US 12,436,476 B2
Method for producing pigment dispersion, and method for producing toner for developing electrostatic charge images
Yuta Saeki, Kanagawa (JP); and Takeshi Tanabe, Kanagawa (JP)
Assigned to FUJIFILM Business Innovation Corp., Tokyo (JP)
Filed by FUJIFILM Business Innovation Corp., Tokyo (JP)
Filed on Sep. 6, 2022, as Appl. No. 17/903,503.
Claims priority of application No. 2022-024960 (JP), filed on Feb. 21, 2022.
Prior Publication US 2023/0266686 A1, Aug. 24, 2023
Int. Cl. C09D 17/00 (2006.01); G03G 9/08 (2006.01)
CPC G03G 9/0804 (2013.01) [C09D 17/003 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for producing a pigment dispersion, the method comprising:
wet-dispersing a mixture A containing an organic pigment, a flame retardant, a dispersant, and an aqueous medium by using a media disperser to form a mixture B; and
wet-dispersing the mixture B by using a media disperser to form a mixture C,
wherein the media disperser in the wet-dispersing of the mixture A and the media disperser in the wet-dispersing of the mixture B are annular-type media dispersers each having a cylindrical vessel, a cylindrical rotor that is disposed inside the cylindrical vessel and that rotates to disperse the mixture, and a screen-type media separator that separates media particles and the mixture, and
a number-average particle size MA of the media particles in the media disperser in the wet-dispersing of the mixture A and a number-average particle size MB of the media particles in the media disperser in the wet-dispersing of the mixture B satisfy the following formula (1) and the following formula (2):
0.5 mm≥MA>MB≥0.05 mm,  Formula (1):
0.3 mm≥MB≥0.05 mm.  Formula (2).