Magnetic Carrier Patents (Class 430/111.3)
  • Patent number: 11099495
    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.
    Type: Grant
    Filed: March 6, 2018
    Date of Patent: August 24, 2021
    Assignee: POWDERTECH CO., LTD.
    Inventors: Hiroki Sawamoto, Tetsuya Uemura
  • Patent number: 10996579
    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.
    Type: Grant
    Filed: January 15, 2018
    Date of Patent: May 4, 2021
    Assignee: POWDERTECH CO., LTD.
    Inventors: Hiroki Sawamoto, Tetsuya Uemura
  • Patent number: 10698331
    Abstract: To provide a two-component developer for electrostatic charge image development, the two-component developer enabling a high image quality to be kept and enabling the occurrence of fogging to be suppressed even in continuous printing of an image high in coverage rate. The two-component developer for electrostatic charge image development includes a toner particle including a toner base particle and an external additive disposed on the surface of the toner base particle, and a carrier particle including a core material particle and a covering section disposed on the surface of the core material particle, wherein the external additive includes an alumina particle, and the percentage of exposed area of the core material particle is 4.0% or more and 15.0% or less.
    Type: Grant
    Filed: May 6, 2019
    Date of Patent: June 30, 2020
    Assignee: KONICA MINOLTA, INC.
    Inventors: Shinya Obara, Koji Shibata, Junya Ueda, Takuya Takahashi, Satoshi Uchino
  • Patent number: 10234783
    Abstract: A carrier including a resin layer including at least one kind of particles, wherein the at least one kind of the particles are particles of barium sulfate, wherein an amount of Ba detected is 0.3 atomic % or greater in a Ba analysis through X-ray photoelectron spectroscopy (XPS) of the carrier, and wherein circle-equivalent diameters of the particles of the barium sulfate are 400 nm or greater but 900 nm or smaller.
    Type: Grant
    Filed: April 28, 2016
    Date of Patent: March 19, 2019
    Assignee: Ricoh Company, Ltd.
    Inventors: Koichi Sakata, Tohru Suganuma, Shohichi Sugimoto, Hiroshi Tohmatsu, Hiroyuki Kishida, Kenichi Mashiko, Toyoaki Tano
  • Patent number: 9500975
    Abstract: Provided is a magnetic carrier, including magnetic carrier particles each including: a magnetic carrier core including a magnetic material and a resin; and a resin coating layer formed on a surface of the magnetic carrier core, in which: the resin included in the magnetic carrier core has a hydroxy group; a surface portion of the magnetic carrier core includes a specific compound; and the magnetic carrier has an adsorbed moisture amount of 0.40 mass % or less when the magnetic carrier is left to stand in an environment of a temperature of 30° C. and a humidity of 80% RH for 72 hours.
    Type: Grant
    Filed: February 25, 2015
    Date of Patent: November 22, 2016
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Nobuyoshi Sugahara, Hironori Minagawa, Yuto Onozaki, Minoru Yoshifuku, Wakashi Iida
  • Patent number: 9429862
    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: October 16, 2015
    Date of Patent: August 30, 2016
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., DOWA IP CREATION CO., LTD.
    Inventor: Takeshi Kawauchi
  • Patent number: 9285698
    Abstract: Black magnetic iron oxide particles having an average particle diameter of 0.05 to 2.0 ?m and an electric resistance value at an applied voltage of 100 V of not less than 1×108 ?·cm. Also a magnetic carrier for electrophotographic developer having spherical magnetic composite particles obtained by dispersing black magnetic iron oxide particles in a binder resin. The magnetic carrier has an electric resistance value R100 at an applied voltage of 100 V of 1×108 to 1×1014 ?·cm, and an electric resistance value R300 at an applied voltage of 300 V which satisfies the relationship represented by the formula: 0.1?R300/R100?1.
