Ferrite Core-resin Shell Carrier Patents (Class 430/111.32)
  • Patent number: 10543472
    Abstract: A method of encapsulating particulate materials that enables the particulate materials to be used in end use applications where they currently are not useful. The method uses specific sol gel technology to encapsulate solid particles. In addition, the method can be used to multiple coat a coated particle.
    Type: Grant
    Filed: March 25, 2016
    Date of Patent: January 28, 2020
    Inventor: John D. Blizzard
  • Patent number: 10409188
    Abstract: Provided is a magnetic carrier comprising a magnetic carrier particle having a magnetic body-dispersed resin carrier core material and a resin coating layer; the core material includes magnetic particles A and B having number average primary particle diameter of ra and rb (?m), respectively, satisfying ra?rb; the particles A each include an oxide of at least one nonferrous metal of Mn, Al, Mg, Ti, and Ni; and an iron oxide; M1 represents total content of the nonferrous metal and F1 represents content of an iron of the magnetic carrier particle measured by XRF diffraction, M1/F1 is 0.010 to 0.100; M2 represents total content of the nonferrous metal and F2 represents content of an iron is F2 of the magnetic carrier particle measured by XPS, M2/F2 is 1.0 to 10.0.
    Type: Grant
    Filed: February 6, 2018
    Date of Patent: September 10, 2019
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Nobuyoshi Sugahara, Hironori Minagawa, Wakashi Iida
  • Patent number: 9798264
    Abstract: Provided is a method for producing a carrier for developing an electrostatic latent image, the carrier including carrier particles each including a core particle with a surface coated with a coating material including a resin, and the method including the steps of: a) obtaining first coating resin particles by polymerizing an alicyclic methacrylate monomer using, as a polymerization initiator, an azo compound having a nitrogen atom-containing substituent; b) obtaining second coating resin particles by polymerizing an alicyclic methacrylate monomer using a persulfate as a polymerization initiator; and c) forming carrier particles by coating surfaces of core particles with a coating material obtained by mixing at least the first and second coating resin particles.
    Type: Grant
    Filed: October 3, 2016
    Date of Patent: October 24, 2017
    Assignee: KONICA MINOLTA, INC.
    Inventors: Kosuke Nakamura, Satoshi Uchino, Koji Shibata
  • Patent number: 9778586
    Abstract: The present invention provides a magnetic carrier for an electrophotographic developer which has an excellent durability and a stable charging property and is free from occurrence of spent toner thereonto, and a two-component system developer comprising the magnetic carrier for an electrophotographic developer and a toner. The present invention relates to a core material of a magnetic carrier for an electrophotographic developer comprising spherical composite particles comprising at least ferromagnetic iron oxide fine particles and a cured phenol resin and having an average particle diameter of 1 to 100 ?m, a resin index of the spherical composite particles being within the range of 35 to 80%, and a magnetic carrier obtained by coating a surface of respective particles of the magnetic carrier core material with a resin.
    Type: Grant
    Filed: April 12, 2012
    Date of Patent: October 3, 2017
    Assignee: TODA GOKYO CORPORATION
    Inventors: Kaori Kinoshita, Eiichi Kurita
  • Patent number: 9513571
    Abstract: A magnetic carrier contains a resin-filled magnetic core particle and a resin covering layer provided on a surface of the resin-filled magnetic core particle. The resin-filled magnetic core particle is a porous magnetic particle containing a resin in pores thereof. The magnetic carrier has a 50% particle diameter (D50) of 30.0 ?m or more and 80.0 ?m or less on a volume basis. An electric current flowing through the magnetic carrier at a voltage of 500 V ranges from 8.0 to 50.0 ?A. A proportion JR1 of a composition that is made up of the resin in a magnetic carrier portion of a region R1 and a proportion JR2 of the composition in a magnetic carrier portion of a region R2 satisfy the following relationship. The region R1 and the region R2 are illustrated in FIG. 1. 1.20?JR2/JR1?2.00.
    Type: Grant
    Filed: May 29, 2014
    Date of Patent: December 6, 2016
    Assignee: Canon Kabushiki Kaisha
    Inventors: Nobuyoshi Sugahara, Hironori Minagawa, Yuto Onozaki, Minoru Yoshifuku, Wakashi Iida
  • Patent number: 9341973
    Abstract: There is provided a magnetic carrier having a resin coating layer formed on the surface of each of particles prepared by putting resin in the pores of porous magnetic particles, wherein (i) the surface roughness Ra of the porous magnetic particles ranges from 0.180 ?m to 0.250 ?m, (ii) the pore size ranges from 0.40 ?m to 1.00 ?m, (iii) the amount of the resin held in the pores ranges from 3.0 parts by mass to 5.5 parts by mass relative to 100 parts by mass of the porous magnetic particles, (iv) the amount of resin used for forming the coating resin layer ranges from 1.0 parts by mass to 3.0 parts by mass relative to 100 parts by mass of the porous magnetic particles, and (v) the surface roughness Ra of the magnetic carrier ranges from 0.160 ?m to 0.220 ?m.
