One Component Toner Patents (Class 430/903)
  • Patent number: 4891294
    Abstract: Electrostatic development toner for use in nonmagnetic one-component development comprising a binder resin, calcium carbonate and ceramic fine powder having an average particle size of 3 .mu.m or less.
    Type: Grant
    Filed: July 7, 1988
    Date of Patent: January 2, 1990
    Assignee: Hitachi Metals, Ltd.
    Inventor: Koji Noguchi
  • Patent number: 4886725
    Abstract: A triboelectrically chargeable composition for use in development of electrostatic latent images. The composition contains an organotin oxide represented by the formula: ##STR1## wherein R.sup.1 and R.sup.2 are the same or different groups selected from cycloalkyl groups, substituted cycloalkyl groups, aralkyl groups and substituted aralkyl groups. The composition is embodied typically as a positively chargeable toner and also as a charge-imparting material for charging a toner.
    Type: Grant
    Filed: September 14, 1987
    Date of Patent: December 12, 1989
    Assignee: Canon Kabushiki Kaisha
    Inventors: Katsuhiko Tanaka, Hiroshi Fukumoto
  • Patent number: 4877707
    Abstract: A single component pressure fixable toner composition comprised of resin particles selected from the group consisting of ethylene/propylene copolymers, ethylene-co-vinyl acetate polymers, polyamides, and mixtures thereof, magnetite, and a release fluid therein, which toner contains conductive particles on the surface thereof, and wherein the magnetite is present in an amount of from about 50 to about 80 percent by weight, and the toner has a resistivity of about 10.sup.4 to about 10.sup.7 ohm-cm.
    Type: Grant
    Filed: May 26, 1988
    Date of Patent: October 31, 1989
    Assignee: Xerox Corporation
    Inventors: Bernard Grushkin, Hui Chang, John G. Ruhland
  • Patent number: 4873185
    Abstract: A toner for dry electrophotography comprises a binder resin, a metal complex compound (A) of an aromatic hydroxycarboxylic acid having a lipophilic group, and a metal complex salt-type monoazo dye (B) having a hydrophilic group. The compound (A) functions to enhances the negative triboelectric chargeability of the toner, and the dye (B) functions to leak an excessive charge of the toner, so that the toner is caused to have a uniform and sharp triboelectric charge distribution. As a result, the toner involves little liability of causing "tailing", an irregularity caused by undesirable toner scattering.
    Type: Grant
    Filed: July 2, 1987
    Date of Patent: October 10, 1989
    Assignee: Canon Kabushiki Kaisha
    Inventors: Mitsuru Uchida, Satoshi Yasuda, Tetsuya Kuribayashi
  • Patent number: 4849316
    Abstract: Resin composition containing vinyl polymer and olefin polymer for use in electrophotography, electrostatic recording and electrostatic printing and the like, more particularly the resin composition obtained by uniformly dispersing the olefin polymer in the vinyl polymer, and the toner containing this resin composition are disclosed.
    Type: Grant
    Filed: December 13, 1988
    Date of Patent: July 18, 1989
    Assignee: Mitsui Toatsu Chemicals, Incorporated
    Inventors: Shoji Kawaski, Hisatomo Sato, Masaaki Shin, Takashi Yamamoto
  • Patent number: 4837391
    Abstract: New electrostatographic developers are provided, containing dual function polymeric binder/charge agents. The new developers contain toner particles comprising a vinyl addition binder polymer containing a quaternary phosphonium salt, wherein the phosphonium salt has an anionic portion covalently bonded to the binder polymer.
    Type: Grant
    Filed: August 5, 1988
    Date of Patent: June 6, 1989
    Assignee: Eastman Kodak Company
    Inventors: James H. Anderson, Douglas E. Bugner
  • Patent number: 4833056
    Abstract: A triboelectrically chargeable monocomponent toner powder is provided which comprises as a binder a mixture of a copolymer of styrene and an acrylate with an amine-containing aliphatic wax as a charge-control agent. The toner is inherently strongly chargeable positively through triboelectric forces.
