US 11,835,920 B2
Toner and manufacturing method thereof and developer containing the same
Tadanori Kano, Sakai (JP)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP)
Filed by SHARP KABUSHIKI KAISHA, Sakai (JP)
Filed on Feb. 1, 2021, as Appl. No. 17/164,206.
Claims priority of application No. 2020-022445 (JP), filed on Feb. 13, 2020.
Prior Publication US 2021/0255560 A1, Aug. 19, 2021
Int. Cl. G03G 9/097 (2006.01); G03G 9/08 (2006.01)
CPC G03G 9/09725 (2013.01) [G03G 9/0808 (2013.01); G03G 9/0812 (2013.01); G03G 9/0819 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A toner comprising at least a negatively-charged toner master particle, and an external additive externally added onto a surface of the toner master particle,
wherein the external additive comprises a fine powder and a small particle size silica having an average particle diameter smaller than that of the fine powder, and wherein the fine powder is a composition comprising at least aluminum hydroxide and silica and has a surface treated with silane,
wherein the toner master particle is further externally added with a large particle size silica having an average particle diameter larger than that of the fine powder,
wherein when an electrostatic capacity value of the toner master particle is less than 1, a coating ratio of the small particle size silica, the fine powder (P), and the large particle size silica (Q) on the toner master particle, 1:P:Q, satisfies relations of the following formulae:
P≥0.20 and 0.27≥Q≥0.04; and
wherein when the electrostatic capacity value of the toner master particle is 1 or more, a coating ratio of the small particle size silica, the fine powder (X), and the large particle size silica (Y) on the toner master particle, 1:X:Y, satisfies relations of the following formulae:
X≥0.46 and 0.27≥Y≥0.04.