    Type: Grant
    Filed: May 29, 2014
    Date of Patent: May 17, 2016
    Assignee: Canon Kabushiki Kaisha
    Inventors: Minoru Yoshifuku, Wakashi Iida, Hironori Minagawa, Nobuyoshi Sugahara, Yuto Onozaki
  • Patent number: 9274446
    Abstract: A method for manufacturing carrier core particles for electrophotographic developer that include manganese, magnesium, and iron as a core composition. The method includes a granulation step (A) of granulating a mixture of raw materials containing manganese, magnesium, and iron with a reducing agent added at a ratio of 0.10% to 1.00% by mass to a total mass of the raw materials containing manganese, magnesium, and iron, and a firing step of firing the granular material granulated in the granulation step. The firing step includes a first heating step (C) of applying heat at a constant temperature ranging from 500° C. to 800° C. in an atmosphere with an oxygen concentration of 1000 ppm to 15000 ppm for a predetermined period of time and a second heating step (D) of applying heat at a temperature higher than 800° C. for a predetermined period of time after the first heating step.
    Type: Grant
    Filed: November 30, 2012
    Date of Patent: March 1, 2016
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventor: Takeshi Kawauchi
  • Patent number: 9268246
    Abstract: Provided is a method for manufacturing carrier core particles for electrophotographic developer capable of stably maintaining high chargeability over a long time. The method for manufacturing carrier core particles includes a granulation step of granulating a mixture of raw materials containing manganese, iron, strontium, and calcium and a firing step of firing the mixture granulated in the granulation step. The firing step includes a heating process of heating the granular mixture with an increase in temperature to a predetermined degree and a cooling process of cooling the granular mixture, after the heating process, in an atmosphere with an oxygen concentration ranging from 5000 ppm to 20000 ppm. The molar ratio of the sum of strontium and calcium to the sum of the manganese, iron, strontium, and calcium is 0.0026 to 0.013.
    Type: Grant
    Filed: February 20, 2014
    Date of Patent: February 23, 2016
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Takeshi Kawauchi, Sho Ogawa, Haruka Seki
  • Patent number: 9256150
    Abstract: A two-component developer of the present disclosure contains a carrier and toner particles. The carrier includes a carrier core, a first layer coating a surface of the carrier core, and a second layer coating a surface of the first layer. The first layer contains a fluorine-based resin, and the second layer contains a polyamide-imide resin and/or a melamine resin. The toner particles each include a toner core containing a binder resin and a shell layer coating a surface of the toner core. The shell layer contains a thermosetting resin.
    Type: Grant
    Filed: October 13, 2014
    Date of Patent: February 9, 2016
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Yusuke Kurano, Hiroaki Moriyama
  • Patent number: 9034552
    Abstract: The carrier core particles for electrophotographic developer have a volume size distribution with a median particle size ranging from 30 ?m to 40 ?m, the ratio of the carrier core particles having a diameter of 22 ?m or lower in the volume size distribution is from 1.0% to 2.0%, the ratio of the carrier core particles having a diameter of 22 ?m or lower in a number size distribution is 10% or lower, and the magnetization of the carrier core particles in an external magnetic field of 1000 Oe is from 50 emu/g to 75 emu/g.
    Type: Grant
    Filed: March 1, 2012
    Date of Patent: May 19, 2015
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventors: Tomohide Iida, Tomoya Yamada, Takashi Fujiwara
  • Patent number: 9034551
    Abstract: Provided is a two-component developer containing: a magnetic carrier obtained by coating a magnetic core with a resin; and toner, in which: the magnetic core contains at least a ferrite component and at least one kind of an oxide selected from the group consisting of SiO2 and Al2O3; the content of the oxide is 4.0 mass % or more and 40.0 mass % or less with respect to the magnetic core; the magnetic core has a specific resistance of 5.0×104 ?·cm or more and 5.0×108 ?·cm or less at the time of the application of 1,000 V/cm; the magnetic carrier has an intensity of magnetization in 79.6 kA/m of 40.0 Am2/kg or more and 65.0 Am2/kg or less, and a residual magnetization after the application of an external magnetic field of 79.6 kA/m of 3.0 Am2/kg or less; and the toner has a weight-average particle diameter (D4) of 3.0 ?m or more and 10.0 ?m or less and an average circularity of 0.940 or more and 0.990 or less.