    Type: Grant
    Filed: February 11, 1988
    Date of Patent: May 23, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Sudershan K. Bhateja, Chung I. Young, Nancy N. Quan
  • Patent number: 4826746
    Abstract: A process for forming a visible image in which an electrophotographic element having a homogeneous and amorphous silicon layer as the sole photoconductive layer is provided with a charge image and the charge image is developed by a developing powder. The electrophotographic element has a very thin silicon layer with a thickness between 0.5 and 3 .mu.m and a dark decay time greater than 25 seconds. The photoconductive layer is developed by a one-component developing powder having a resistivity of less than 10.sup.5 ohm.meter.
    Type: Grant
    Filed: June 1, 1987
    Date of Patent: May 2, 1989
    Assignee: Oce-Nederland B.V.
    Inventors: Marinus Groeneveld, Gerardus G. Draisma
  • Patent number: 4824754
    Abstract: A toner particle for electrostatography or magnetography which has an inorganic material such as a specific metallic oxide, a carbonate or a silicate in or on its surface. This inorganic material is in the form of particles and has been treated with a titanate coupling agent on its surface.
    Type: Grant
    Filed: April 8, 1987
    Date of Patent: April 25, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventor: Takeshi Mikami
  • Patent number: 4824752
    Abstract: A magnetic dry developer, comprising negatively chargeable insulating magnetic toner particles containing, at least, a binder resin, a magnetic substance, and an organo-chromium or -zinc complex; cerium oxide particles containing CeO.sub.2 as a predominant component and having a volume average particle size of 1.0 to 4.0 microns, a heating loss of 0.5 wt. % or less on heating up to 100.degree. C. and a BET specific surface area of 15 m.sup.2 /g or less as measured by the nitrogen adsorption method; and hydrophobicity-imparted negatively chargeable silicon oxide particulates. The cerium oxide particles have a function of disintegrating particularly the hydrophobicity-imparted silicon oxide particulates and enhance the attachment thereof to the toner particles, whereby the developing characteristics including the magnetic triboelectric chargeability are stabilized from the initial stage of electrophotographic copying operation.
    Type: Grant
    Filed: September 12, 1988
    Date of Patent: April 25, 1989
    Assignee: Canon Kabushiki Kaisha
    Inventors: Satoshi Yasuda, Mitsuru Uchida, Seiichi Takagi, Yusuke Karami
  • Patent number: 4820603
    Abstract: A magnetic toner comprises a binder resin and a magnetic iron oxide. The magnetic iron oxide has a silicon content of 0.1-1.5 wt. % based on the iron contained therein and is in the form fine particles containing the silicon preferentially in the inner part thereof. Because of these features, the magnetic iron oxide particles have a sharp particle size distribution, have uniform surface properties including those under various environmental conditions and freeness from agglomeration, have a good black hue, and are uniformly dispersed in the binder resin to provide a magnetic toner having uniform properties particularly suited for electrophotography.
    Type: Grant
    Filed: May 27, 1987
    Date of Patent: April 11, 1989
    Assignee: Canon Kabushiki Kaisha
    Inventor: Kiichiro Sakashita
  • Patent number: 4810610
    Abstract: Disclosed are single component conductive cold pressure fixable toner compositions with a resistivity of from about 5.times.10.sup.4 to about 10.sup.7 ohm-cm for ionographic development systems and comprised of a blend of resin particles and magnetite particles; and present on the surface thereof pigment particles having absorbed thereon release fluids.
