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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
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：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
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.
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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
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.
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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
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：US11150569B2
公开(公告)日：2021-10-19
申请号：US16200338
申请日：2018-11-26
Applicant: POWDERTECH CO., LTD.
Inventor： Yuzuru Yamasaki , Takao Sugiura , Takeshi Naito , Tetsuya Uemura
Abstract: Provided are a ferrite carrier core material for an electrophotographic developer having a full length L1 of grain boundary and a circumference length L2 of the core material in a cross-section of the core material, and satisfying a relationship of 2≤L1/L2≤9; a carrier for an electrophotographic developer including the ferrite carrier core material and a coating layer containing a resin provided on a surface of the ferrite carrier core material; and an electrophotographic developer including the carrier and a toner.
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Patent Agency Ranking
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
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
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.
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8.发明授权Resin-coated carrier for electrophotographic developer and electrophotographic developer using the resin-coated carrier 有权用于电子照相显影剂的树脂涂覆载体和使用树脂涂布载体的电子照相显影剂公开(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
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
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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
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.
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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
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.
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