    Type: Grant
    Filed: June 15, 2009
    Date of Patent: March 15, 2016
    Assignee: TODA KOGYO CORPORATION
    Inventors: Shinji Uemoto, Hiromitsu Misawa, Ryo Iwai, Naoki Uchida, Koso Aoki, Kazuya Fujita, Kaori Kinoshita, Kazushi Takama, Eiichi Kurita
  • Patent number: 9182690
    Abstract: A method for reducing toning spacing sensitivity in an electrophotographic process is disclosed. The method includes providing a rotating magnetic member within a conductive non-magnetic development sleeve; providing a developer to the non-magnetic development sleeve for use with the rotating magnetic member including: i) hard magnetic particles with a coercivity of greater than 300 oersted and an induced moment of less than 20 emu per gram at an applied field of 1000 oersted; and ii) soft magnetic particles with a coercivity of less than 300 oersted and an induced moment of greater than 20 emu per gram an applied field of 1000 oersted; and iii) toner particles. The method further includes moving a charged receiving medium into a toner transfer relationship with the developer on the non-magnetic development sleeve so as to provide a developed image on the receiving medium with reduced toning spacing sensitivity.
    Type: Grant
    Filed: September 25, 2014
    Date of Patent: November 10, 2015
    Assignee: EASTMAN KODAK COMPANY
    Inventors: Peter Steven Alexandrovich, Rodney Ray Bucks
  • 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: 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: 9005861
    Abstract: An electrostatic latent image developer contains: an electrostatic-latent-image-developing toner that has toner particles formed by aggregating and fusing particles of a polyester resin, particles of a styrene resin and particles of a coloring agent in a starting material dispersion liquid of those particles dispersed in an aqueous solvent; and a carrier having a core particle and a resin coating layer to coat the surface of the core particle, wherein the ratio of the exposed area of the core particle to the surface of the carrier is about 7% or less.
    Type: Grant
    Filed: July 16, 2012
    Date of Patent: April 14, 2015
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Norihito Fukushima, Manabu Serizawa
  • Patent number: 8974995
    Abstract: The disclosure describes acrylate carrier resins, optionally, with a C/O of at least about 4, comprising a heterocycle comprising sulfur, exhibiting high charge and improved RH sensitivity, carrier compositions comprising the acrylate-coated carriers and developers comprising a toner and the acrylate-coated carrier.
    Type: Grant
    Filed: April 3, 2013
    Date of Patent: March 10, 2015
    Assignee: Xerox Corporation
    Inventors: Richard P N Veregin, Qingbin Li, Andriy Kovalenko, Sergey Gusarov
  • 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: 8916325
    Abstract: A carrier for developing electrostatic latent image, including a particulate magnetic core material; and a coated layer covering the surface of the particulate magnetic core material, wherein the coated layer includes a resin including a silicone resin and a methacrylic ester or an acrylic ester resin, and a filler including a substrate; and an electroconductive layer comprising tin dioxide (SnO2), overlying the substrate, and wherein the carrier includes tin (Sn) in an amount not less than 0.5% by atom and has a ratio (Sn/Si) of tin (Sn) to silicon (Si) of from 0.03 to 0.2 when subjected to an XPS analysis.
    Type: Grant
    Filed: March 8, 2013
    Date of Patent: December 23, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigenori Yaguchi, Hiroshi Tohmatsu, Koichi Sakata, Hitoshi Iwatsuki, Hiroyuki Kishida, Toyoaki Tano
  • Publication number: 20140356781
    Abstract: A magnetic carrier includes resin-filled magnetic core particles including porous magnetic particles whose pores are filled with a resin, and resin coating layers on the surfaces of the resin-filled magnetic core particles. The porous magnetic particles have specific electrical properties.
    Type: Application
    Filed: May 29, 2014
    Publication date: December 4, 2014
    Inventors: Hironori Minagawa, Wakashi Iida, Nobuyoshi Sugahara, Minoru Yoshifuku, Yuto Onozaki
  • Patent number: 8895218
    Abstract: Employment of a carrier core material for an electrophotographic developer containing 0.8 to 5% by weight of Mg, 0.1 to 1.5% by weight of Ti, 60 to 70% by weight of Fe and 0.2 to 2.5% by weight of Sr and having an amount of Sr dissolved with a pH4 standard solution of 80 to 1000 ppm, a carrier using the core material and a process for producing them, and an electrophotographic developer using the carrier.
    Type: Grant
    Filed: January 12, 2010
    Date of Patent: November 25, 2014
    Assignee: Powdertech Co., Ltd.
