公开(公告)号：US10969706B2

公开(公告)日：2021-04-06

申请号：US16483709

申请日：2018-01-15

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Tetsuya Uemura

IPC: G03G9/083 ,  G03G9/107 ,  G03G9/113 ,  H01F1/36

Abstract: Provided are a magnetic core material for electrophotographic developer and a carrier for electrophotographic developer, which are excellent in charging characteristics and strength with low specific gravity and with which a satisfactory image free of defects can be obtained, and a developer containing the carrier.
A magnetic core material for electrophotographic developer, having a sulfur component content of from 60 to 800 ppm in terms of a sulfate ion and a pore volume of from 30 to 100 mm3/g.

公开(公告)号：US09588453B2

公开(公告)日：2017-03-07

申请号：US14673557

申请日：2015-03-30

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Takao Sugiura

IPC: G03G9/113 ,  G03G9/10 ,  G03G9/107

CPC classification number: G03G9/10 ,  G03G9/1075 ,  G03G9/113 ,  G03G9/1131 ,  G03G9/1136 ,  G03G9/1138

Abstract: There is provided a resin-filled ferrite carrier for an electrophotographic developer, in which a void of a porous ferrite particle used as a ferrite carrier core material is filled with silicone resin, wherein a true specific gravity (Y) of the porous ferrite particle filled with the silicone resin and a Si/Fe value (X) measured by fluorescent X-ray elemental analysis satisfy the following inequality (1): −350X≦Y−4.83≦−100X  (1).

Abstract translation: 提供一种用于电子照相显影剂的树脂填充铁氧体载体，其中用作铁氧体载体芯材料的多孔铁氧体颗粒的空隙填充有硅树脂，其中填充的多孔铁氧体颗粒的真比重（Y） 与硅树脂和通过荧光X射线元素分析测得的Si / Fe值（X）满足以下不等式（1）： - 350 ¢X‰¤Y - 4.83‰¤ - 100 ¢X

公开(公告)号：US11112716B2

公开(公告)日：2021-09-07

申请号：US16751031

申请日：2020-01-23

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Atsushi Nil ,  Yuji Ito ,  Hajime Akiba ,  Shinya Hanyu

IPC: G03G9/00 ,  G03G9/107 ,  G03G9/08

Abstract: The present invention relates to a carrier core material for electrophotographic developer, having a ferrite composition and having a supernatant transmittance of 85.0% or more, a method for producing the carrier core material, a carrier for electrophotographic developer, containing the carrier core material, and a developer containing the carrier.

公开(公告)号：US10996579B2

公开(公告)日：2021-05-04

申请号：US16483718

申请日：2018-01-15

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Tetsuya Uemura

IPC: G03G9/00 ,  G03G9/107 ,  G03G9/083 ,  G03G9/113 ,  H01F1/11

Abstract: A magnetic core material for electrophotographic developer, satisfying a value of Expression (1): a+b×10+c+d+e+f, being from 200 to 1,400, 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 pore volume of from 30 to 100 mm3/g.

公开(公告)号：US10036982B2

公开(公告)日：2018-07-31

申请号：US15007415

申请日：2016-01-27

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Tetsuya Uemura

IPC: G03G9/10 ,  G03G9/107 ,  G03G9/113 ,  G03G15/09

CPC classification number: G03G15/0928 ,  G03G9/10 ,  G03G9/1075 ,  G03G9/1131 ,  G03G9/1132 ,  G03G9/1138

Abstract: An object of the present invention is to provide a carrier in which decrease in specific gravity is achieved and a volatile organic compound (VOC) is reduced and to provide an electrophotographic developer using the carrier. There is provided a carrier including a core material coated with a resin, the core material including a magnetic component and a nonmagnetic component, wherein the sum total of volatile organic compounds is 1 ppb or more and 1.5 ppm or less. There is also provided an electrophotographic developer using the carrier.

公开(公告)号：US10996576B2

公开(公告)日：2021-05-04

申请号：US16474497

申请日：2017-12-25

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Tetsuya Uemura

IPC: G03G9/113 ,  G03G9/107 ,  G03G9/10 ,  G03G9/083

Abstract: Provided are a magnetic core material for electrophotographic developer and a carrier for electrophotographic developer, which are excellent in charge characteristics and strength and with which a satisfactory image free from defects can be obtained, and a developer containing the carrier.
A magnetic core material for electrophotographic developer, having a sulfur component content of from 50 to 700 ppm in terms of a sulfate ion and a BET specific surface area of from 0.06 to 0.25 m2/g.

公开(公告)号：US10248039B2

公开(公告)日：2019-04-02

申请号：US15696698

申请日：2017-09-06

Applicant: POWDERTECH CO., LTD.

Inventor： Hiroki Sawamoto ,  Hajime Akiba ,  Tetsuya Uemura

IPC: G03G9/113 ,  G03G9/107 ,  G03G9/10

Abstract: An object of the present invention is to provide a carrier low in specific gravity and less in both environmental fluctuation and change of the charge amount after aging, an electrophotographic developer using the carrier, and a method of manufacturing the carrier. To achieve the object, the carrier is manufactured by coating a core material composed of a magnetic component and a non-magnetic component with a resin, and the carrier is characterized in that water content is 200 ppm or less and cyclic siloxane content is 100 ppb or less. Further, an electrophotographic developer containing the carrier is provided.

公开(公告)号：US12204280B2

公开(公告)日：2025-01-21

申请号：US17430440

申请日：2020-02-13

Applicant: POWDERTECH CO., LTD.

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

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

Abstract: The present invention relates to a carrier including: a magnetic core material; and a resin coating layer coating a surface of the magnetic core material, in which the resin coating layer contains a binder resin, and fluorine element-containing resin particles dispersed in the binder resin, the resin coating layer has a coefficient of variation of a film thickness of 25% or less, and the resin coating layer has an average value of the number of the fluorine element-containing resin particles being 3 particles/μm2 or more and 350 particles/μm2 or less per unit area in a cross section of the resin coating layer, and has a coefficient of variation thereof being 20% or less.

公开(公告)号：US11422480B2

公开(公告)日：2022-08-23

申请号：US16492894

申请日：2018-03-29

Applicant: POWDERTECH CO., LTD.

Inventor： Makoto Ishikawa ,  Hiroki Sawamoto ,  Tetsuya Uemura

IPC: G03G9/107 ,  G03G9/08 ,  G03G9/083 ,  G03G9/113

Abstract: The present invention provides: a ferrite carrier core material for an electrophotographic developer, the material having a mesh passing amount of 3 wt % or less as indicated by the ratio of the weight of particles passing through a 16 μm-mesh to the weight of whole particles constituting a powder, and having a particle strength index of 2 wt % or less as indicated by a difference between the mesh passing amounts before and after crushing; a ferrite carrier which is for an electrophotographic developer and in which the surface of the ferrite carrier core material is coated with a resin; and an electrophotographic developer which includes the ferrite carrier and a toner.

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.