Electrical Or Magnetic Parameter Patents (Class 430/111.41)
  • Publication number: 20080044752
    Abstract: The color toner for developing electrostatic latent images comprising a colored resin particle containing at least a binder resin, a colorant, a charge control agent and a parting agent, wherein an extracted liquid with water by means of a hot water extraction method from said colorant has a pH value in the range from 6.0 to 8.0, said colored resin particle has a volume average particle diameter (Dv) in the range from 4 to 10 ?m and an average circularity in the range from 0.93 to 0.995, an amount of extracted components with methanol is 7% by weight or less, and an amount of residual volatile compounds is 500 ppm or less. The color toner for developing electrostatic latent images has excellent image-reproducibility and environmental durability and can form an image with a stable image density under a high temperature and high humidity condition.
    Type: Application
    Filed: March 14, 2005
    Publication date: February 21, 2008
    Applicant: ZEON CORPORATION
    Inventors: Hiroshi Nakatani, Toshihiko Yamato, Hiroto Kidokoro
  • Patent number: 7323279
    Abstract: The present invention provides a one-component magnetic toner for developing an electrostatic charge image, which do not cause an image defect by toner aggregation or fusion even though a device is miniaturized and the processing speed of the device is accelerated, and which allows easy recycling of a toner cartridge. The one-component magnetic toner for developing an electrostatic charge image of the present invention is one comprising: toner particles comprising fine magnetic particles (A) and a binder resin; and fine magnetic particles (B) externally added to the toner particles, in which the maximum permeability (?mA) of the fine magnetic particles (A) contained in the toner particles and the maximum permeability (?mB) of the fine magnetic particles (B) externally added to the toner particles satisfy a relationship represented by the following formula (1) ?mB/?mA?1.8 .
    Type: Grant
    Filed: July 15, 2004
    Date of Patent: January 29, 2008
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kazunori Kato, Shuichi Aita
  • Patent number: 7314696
    Abstract: Toners and developers are disclosed. The toner of the present invention contains at least one toner resin, at least one charge control agent, at least one surface treatment agent, and optionally at least one release agent and/or colorant. The toners of the present invention have excellent triboelectric stability over a wide range of temperatures and relative humidity environmental conditions. Further, the toners of the present invention have excellent charge to mass stability over long periods of time. Development systems and methods for developing electrostatic images with toner are further disclosed.
    Type: Grant
    Filed: June 13, 2001
    Date of Patent: January 1, 2008
    Assignee: Eastman Kodak Company
    Inventors: Robert D. Fields, Patrick M. Lambert, Dinesh Tyagi, James H. Anderson
  • Patent number: 7309556
    Abstract: A developer includes black toner particles and carrier particles, the black toner particles including at least one binder, at least one black colorant and one or more external additives, wherein the toner particles comprise from about 7 to about 15 pph of the developer, and wherein the toner particles exhibit a triboelectric charge of from about ?25 to about ?50 ?C/g at toner particle concentrations of about 7 to about 15 pph of the developer. The developer is ideally suited for use in a high speed (greater than 100 prints per minute) semiconductive magnetic brush development apparatus. Preferably, the black toner particles include a styrene acrylate binder, and the external additives include from about 1.3 to about 2.1% by weight of the toner particles of a first silica having an average particle size of from about 35 to about 45 nm, from about 0.5 to about 1.0% by weight of the toner particles of a second silica having an average particle size of from about 135 to about 160 nm, and from about 0.
    Type: Grant
    Filed: March 21, 2005
    Date of Patent: December 18, 2007
    Assignee: Xerox Corporation
    Inventors: Maria N. V. Mc Dougall, Richard P. N. Veregin, Vladislav Skorokhod, Mary L. Mc Stravick, Deepak R. Maniar, Paul W. Morehouse, Jr., Rachael L. Mc Grath, Jackie Parker, Shigang Qui, Mary B. Schlitzer, Michael D. Thompson, Christopher M. Pattison, Thomas C. Dombroski
  • Patent number: 7300734
    Abstract: A toner composition comprising a binder, colorant, and a charge control surface additive mixture comprising a mixture of a first titanium dioxide possessing a first conductivity and a second titanium dioxide possessing a second conductivity and which second conductivity is dissimilar than the first conductivity; wherein the mixture of the first titanium dioxide and the second titanium dioxide is selected in a ratio sufficient to impart a selected triboelectric charging characteristic to the toner composition.