    Inventors: Takashi Kojima, Toru Iwata, Koji Aga
  • Patent number: 8889326
    Abstract: A toner including a colorant, a resin, and a volatile organic compound in an amount from 1 to 200 ?g/g is provided. The toner has a softening index Ct within a range from 70 to 100° C.
    Type: Grant
    Filed: February 1, 2013
    Date of Patent: November 18, 2014
    Assignee: Ricoh Company, Ltd.
    Inventor: Hideki Sugiura
  • 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: 8859179
    Abstract: A developer, including a toner including a binder resin comprising a crystalline resin; and a colorant, and a resin carrier comprising a resin; a magnetic particulate material having a magnetic anisotropy, dispersed in the resin, and having a saturated magnetization of from 16 to 30 emu/g, a coercive force of from 15 to 40 kA/m and an average particle diameter not less than 15 ?m and less than 100 ?m.
    Type: Grant
    Filed: November 16, 2012
    Date of Patent: October 14, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideyuki Santo, Masahide Yamada, Kazumi Suzuki, Shinya Nakayama, Atsushi Yamamoto, Tatsuya Morita, Shingo Sakashita, Yukiko Nakajima, Keiji Makabe, Daiki Yamashita
  • Patent number: 8852840
    Abstract: The present invention relates to magnetic composite particles comprising at least magnetic fine particles and a bio-based polymer, wherein the magnetic composite particles have an average particle diameter of 10 to 100 ?m, and a content of the magnetic fine particles in the magnetic composite particles is 50 to 99.9% by weight; a magnetic carrier; and a developer. The magnetic composite particles, magnetic carrier and developer according to the present invention are effective for reduction of environmental burden such as saving of underground sources and prevention of global warming, have a high safety for human bodies and a high durability, and are capable of forming developed images with a high quality.
    Type: Grant
    Filed: March 24, 2010
    Date of Patent: October 7, 2014
    Assignee: Toda Kogyo Corporation
    Inventors: Muneyoshi Sakamoto, Eiichi Kurita, Hiromitsu Misawa
  • Publication number: 20140295342
    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<x<100).
    Type: Application
    Filed: March 27, 2014
    Publication date: October 2, 2014
    Applicant: POWDERTECH CO., LTD.
    Inventors: Makoto ISHIKAWA, Tetsuya UEMURA, Masashi AOKI
  • Patent number: 8771914
    Abstract: The present invention provides a toner which, despite its spherical shape, makes it possible to prevent an external additive from being embedded in the toner easily or by a load generating low stress, reduce variation in image density, maintain cleaning ability and transfer ability throughout its long-term use and obtain excellent image quality, and further, provides a two-component developer, an image forming method and an image forming apparatus with the use of the toner. There is a toner including: base particles including a colorant and a resin, and hard fine particles, wherein the base particles and the hard fine particles are mixed together, and protruding portions formed of fine organic resin particles which are different in composition from a resin contained as a main component in the base particles are provided on surfaces of the base particles.
    Type: Grant
    Filed: March 17, 2008
    Date of Patent: July 8, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Akihiro Kotsugai, Hiroshi Yamashita
  • Patent number: 8741525
    Abstract: The resin coated carrier is used with a toner in which an external additive having an average primary particle size of 50 nm or more is added to a toner particle, and has a carrier core and a resin coating layer on the surface of the carrier core. In the resin coated carrier, the following expression (1) is satisfied: 0.5??log {(A/C)/(B/C)}?2.5??(1) wherein A represents a volume resistance value (?/cm) of the resin coated carrier in an electric field of 1000 V/cm that is obtained by conducting a stirring test, B represents a volume resistance value (?/cm) of the resin coated carrier in an electric field of 1000 V/cm before the stirring test, and C represents a volume resistance value (?/cm) of the carrier core in an electric field of 1000 V/cm.
    Type: Grant
    Filed: July 1, 2009
    Date of Patent: June 3, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Osamu Wada, Takanori Kamoto, Tadashi Iwamatsu, Nobuyuki Yoshioka, Hiroyuki Hirakawa, Yoshinori Mutoh, Takashi Hara, Hirofumi Kanda, Yoshio Ichii
  • Patent number: 8722305
    Abstract: A method of preparing a carrier for electrophotography, including a core material and a coating material layer formed on the surface of the core material, including: coating the core material with the coating material; and burning the coating material with a high-frequency induction heater, wherein the core material has a saturated magnetization of from 40 to 95 Am2/kg.