    Type: Grant
    Filed: March 10, 2009
    Date of Patent: May 19, 2015
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Tomoko Endo, Koh Ishigami, Naoki Okamoto, Yoshinobu Baba
  • Patent number: 9029060
    Abstract: A carrier for electrostatic latent image developing is composed of carrier core containing a binder resin and magnetic material particles, and a shell layer that covers the carrier core. The binder has an acid value of at least a predetermined value, and contains a resin having a carboxyl group. The shell layer is composed of a resin selected from melamine resin and urea resin.
    Type: Grant
    Filed: September 25, 2013
    Date of Patent: May 12, 2015
    Assignee: KYOCERA Document Solutions Inc.
    Inventors: Masami Tujihiro, Yoshio Ozawa
  • Patent number: 8945805
    Abstract: The present invention provides an image of high image quality by using a magnetic carrier coated with a novel coating resin composition. Further, the present invention stably provides a good image which is hardly influenced by environmental fluctuation and long-term use and has a superior stability of a charging amount when left to stand especially under high temperature and high humidity environments. The present invention also provides a magnetic carrier characterized in that a carrier core surface is coated with a copolymer containing at least, as copolymerization components, an acrylic monomer having a specific structure and an acrylic macromonomer having a specific structure.
    Type: Grant
    Filed: February 26, 2009
    Date of Patent: February 3, 2015
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshinobu Baba, Koh Ishigami, Naoki Okamoto, Tomoko Endo
  • Patent number: 8921023
    Abstract: Provided is a magnetic carrier excellent in leakage, uniformity of a solid image having satisfactory charging stability and developing performance at low electric field. The magnetic carrier is a magnetic carrier comprising: a magnetic substance-dispersed resin carrier core, which contains a magnetic substance and a binding resin, and a coating resin on a surface thereof, wherein: the carrier core has resistivity at 1000 V/cm of 5.0×106-8.0×107 ?·cm, the magnetic substance has a number average particle diameter of 0.20-0.35 ?m; and comprises magnetic-substance particles having vertexes and a particle diameter of 0.53 ?m or more in an amount of 10.0-32.0 vol % based on a total amount of the magnetic substance; and wherein: the carrier core has Fe2O3 content of 98.00% by mass or more; and ZnO content of 0.06-0.50% by mass.
    Type: Grant
    Filed: August 7, 2013
    Date of Patent: December 30, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshinobu Baba, Koh Ishigami, Masayuki Hama, Kentaro Kamae, Hiroaki Kawakami
  • Publication number: 20140370432
    Abstract: The instant disclosure describes acrylate-coated carrier resins exhibiting both high charge and improved RH sensitivity, carrier compositions comprising the acrylate coated carriers and developers comprising the carrier resins.
    Type: Application
    Filed: June 14, 2013
    Publication date: December 18, 2014
    Inventors: Richard PN Veregin, Qingbin Li, Andriy Kovalenko, Sergey Gusarov, Daryl W. Vanbesien, Michael S. Hawkins
  • Patent number: 8865386
    Abstract: A carrier core particle for an electrophotographic developer includes a core composition expressed by a general formula: MnxFe3?xO4+y (0<x?1, 0<y) as a main ingredient, 0.1 wt % or more of Si, and 0.03 wt % or more of at least one metal element selected from the group consisting of Ca, Sr and Mg.
    Type: Grant
    Filed: March 29, 2011
    Date of Patent: October 21, 2014
    Assignees: Dowa Electronics Materials Co., Ltd., Dowa IP Creation Co., Ltd.
    Inventors: Takeshi Kawauchi, Sho Ogawa
  • Patent number: 8790858
    Abstract: An electrostatic charge image developing carrier has magnetic particles and a coating resin layer that coats surfaces of the magnetic particles and contains a hindered amine compound.
    Type: Grant
    Filed: August 10, 2012
    Date of Patent: July 29, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Toshiaki Hasegawa, Mona Tasaki, Fusako Kiyono
  • Patent number: 8790615
    Abstract: A method of synthesizing carbon-magnetite nanocomposites. In one embodiment, the method includes the steps of (a) dissolving a first amount of an alkali salt of lignosulfonate in water to form a first solution, (b) heating the first solution to a first temperature, (c) adding a second amount of iron sulfate (FeSO4) to the first solution to form a second solution, (d) heating the second solution at a second temperature for a first duration of time effective to form a third solution of iron lignosulfonate, (e) adding a third amount of 1N sodium hydroxide (NaOH) to the third solution of iron lignosulfonate to form a fourth solution with a first pH level, (f) heating the fourth solution at a third temperature for a second duration of time to form a first sample, and (g) subjecting the first sample to a microwave radiation for a third duration of time effective to form a second sample containing a plurality of carbon-magnetite nanocomposites.
    Type: Grant
    Filed: March 22, 2011
    Date of Patent: July 29, 2014
    Assignee: Board of Trustees of the University of Arkansas
    Inventor: Tito Viswanathan
  • Patent number: 8785100
    Abstract: The present invention relates to a two-component developer which comprises a toner, and a carrier having a surface of a core material particle coated with a resin having a unit of general formula (1). The present invention provides a two-component developer which has enhanced environmental stability of carrier charging performance.