    Type: Grant
    Filed: February 29, 1988
    Date of Patent: March 7, 1989
    Assignee: Xerox Corporation
    Inventors: Bernard Grushkin, John G. Ruhland
  • Patent number: 4803144
    Abstract: An electrostatographic toner material suitably employable for the pressure fixing process, which comprises encapsulated toner particles having an average particle size in the range from about 0.5 to 1,000 microns, in which the toner particle comprises a pressure fixable adhesive core material containing colorant and magnetizable substance and a pressure rupturable shell enclosing the core material, the outer surface of the shell being provided with white electroconductive powder.
    Type: Grant
    Filed: February 19, 1987
    Date of Patent: February 7, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventor: Noriyuki Hosoi
  • Patent number: 4803143
    Abstract: Colored single-component toners essentially consist of a magnetic pigment, a binder based on an organic polymer and/or a wax, a dye or colored pigment homogeneously distributed in the binder, and other assistants, the magnetic pigment being iron powder which has a spherical or elliptical shape.
    Type: Grant
    Filed: December 1, 1986
    Date of Patent: February 7, 1989
    Assignee: BASF Aktiengesellschaft
    Inventors: Werner Ostertag, Erwin Czech, Franz-Ulrich Schmitt, Detlef Schulze-Hagenest
  • Patent number: 4760007
    Abstract: An improved dry toner for developing latent images is disclosed which comprises essentially a resin and a magnetic powder. The resin includes, as the copolymerization components, at least one monomer selected from the group consisting of styrene and its derivatives and at least one monomer selected from the group consisting of maleic acid and its derivatives.
    Type: Grant
    Filed: September 9, 1985
    Date of Patent: July 26, 1988
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshio Takasu, Tetsuo Hasegawa, Shigeo Kato, Yoshihiro Nishikawa
  • Patent number: 4758506
    Abstract: Disclosed is an improved single component cold pressure fixable toner composition comprised of a core containing (1) magnetite particles, and a styrene-butadiene-styrene triblock polymer and a polymeric shell material generated by an interfacial polymerization process.
    Type: Grant
    Filed: June 15, 1984
    Date of Patent: July 19, 1988
    Assignee: Xerox Corporation
    Inventors: Kar P. Lok, Marcel P. Breton, John R. Fuller
  • Patent number: 4758490
    Abstract: Color magnetic toner particles suitable for an electrophotographic copying machine comprise magnetic particles whose diameter is selected less than about 200 angstroms, a coloring agent and a binding agent. Because of the fineness of the magnetic particles, the transparency of the toner particles becomes so good that the color emitted by the coloring agent becomes clear and vivid.
    Type: Grant
    Filed: July 2, 1987
    Date of Patent: July 19, 1988
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Yasuo Kitabatake
  • Patent number: 4758493
    Abstract: A single component toner composition comprised of crosslinked resin particles, a low molecular weight wax component, magnetite, and external additive particles selected from the group consisting of first flow aid additive particles, and second metal oxide additive particles.
    Type: Grant
    Filed: November 24, 1986
    Date of Patent: July 19, 1988
    Assignee: Xerox Corporation
    Inventors: Eugene F. Young, Thomas J. McGowan
  • Patent number: 4699865
    Abstract: A process for developing a latent image with a developer is provided which comprises(1) forming a layer of a developer comprising a magnetic toner containing magnetic powder having a BET specific surface area of 2 to 20 m.sup.2 /g on a member for supporting the developer,(2) bringing an electrophotographic photosensitive member holding the latent image into contact with said developer layer, said electrophotographic photosensitive member comprising an organic photoconductive material having a surface hardness more than 10 g,(3) forming a toner image on said electrophotographic photosensitive member,(4) transferring the toner image onto the transfer material, and(5) cleaning the electrophotographic photosensitive member having passed through the transferring step with a cleaning member. Said developer may alternatively comprises magnetic particles containing a binder and magnetic powder having a BET specific surface area of 2 to 20 m.sup.