    Type: Grant
    Filed: March 21, 2012
    Date of Patent: May 13, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Masato Taikoji, Kousuke Suzuki, Shinichiro Yagi, Yuuki Mizutani
  • Patent number: 8709695
    Abstract: A carrier for developing an electrostatic charge image includes a core containing a magnetic material and a coating layer, in which the coating layer includes porous carbon having a volume average particle size of from 0.5 ?m to 2 ?m and a BET specific surface area of from 1 m2/g to 5 m2/g, and a resin.
    Type: Grant
    Filed: July 20, 2012
    Date of Patent: April 29, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventor: Yasushige Nakamura
  • Patent number: 8697326
    Abstract: A method of manufacturing a carrier including covering a core material with a covering material to form a covering layer on the core material and baking the covering material by heating the core material by high frequency induction applied thereto by a high frequency induction heating device.
    Type: Grant
    Filed: June 27, 2011
    Date of Patent: April 15, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Kousuke Suzuki, Shinichiro Yagi, Masato Taikoji, Masanori Rimoto
  • Patent number: 8679719
    Abstract: An object of the present invention is to provide a carrier containing core material particles having magnetism and a coating layer on the surfaces of the core material particles, wherein the core material particles have a magnetization at a magnetic field of 1,000 Oersted of 40 emu/g to 100 emu/g, and the carrier has a weight average particle diameter of 20 ?m to 45 ?m, a resistance (Log R) of 11 ?·cm to 17 ?·cm and a relaxation time ? of 150 seconds to 800 seconds.
    Type: Grant
    Filed: March 14, 2008
    Date of Patent: March 25, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Naoki Imahashi, Kousuke Suzuki
  • Publication number: 20140080052
    Abstract: A carrier for developing electrostatic latent images produced in an image developer includes a magnetic particulate core material and a covering layer covering the surface of the core material. The image developer includes an image bearer, a developer bearer including comprising a magnetic field generator inside and a developer regulation member facing the surface of the image developer with a predetermined gap. The carrier has a bulk density of from 1.6 to 2.25 g/cm3, a BET specific surface area of from 0.5 to 2.0 m3/g, a saturated magnetization (?5000) not less than 70 emu/g at 5 kOe, and a residual magnetization (?r) not greater than 2 emu/g.
    Type: Application
    Filed: August 7, 2013
    Publication date: March 20, 2014
    Inventors: Shigenori YAGUCHI, Hiroshi TOHMATSU, Koichi SAKATA, Hitoshi IWATSUKI, Hiroyuki KISHIDA, Toyoaki TANO, Kenichi MASHIKO
  • Publication number: 20140051023
    Abstract: Provided is the following magnetic carrier. The magnetic carrier maintains high developing performance even when the number of sheets to be output is large. Its charge-providing performance hardly reduces even when toner or an external additive is spent on the magnetic carrier. In addition, the magnetic carrier is strong in resistance against standing. The magnetic carrier includes a magnetic carrier core and a resinous coating layer formed on a surface of the magnetic carrier core, in which the resinous coating layer contains a resin composition and silica-alumina composite particles.
    Type: Application
    Filed: April 25, 2012
    Publication date: February 20, 2014
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Yojiro Hotta, Naoki Okamoto, Kazuo Terauchi, Ryuichiro Matsuo, Tetsuya Ida
  • Patent number: 8652735
    Abstract: A carrier including a magnetic core particle and a resin layer covering a surface of the magnetic core particle. The magnetic core particle is a ferrite particle including strontium in an amount of 0.005 to 3% by mass, measured by fluorescent X-ray spectroscopy. The resin layer comprises a resin obtained by heating a copolymer comprising a silicon-containing unit A and another silicon-containing specific unit B.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: February 18, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Koichi Sakata, Shigenori Yaguchi, Toyoshi Sawada, Kimitoshi Yamaguchi, Hitoshi Iwatsuki, Hiroshi Tohmatsu, Hiroyuki Kishida, Toyoaki Tano, Mariko Takii
  • Patent number: 8652738
    Abstract: A contact developing method including supplying a two-component developer to an electrostatic latent image on a rotating image bearing member by rotating a developing sleeve and a rotatable magnet having multiple magnetic poles provided inside the developing sleeve, to develop the electrostatic latent image into a toner image. The developing sleeve and the image bearing member rotate in the same direction while facing each other. The two-component developer comprises a non-magnetic toner and a carrier. The carrier comprises a magnetic core particle and a resin layer covering the magnetic core particle. The resin layer comprises a conductive particle and a resin. The conductive particle comprises an alumina-based material and a conductive layer covering the alumina-based material. The resin is obtained by heating a copolymer comprising a monomer A unit and a monomer B unit.