    Type: Grant
    Filed: December 27, 2012
    Date of Patent: July 22, 2014
    Assignee: Konica Minolta Business Technologies, Inc.
    Inventors: Hitomi Motani, Tomoko Mine, Tomomi Oshiba
  • Patent number: 8778587
    Abstract: A carrier for developing an electrostatic latent image, including a particulate core material having a magnetism having developed spontaneous magnetization; and a covering layer comprising an electroconductive material, covering the surface of the particulate core material, wherein the carrier has an electrical resistivity Log R [?cm] of from 8.0 to 12.0 when measured by a method, including filling the carrier in a cell containing a pair of facing electrodes, each having a surface area of 2×4 [cm2] with a gap of 2 [mm] therebetween; and applying a DC voltage of 1,000 [V] therebetween to measure a DC resistivity, and a weight-average particle diameter (Dw) of from 25 to 45 ?m.
    Type: Grant
    Filed: October 10, 2012
    Date of Patent: July 15, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Shigenori Yaguchi, Toyoshi Sawada, Hiroshi Tohmatsu, Hitoshi Iwatsuki, Toyoaki Tano
  • Patent number: 8765347
    Abstract: A two-component developing agent includes toner and a carrier including carrier particles. The toner includes a binding resin. The carrier particle includes a porous ferrite core particle and a resin covering layer. The resin covering layer covers the porous ferrite core particle. The resin covering layer includes ferrite particles. An average particle diameter of the ferrite particles ranges from 0.1 to 1.0 ?m.
    Type: Grant
    Filed: December 27, 2012
    Date of Patent: July 1, 2014
    Assignee: Konica Minolta Business Technologies, Inc.
    Inventors: Kosuke Nakamura, Okushi Okuyama
  • Patent number: 8735041
    Abstract: A method for producing a low density resin-coated carrier having a small resin amount to a carrier core material and having a uniform resin coating layer formed on the carrier core material is provided. A resin-coated carrier has a carrier core material and a resin coating layer formed on the surface of the carrier core material. The carrier core material has pores and an apparent density of 1.6 g/cm3 to 2.0 g/cm3 and a remanent magnetization of 10 emu/g of less. The resin coating layer is formed by a dry process of adhering resin particles to a surface of the carrier core material and applying heat and impact force to the resin particles. A volume average particle size of the resin particles is less than 1 ?m. A two-component developer containing the resin-coated carrier is charged in a developing device in an image forming apparatus, and an image is formed.
    Type: Grant
    Filed: March 24, 2010
    Date of Patent: May 27, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takanori Kamoto, Takayuki Yamanaka, Osamu Wada, Tadashi Iwamatsu, Nobuyuki Yoshioka
  • Patent number: 8728698
    Abstract: The present invention is to provide a carrier and a developer, which have fewer occurrences of carrier adhesion and background smear, excellent granularity and longer durability. The carrier comprises the core material particles having magnetism and resin coating layer covering the core material particles, and wherein the weight average particle diameters is in the range of 22 m to 32 m, the proportion of the weight average particle diameters relative to the number average particle diameter is in the range of 1.00 to 1.20, the content of particles having a diameter of 20 m or smaller is 7% by mass, the content of carrier particles having a diameter of 36 m or smaller is in the range of 90% by mass to 100% by mass, and the proportion of the particle density of the core material particles is in the range of 85% to 100% of the true density of the core material particles.
    Type: Grant
    Filed: March 6, 2007
    Date of Patent: May 20, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Masashi Nagayama, Kimitoshi Yamaguchi, Naoki Imahashi
  • Patent number: 8728699
    Abstract: A porous ferrite core material for an electrophotographic developer, the porous ferrite core material including Mg in a content of 0.3 to 3% by weight, Ti in a content of 0.4 to 3% by weight and Fe in a content of 60 to 70% by weight, and the porous ferrite core material having a pore volume of 0.04 to 0.16 ml/g, a peak pore size of 0.4 to 1.6 ?m, a saturation magnetization of 40 to 80 Am2/kg, a remanent magnetization of less than 7 Am2/kg and a coercive force of less than 43 A/m; a resin-filled ferrite carrier for an electrophotographic developer obtained by filling a resin in the voids of the porous ferrite core material; and an electrophotographic developer using the ferrite carrier.
    Type: Grant
    Filed: October 19, 2010
    Date of Patent: May 20, 2014
    Assignee: Powedertech Co., Ltd.