    Type: Grant
    Filed: December 3, 2004
    Date of Patent: November 27, 2007
    Assignee: Xerox Corporation
    Inventors: Maria N. V. McDougall, Richard P. N. Veregin
  • Patent number: 7295788
    Abstract: An image forming apparatus includes an object to be charged whose surface moves. A charging device for charging the object uses an electrical discharge generated by applying a voltage including an alternating current component to a charging member provided in contact with or in proximity to the object. A latent image forming device forms an electrostatic latent image on the surface of the object. A developing device causes a two-component developer to come into contact with the image portion of the electrostatic latent image formed by the latent image forming device and affixes toner thereto. A protective substance is present on the surface of the object in the discharge region for charging the object, and the saturation magnetization of the carrier of the two-component developer with respect to an applied magnetic field of 1000 oersted is 40 to 80 emu/g.
    Type: Grant
    Filed: April 25, 2005
    Date of Patent: November 13, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Nakai, Yasuo Suzuki, Nozomu Tamoto, Takahiko Tokumasu, Kazahiko Watanabe, Kohichi Ohshima, Noboru Tsukude, Nekka Matsuura, Hiroshi Ikuno
  • Patent number: 7291436
    Abstract: An electrophotographic toner having a core-shell structure including a crystalline resin in its core region or a sea-island structure including a crystalline resin in its island region, wherein the toner has 1) a resistance of 5.0×1012 ?·cm or higher, 2) a dynamic viscosity coefficient of 3×103 Pa·s or higher at a temperature which is 50° C. higher than a melting point of the crystalline resin, and 3) a dynamic viscosity coefficient of 1×105 Pa·s or lower at a temperature which is 10° C. higher than the melting point of the crystalline resin.
    Type: Grant
    Filed: October 14, 2004
    Date of Patent: November 6, 2007
    Assignee: Fuji Xerox., Ltd.
    Inventors: Masaki Nakamura, Takashi Imai, Katsumi Daimon, Yuka Ishihara, Hirokazu Yamada, Hirokazu Hamano, Norihito Fukushima, Yasuhiro Arima
  • Publication number: 20070231726
    Abstract: A positive electrified charge control agent comprising a silicon complex compound of an effective component represented by the following chemical formula (I) and/or chemical formula (II) (in the formula (I) and formula (II), [D-(SO3)2]2? is a bivalent anion of an organic acid having at least two sulfonic acid groups, p is 0 or 1, B is a bonding line when p is 0, B is a carbon atom or a nitrogen atom when p is 1, J is a carbon atom or a nitrogen atom, A is an organic group which forms a ring with (B)p and J, both of R are same or different to each other and are an organic group, and these both of R are independent or form a heterocyclic ring). A positive electrified toner for developing an electrostatic image comprises the positive electrified charge control agent. A charge control method of the positive electrified toner for developing the electrostatic image comprises a step for making the toner positively electrified by friction.
    Type: Application
    Filed: April 2, 2007
    Publication date: October 4, 2007
    Applicant: Orient Chemical Industries, Ltd.
    Inventors: Osamu Yamate, Masashi Yasumatsu
  • Publication number: 20070231731
    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: Application
    Filed: March 30, 2007
    Publication date: October 4, 2007
    Applicant: Powdertech Co., Ltd.
    Inventors: Tomoyuki Suwa, Tsuyoshi Itagoshi
  • Publication number: 20070218394
    Abstract: A carrier contained in a two component developer used for an image formation method of forming a color image by sequentially transferring multiple color toner images, wherein the carrier resistance R1 of a carrier in a developer, with which a toner image is transferred first, is adjusted to be less than the carrier resistances R2 to Rn (“n” represents a total color number of toners which form images, n?2) of the carrier in two component developers for each color, which are transferred thereafter. The carrier resistances R1 to Rn of each carrier are adjusted as follows: R1<R2< . . . <Rn according to the order of toner images to be transferred.
    Type: Application
    Filed: March 16, 2007
    Publication date: September 20, 2007
    Inventors: Takeo Mizobe, Norio Kubo
  • Patent number: 7261991
    Abstract: An image forming method, comprising the steps of: charging a organic photoreceptor having a specific layer including at least a photosensitive layer; forming an electrostatic latent image on the organic photoreceptor; developing the electrostatic latent image to form a visible toner image by using a developing agent; transferring the toner images to be superimposed on a toner image receiving member; and removing the toner remaining on the organic photoreceptor, wherein the total thickness of the specific layer in the organic photoreceptor, is 5-15 ?m, and wherein the developing agent comprises a toner and a carrier having the volume resistivity of 108-1012 ? cm.
