Electrical Or Magnetic Parameter Patents (Class 430/111.41)
  • Patent number: 10852652
    Abstract: A toner containing a toner particle, in which the toner particle contains a binder resin and a pigment, and As and Al satisfy a specific relation, in a case when the toner is divided into two groups i.e. a first group and a second group with an inertial classifier, the first group including a larger size of the toner particles, and the second group including a smaller size of the toner particles, and the number of the toner particles in the first group being substantially equal to the number of the toner particles in the second group. Each of As and Al is a change rate of a surface potential of a pellet type molded product obtained by molding each of the toner in the first group and the toner in the second group under specific conditions is observed using a surface potentiometer under a specific conditions.
    Type: Grant
    Filed: August 9, 2019
    Date of Patent: December 1, 2020
    Assignee: CANON KABUSHIKI KAISHA
    Inventors: Daisuke Yamashita, Masaharu Miura, Takaho Shibata, Wakiko Katsumata, Yuichi Mizo
  • Patent number: 10642180
    Abstract: Herein is disclosed an electrostatic ink composition. In some examples, the electrostatic ink compositions comprise: a carrier liquid; a resin; and a phosphorescent pigment.
    Type: Grant
    Filed: July 17, 2015
    Date of Patent: May 5, 2020
    Assignee: HP Indigo B.V.
    Inventors: Biana Noikas, Guy Nesher, Dror Kella, Yaron Grinwald, Regina Guslitzer, Emad Masoud
  • Patent number: 10191400
    Abstract: A toner for electrostatic charge image development includes toner base particles including at least a binder resin, has a volume resistivity of 1.0×1014 ?·cm or more at 25° C. with 50% RH by a temperature change method, and has a volume resistivity of 1.0×1015 ?·cm or less at 67° C. by the temperature change method.
    Type: Grant
    Filed: January 19, 2018
    Date of Patent: January 29, 2019
    Assignee: KONICA MINOLTA, INC.
    Inventors: Tatsuya Fujisaki, Junichi Furukawa
  • Patent number: 9874828
    Abstract: Herein is disclosed an electrostatic ink composition comprising a resin and a conductive pigment, wherein the resin comprises a co-polymer formed from an alkylene monomer, an acrylic ester monomer and a maleic anhydride monomer, wherein, in some examples, the acrylic ester monomer constitutes at least about 8 wt % of the co-polymer. Herein is also disclosed a print substrate having printed thereon an electrostatic ink comprising a resin and a conductive pigment, wherein the resin comprises a co-polymer formed from an alkylene monomer, an acrylic ester monomer and a maleic anhydride monomer, wherein, in some examples, the acrylic ester monomer constitutes at least about 8 wt % of the co-polymer.
    Type: Grant
    Filed: October 25, 2013
    Date of Patent: January 23, 2018
    Assignee: Hewlett-Packard Indigo B.V.
    Inventors: Reut Avigdor, Nurit Carmel-Barnea, Rada Nuchimov, Yaron Grinwald
  • 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
  • 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: 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: 8852836
    Abstract: A toner including: a base resin; and charge-controlling resin particles contained in the base resin, wherein the toner is in shape of particles, and the charge-controlling resin particles are present in a region of each toner particle which is 500 nm in depth from a surface of the toner particle and an average of amounts of the charge-controlling resin particles present in the regions of the toner particles is 20% by volume to 70% by volume, wherein an average of embedment rates of the charge-controlling resin particles in the toner particles is 90% or higher, where each embedment rate is an average of embedment rates of the charge-controlling resin particles in each toner particle, and wherein the charge-controlling resin particles have a charge amount of 60 ?C/m2 or more as measured by a blow-off method.
    Type: Grant
    Filed: June 18, 2012
    Date of Patent: October 7, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahiro Seki, Yoshitaka Sekiguchi, Ryota Inoue, Kazuoki Fuwa
  • Patent number: 8815486
    Abstract: A carrier for a two-component developer, includes: magnetic particles and a resin coating layer that is coated on the magnetic particles, the resin coating layer containing metal nitride particles having a volume average primary particle diameter of from about 300 to about 2,000 nm.