    Inventors: Toru Iwata, Koji Aga
  • Patent number: 8722303
    Abstract: An image forming method using a two component developing system is provided in which a print speed is not less than 300 mm/s, a peak-to-peak voltage of an AC component in a developing bias is not more than 1.3 kV, a sufficient image density can be ensured, and a recorded image having a small amount of magnetic carrier remaining on the image and having high image quality can be obtained. A magnetic carrier that forms a two component developer contains a magnetic core and a resin. The magnetic core is a ferrite containing Sr and Ca inside thereof at the same time, having a small crystal grain diameter, a high density crystal-grain boundary structure, and an extremely large capacitance of the grain boundary. Use of the ferrite can provide the above method.
    Type: Grant
    Filed: August 24, 2012
    Date of Patent: May 13, 2014
    Assignee: Canon Kabushiki Kaisha
    Inventors: Juun Horie, Takeshi Yamamoto, Yoshinobu Baba, Koh Ishigami
  • Patent number: 8697325
    Abstract: To provide a carrier for an electrophotographic developer in which high image quality and full colorization are possible while carrier scattering is reduced, and a method for producing the carrier, and an electrophotographic developer including the carrier. A carrier core material for an electrophotographic developer is produced so that the half-value width B of a peak having a maximum intensity in an XRD pattern satisfies B?0.160 (degree). A carrier for an electrophotographic developer and an electrophotographic developer are produced from the carrier core material for an electrophotographic developer.
    Type: Grant
    Filed: March 21, 2008
    Date of Patent: April 15, 2014
    Inventors: Tomoya Yamada, Takashi Fujiwara, Ryusuke Nakao, Yukihiro Matuda, Tomokazu Mouri
  • Patent number: 8673529
    Abstract: The present invention relates to a magnetic carrier for an electrophotographic developer comprising spherical composite particles comprising spherical composite core particles comprising at least ferromagnetic iron oxide fine particles and a cured phenol resin and having an average particle diameter of 1 to 100 ?m, and a melamine resin coating layer formed on the respective core particles, wherein a ratio of R100 to R300 (R100/R300) in which R100 is an electric resistance value as measured when applying a voltage of 100 V to the magnetic carrier; and R300 is an electric resistance value as measured when applying a voltage of 300 V to the magnetic carrier, is controlled to lie within the range of 1 to 50.
    Type: Grant
    Filed: June 15, 2010
    Date of Patent: March 18, 2014
    Assignee: Toda Kogyo Corporation
    Inventors: Kaori Kinoshita, Shinji Uemoto, Eiichi Kurita
  • Patent number: 8663892
    Abstract: A latent electrostatic image developing carrier including: core particles each having magnetism; and a coating layer covering each of the core particles, wherein the latent electrostatic image developing carrier has a shape factor SF-2 of 115 to 150 and has a bulk density of 1.8 g/cm3 to 2.4 g/cm3, wherein the core particles have a shape factor SF-2 of 120 to 160 and have an arithmetic mean surface roughness Ra of 0.5 ?m to 1.0 ?m, and wherein the coating layer contains a resin and a filler and an amount of the filler contained in the coating layer is 50 parts by mass to 500 parts by mass per 100 parts by mass of the resin contained in the coating layer.
    Type: Grant
    Filed: August 23, 2012
    Date of Patent: March 4, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigenori Yaguchi, Kimitoshi Yamaguchi, Toyoshi Sawada, Hitoshi Iwatsuki, Toyoaki Tano, Hiroshi Tohmatsu
  • Patent number: 8628905
    Abstract: A ferrite core material for a resin-filled type carrier, and a resin-filled type carrier which is used as an electrophotographic developer by mixing a toner, sufficiently secure the image density, have no carrier adhesion and can maintain high-quality images over a long period, and an electrophotographic developer using the carrier, are provided. A ferrite core material for a resin-filled type carrier characterized in a void fraction of 10 to 60%, a resin-filled type carrier filled in the carrier core material with a resin, and an electrophotographic developer composed of the resin-filled type carrier and a toner, are provided.
    Type: Grant
    Filed: May 31, 2006
    Date of Patent: January 14, 2014
    Assignee: Powdertech Co. Ltd.
    Inventors: Hiromichi Kobayashi, Tsuyoshi Itagoshi, Tomoyuki Suwa, Toshio Honjo
  • Patent number: 8617781
    Abstract: The carrier core particles 11 for electrophotographic developer contain lithium as a core composition. When the carrier core particles 11 are immersed in pure water at a weight ratio of 1 part core particles 11 to 10 parts pure water and shaken, the amount of lithium that leaches out to the pure water is 0.10 ppm or lower.
    Type: Grant
    Filed: January 25, 2011
    Date of Patent: December 31, 2013
    Assignees: Dowa Electronics Materials Co., Ltd., Dowa IP Creation Co., Ltd.