    Type: Grant
    Filed: August 23, 2004
    Date of Patent: August 28, 2007
    Assignee: Konica Minolta Holdings, Inc.
    Inventors: Hideo Yoshizawa, Hiroshi Yamazaki
  • Patent number: 7244539
    Abstract: A magnetic carrier includes a magnetic material-dispersed resin core containing at least a magnetic material and a binder resin. The surface of the magnetic material-dispersed resin core is coated with a coating material containing at least a fluorine resin and 1 to 40 parts by weight of fine particles based on 100 parts by weight of the fluorine resin. The coating material is in an amount of 0.3 to 4.0 parts by weight based on 100 parts by weight of the magnetic material-dispersed resin core. The magnetic carrier has a contact angle of 95 to 125°. A two-component developer is also provided which makes use of the magnetic carrier.
    Type: Grant
    Filed: April 29, 2004
    Date of Patent: July 17, 2007
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshinobu Baba, Ryoichi Fujita, Takaaki Kaya, Kazuo Terauchi
  • Patent number: 7226713
    Abstract: A carrier including a magnetic core material and a layer located on a surface of the magnetic core material, wherein the carrier satisfies the following relationships (1) to (3): 0.90?(?a/?b)<1.00 (1); 200?(?b·?c)?400 (2); 10?(?b/?c)?20 (3), wherein ?b represents a magnetization of the carrier at 1,000 Oe, ?a represents a magnetization of the carrier after frictionized with a cylindrical sleeve under a specific condition and ?c represents a true specific gravity of the carrier, wherein the carrier has a weight-average particle diameter of about 25 to about 65 ?m and includes carrier particles having a weight-average particle diameter not greater than about 12 ?m in an amount of not greater than about 0.3% by weight, wherein a ratio between the weight-average particle diameter and a number-average particle diameter of the carrier is about 1 to about 1.3, and wherein an electric resistance is from about 1.0×109 to about 1.
    Type: Grant
    Filed: January 30, 2004
    Date of Patent: June 5, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahide Yamashita, Satoshi Mochizuki, Tomio Kondou, Kohsuke Suzuki
  • Patent number: 7192679
    Abstract: The present invention relates to a carrier for electrophotographic developers, a developer containing the carrier, a container for the developer, a image forming apparatus using the developer, an image forming method using the same, and a method of making the carrier.
    Type: Grant
    Filed: March 18, 2004
    Date of Patent: March 20, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Naoki Imahashi, Akihiro Kotsugai, Hiroaki Takahashi
  • Patent number: 7183033
    Abstract: A carrier core material for an electrophotographic developing agent, which comprises 100 parts by weight of a ferrite component represented by a formula (A) and 0.1 to 5.0 parts by weight of ZrO2 that is present in the ferrite component without forming a solid solution, and which has a magnetization, at 1000(103/4?·A/m), of 65 to 85 Am2/kg and an electrical resistance, at an applied voltage of 1000 V, of 105 to 109 ?. (MnO)x(MgO)y(Fe2O3)z??(A) wherein x, y and z are each expressed in % by mol and are numbers satisfying the conditions of 40?x?60, 0.1?y?10 and x+y+z=100. Also disclosed is a two-component developing agent comprising a coated carrier, which is obtained by coating the above carrier core material with a resin, and toner particles. Further disclosed is an image forming method comprising developing an electrostatic latent image formed by the use of an alternating electric field, with the two-component developing agent.
    Type: Grant
    Filed: February 6, 2004
    Date of Patent: February 27, 2007
    Assignee: Powdertech Co., Ltd.
    Inventors: Issei Shinmura, Hiromichi Kobayashi, Tsuyoshi Itagoshi, Yuji Sato
  • Patent number: 7172846
    Abstract: A carrier including a manganese ferrite core material having a layer on its surface such that 0.1?K?30, where K=(S/M)×100, S and M represent the standard deviation and average of M2/(M1+M2), respectively, M ranging from 0.05 to 0.45, and M1 and M2 represent the content of iron and manganese, respectively, in a carrier particle. The carrier has a magnetization ranging from 45 to 75 emu/g at 1,000 Oe, a mass-averaged particle diameter, D4, ranging from 25 to 65 ?m and carrier particles having a particle diameter not greater than 12 ?m are included in an amount not greater than 0.3% by weight, and a ratio, D4/D1, ranging from 1 to 1.3, where D1 is a number-averaged particle diameter of the carrier.
