J 2/17556 (2013.01) [B41J 2/1707 (2013.01); B41J 2/17503 (2013.01); B41J 2/1714 (2013.01); B41J 2/175 (2013.01)] 7 Claims
OG exemplary drawing
 
1. An inkjet printing method, comprising:
discharging ink contained in an ink storage unit, from a nozzle of a nozzle forming surface of a discharging unit; and
supplying the ink from the ink storage unit to the discharging unit, wherein
the ink comprises a silicone-based surfactant, an organic solvent, a resin, and water,
the ink satisfies the following relational expression (1),
σ=a×Log10(t)+b  Expression (1)
where, in the expression (1), a and b represent constants, the constant a is −17.5 or more and −5.9 or less, the constant b is 38.0 or more and 68.1 or less, σ represents dynamic surface tension of ink (unit: mN/m) at 25° C., and t represents time (unit: millisecond),
the supplying includes
forming a closed space by covering the nozzle forming surface with a lid member, and freely controlling a pressure between the discharging unit and the ink storage unit; and
forming an open space by opening the lid member on the nozzle forming surface, and setting the pressure between the discharging unit and the ink storage unit to be the same as atmospheric pressure,
a negative pressure difference between the ink storage unit and the discharging unit before discharge of the ink is 70 mmAq or more and 120 mmAq or less,
a negative pressure difference between the ink storage unit and the discharging unit during the discharging is 30 mmAq or more and 80 mmAq or less, and
the negative pressure difference between the ink storage unit and the discharging unit before discharge of the ink is equal to or greater than the negative pressure difference between the ink storage unit and the discharging unit during the discharging.