公开(公告)号：US11099495B2

公开(公告)日：2021-08-24

申请号：US16641987

申请日：2018-03-06

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Tetsuya Uemura

IPC: G03G9/08 ,  G03G9/107 ,  G03G9/113

Abstract: To provide a magnetic core material and carrier for electrophotographic developer, which have small environmental dependence of the electric resistance, can suppress the carrier scattering, and can stably provide good images; a developer contains the carrier; and methods for producing them. The magnetic core material satisfying a value of Formula (1): a+b×10+c+d+e+f, being from 20 to 150, when a fluoride ion amount is denoted by a (ppm), a chloride ion amount is denoted by b (ppm), a bromide ion amount is denoted by c (ppm), a nitrite ion amount is denoted by d (ppm), a nitrate ion amount is denoted by e (ppm), and a sulfate ion amount is denoted by f (ppm), which are measured by a combustion ion chromatography method.

公开(公告)号：US11029618B2

公开(公告)日：2021-06-08

申请号：US16059405

申请日：2018-08-09

Applicant: POWDERTECH CO., LTD.

Inventor： Aya Sakuta ,  Makoto Ishikawa ,  Hiroki Sawamoto ,  Tetsuya Uemura

IPC: G03G9/113

Abstract: There is provided a carrier including a magnetic core material having a surface coated with a surfactant-containing resin mixture of an elemental fluorine-containing resin and a polyimide resin. The carrier has an elution amount of an eluted material into water in an elution test ranging from 180 ppm to 3,500 ppm.

公开(公告)号：US10754271B2

公开(公告)日：2020-08-25

申请号：US16474508

申请日：2017-12-25

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Tetsuya Uemura

IPC: G03G9/107 ,  G03G9/113

Abstract: A magnetic core material for electrophotographic developer, satisfying a value of Expression (1): a+b×10+c+d+e+f, being from 300 to 1,300, when an amount of fluorine ion is denoted by a (ppm), an amount of chlorine ion is denoted by b (ppm), an amount of bromide ion is denoted by c (ppm), an amount of nitrite ion is denoted by d (ppm), an amount of nitrate ion is denoted by e (ppm), and an amount of sulfate ion is denoted by f (ppm), which are measured by combustion ion chromatography, and having a BET specific surface area being from 0.06 to 0.25 m2/g.