    Type: Grant
    Filed: May 13, 2004
    Date of Patent: February 6, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahide Yamashita, Tomio Kondou, Kohsuke Suzuki
  • Patent number: 7166404
    Abstract: A carrier for an image developer for electrophotography, including core particles, and a coating layer covering each of the core particles, wherein the core particles have a weight average particle diameter of Dv which is 25–45 ?m and a number average particle diameter of Dp which meets with the following condition: 1?Dv/Dp?1.3, wherein the core particles have such a particle size distribution that particles having a particle diameter of less than 44 ?m is at least 70% by weight and particles having a particle diameter of less than 22 ?m is not more than 7% by weight.
    Type: Grant
    Filed: March 4, 2002
    Date of Patent: January 23, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroaki Matsuda, Fumihiro Sasaki, Hiroyuki Yoshikawa
  • Patent number: 7160662
    Abstract: The present invention relates to an image forming method including: a charging step; an electrostatic latent image forming step; a developing step; a transfer step; a fixing step; and a cleaning step, wherein an electrostatic latent image developing agent comprises a toner and a carrier, wherein particles which have a volume resistivity of at least 1×1014 ?cm and an average primary particle diameter of 50 nm or less has a higher covering ratio than other particles on the toner particle surfaces, a shape factor SF1 of the toner is in the range of from 100 to 140, the carrier is a resin coated carrier, and at least a coating resin layer comprises a positively charging resin and a quaternary ammonium salt compound.
    Type: Grant
    Filed: December 11, 2003
    Date of Patent: January 9, 2007
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Susumu Yoshino, Yoshifumi Iida, Seki Yamaguchi, Motoko Sakai, Sueko Sakai
  • Patent number: 7157200
    Abstract: A black toner of toner particles including at least one binder, at least one black colorant, and a package of external additives is described, wherein the at least one binder includes a styrene acrylate binder and wherein the external additives include each of a first silica having an average particle size of from about 35 to about 45 nm, a second silica having an average particle size of from about 135 to about 160 nm, and a titania having an average particle size of from about 35 to about 45 nm. Also described is a developer that includes the black toner and carrier particles comprising a core of ferrite coated with a coating comprising a polymethyl methacrylate polymer and fluoro-copolymer, carbon black and melamine beads. The black toner and developer are preferably used in a semiconductive magnetic brush development system.
    Type: Grant
    Filed: May 6, 2004
    Date of Patent: January 2, 2007
    Assignee: Xerox Corporation
    Inventors: Mary L. Mc Stravick, Paul C. Julien, Sue E. Blaszak, William H. Hollenbaugh, Jr.
  • Patent number: 7144670
    Abstract: A resin-coated carrier for an electrophotographic developer and a process of producing the carrier. The carrier comprises a ferrite core mainly comprising iron oxide, primarily having a spinel structure, and having a volume average particle size of 20 to 45 ?m and a resin coat, wherein the carrier has a magnetization of 65 to 80 emu/g in a magnetic field of 1 KOe, the core has an electric current value of 50 to 150 ?A and a surface smoothness uniformity of 75% or higher, and the amount of the resin coat is 0.1 to 5.0% by weight based on the core.
    Type: Grant
    Filed: March 21, 2003
    Date of Patent: December 5, 2006
    Assignee: Powertech Co., Ltd.
    Inventors: Kanao Kayamoto, Issei Shinmura, Yuji Sato
  • Patent number: 7144626
    Abstract: There are provided magnetic iron oxide particles having an average particle diameter (Dp50) of primary particles of 0.05 to 0.3 ?m, an average particle diameter (Da50) of secondary particles of 0.055 to 0.9 ?m, and a ratio of the average particle diameter (Da50) of the secondary particles to the average particle diameter (Dp50) of the secondary particles (Da50/Dp50) of 1.1 to 3.0, as well as a magnetic toner containing the magnetic iron oxide particles. The magnetic iron oxide particles of the present invention are in the form of small agglomerated particles and exhibit an excellent dispersibility, and the magnetic toner using the magnetic iron oxide particles is excellent in electrification stability.