    Type: Grant
    Filed: July 13, 2011
    Date of Patent: February 18, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Shigenori Yaguchi, Hitoshi Iwatsuki, Mariko Takii, Toyoshi Sawada, Toyoaki Tano, Hiroshi Tohmatsu, Koichi Sakata, Hiroyuki Kishida, Saori Yamada
  • Patent number: 8652736
    Abstract: The present invention provides a carrier core material for use in the production of an electrophotographic developer which, even when applied, for example, to MFPs (multifunction printers), can realize stable, high-quality and high-speed development, and has a prolonged replacing life of magnetic carriers, and a method of manufacturing the same, a magnetic carrier including the carrier core material, and an electrophotographic developer manufactured from the magnetic carrier. An electrophotographic development carrier is prepared by adding resin particles, a binder, a dispersant, a wetting agent, and water to a raw material powder, wet pulverizing the mixture, drying the pulverized product to give granulated powder, calcinatng the granulated powder, and then sintering the granulated powder to prepare a carrier core material having an internally hollow structure, and coating the carrier core material with a resin.
    Type: Grant
    Filed: September 25, 2006
    Date of Patent: February 18, 2014
    Assignees: Dowa IP Creation Co., Ltd., Dowa Electronics Materials Co., Ltd.
    Inventors: Ryusuke Nakao, Takeshi Kawauchi
  • Patent number: 8647804
    Abstract: A method of preparing carrier for electrophotography, which includes a core material and a coating material layer formed on the surface of the core material, including coating a coating material of the coating material layer on the core material; and burning the coating material by an induction heater, wherein the induction heater applies an alternative current to parallely-located plural coil circuits including a conductive wire including the shape of a coil to generate a magnetic line changing its direction and intensity for inductively heating the core material to heat the coating material.
    Type: Grant
    Filed: May 30, 2012
    Date of Patent: February 11, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Yuuki Mizutani, Shinichiro Yagi, Kousuke Suzuki, Masato Taikoji
  • Publication number: 20140038098
    Abstract: A method of producing a magnetic carrier, having a coating process step in which a surface of a magnetic carrier core is coated with particles of a resin composition by a mechanical impact force. The coating process step has a first coating process step of mixing, dispersing, and fixing the particles on the surface of the core, and a second coating process step, which is performed after the first coating process step, of carrying out a film-forming coating process on the particles. In the first and second coating process steps, the peripheral velocity of the outermost end of stirring members, the coating process time, the product temperature at the end of the coating process, and the glass-transition temperature of the resin component satisfy specific relationships.
    Type: Application
    Filed: July 26, 2013
    Publication date: February 6, 2014
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Takeshi Naka, Masayuki Hama, Kentaro Kamae, Koh Ishigami, Yoshinobu Baba, Hiroaki Kawakami, Yojiro Hotta, Satoshi Mita
  • Patent number: 8628904
    Abstract: The present invention provides a carrier for replenishment including an associated particle in which single particles each having a core material and a resin layer covering the core material, are bound via the resin layer, the carrier being used in a developer for replenishment of a trickle development system, and the system including performing development while the developer for replenishment is replenished, upon development of a latent image on a latent image holding member using a development unit.
    Type: Grant
    Filed: July 24, 2009
    Date of Patent: January 14, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Moegi Iguchi, Satoshi Inoue, Koutarou Yoshihara, Masahiro Takagi
  • 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: 8592122
    Abstract: The invention provides a developer for developing an electrostatic latent image, the developer having at least: a transparent toner; and a carrier. The carrier contains at least: a magnetic particle; and a resin coating layer. The resin coating layer coats the surface of the magnetic particle and has cyan color. The invention further provides a developer cartridge storing the developer. The invention further provides a process cartridge storing the developer. The invention further provides an image formation apparatus having at least a color toner image-forming unit, a transparent toner image-forming unit that uses the developer to form a transparent toner image, and a fixing unit.
