公开(公告)号：US12253825B2

公开(公告)日：2025-03-18

申请号：US17433593

申请日：2020-02-20

Applicant: POWDERTECH CO., LTD.

Inventor： Makoto Ishikawa ,  Tetsuya Uemura

IPC: G03G9/107 ,  C01G49/00 ,  C01G49/06 ,  G03G9/113 ,  H01F1/34 ,  H01F1/36

Abstract: The present invention relates to a ferrite particle, containing a crystal phase component containing a perovskite crystal represented by the compositional formula:
RZrO3 (provided that R represents an alkaline earth metal element), and having an apparent density in a range represented by the following formula: 1.90≤Y≤2.45 provided that Y in the formula is the apparent density (g/cm3) of the ferrite particle.

公开(公告)号：US09329515B2

公开(公告)日：2016-05-03

申请号：US14227564

申请日：2014-03-27

Applicant: POWDERTECH CO., LTD.

Inventor： Makoto Ishikawa ,  Tetsuya Uemura ,  Masashi Aoki

IPC: G03G9/00 ,  G03G9/113 ,  G03G9/107

CPC classification number: G03G9/1132 ,  G03G9/1075 ,  G03G9/1133 ,  G03G9/1134 ,  G03G9/1135 ,  G03G9/1136

Abstract: Provided is a resin-coated carrier for an electrophotographic developer, wherein the surface of a magnetic particle is coated with a mixed resin composed of two resins, and when the two resins are denoted by the resin 1 and the resin 2, respectively, the relative difference between the respective adsorbed moisture amounts of the resin 1 and the resin 2 at a temperature of 30° C. and a relative humidity of 80% satisfies the following formula (1): 1≦|ax−b(100−x)|≦10  (1) a: the adsorbed moisture content (% by weight) of the resin 1 b: the adsorbed moisture content (% by weight) of the resin 2 x: the content percentage of the resin 1 (0

Abstract translation: 提供一种用于电子照相显影剂的树脂涂覆载体，其中磁性颗粒的表面涂覆有由两种树脂组成的混合树脂，并且当两种树脂分别由树脂1和树脂2表示时，相对 在30℃，相对湿度80％的树脂1和树脂2的各吸附水分量之间的差别满足下式（1）：1＆nlE; | ax-b（100-x）| ＆lt; nlE; 10（1）a：树脂1b的吸附水分含量（重量％）b：树脂吸附的水分含量（重量％）2 x：树脂1的含量百分比（0

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：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：US09201329B2

公开(公告)日：2015-12-01

申请号：US13738324

申请日：2013-01-10

Applicant: Powdertech Co., Ltd.

Inventor： Koji Aga ,  Makoto Ishikawa ,  Masashi Aoki

IPC: G03G9/10 ,  G03G9/107

CPC classification number: G03G9/1075 ,  G03G9/107

Abstract: A porous ferrite core material for an electrophotographic developer wherein the apparent density thereof is 1.5 to 1.9 g/cm3, the shape factor SF-2 thereof is 101 to 110 and the magnetization as measured with a VSM at 1K·1000/4π·A/m is 40 to 60 Am2/kg, a resin-coated ferrite carrier for an electrophotographic developer obtained by coating the surface of the porous ferrite core material with a resin, and an electrophotographic developer using the ferrite carrier.

Abstract translation: 一种用于电子照相显影剂的多孔铁氧体芯材料，其表观密度为1.5至1.9g / cm 3，其形状系数SF-2为101至110，并且以1K·1000/4＆amp; / m为40〜60Am 2 / kg，通过用树脂涂布多孔铁素体芯材的表面而得到的电子照相显影剂用树脂被覆铁氧体载体和使用该铁氧体载体的电子照相显影剂。