    Type: Grant
    Filed: March 11, 1987
    Date of Patent: October 13, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventor: Yasuo Mitsuhashi
  • Patent number: 4681830
    Abstract: A flowable, dry powder of particles of a developing composition are provided. The compositions may be either heat- or pressure-fixable and utilize from about 0.4 to 10 parts by weight of fluorinated carbon per 100 parts by weight of a thermoplastic binder and a magnetically responsive material. The fluorinated carbon has a degree of fluorination in the range of 10% to 100% and an average diameter below about 2 microns. The developing powder compositions possess improved flow humidity resistance and provide dramatically improved copy quality.
    Type: Grant
    Filed: April 24, 1986
    Date of Patent: July 21, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Randall H. Helland, Craig A. Burton
  • Patent number: 4640881
    Abstract: Mixing into a combination of thermoplastic organic resin and magnetic powder used to make a toner, a silanol methylsiloxane resin readily gives a dry toner powder useful in making photocopies.
    Type: Grant
    Filed: July 15, 1985
    Date of Patent: February 3, 1987
    Assignee: Dow Corning Corporation
    Inventor: William E. Dennis
  • Patent number: 4636451
    Abstract: Pressure-fixable toner particles suitable for use in electrostatic copying machines and method of preparing same. The toner particle is spherical in shape and comprises a thin, substantially continuous surface layer of polyurea, and an interior portion comprising a matrix of polyurea, said matrix having a colorant and pressure-fixable material contained therein, said polyurea matrix forming a continium extending from the surface layer inwardly toward the center of said particle.
    Type: Grant
    Filed: February 13, 1986
    Date of Patent: January 13, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Josef Matkin, Richard J. Treleaven
  • Patent number: 4634650
    Abstract: A toner for developing latent electrostatic images comprising particles is disclosed, which is composed of a mixture of a colorant and/or magnetic material, a binder agent and a charge controlling agent of the formula ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represent an unsubstituted or substituted aryl group; and X represents an anionic functional group.
    Type: Grant
    Filed: July 26, 1985
    Date of Patent: January 6, 1987
    Assignee: Ricoh Company, Ltd.
    Inventor: Tetsuro Suzuki
  • Patent number: 4612272
    Abstract: A pressure fixable single component electrophotographic toner or developer composition comprising a low melt viscosity polyamide resin composition and a magnetic oxide component. Highly conductive carbon may be added to control the resistivity of the developer particles. The toner includes a magnetic oxide component in a range of from 50 to 65 percent by weight and a polyamide resinous component in a range of from 50 to 35 percent by weight.
    Type: Grant
    Filed: March 29, 1985
    Date of Patent: September 16, 1986
    Assignee: AM International, Inc.
    Inventor: Virgil W. Westdale
  • Patent number: 4612273
    Abstract: A pressure fixable single component electrophotographic toner or developer composition of a particle size of from 10-40 microns comprising a specialized low melt viscosity polyamide resin composition and a magnetic oxide component. Highly conductive carbon may be added to control the resistivity of the developer particles. The developer comprises from 65.50 percent of the magnetic oxide component and from 35-50 percent of the polyamide resinous component.
    Type: Grant
    Filed: March 29, 1985
    Date of Patent: September 16, 1986
    Assignee: AM International, Inc.
    Inventors: Virgil W. Westdale, James L. Hanrahan
  • Patent number: 4608329
    Abstract: An imageable toner powder comprising a solid material capable of existing as a supercooled liquid after being heated above its melting temperature and subsequently cooled and a colorant.
    Type: Grant
    Filed: January 8, 1985
    Date of Patent: August 26, 1986
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Thomas C. Geisler
  • Patent number: 4592957
    Abstract: Microcapsules having a hydrophobic core material and capsule walls formed by the reaction of water-insoluble polyamines with water-soluble bisulphite adducts of polyisocyanates, a process for the production thereof which is characterized in that a mixture of a hydrophobic core material and water-insoluble polyamines is emulsified in water or in an aqueous protective colloid solution to the required particle size, water-soluble bisulphite adducts of polyisocyanates in the form of powders or aqueous solutions are added and the mixture is left to react to completion at temperatures of from 1.degree. to 140.degree. C., and applications thereof.