    Type: Grant
    Filed: April 4, 2005
    Date of Patent: December 5, 2006
    Assignee: Toda Kogyo Corporation
    Inventors: Hiroshi Akai, Koso Aoki, Hiromitsu Misawa, Naoki Uchida, Ryo Iwai
  • Patent number: 7141343
    Abstract: A toner exhibits excellent image characteristics, and also has an excellent charging property even if the toner is used in a cleaning-simultaneous-with-developing system having a direct injection charging mechanism. The toner includes toner particles and non-magnetic metallic-compound fine particles. The weight average particle diameter of the toner is 3.0 ?m to 12.0 ?m. The metallic-compound fine particles are conductive metallic-compound fine particles having a specific surface area (cm2/cm3) of 5×105 to 100×105; a medium diameter (D50) of 0.4 ?m to 4.0 ?m with respect to a volume-based particle diameter distribution, the medium diameter (D50) being smaller than the weight average particle diameter of the toner; and a 90% particle diameter D90 of 6.0 ?m or less with respect to a volume-based particle diameter.
    Type: Grant
    Filed: April 18, 2003
    Date of Patent: November 28, 2006
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tsuyoshi Takiguchi, Yosuke Morikawa, Takashige Kasuya, Kimihiro Yoshimura, Katsuhisa Yamazaki, Kaori Hiratsuka
  • Patent number: 7097952
    Abstract: An electrophotographic toner is formed as a blend of toner particles and external additives. The external additives include (1) first inorganic fine particles having an average primary particle size of 80-800 nm of oxide of a metal selected from the group consisting of titanium, aluminum, zinc and zirconium, (2) second inorganic fine particles other than silica having an average primary particle size of below 80 nm and (3) silica fine particles having an average primary particle size of below 30 nm. As a result, the toner can be made free from difficulties, such as melt-sticking onto an image-bearing member in a low humidity environment, roughening of halftone images in a low humidity environment, toner blot-down after storage at high temperatures or in continuous image formation on a large number of sheets, fog in continuous formations of images of low color area percentage in a low humidity environment, and re-transfer in multi-color image formation.
    Type: Grant
    Filed: May 10, 2005
    Date of Patent: August 29, 2006
    Assignee: Canon Kabushiki Kaisha
    Inventors: Keita Nozawa, Atsushi Kubo, Masanori Ito, Tomoaki Igarashi, Kiyokazu Suzuki
  • Patent number: 7090955
    Abstract: A toner for developing an electrostatic latent image, including toner particles each containing a black colorant and a binder resin, wherein the black colorant comprises a metal oxide having a number average particle diameter in the range of 20 to 100 nm in an amount of 10 to 40% by weight based on a total weight of the toner particles.
    Type: Grant
    Filed: June 7, 2005
    Date of Patent: August 15, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Hachiro Tosaka, Tomiaki Ito, Yuji Natori
  • Patent number: 7079795
    Abstract: An image forming apparatus includes an image bearing member having a surface on which an electrostatic latent image is to be formed; a black developing device, containing a black developer including toner and carrier, for developing the electrostatic latent image; at least one color developing device containing a color developer having a color other than black; a supplying device, provided for each of the black developing device and the color developing device, for supplying a supply material containing toner and carrier; a discharging device for discharging the developer. A resistivity of the carrier contained in the black developer is higher than resistivity of the carrier contained in the color developer, and a weight percentage of the carrier contained in the supply material for the black developing device is higher than a weight percentage of the carrier contained in the supply material for the color developing device.
    Type: Grant
    Filed: April 26, 2005
    Date of Patent: July 18, 2006
    Assignee: Canon Kabushiki Kaisha
    Inventor: Masaru Hibino
  • Patent number: 7070899
    Abstract: An electrophotographic developer is provided for realizing high-quality images and superior reproducibility of laser dots in a low coverage region and reduced unevenness of color in halftone solid images. The electrophotographic developer includes a toner and a carrier. The toner has a shape factor of 140 or less and a volume average particle size distribution GSDv of 1.3 or less. The carrier has a coat resin layer on a core material, the coat resin layer containing a conductive powder. The core material has a dynamic electric resistivity of 1 ?·cm or less under an electric field of 104 V/cm in a form of a magnetic brush. The conductive powder has an electric resistivity of 101 ?·cm or greater and 106 ?·cm or less. The carrier has an electric resistivity in a range between 10 and 1×108 ?·cm. An image forming method is also provided wherein the electrophotographic developer is used for development in a developing stage.
