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公开(公告)号：US20230296999A1
公开(公告)日：2023-09-21
申请号：US18022961
申请日：2021-08-24
Applicant: POWDERTECH CO.,LTD.
Inventor： Makoto ISHIKAWA , Tetsuya UEMURA
IPC: G03G9/107
CPC classification number: G03G9/1085
Abstract: The present invention relates to a ferrite particle containing a crystal phase component containing a perovskite-type crystal represented by a composition formula of RZrO3 (wherein R is an alkaline earth metal element), and a Mg content of 0.45 mass % or less. The present invention also relates to a carrier core material for an electrophotographic developer, containing the ferrite particle; a carrier for an electrophotographic developer, containing the ferrite particle and a resin coating layer provided on a surface of the ferrite particle; and an electrophotographic developer containing the carrier for an electrophotographic developer and a toner.
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公开(公告)号：US20220019151A1
公开(公告)日：2022-01-20
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：US20190049870A1
公开(公告)日：2019-02-14
申请号：US16059405
申请日：2018-08-09
Applicant: POWDERTECH CO., LTD.
Inventor： Aya SAKUTA , Makoto ISHIKAWA , Hiroki SAWAMOTO , Tetsuya UEMURA
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.
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公开(公告)号：US20190204761A1
公开(公告)日：2019-07-04
申请号：US15779501
申请日：2018-03-06
Applicant: POWDERTECH CO., LTD.
Inventor： Hiroki SAWAMOTO , Tetsuya UEMURA
CPC classification number: G03G9/1075 , G03G9/0819 , G03G9/107 , G03G9/1131 , G03G9/1139
Abstract: To provide a magnetic core material for electrophotographic developer and carrier for electrophotographic developer which are excellent in a rising-up of charge amount, can suppress a carrier scattering, and can stably provide good images; a developer containing the carrier; a method for producing the magnetic core material for electrophotographic developer; a method for producing the carrier for electrophotographic developer; and a method for producing the developer.The magnetic core material for electrophotographic developer, containing a sulfur component in a content of from 1 to 45 ppm in terms of a sulfate ion.
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公开(公告)号：US20220155702A1
公开(公告)日：2022-05-19
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.-
Patent Agency Ranking
公开(公告)号：US20200057399A1
公开(公告)日：2020-02-20
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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7.发明申请公开(公告)号：US20200026211A1
公开(公告)日：2020-01-23
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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8.发明申请公开(公告)号：US20190163081A1
公开(公告)日：2019-05-30
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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公开(公告)号：US20180074426A1
公开(公告)日：2018-03-15
申请号：US15696698
申请日：2017-09-06
Applicant: POWDERTECH CO., LTD.
Inventor： Hiroki SAWAMOTO , Hajime AKIBA , Tetsuya UEMURA
CPC classification number: G03G9/1133 , G03G9/10 , G03G9/107 , G03G9/1075 , G03G9/1131 , G03G9/1132 , G03G9/1136
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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10.发明公开公开(公告)号：US20240264546A1
公开(公告)日：2024-08-08
申请号：US18564577
申请日：2022-05-27
Applicant: POWDERTECH CO., LTD.
Inventor： Yuzuru YAMASAKI , Makoto ISHIKAWA , Tetsuya UEMURA
CPC classification number: G03G9/1085 , C01G49/06 , C01P2002/32 , C01P2002/70 , C01P2006/12
Abstract: The present invention provides a ferrite particle containing: a ferrite particle body having a spinel crystal structure belonging to a space group Fd-3m and having a spinel composition represented by the following formula (1); and a coating layer having a spinel crystal structure belonging to the space group Fd-3m and coating a surface of the ferrite particle body, in which the coating layer is a layer obtained by subjecting the ferrite represented by the following formula (1) to a heat treatment, and a content ratio of the coating layer in the ferrite particle obtained by subjecting a powder X-ray diffraction pattern to Rietveld analysis is 5 mass % or more and 35 mass % or less, and the ferrite particle satisfies a specific formula (2). The present invention also provides a carrier for an electrophotographic developer.
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