    Type: Grant
    Filed: September 2, 2011
    Date of Patent: August 26, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Norihito Fukushima, Toshiaki Hasegawa, Yosuke Tsurumi
  • Patent number: 8808957
    Abstract: A carrier for developing an electrostatic image, includes: magnetic core material particles and a coated layer coated on the magnetic core material particles, the coated layer containing a resin having a monomer unit represented by formula (A): wherein R1 represents a hydrogen atom or a methyl group; R2 to R4 each independently represent a hydrogen atom, an alkyl group, an aryl group or an aralkyl group; R5 independently represents an alkyl group, an aryl group or an aralkyl group; n represents an integer of from 0 to 7; and L1 represents a single bond or an alkylene group, provided that at least one of R3 and R4 is not a hydrogen atom.
    Type: Grant
    Filed: April 21, 2011
    Date of Patent: August 19, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Yasuaki Hashimoto, Yosuke Tsurumi
  • Patent number: 8802342
    Abstract: The present invention relates to a crystalline resin for toners which includes a composite resin including a polycondensation-based resin component obtained by polycondensing an alcohol component containing an aliphatic diol having 2 to 10 carbon atoms with a carboxylic acid component containing an aromatic dicarboxylic acid, and a styrene-based resin component; a resin binder containing the crystalline resin and a non-crystalline resin; and a toner for electrophotography which contains the resin binder. According to the present invention, there are provided a crystalline resin for toners which is capable of producing a toner that is excellent in not only low-temperature fixing ability but also gloss of images and anti-filming property, a resin binder, and a toner for electrophotography.
    Type: Grant
    Filed: December 9, 2009
    Date of Patent: August 12, 2014
    Assignee: Kao Corporation
    Inventors: Eiji Shirai, Tetsuya Ueno
  • 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: 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: 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
  • 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: 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: 8603718
    Abstract: An anisotropic magnetic material-dispersed resin carrier including: fine magnetic particles; and a binder resin in which at least the fine magnetic particles are dispersed, wherein the anisotropic magnetic material-dispersed resin carrier has a magnetic anisotropy where magnetic fields of the fine magnetic particles are orientated in the same direction, and wherein the anisotropic magnetic material-dispersed resin carrier has a saturation magnetization of 16 emu/g to 30 emu/g, a coercive force of 15 kA/m to 40 kA/m, and a number average particle diameter of 15 ?m or more but less than 100 ?m.
    Type: Grant
    Filed: January 31, 2012
    Date of Patent: December 10, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazumi Suzuki, Masaki Yoshino, Hisao Kurosu, Tatsuya Morita, Tomoko Kino, Shingo Sakashita
  • 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: 8512925
    Abstract: Provided is a magnetic toner capable of preventing electrostatic offset while attaining a high image quality by a high speed machine. The magnetic toner comprises magnetic toner particles, each of which contains a binder resin and a magnetic material, and a fine inorganic powder, in which the binder resin contains a polyester unit, and the magnetic toner has a dielectric loss factor at 40° C. and 100 kHz of 0.40 pF/m or more but 1.00 pF/m or less and a dielectric loss factor at 150° C. and 100 kHz of 0.50 pF/m or more but 4.00 pF/m or less.
    Type: Grant
    Filed: January 19, 2012
    Date of Patent: August 20, 2013
    Assignee: Canon Kabushiki Kaisha
    Inventors: Shuhei Moribe, Katsuhisa Yamazaki, Toru Takahashi, Daisuke Tsujimoto, Masami Fujimoto
  • Patent number: 8512927
    Abstract: An electrostatic image developing carrier including at least a core material and a coating resin layer which coats the surface of the core material, the resin layer comprising a thermoplastic resin having an alicyclic group, a thermal reduction in accordance with the TGA method being in the range of 0.5 weight % to 5 weight % of the whole of the carrier in the range of 100° C. to 400° C., and further an endothermic quantity of the whole of the carrier in accordance with the DTA method is in the range of 7 mJ/g to 40 mJ/g in the range of 100° C. to 400° C.
    Type: Grant
    Filed: April 4, 2007
    Date of Patent: August 20, 2013
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Akihiro Iizuka, Fusako Kiyono, Tsuyoshi Murakami
  • Patent number: 8501377
    Abstract: Provided is a magnetic toner capable of providing a stable image by suppressing sleeve contamination even under a high-temperature and high-humidity environment and under a normal-temperature and low-humidity environment and further suppressing large-particle fogging caused after the toner is left alone for a week. The magnetic toner contains toner particles, each of which contains a binder resin and a magnetic iron oxide particle, in which the binder resin has a polyester unit, the toner has i) a dielectric loss factor at 40° C. and 100 kHz of 0.50 pF/m or more but 0.90 pF/m or less, and ii) a true specific gravity of 1.50 g/cm3 or more but 1.85 g/cm3 or less.