    Type: Grant
    Filed: January 14, 1985
    Date of Patent: June 3, 1986
    Assignee: Bayer Aktiengesellschaft
    Inventors: Manfred Dahm, Norbert Weimann, Ulrich Nehen, Hanns P. Muller, Gert Jabs, Albert Awater, James M. Barnes
  • Patent number: 4555467
    Abstract: A developer comprises toner particles and flowability improver granules having a granule size of 0.1-20 times the average particle size of the toner particles. The developer has high durability, fixability and good developing characteristics.
    Type: Grant
    Filed: December 6, 1983
    Date of Patent: November 26, 1985
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tetsuo Hasegawa, Koushi Suematsu
  • Patent number: 4543312
    Abstract: A magnetic toner comprises magnetic powders having a particle distribution that the particle size of 50% accumulated volume, the particle size of 25% accumulated volume and the particle size of 75% accumulated volume of the magnetic powders are 1.5-4.5.mu., 1.0-4.0.mu. and 2.5-6.0.mu., respectively. This magnetic toner can produce high density and clear images and further, can produce colorful images.
    Type: Grant
    Filed: April 26, 1983
    Date of Patent: September 24, 1985
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kazunori Murakawa, Yasuo Mitsuhashi, Hitoshi Uchide, Seiichi Takagi, Masaki Uchiyama, Hisayuki Ochi, Motoo Urawa, Eiichi Imai
  • Patent number: 4540646
    Abstract: Method and apparatus for developing electrostatic latent images comprising a developer which in turn is composed of a toner made up of resin and particles of magnetic materials having negative triboelectricity with respect to the resin dispersed in said resin. The developer is fed to a surface having magnets associated therewith for causing the developer to rise from the magnets in ear-like fashion to brush and deposit the developer on the latent image carrying surface.
    Type: Grant
    Filed: July 9, 1984
    Date of Patent: September 10, 1985
    Assignee: Konishiroku Photo Industry Co., Ltd.
    Inventors: Jun Kambara, Yuzo Ohmuro, Nin-ichi Kamogawa
  • Patent number: 4536462
    Abstract: A novel magnetic, electrophotographic, development or toner powder is provided comprising essentially spherical particles with a diameter between 5 and 50.mu.. The particles contain small ferromagnetic particles, highly conducting carbon, at least 5% sublimable dyestuff and at least 4% of a surface active agent. The particles are preferably structured to have an inside nucleus zone containing dyestuff and surfactant and an outside shell zone which contains the magnetic material and the highly conducting carbon.
    Type: Grant
    Filed: November 22, 1983
    Date of Patent: August 20, 1985
    Assignee: International Toner Specialties
    Inventor: Wolfgang Mehl
  • Patent number: 4530893
    Abstract: Disclosed is a one-component type red color magnetic developer having a self-electroscopic property, which comprises particles prepared from a kneaded composition comprising 100 parts by weight of a magnetic powder composed mainly of ocherous gamma-type diiron trioxide, 2.5 to 30 parts by weight of a red azo pigment and 40 to 200 parts by weight of a binder resin, wherein a fixed image of the particles is measured by a color difference meter, the value x is from 0.51 to 0.73, the value y is from 0.22 to 0.40 and the value Y is from 5 to 65%.
    Type: Grant
    Filed: November 29, 1983
    Date of Patent: July 23, 1985
    Assignee: Mita Industrial Co. Ltd.
    Inventors: Kouji Maekawa, Nobuhiro Miyakawa
  • Patent number: 4529680
    Abstract: A magnetic toner for pressure fixation containing at least a resin and a magnetic powder as the main components, where the resin is a polymer essentially, containing methyl-1-pentene as the main component and having a softening point of at least 80.degree. C. and a compression yield strength of not more than 150 kg/cm.sup.2, has a good fixability under a low pressure and a good preservability at a high temperature.