    Type: Grant
    Filed: August 21, 2009
    Date of Patent: November 26, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Akira Matsumoto, Yukiaki Nakamura
  • Patent number: 8586276
    Abstract: A carrier for developing an electrostatic latent image includes carrier particles, and the carrier particles include magnetic particles and a coating layer coating the surfaces of the magnetic particles. The BET specific surface area of the magnetic particles is 0.1300 m2/g to 0.2500 m2/g, and the difference in BET specific surface areas obtained by subtracting the BET specific surface area of the magnetic particles from the BET specific surface area of the carrier particles is 0.0300 m2/g to 0.400 m2/g.
    Type: Grant
    Filed: March 27, 2008
    Date of Patent: November 19, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Akira Matsumoto, Taichi Yamada, Yosuke Tsurumi, Fusako Kiyono, Akihiro Iizuka, Fumiaki Mera, Hirotaka Matsuoka
  • Patent number: 8577256
    Abstract: An electrostatic image developing carrier includes a ferrite particle that contains magnesium element in an amount of about 3.0 wt % or more and about 10.0 wt % or less and manganese element in an amount of about 0.2 wt % or more and less than about. 1.0 wt %; and a resin layer that covers the ferrite particle.
    Type: Grant
    Filed: September 14, 2012
    Date of Patent: November 5, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Yosuke Tsurumi, Rieko Kataoka
  • Publication number: 20130252168
    Abstract: A carrier for developing an electrostatic charge image includes a core containing a magnetic material and a coating layer, in which the coating layer includes porous carbon having a volume average particle size of from 0.5 ?m to 2 ?m and a BET specific surface area of from 1 m2/g to 5 m2/g, and a resin.
    Type: Application
    Filed: July 20, 2012
    Publication date: September 26, 2013
    Applicant: FUJI XEROX CO., LTD.
    Inventor: Yasushige NAKAMURA
  • Patent number: 8518626
    Abstract: The carrier is used for a two-component developer for developing an electrostatic latent image, and includes a particulate magnetic core material; and a cover layer located on a surface of the particulate magnetic core material and including a crosslinked material. The crosslinked material is formed by hydrolyzing a copolymer including at least a unit (A) having a specific acrylic siloxane structure including a tris(trialkylsiloxy)silanyl group and a unit (B) having a specific acrylic silicone structure to form a material having a silanol group, and subjecting the material having a silanol group to a condensation reaction using an organic zirconium-containing catalyst.
    Type: Grant
    Filed: March 1, 2011
    Date of Patent: August 27, 2013
    Assignee: Ricoh Company, Limited
    Inventors: Saori Yamada, Minoru Masuda, Hisashi Nakajima, Kimitoshi Yamaguchi, Koichi Sakata, Hitoshi Iwatsuki, Yutaka Takahashi, Toyoaki Tano, Mariko Takii
  • Patent number: 8512928
    Abstract: A carrier comprising a magnetic core particle having a shape factor SF-2 of 130 to 160 and a resin layer covering a surface of the magnetic core particle. The resin layer comprises a conductive particle and a resin obtained by heating a copolymer comprising a silicon-containing A unit and another silicon-containing B unit.
    Type: Grant
    Filed: September 6, 2011
    Date of Patent: August 20, 2013
    Assignee: Rocoh Company, Ltd.
    Inventors: Hiroyuki Kishida, Shigenori Yaguchi, Kimitoshi Yamaguchi, Toyoshi Sawada, Hiroshi Tohmatsu, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano, Mariko Takii
  • Patent number: 8481239
    Abstract: A carrier, including a magnetic particulate core material and a resin layer on the core material, wherein the resin layer includes a resin obtained by heat treatment of a copolymer including a site derived from a monomer component having the following formula (1) and a site derived from a monomer component having the following formula (2), and includes a cross-linked material obtained by hydrolysis of the copolymer to produce a silanol group and condensation using an organotitanium compound: wherein R1 represents a hydrogen atom or a methyl group; m represents an alkylene group having 1 to 8 carbon atoms; R2 represents an alkyl group having 1 to 4 carbon atoms; R3 represents an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; X represents 10 to 90 mol %; and Y represents 10 to 90 mol %.
