Ferrite Containing Magnetic Carrier Patents (Class 430/111.31)
  • Publication number: 20030022087
    Abstract: A positively chargeable toner for two-component development comprising a resin binder; a colorant; a releasing agent comprising a wax having a melting point of 50° to 120° C.; and an external additive comprising a positively chargeable silica, the positively chargeable silica having an absolute deviation of an error of 0.1 or less, against an approximate straight line showing an adhesion state of silicon atoms to carbon atoms, and a free ratio of 5% or less, wherein the positively chargeable toner is usable together with a ferrite carrier having a saturation magnetization of from 40 to 100 Am2/kg. This positively chargeable toner is used for development of an electrostatic latent image formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.
    Type: Application
    Filed: April 25, 2002
    Publication date: January 30, 2003
    Inventors: Hidenori Tachi, Shinji Moriyama, Yoshihiro Fukushima
  • Patent number: 6506531
    Abstract: A magnetic carrier exhibiting excellent durability against mechanical impact as exerted by vibration and capable of exhibiting a stable charging performance in electrophotography is provided.
    Type: Grant
    Filed: November 5, 1999
    Date of Patent: January 14, 2003
    Assignee: Canon Kabushiki Kaisha
    Inventors: Toshiyuki Hakata, Hiroomi Kakihara, Masaaki Fukugauchi, Kenji Okada, Yushi Mikuriya, Kazumi Yoshizaki
  • Publication number: 20030008226
    Abstract: A carrier for electrophotography and a two component type developer using the carrier. The carrier is composed of magnetic particles of a magnetic ferrite component represented by Formula: (Fe2O3)X(MnO)Y(A)Z. An image forming method is also disclosed which uses the two component type developer.
    Type: Application
    Filed: March 28, 2002
    Publication date: January 9, 2003
    Inventors: Tsuyoshi Takiguchi, Kenji Okado, Tetsuya Ida
  • Patent number: 6464797
    Abstract: A method for use in two-components electrostatic image developers is disclosed, in which secure separation of a carrier coating resinous materials from a core magnetic material is achieved without affecting the properties of the core materials through process steps benign to the environment in super- or sub-critical water compositions under the conditions of a temperature of 300° C. or more and a pressure of 20 MPa. The core magnetic material is subsequently recycled for forming carrier. This method may also be useful for processing waste including magnetic materials with silicone resin coating.
    Type: Grant
    Filed: July 28, 2000
    Date of Patent: October 15, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Kunitoshi Sugiyama, Yoshihiko Itoh, Hideyuki Santoh, Kunio Arai, Tadafumi Ajiri
  • Publication number: 20020037470
    Abstract: A carrier for electrophotography and a two component type developer using the carrier.
    Type: Application
    Filed: August 30, 2001
    Publication date: March 28, 2002
    Inventors: Tsuyoshi Takiguchi, Kenji Okado, Tetsuya Ida
  • Publication number: 20020025487
    Abstract: Methods for development of an electrostatic image are disclosed that utilize developer compositions with hard magnetic carrier compositions which can provide improved development efficiencies and reduced amounts of image carrier pick-up. The methods utilize hard magnetic carrier particles that are modified to have specific levels of resistivity, such as, for example, of from about 1×105 ohm-cm to about 1×1010 ohm-cm, and a carrier charge-to-mass of greater than about 1.0 &mgr;C/g, which carriers can provide greater development speeds without unacceptable levels of image carrier pick-up. In embodiments, the hard magnetic materials are doped, i.e., bulk substituted, with multi-valent metals to adjust resistivity, while in other embodiments, the hard magnetic materials are coated with at least one multi-valent metal oxide.
    Type: Application
    Filed: May 11, 2001
    Publication date: February 28, 2002
    Inventors: Patrick Lambert, Li C. Stelter, William K. Goebel, Peter S. Alexandrovich
  • Publication number: 20010055723
    Abstract: Disclosed are methods and apparatus for electrographic development which utilize a rotating magnetic core, a toner shell disposed around the rotating magnetic core, and developer compositions disposed on the toner shell which include a hard magnetic material, such as a strontium ferrite. The shell in embodiments has an outer surface with a surface roughness Ra of less than 32 microinches. The methods and apparatus do not require special manufacturing steps to place surface roughness or irregularities on the shell, and, thus, can provide the same or better image quality with relatively less complex manufacturing steps and at reduced cost.
    Type: Application
    Filed: May 11, 2001
    Publication date: December 27, 2001
    Inventors: Eric C. Stelter, Robert D. Fields, Thomas A. Jadwin
  • Patent number: 6294304
    Abstract: A ferrite carrier includes manganese oxide, ferric oxide and minor amounts of titanium dioxide and provides an environmentally benign, highly conductive, reprographic carrier powder.
    Type: Grant
    Filed: January 25, 1999
    Date of Patent: September 25, 2001
    Assignee: PowderTech Corporation
    Inventors: Alan Sukovich, William R. Hutcheson