    Type: Grant
    Filed: January 19, 2012
    Date of Patent: August 6, 2013
    Assignee: Canon Kabushiki Kaisha
    Inventors: Toru Takahashi, Katsuhisa Yamazaki, Shuhei Moribe, Daisuke Tsujimoto, Masami Fujimoto
  • 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: 8426091
    Abstract: To solve a thin image density and sweeping occurring when a toner carrying member having a small diameter is used, provided is an image-forming method including: a charging step; an electrostatic latent image-forming step; a developing step; a transferring step; and a fixing step, in which a magnetic toner to be used in the method has a specific weight average particle diameter (D4); the magnetic toner has a specific intensity of magnetization in a specific magnetic field; and a surface free energy of a surface of the magnetic toner and a surface free energy of a surface of a toner carrying member to be used in the method satisfy specific relationships.
    Type: Grant
    Filed: October 29, 2008
    Date of Patent: April 23, 2013
    Assignee: Canon Kabushiki Kaisha
    Inventors: Michihisa Magome, Tadashi Dojo, Eriko Yanase, Takashi Matsui, Tomohisa Sano, Shuichi Hiroko
  • 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: 20130059248
    Abstract: Method for producing structured particles specifically nanoparticles, toners for laser printers and photocopiers, particularly chemical toner with particular product properties. The method produces toners of improved performance. Method relates particularly to the selection and properties of the base materials and utilizing these properties to design the toner product properties that result in improved performance.
    Type: Application
    Filed: May 6, 2011
    Publication date: March 7, 2013
    Applicant: Navran Advanced Nanoproducts Development International PVT. LTD.
    Inventor: Abhinava Kumar
  • Patent number: 8367293
    Abstract: A method for producing a carrier, including a step of periodically forming and discharging liquid droplets of a carrier core composition liquid from a plurality of nozzles formed in a thin film, using a liquid droplet forming unit having the thin film and a ring-shaped vibration generating unit disposed in a deformable area of the thin film so as to be along a circumference of the area and to vibrate the thin film, a step of forming carrier core particles by solidifying the discharged liquid droplets, and a step of coating the carrier core particles with a resin layer.
    Type: Grant
    Filed: December 18, 2008
    Date of Patent: February 5, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Shinji Ohtani, Ryota Inoue, Yoshihiro Norikane
  • 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: 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: 8213833
    Abstract: An image forming apparatus including at least an image bearer; a charger charging the image bearer; an irradiator irradiating the image bearer to form an electrostatic latent image thereon; an image developer developing the electrostatic latent image with a developer comprising a toner and a carrier to form a toner image on the image bearer; a developer feeder feeding a supplemental developer including the toner and the carrier into the image developer; and a developer collector collecting the developer in the image developer, wherein the developer feeder includes a cylindrical supplemental developer container containing the supplemental developer, including a spiral developer guide race on the inner circumferential surface thereof; and a sub-hopper configured to store the supplemental developer, and wherein the carrier includes a core material; and a layer coated on the core material, including a binder resin and non-black or a non-color inorganic particulate material.
    Type: Grant
    Filed: January 11, 2008
    Date of Patent: July 3, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Shinichiro Yagi, Tomio Kondou, Masashi Nagayama, Hltoahi Iwatsuki
  • Patent number: 8137879
    Abstract: A toner including stabilized magnetic single-crystal nanoparticles, wherein the value of the magnetic anisotropy of the magnetic nanoparticles is greater than or equal to 2×104 J/m3. The magnetic nanoparticle may be a ferromagnetic nanoparticle, such as FePt. The toner includes a magnetic material that minimizes the size of the particle, resulting in excellent magnetic pigment dispersion and dispersion stability, particularly in emulsion/aggregation toner processes. The smaller sized magnetic particles of the toner also maintains excellent magnetic properties, thereby reducing the amount of magnetic particle loading required in the toner.
    Type: Grant
    Filed: June 26, 2008
    Date of Patent: March 20, 2012
    Assignee: Xerox Corporation
    Inventors: Richard P. N. Veregin, Karen A. Moffat, Marcel P. Breton, Peter M. Kazmaier, Patricia A. Burns, Paul F. Smith
  • Patent number: 8137886
    Abstract: A magnetic carrier is provided which uses a toner having high coloring power and enables development to be performed at low electric field intensity and can form high quality images while keeping gradation characteristics. The magnetic carrier includes magnetic carrier particles including at least porous magnetic core particles and a resin. The electric field intensity just before the break-down of the magnetic carrier is 1,300 V/cm or more and 5,000 V/cm or less.