    Inventor: Takeshi Kawauchi
  • Patent number: 8603716
    Abstract: An electrostatic image developing carrier includes a ferrite particle and a resin layer that coats the ferrite particle, wherein a magnesium element content of the ferrite particle is from about 3.0% by weight to about 20.0% by weight; wherein a manganese element content of the ferrite particle is from about 0.2% by weight to about 0.8% by weight; and wherein a content of toluene is more than about 100 ppm and not more than about 2,000 ppm.
    Type: Grant
    Filed: April 7, 2010
    Date of Patent: December 10, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Takeshi Shoji, Akihiro Iizuka, Yosuke Tsurumi, Fusako Kiyono
  • Patent number: 8592123
    Abstract: To provide a carrier for electrophotographic developer, capable of realizing a high image quality and full colorization and reducing carrier scattering, and a manufacturing method of the same, and an electrophotographic developer containing the carrier. A carrier core material for electrophotographic developer, with a general formula expressed by MgxMn(1-x)FeyO4 (where 0<x<1, and 1.6?y?2.4), wherein a half-value width B of a peak having a maximum intensity in a powder XRD pattern satisfies B?0.180 (degree), is manufactured and from this carrier core material for electrophotographic developer, the carrier for electrophotographic developer and the electrophotographic developer are manufactured.
    Type: Grant
    Filed: April 9, 2008
    Date of Patent: November 26, 2013
    Assignees: Dowa Electronics Materials Co., Ltd., Dowa IP Creation Co., Ltd.
    Inventors: Tomoya Yamada, Takashi Fujiwara, Ryusuke Nakao, Yukihiro Matuda, Tomokazu Mouri
  • Patent number: 8580475
    Abstract: An electrostatic charge image developing carrier includes a core particle and a coating layer with which the surface of the core particle is coated. The coating layer includes an acrylic resin having a constituent unit in which a silicone chain is disposed in a branch.
    Type: Grant
    Filed: October 27, 2011
    Date of Patent: November 12, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Takeshi Shoji, Toshiaki Hasegawa
  • Patent number: 8535867
    Abstract: There is provided a ferrite core material for an electrophotographic developer, the ferrite core material having a ferrite particle composition represented by the formula (1) shown below, containing SrO replacing a part of (MnO) and/or (MgO) in the formula (1) shown below, and having a Cl concentration of 0.1 to 100 ppm, as measured by an elution method of the ferrite core material: (MnO)x(MgO)y(Fe2O3)z??(1) wherein x=35 to 45 mol %, y=5 to 15 mol %, z=40 to 60 mol %, and x+y+z=100 mol %.
    Type: Grant
    Filed: February 3, 2011
    Date of Patent: September 17, 2013
    Assignee: Powdertech Co., Ltd.
    Inventors: Tomoyuki Suwa, Toru Iwata, Koji Aga
  • Patent number: 8507169
    Abstract: A two-component developer is disclosed, composing a toner comprising parent toner particles with an attached external additive and a carrier provided with a resin covering layer on a surface of a core particle, wherein the resin covering layer comprises a binder resin comprising an acrylic resin and when the resin covering layer is divided in half to a core particle side and a surface side, a nitrogen element content of the core particle side is larger than a nitrogen element content of the surface side.
    Type: Grant
    Filed: February 28, 2012
    Date of Patent: August 13, 2013
    Assignee: Konica Minolta Business Technologies, Inc.
    Inventors: Tomoko Mine, Mikihiko Sukeno, Tatsuya Nagase, Tomomi Oshiba, Hiroyuki Kozuru, Saburou Hiraoka, Yoshiyasu Matsumoto, Kosuke Nakamura, Hitomi Motani, Takanari Kayamori
  • Patent number: 8486600
    Abstract: A carrier for developing an electrostatic charge image, including a core, and a coating layer including a resin and inorganic oxide particles that exhibit electroconductivity, by which the core is coated, wherein the inorganic oxide particles have, when they are aggregated, an aggregation size of, or when they are not aggregated, a primary particle size of, from 230 nm to 970 nm.
    Type: Grant
    Filed: February 24, 2011
    Date of Patent: July 16, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Norihito Fukushima, Akihiro Iizuka, Yosuke Tsurumi, Takahiro Yamashita, Shintaro Anno, Yasuaki Hashimoto
  • Publication number: 20130171559
    Abstract: A two-component developing agent includes toner and a carrier including carrier particles. The toner includes a binding resin. The carrier particle includes a porous ferrite core particle and a resin covering layer. The resin covering layer covers the porous ferrite core particle. The resin covering layer includes ferrite particles. An average particle diameter of the ferrite particles ranges from 0.1 to 1.0 ?m.
    Type: Application
    Filed: December 27, 2012
    Publication date: July 4, 2013
    Applicant: KONICA MINOLTA BUSINESS TECHNOLOGIES, INC.