    Type: Grant
    Filed: December 21, 1983
    Date of Patent: July 16, 1985
    Assignees: Hitachi Metals, Ltd., Mitsui Petrochemical Industries, Ltd.
    Inventors: Masumi Asanae, Koji Noguchi, Hideyuki Itoi, Katsumi Funakoshi
  • Patent number: 4517141
    Abstract: Microcapsules having a hydrophobic core material and capsule walls formed by the reaction of water-insoluble polyamines with water-soluble bisulphite adducts of polyisocyanates, a process for the production thereof which is characterized in that a mixture of a hydrophobic core material and water-insoluble polyamines is emulsified in water or in an aqueous protective colloid solution to the required particle size, water-soluble bisulphite adducts of polyisocyanates in the form of powders or aqueous solutions are added and the mixture is left to react to completion at temperatures of from 1.degree. to 140.degree. C., and applications thereof.
    Type: Grant
    Filed: June 21, 1983
    Date of Patent: May 14, 1985
    Assignee: Bayer Aktiengesellschaft
    Inventors: Manfred Dahm, Norbert Weimann, Ulrich Nehen, Hanns P. Muller, Gert Jabs, Albert Awater, James M. Barnes
  • Patent number: 4507378
    Abstract: The invention relates to a method for producing a toner by polymerizing an aqueous suspension of a monomer in the presence of a dispersant selected from orthophosphate, pyrophosphate and polyphosphate, a colorant and an anionic surfactant. The polymerization product is then treated with dilute acid and rinsed with water whereby the dispersant is removed from the polymerization product.
    Type: Grant
    Filed: December 6, 1983
    Date of Patent: March 26, 1985
    Assignee: Konishiroku Photo Industry Co., Ltd.
    Inventors: Tsuneo Wada, Kiyoshi Tamaki, Hideki Murata, Sadatugu Terada, Hiroyuki Takagiwa
  • Patent number: 4504562
    Abstract: Disclosed is a one-component type magnetic developer consisting essentially of a particulate shaped article of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, wherein said magnetic material comprising (A) a non-pulverizing agglomerate of cubic particles of magnetite having a particle size of 1 to 10 .mu.m as measured by an electron microscope and (B) magnetite particles having a particle size of 0.2 to 1 .mu.m at an (A)/(B) weight ratio of from 95/5 to 10/90, especially from 95/5 to 30/70.
    Type: Grant
    Filed: June 27, 1983
    Date of Patent: March 12, 1985
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Nobuhiro Miyakawa, Masanori Fujii, Kouzi Maekawa
  • Patent number: 4495268
    Abstract: Disclosed is a transfer-type one-component dry magnetic developer which comprises a binder medium having a high electric resistance and particles of triiron tetroxide of an isometric system having a particle size of 0.25 to 1 micron and a coercive force of 30 to 80 Oe, in which the triiron tetroxide particles are dispersed in the binder medium.This developer provides a transferred image excellent in the density, sharpness and clarity on a plain paper as a transfer sheet in the electrostatic photography.
    Type: Grant
    Filed: June 30, 1982
    Date of Patent: January 22, 1985
    Assignee: Mita Industrial Co., Ltd.
    Inventor: Nobuhiro Miyakawa
  • Patent number: 4495267
    Abstract: Disclosed is a magnetic toner having an improved humidity dependency, which comprises as main ingredients a magnetic material composed of magnetite and a binder medium, wherein the water-soluble component content in the magnetite is lower than 0.15% by weight and the water content of the magnetite at a temperature of 20.degree. C. and a relative humidity of 60% is lower than 0.3% by weight.If this magnetic toner is used for developing an electrostatically charged image, a sharp and clear copy having a high image density with no fogging can be obtained even under a high humidity condition.