    Type: Grant
    Filed: January 21, 2010
    Date of Patent: March 20, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshinobu Baba, Koh Ishigami, Tomoko Endo, Hiroyuki Fujikawa, Kunihiko Nakamura, Nozomu Komatsu, Chika Inoue, Takayuki Itakura
  • Patent number: 8114562
    Abstract: A two-component developer containing a yellow toner and a magnetic carrier, wherein the yellow toner has the characteristics: (i) when the concentration of the yellow toner in a solution of the yellow toner in chloroform is represented by Cy (mg/ml) and the absorbance of the solution at a wavelength of 422 nm is represented by A422, a relationship between Cy and A422 satisfies the relationship of 6.00<A422/Cy<14.40; (ii) the lightness L* and chroma C* of the yellow toner determined in a powder state satisfy the relationships of 85.0?L*?95.0 and 100.0?C*?115.0; and (iii) the absolute value for the triboelectric charge quantity of the yellow toner measured by a two-component method using the yellow toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less.
    Type: Grant
    Filed: March 3, 2010
    Date of Patent: February 14, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventors: Koh Ishigami, Kazuo Terauchi, Noriyoshi Umeda, Tetsuya Ida, Naoki Okamoto, Yojiro Hotta, Yoshinobu Baba, Takayuki Itakura, Takeshi Yamamoto, Manami Haraguchi, Kenta Kubo
  • Patent number: 8110331
    Abstract: An electrophotographic developer including: magnetic particles, and a toner containing toner particles charged with the magnetic particles and having a particle diameter distribution, wherein the toner exhibits cumulative toner weight distributions of both square of charge amount q2 [C2] and attachment force F [N] per particle with respect to a representative toner particle diameter in the particle diameter distribution, giving a linear approximation of plots of the attachment force F [N] versus the square of charge amount q2 [C2] per particle at a plurality of corresponding cumulative toner weight ratios, and the linear approximation satisfies a slope of the linear approximation of from 5×1020 to 3×1022 and a squared multiple correlation coefficient (R2) of 0.6 or more. As a result, the developer allows good control of transferability under the control of an electric field and allows a reduction in transfer residual amount of the toner.
    Type: Grant
    Filed: September 14, 2009
    Date of Patent: February 7, 2012
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Tec Kabushiki Kaisha
    Inventor: Shoko Shimmura
  • Patent number: 8062822
    Abstract: An electrostatic latent image developing carrier is provided which comprises a core particle and a resin coating layer containing conductive particles dispersed therein, the carrier having a volume average particle diameter of 25 to 60 ?m and an average degree of circularity of 0.975 or more, wherein the core particle has a BET specific surface area of 0.1 to 0.3 m2/g and an internal void ratio of 10% or less.
    Type: Grant
    Filed: December 7, 2005
    Date of Patent: November 22, 2011
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Satoshi Inoue, Masahiro Takagi, Koutarou Yoshihara
  • Patent number: 7981582
    Abstract: A toner having a crystalline or semi-crystalline polyester resin, an amorphous resin and a colorant. The toner preferably exhibits a resistivity of at least 1×1011 ohm-cm. A developer may be produced including the toner and optionally a carrier. If a carrier is included, the carrier preferably exhibits a resistivity of greater than 1×107 ohm-cm. An electrophotographic machine includes the toner exhibiting high resistivity.
    Type: Grant
    Filed: June 23, 2005
    Date of Patent: July 19, 2011
    Assignee: Xerox Corporation
    Inventors: Richard P. N. Veregin, Michael S. Hawkins, Vladislav Skorokhod, Valerie M. Farrugia
  • Publication number: 20110151371
    Abstract: A toner for electrostatic latent image development is disclosed, comprising colored particles containing a binder resin and a colorant, and an external-additive, wherein the external additive comprises boron nitride particles exhibiting a number average primary particle size of 10 to 500 nm. The production method of the toner is also disclosed.
    Type: Application
    Filed: December 3, 2010
    Publication date: June 23, 2011
    Applicant: KONICA MINOLTA BUSINESS TECHNOLOGIES, INC.