    Inventors: Kosuke NAKAMURA, Okushi OKUYAMA
  • Patent number: 8475988
    Abstract: Disclosed are a resin-filled ferrite carrier core material for an electrophotographic developer, including a porous ferrite particle, wherein the composition of the porous ferrite particle is represented by the following formula (1), and part of (MgO) and/or (Fe2O3) in the following formula (1) is replaced with SrO; a ferrite carrier obtained by filling a resin in the voids of the ferrite carrier core material; and an electrophotographic developer using the ferrite carrier: ( MgO ) ? x ? ( Fe 2 ? O 3 ) ? y ? ( x = 10 ? ? mol ? ? % ? ? or ? ? more ? ? and ? ? less ? ? than ? ? 25 ? ? mol ? ? % y = exceeding ? ? 75 ? ? mol ? ? % ? ? and ? ? 90 ? ? mol ? ? % ? ? or ? ? less x + y = 100 ? ? mol ? ? % ) .
    Type: Grant
    Filed: February 2, 2011
    Date of Patent: July 2, 2013
    Assignee: Powdertech Co., Ltd.
    Inventors: Takao Sugiura, Takashi Hikichi, Hiromichi Kobayashi
  • Patent number: 8465898
    Abstract: There are provided a ferrite carrier core material for an electrophotographic developer, which contain 10 to 30% by weight of Mn, 1.0 to 3.0% by weight of Mg, 0.3 to 1.5% by weight of Ti and 40 to 60% by weight of Fe, a ferrite carrier for an electrophotographic developer obtained by coating the ferrite core material, and an electrophotographic developer using the ferrite carrier.
    Type: Grant
    Filed: June 16, 2011
    Date of Patent: June 18, 2013
    Assignee: Powdertech Co., Ltd.
    Inventors: Toru Iwata, Koji Aga
  • Patent number: 8431312
    Abstract: The present invention provides a carrier which includes core material particles, and a coating layer on surfaces of the core material particles, wherein the coating layer contains a crosslinked product which is obtained by condensation of a silicone resin with an organic zirconium catalyst, the silicone resin having at least one of a silanol group and a functional group capable of generating a silanol group by means of hydrolysis.
    Type: Grant
    Filed: November 10, 2009
    Date of Patent: April 30, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Minoru Masuda, Kimitoshi Yamaguchi, Yutaka Takahashi, Koichi Sakata, Hitoshi Iwatsuki
  • Patent number: 8409778
    Abstract: A resin coated carrier is provided that can stably charge a toner having added thereto an external additive having a large particle size over a long period of time and can prevent blocking of a developer. The resin coated carrier satisfies the following formula (1): log(Mb/Ma)>2??(1) in which Ma is a weight average molecular weight of a silicone resin having the minimum weight average molecular weight, contained in a resin coating layer, and Mb is a weight average molecular weight of a silicone resin having the maximum weight average molecular weight, and the following formula (2) is satisfied: 0.5??log(A/B)?2.5??(2) in which A is a volume resistance (?/cm) under electric field of 1,000 V/cm obtained by conducting a stirring test, and B is a volume resistance (?/cm) under electric field of 1,000 V/cm before the stirring test.
    Type: Grant
    Filed: January 21, 2010
    Date of Patent: April 2, 2013
    Assignees: Sharp Kabushiki Kaisha, Kanto Denka Kogyo Co., Ltd.
    Inventors: Osamu Wada, Tadashi Iwamatsu, Takanori Kamoto, Nobuyuki Yoshioka, Natsuki Matsuura, Nobuhiro Seki, Masatomo Hayashi
  • Patent number: 8389191
    Abstract: The present disclosure provides carriers for use with toner compositions. In embodiments, a carrier may include a core, having a dry powder polymer coating. The polymer coating possesses a carbon to oxygen from about 3:1 to about 8:1. In embodiments, the coating may also include a colorant, such as carbon black. Processes for coating such carriers with the dry powder polymer coatings are also provided.
    Type: Grant
    Filed: October 22, 2009
    Date of Patent: March 5, 2013
    Assignee: Xerox Corporation
    Inventors: Daryl W. Vanbesien, Michael S. Hawkins, Suxia Yang, Richard P. N. Veregin, Karen Ann Moffat
  • Patent number: 8383308
    Abstract: A positively chargeable two-component developer, including at least a toner and a carrier, wherein the toner contains a binder resin, a colorant, a wax, and a charge control agent, the binder resin contains at least a polyester resin and an addition polymerization resin grafted with a polyolefin, the wax and the addition polymerization resin grafted with a polyolefin are contained at a wax:addition polymerization resin grafted with a polyolefin ratio of from about 40:60 to about 80:20, and the carrier is a magnetic powder having a coating layer containing a methyl-containing silicone resin.