    Type: Grant
    Filed: March 22, 1983
    Date of Patent: January 22, 1985
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Nobuyasu Honda, Toshiro Yamakawa, Toshimitsu Ikeda
  • Patent number: 4487825
    Abstract: This invention relates to a conductive single component magnetic dry toner comprised of resins selected from polystyrene allyl alcohol copolymers, and epoxy resins, a magnetic material such as magnetite, and a conductive carbon black which is adhered and/or embedded on the surface of the copolymer or epoxy resin-magnetic material mixture. Such toner compositions, which have excellent conductivity, superior flow properties and low melt fusing temperatures, 95.degree. C.-130.degree. C., are useful for causing the development of images in commercial printers and recorders such as the Versatec printers.
    Type: Grant
    Filed: January 22, 1981
    Date of Patent: December 11, 1984
    Assignee: Xerox Corporation
    Inventors: Robert J. Gruber, John F. Knapp
  • Patent number: 4485163
    Abstract: A one-component magnetic dry developer for use in development of positively charged images and transfer of developed images, comprises particles of a composition comprising a vinyl aromatic polymer, an aliphatic carboxylic acid having at least 14 carbon atoms, inclusive of the carbon atom of the carboxyl group, per carboxyl group or its metal salt and a finely divided magnetic material having a coercive force not larger than 120 Oe and a bulk density of at least 0.45 g/ml.This magnetic developer provides an excellent transferred image having high image density and image sharpness on a plain paper as a transfer sheet without fogging or broadening of the contour of the image.
    Type: Grant
    Filed: June 2, 1982
    Date of Patent: November 27, 1984
    Assignee: Mita Industrial Company Limited
    Inventor: Nobuhiro Miyakawa
  • Patent number: 4474866
    Abstract: A color magnetic single component toner composition possessing a magnetic saturation moment of from about 2 emu/gram to about 30 emu/gram comprised of toner resin particles, pigment particles, and a low optical density superparamagnetic polymer comprised of an ion exchange resin containing trapped within its matrices a magnetic component species.
    Type: Grant
    Filed: September 28, 1983
    Date of Patent: October 2, 1984
    Assignee: Xerox Corporation
    Inventor: Ronald F. Ziolo
  • Patent number: 4473483
    Abstract: A magnetic toner or ink is used in an electrophotography. It comprises a resinous component and a magnetic having a spinel structure and having the formula ##EQU1## wherein M represents at least one of Mn, Ni, Co, Mg, Cu, Zn or Cd; and x is in a range of 0.5 to 1 and y is in a range of 0.1 to 0.571.
    Type: Grant
    Filed: December 10, 1981
    Date of Patent: September 25, 1984
    Assignees: TDK Electronics Co., Ltd., Canon Kabushiki Kaisha
    Inventors: Kenji Imamura, Yoshinori Kurosawa, Motohiko Makino
  • Patent number: 4448870
    Abstract: Red to sepia magnetic toners stable to heat and light which do not fade or discolor for a long period of time are prepared by incorporating a partially .alpha.-transformed .gamma.-Fe.sub.2 O.sub.3 as a component in a toner.
    Type: Grant
    Filed: April 11, 1983
    Date of Patent: May 15, 1984
    Assignee: Canon Kabushiki Kaisha
    Inventors: Eiichi Imai, Hitoshi Uchide, Kazunori Murakawa, Masaki Uchiyama, Hisayuki Ochi, Motoo Urawa, Seiichi Takagi, Yasuo Mitsuhashi
  • Patent number: 4436802
    Abstract: An electrophotography developing method according to this invention uses a one-component magnetic toner having an electric resistivity of 10.sup.7 or more ohm.multidot.centimeter, still remaining within the range of inter-particle electric induction, and a coercive force of 150 or more oersteds, thereby preventing appearance of fog in a reversal photographic image, which fog otherwise, would appear in case of reversal, magnetic brush development.