    Inventors: Shinya OBARA, Masahiro ANNO, Satoshi UCHINO, Hitomi MOTANI, Hidehito HARUKI
  • Patent number: 7964330
    Abstract: There are adopted an electrophotographic resin-coated ferrite carrier having a carrier core coated with a resin, wherein a product of an apparent density ? (g/cm3), average particle size d (?m) and BET specific surface area S (m2/g) of the carrier core satisfies the following condition, a method for producing the same, and an electrophotographic developer. 4.5??×d×S?8.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: June 21, 2011
    Assignee: Powertech Co., Ltd.
    Inventors: Issei Shinmura, Kanao Kayamoto
  • Patent number: 7939231
    Abstract: A magnetic toner is disclosed having magnetic toner particles containing a binder resin and a magnetic iron oxide. The magnetic toner has a specific saturation magnetization and a specific residual magnetization in ascertain magnetic field. The binder resin includes a polyester component polymerized with an aromatic carboxylic acid titanium compound as a catalyst.
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: May 10, 2011
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshihiro Ogawa, Yusuke Hasegawa, Shinichiro Abe, Junko Nishiyama, Takashige Kasuya
  • Patent number: 7935468
    Abstract: There is provided a toner which is excellent in temporal stability and environmental stability of charges and which is capable of forming images that contains almost no background fog and has high density even in a long-term use and in use at a high-temperature and high-humid circumstance, and furthermore the toner which is not scattered inside an image forming apparatus and thus causes no contamination inside the apparatus, and there is further provided a method of manufacturing the above toner. An organic boron compound is contained as a charge control agent, a surface CCA concentration per specific surface area of toner falls in a range from 2.1×10?6 g/cm2 to 5.5×10?6 g/cm2, and a surface CCA concentration is 1.8×10?3 g/g or more.
    Type: Grant
    Filed: June 18, 2007
    Date of Patent: May 3, 2011
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshinori Yamamoto, Satoshi Ogawa, Masao Suzuki, Yoshiaki Akazawa
  • Publication number: 20110091805
    Abstract: Toner particles are provided which may, in embodiments, include an additive package including a titanium dioxide that has been subjected to a fluorine treatment. In embodiments, additional additives, including a silica, optionally in combination with a metal salt of a fatty acid, for example a zinc stearate, may be included. The additives provide toners with excellent charging characteristics and good blocking performance.
    Type: Application
    Filed: October 21, 2009
    Publication date: April 21, 2011
    Applicant: XEROX CORPORATION
    Inventors: Maria N.V. McDougall, Richard P.N. Veregin, Eric Rotberg, Michael S. Hawkins
  • Patent number: 7910278
    Abstract: The present invention provides a toner for developing electrostatic image comprising a colored particle containing a binder resin, a colorant and a release agent, wherein the toner for developing electrostatic image has two or more peaks of loss tangent (tan ?) in the range from 50 to 120° C., a loss tangent (tan ?) in the range from 100 to 200° C. is 0.8 or less, and a dispersed diameter of the release agent is 0.1 times or less shorter than a volume average particle diameter of the colored particle.
    Type: Grant
    Filed: December 28, 2005
    Date of Patent: March 22, 2011
    Assignee: Zeon Corporation
    Inventors: Gen-ichi Ohta, Hiroto Kidokoro
  • Patent number: 7906262
    Abstract: A two-component developer containing a cyan toner and a magnetic carrier, wherein the cyan toner has the characteristics: (i) when the concentration of the cyan toner in a solution of the cyan toner in chloroform is represented by Cc (mg/ml) and the absorbance of the solution at a wavelength of 712 nm is represented by A712, a relationship between Cc and A712 satisfies the relationship of 2.00<A712/Cc<8.15; (ii) the lightness L* and chroma C* of the cyan toner determined in a powder state satisfy the relationships of 25.0?L*?40.0 and 50.0?C*?60.0; and (iii) the absolute value for the triboelectric charge quantity of the cyan toner measured by a two-component method using the cyan toner and the magnetic carrier is 50 mC/kg or more and 120 mC/kg or less.
    Type: Grant
    Filed: March 3, 2010
    Date of Patent: March 15, 2011
    Assignee: Canon Kabushiki Kaisha
    Inventors: Koh Ishigami, Kazuo Terauchi, Noriyoshi Umeda, Tetsuya Ida, Naoki Okamoto, Yojiro Hotta, Yoshinobu Baba, Takayuki Itakura, Takeshi Yamamoto, Manami Haraguchi, Kenta Kubo
  • Patent number: 7906265
    Abstract: A ferrite carrier for an electrophotographic developer having a compression breaking strength of 150 MPa or more, a rate of compressive change of 15.0% or more and a shape factor SF-1 of 100 to 125, a method for producing the same, and an electrophotographic developer containing the ferrite carrier.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: March 15, 2011
    Assignee: Powdertech Co., Ltd.