    Type: Grant
    Filed: October 1, 2010
    Date of Patent: July 9, 2013
    Assignee: Ricoh Company Limited
    Inventors: Hisashi Nakajima, Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata, Hitoshi Iwatsuki, Saori Yamada, Toyoaki Tano
  • Patent number: 8475989
    Abstract: The carrier is used for a two-component developer for developing an electrostatic latent image, and includes a particulate magnetic core material; and a cover layer located on a surface of the core material and including a crosslinked material and barium sulfate. The cover layer is formed by applying a coating medium including barium sulfate, a copolymer including a unit (A) having a specific acrylic siloxane structure including a tris(trialkylsiloxy)silanyl group and a unit (B) having a specific acrylic silicone structure having a crosslinking ability, and a condensation reaction catalyst, heating the applied medium to a temperature of from 100° C. to 230° C. so that the copolymer is hydrolyzed to produce a material having a silanol group, and the material and the catalyst are subjected to a condensation reaction to form the crosslinked material.
    Type: Grant
    Filed: October 4, 2010
    Date of Patent: July 2, 2013
    Assignee: Ricoh Company, Limited
    Inventors: Yutaka Takahashi, Minoru Masuda, Kimitoshi Yamaguchi, Hisashi Nakajima, Koichi Sakata, Hitoshi Iwatsuki, Saori Yamada, Toyoaki Tano, Mariko Takii
  • 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: 8431311
    Abstract: A resin-filled carrier for an electrophotographic developer obtained by filling resin into voids of a porous ferrite core material, wherein the porous ferrite core material has a pore volume of 0.055 to 0.16 mL/g and a peak pore size of 0.20 to 0.7 ?m, and an electrophotographic developer using this resin-filled carrier.
    Type: Grant
    Filed: December 23, 2008
    Date of Patent: April 30, 2013
    Assignee: Powdertech Co., Ltd.
    Inventors: Takao Sugiura, Takeshi Gondo, Hiromichi Kobayashi
  • Patent number: 8420285
    Abstract: A coated carrier regenerating method in accordance with the present invention includes the step of: determining an amount of a worn-away coating resin of a used coated carrier. Accordingly, an amount of the coating resin layer to be supplemented, namely an amount of the coating resin with which the coating resin layer is to be supplementarily coated is found based on this amount of the worn-away coating resin, whereby the supplementary coating of the used coated carrier can be carried out with the coating resin in the amount thus determined. This allows regeneration of a coated carrier in which a coating resin has a uniform thickness, that is, a coating resin layer has a thickness which is unchanged from the thickness obtained before use of the coated carrier, without the need of completely removing the coating resin from the used coated carrier.
    Type: Grant
    Filed: June 23, 2010
    Date of Patent: April 16, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Takeshi Kato
  • Patent number: 8399171
    Abstract: A manufacturing apparatus provided with a rotary stirring section and a powder passage is used to manufacture the resin-layer coated carrier. At a fine resin particle adhering step, a magnetic base particle and a fine resin particle are inputted into the powder passage with the rotary stirring section rotating and the fine resin particle is adhered onto the surface of the magnetic base particle. At a spraying step, at least a liquid that plasticizes the fine resin particles is sprayed with spray gas from a spraying section on the magnetic base particle and the fine resin particle which are in a fluidized state in the powder passage. At a film-forming step, rotation by the rotary stirring section is continued to fluidize the magnetic base particles and the fine resin particles until the fine resin particles adhered to the magnetic base particles are softened to form a film.
    Type: Grant
    Filed: June 2, 2010
    Date of Patent: March 19, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Hara, Yoshiaki Akazawa, Yoshitaka Kawase, Yoritaka Tsubaki, Yoshinori Mutoh, Keiichi Kikawa
  • Publication number: 20130065171
    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: Application
    Filed: August 23, 2012
    Publication date: March 14, 2013
    Inventors: Shigenori Yaguchi, Kimitoshi Yamaguchi, Toyoshi Sawada, Hitoshi Iwatsuki, Toyoaki Tano, Hiroshi Tohmatsu