US 12,411,429 B2
Toner, developer, toner storage unit, image forming apparatus, and image forming method
Akinori Saitoh, Shizuoka (JP); Akio Takei, Shizuoka (JP); Toma Takebayashi, Shizuoka (JP); Masahiro Yukikawa, Kanagawa (JP); Tomomi Harashima, Shizuoka (JP); and Hiroshi Yamada, Shizuoka (JP)
Assigned to Ricoh Company, Ltd., Tokyo (JP)
Filed by Akinori Saitoh, Shizuoka (JP); Akio Takei, Shizuoka (JP); Toma Takebayashi, Shizuoka (JP); Masahiro Yukikawa, Kanagawa (JP); Tomomi Harashima, Shizuoka (JP); and Hiroshi Yamada, Shizuoka (JP)
Filed on Jul. 6, 2022, as Appl. No. 17/811,054.
Claims priority of application No. 2021-114475 (JP), filed on Jul. 9, 2021.
Prior Publication US 2023/0014605 A1, Jan. 19, 2023
Int. Cl. G03G 9/087 (2006.01); G03G 9/08 (2006.01); G03G 9/093 (2006.01)
CPC G03G 9/08755 (2013.01) [G03G 9/0806 (2013.01); G03G 9/0819 (2013.01); G03G 9/08711 (2013.01); G03G 9/09328 (2013.01); G03G 9/09371 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A toner comprising
toner base particles, each including an amorphous polyester resin, a crystalline polyester resin, a release agent, and resin particles; and
external additives deposited on a surface of each of the toner base particles,
wherein an abundance ratio of the crystalline polyester resin in the surface of the toner base particle as observed by a transmission electron microscope (TEM) is 2.5% or greater but 25% or less,
the resin particles are deposited at the surface of the toner base particle as observed by a scanning electron microscope (SEM), and
a ratio of aggregates of the resin particles occupying the surface of the toner base particle is 1% or greater but 70% or less, where R is a major axis of the minimum particle of the resin particles, and the resin particle having a major axis of 3R or greater is determined as the aggregate,
wherein the resin particles include resin particles (B) comprising two types of styrene acrylic resins (resin (a1) and resin (a2) and resin particles (A) comprising one type of styrene acrylic resin.