    Inventors: Tomoyuki Suwa, Tsuyoshi Itagoshi
  • Patent number: 7879520
    Abstract: A toner for developing an electrostatic image comprises a binding resin for a toner and a charge control agent including an azo-type iron complex salt represented by the following chemical formula (1) (in the chemical formula (1), R1 and R3 are the same or different to each other and are an alkyl group having a straight chain or a branch chain of 3 to 8 carbons; R2a, R2b, R4a and R4b are the same or different to each other and are selected from the group consisting of a hydrogen atom, an alkyl group, an alkoxyl group, a halogen atom, a nitro group and a carboxyl group; A+ indicates m(H+)+n(K+)+p(Na+), which m, n and p satisfy numerical equations of m+n+p=1, 0.7?m?1, 0?n?0.3 and 0?p?0.3), wherein an average particle size thereof is 1 to 4 microns, and a specific volume resistivity thereof is ranging from 0.2×1015 to 7×1015 ?·cm.
    Type: Grant
    Filed: June 5, 2007
    Date of Patent: February 1, 2011
    Assignee: Orient Chemical Industries, Ltd.
    Inventors: Kaori Sato, Masashi Yasumatsu
  • Patent number: 7879521
    Abstract: An objective is to provide a highly durable carrier for a developer which is capable of forming a high-definition image stably with no deterioration of a developing property since the carrier resistance and the charging ability remain stable even though the developer is used for a long duration; a method of manufacturing the carrier; and an image forming method employing the same. Disclosed is an electrophotographic carrier comprising a carrier core material and provided thereon, a resin-coated layer comprising charge control particles and low-resistive particles, wherein an initial carrier resistance is 5×108-3×1010 ?cm; a concentration of the low-resistive particles grows higher toward a surface of the layer from an inner part of the layer; and a concentration of the charge control particles grows lower toward a surface of the layer from an inner part of the layer.
    Type: Grant
    Filed: May 31, 2007
    Date of Patent: February 1, 2011
    Assignee: Konica Minolta Business Technologies, Inc.
    Inventors: Hiroyuki Kozuru, Yoshiaki Kobayashi, Tatsuya Nagase
  • Publication number: 20100310982
    Abstract: A method for producing a carrier, including a step of periodically forming and discharging liquid droplets of a carrier core composition liquid from a plurality of nozzles formed in a thin film, using a liquid droplet forming unit having the thin film and a ring-shaped vibration generating unit disposed in a deformable area of the thin film so as to be along a circumference of the area and to vibrate the thin film, a step of forming carrier core particles by solidifying the discharged liquid droplets, and a step of coating the carrier core particles with a resin layer.
    Type: Application
    Filed: December 18, 2008
    Publication date: December 9, 2010
    Inventors: Shinji Ohtani, Ryota Inoue, Yoshihiro Norikane
  • Publication number: 20100303506
    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: Application
    Filed: June 2, 2010
    Publication date: December 2, 2010
    Inventors: Takashi Hara, Yoshiaki Akazawa, Yoshitaka Kawase, Yoritaka Tsubaki, Yoshinori Mutoh, Keiichi Kikawa
  • Publication number: 20100279221
    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: Application
    Filed: April 28, 2010
    Publication date: November 4, 2010
    Inventors: Osamu Wada, Takanori Kamoto, Nobuyuki Yoshioka, Ayae Nagaoka, Tadashi Iwamatsu
  • Patent number: 7824833
    Abstract: A spherical resin-coated ferrite carrier for an electrophotographic developer which can maintain a stable resistance and chargeability, a favorable charge rising property because of an excellent fluidity, and has a suitable durability, its production method which is excellent in economic efficiency and production stability, and an electrophotographic developer using the resin-coated ferrite carrier, are provided. A resin-coated ferrite carrier for an electrophotographic developer which is a spherical resin-coated ferrite carrier, wherein a carrier core material thereof has an irregular surface to improve the adhesive strength to a resin coat, and wherein the irregularity of the surface takes a finely streaked wrinkle pattern, its production method, and an electrophotographic developer using the resin-coated ferrite carrier, are employed.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: November 2, 2010
    Assignee: Powdertech Co., Ltd.
    Inventors: Kanao Kayamoto, Issei Shinmura, Toshio Honjo