    Type: Grant
    Filed: December 2, 1982
    Date of Patent: March 13, 1984
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Shuichi Ohtsuka, Yasuo Aotsuka
  • Patent number: 4430410
    Abstract: In a method and apparatus for developing a latent electrostatic image formed on the surface of an image-bearing material by applying a powdery developer thereto, which includes magnetically retaining a layer of a relatively conductive one-component developer having a resistivity of not more than 10.sup.13 ohms-cm on the surface of a developer-retaining member, and bringing the developer on the surface of the developer-retaining member into contact with the surface of the image bearing material, the improvement wherein the developer-retaining member has a resistance, measured by a point-plane resistance measuring method in an environment kept at a temperature of 20.degree. C. and a humidity of 50%, of from 3.times.10.sup.7 ohms to 1.times.10.sup.10 ohms. The improved method makes possible good development without causing a background fog or a tail effect.
    Type: Grant
    Filed: August 27, 1979
    Date of Patent: February 7, 1984
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Tatsuo Aizawa, Shoji Matsumoto, Kaoru Sakata, Toshikazu Matsui, Akira Fushida, Toshimitsu Ikeda, Nobuyoshi Hisao
  • Patent number: 4430407
    Abstract: A single component electrophotographic developer composition is disclosed comprising a low melt viscosity polyamide resin and a magnetic oxide component of such particle size as to greatly enhance the development of low background high density images. Highly conductive carbon may be added to control the resistivity of the developer particles.
    Type: Grant
    Filed: March 26, 1982
    Date of Patent: February 7, 1984
    Assignee: AM International, Inc.
    Inventor: Virgil W. Westdale
  • Patent number: 4430413
    Abstract: An improved process for preparing a single component toner or developer composition is disclosed whereby toner fines are removed from the composition prior to the addition of conductive carbon followed by a reclassification step to remove excess carbon particles, i.e., those carbon particles not attached to the toner.
    Type: Grant
    Filed: March 26, 1982
    Date of Patent: February 7, 1984
    Assignee: AM International, Inc.
    Inventors: Virgil W. Westdale, James L. Hanrahan
  • Patent number: 4430408
    Abstract: Developing powder compositions containing a fluorine-modified alkyl siloxane and a surface treatment of carbon black are disclosed. The toner powders exhibit reduced sensitivity to machine conditions and provide copies whose images are sharply defined, have substantially reduced image fill-in, substantially reduced backgrounding, and good image density.
    Type: Grant
    Filed: June 25, 1982
    Date of Patent: February 7, 1984
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: George G. Sitaramiah
  • Patent number: 4415645
    Abstract: A particulate composite developer for electrophotography is disclosed, which has a novel dispersion structure comprising a continuous phase consisting of a homogeneous mixture of a resin and a pigment and a dispersed phase consisting of spherical particles of a soft parting or fixing material having an emulsion grade size and being dispersed in the continuous phase. This particulate developer has in combination improved adaptability to the developing operation, excellent transferring and cleaning properties, good ability to form a sharp image free of fog and good fixing property not causing an offset phenomenon.
    Type: Grant
    Filed: March 5, 1979
    Date of Patent: November 15, 1983
    Assignee: Mita Industrial Company Limited
    Inventors: Toshihiro Kouchi, Tatsuo Aizawa
  • Patent number: 4407923
    Abstract: Disclosed is a dry magnetic developer consisting essentially of a particulate shaped article of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, wherein said composition comprises as the powdery magnetic material a non-pulverizing agglomerate having a secondary particle size of 1 to 10 microns, which is formed by granulating and sintering fine cubic particles of magnetite or other ferrite having a primary particle size of 0.1 to 1 micron.
    Type: Grant
    Filed: June 24, 1982
    Date of Patent: October 4, 1983
    Assignee: Mita Industrial Co., Ltd.
    Inventors: Nobuhiro Miyakawa, Masanori Fujii, Kouzi Maekawa, Haruo Koyama, Takashi Teshima