    Type: Grant
    Filed: October 29, 2008
    Date of Patent: February 26, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Sakon Takahashi, Daisuke Ishizuka, Michio Take, Seijiro Ishimaru, Chiaki Suzuki
  • Patent number: 8357480
    Abstract: There are provided a carrier which enables stable charging of toner and formation of a stable, high-definition and high-quality image which has very few image defects such as a fog, as well as a developer, a developing apparatus, and an image forming apparatus. A carrier is obtained by including a carrier core and a coating layer with which a surface of the carrier core is coated, the coating layer being obtained by curing a resin composition for coating that includes a crosslinked silicone-modified acrylic resin containing a macromonomer represented by the following general formula (1). A developer is obtained by such a carrier and a toner.
    Type: Grant
    Filed: March 6, 2009
    Date of Patent: January 22, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Takanori Kamoto
  • Patent number: 8354214
    Abstract: The present disclosure provides carriers for use with toner compositions. In embodiments, a carrier may include a core, having a dry powder polymer coating. In embodiments, the coating may also include a colorant, such as carbon black. Processes for coating such carriers with the dry powder polymer coatings are also provided.
    Type: Grant
    Filed: September 21, 2009
    Date of Patent: January 15, 2013
    Assignee: Xerox Corporation
    Inventors: Daryl W. Vanbesien, Michael S. Hawkins, Suxia Yang, Richard P. N. Veregin, Karen Ann Moffat
  • Patent number: 8338067
    Abstract: An electrostatic image developer is provided, the electrostatic image developer including: a carrier for an electrostatic image developer, the carrier including a core particle which has a plurality of projections on a surface of the core particle; and electrostatic image developing toners, wherein the electrostatic image developer satisfies following relationships of formulae (1) and (2): 0.5t<H??(1) 21/2t<L<5t??(2) wherein t represents a volume average particle diameter (?m) of the toners; H represents an average height difference (?m) in the recesses and projections of the core particle; and L represents an average distance (?m) between the projections.
    Type: Grant
    Filed: March 26, 2010
    Date of Patent: December 25, 2012
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Susumu Yoshino, Hideo Maehata, Satoshi Hiraoka
  • Patent number: 8309293
    Abstract: The present disclosure provides carriers for use with toner compositions. In embodiments, a carrier may include a core, having a dry powder polymer coating. In embodiments, the coating may also include a colorant, such as carbon black. Processes for coating such carriers with the dry powder polymer coatings are also provided.
    Type: Grant
    Filed: September 21, 2009
    Date of Patent: November 13, 2012
    Assignee: Xerox Corporation
    Inventors: Daryl W. Vanbesien, Michael S. Hawkins, Corey L. Tracy, Richard P. N. Veregin, Karen Ann Moffat, Biby Esther Abraham
  • Patent number: 8298742
    Abstract: In a method for coating electrophotographic carrier core surfaces with a resin composition by rotating a rotator having a plurality of agitating blades on its surface in a casing; a coating treatment material that is introduced to a space defined between the rotator and the casing is in a packing of from 50% to 98% by volume; at the time of coating treatment, the electrophotographic carrier core surfaces are coat-treated with the resin composition while being put forward and put backward; and the electrophotographic carrier cores and the resin composition are, at the time of coating treatment, temperature-controlled at a specific temperature T (° C.) or below. This method enables the electrophotographic carrier core surfaces to be more uniformly coated with a coating resin.
    Type: Grant
    Filed: December 18, 2008
    Date of Patent: October 30, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Naoki Okamoto, Yoshinobu Baba, Koh Ishigami, Tomoko Endo
  • Patent number: 8298669
    Abstract: A coated carrier that peeling and wearing of a coating layer are hard to be generated and a method of manufacturing the coated carrier are provided. The coated carrier includes a core particle including a magnetic body, a first resin layer coating the core particle, a resin particle layer including a resin particle fixed to the first resin layer as a single layer, and a second resin layer. The first resin layer includes a first resin having a first reactive group. The resin particle layer is formed of resin particles including a cross-linking resin having a second reactive group which can undergo a cross-linking reaction with the first reactive group. The second resin layer is provided so as to fill gaps between the resin particles.
    Type: Grant
    Filed: May 19, 2010
    Date of Patent: October 30, 2012
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Yui Kawano
  • Patent number: 8293446
    Abstract: A resin-coated carrier is provided. A resin-coated carrier includes a carrier core and a resin coating layer formed on a surface of the carrier core. The carrier core is composed of a porous material having surface fine pores formed on a surface thereof, and has an apparent density of 1.6 to 2.0 g/cm3. The resin coating layer contains cross-linked fine resin particles. Additionally, the resin-coated carrier is configured such that a volume average particle size of the cross-linked fine resin particles contained in the resin coating layer and an area average diameter of the surface fine pores satisfy a predetermined relational expression.
    Type: Grant
    Filed: April 28, 2010
    Date of Patent: October 23, 2012
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Osamu Wada, Takanori Kamoto, Nobuyuki Yoshioka, Ayae Nagaoka, Tadashi Iwamatsu