    Type: Grant
    Filed: June 27, 2003
    Date of Patent: July 4, 2006
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazuhiko Yanagida, Nobumasa Furuya, Takashi Yukutake
  • Patent number: 7045265
    Abstract: Electrophotographic color toner prepared as a mixture of white toner and chromatic color toner in an electrophotographic toner composition at least containing a colorant, a binder resin and an additive, wherein a colorant of the white toner is one member selected from the group consisting of silver white pigment, titanium white pigment, zinc white pigment, and titanium strontium white pigment.
    Type: Grant
    Filed: October 8, 2003
    Date of Patent: May 16, 2006
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Yuzo Horikoshi, Katsuji Ebisu, Takahiro Kashikawa
  • Patent number: 7033718
    Abstract: A toner including toner particles including a binder resin and a colorant, wherein particles of the toner have such a rolling property as to relatively easily roll in one direction compared to other directions. It is preferable that the toner particles preferably have a spindle form and satisfies the following relationships: 0.5?(r2/r1)?0.8, 0.7?(r3/r2)?1.0, and r3?r2?r1, wherein r1, r2 and r3 represent an average major axis particle diameter, an average minor axis particle diameter and an average thickness of the toner particles. An image forming apparatus including at least an image bearing member; a developing device configured to develop an electrostatic latent image with a developer including the above-mentioned toner; a transferring device configured to transfer a toner image onto a receiving material; and a cleaning device configured to clean a surface of the image bearing member.
    Type: Grant
    Filed: November 14, 2003
    Date of Patent: April 25, 2006
    Assignee: Ricoh Company, Limited
    Inventors: Masami Tomita, Hiroaki Matsuda
  • Patent number: 7014971
    Abstract: Carrier comprised of a mixture of a first carrier and a second carrier, and wherein the first carrier is comprised of a steel core and the second carrier is comprised of a magnetite.
    Type: Grant
    Filed: March 7, 2003
    Date of Patent: March 21, 2006
    Assignee: Xerox Corporation
    Inventors: Vladislav Skorokhod, Wafa F. Bashir, Richard P. N. Veregin, Michael S. Hawkins, Deepak R. Maniar
  • Patent number: 7005223
    Abstract: A toner composition including toner particles including a binder resin; and a colorant, and a charge controlling agent which is at least located on a surface of the toner particles, wherein the toner composition has a spherical degree of from 0.96 to 0.99, and wherein the toner composition satisfies the relationship: 10?M/T?1,000 wherein M represents a quantity of an element on a surface of the toner particles in units of % by weight, wherein the element is included only in the charge controlling agent, and is one of elements of second to fifth periodical elements in the long form periodic table other than hydrogen, carbon, oxygen and rare gas elements; and T represents a quantity of the element in the toner composition in units of % by weight.
    Type: Grant
    Filed: March 8, 2002
    Date of Patent: February 28, 2006
    Assignee: Ricoh Company Limited
    Inventors: Hiroshi Yamashita, Kazuhito Watanabe, Chiaki Tanaka, Tsunemi Sugiyama, Shigeru Emoto, Masami Tomita
  • Patent number: 6972166
    Abstract: An electrophotographic toner is formed as a blend of toner particles and external additives. The external additives include (1) first inorganic fine particles having an average primary particle size of 80-800 nm of oxide of a metal selected from the group consisting of titanium, aluminum, zinc and zirconium, (2) second inorganic fine particles other than silica having an average primary particle size of below 80 nm and (3) silica fine particles having an average primary particle size of below 30 nm. As a result, the toner can be made free from difficulties, such as melt-sticking onto an image-bearing member in a low humidity environment, roughening of halftone images in a low humidity environment, toner blot-down after storage at high temperatures or in continuous image formation on a large number of sheets, fog in continuous formations of images of low color area percentage in a low humidity environment, and re-transfer in multi-color image formation.
    Type: Grant
    Filed: December 23, 2003
    Date of Patent: December 6, 2005
    Assignee: Canon Kabushiki Kaisha
    Inventors: Keita Nozawa, Atsushi Kubo, Masanori Ito, Tomoaki Igarashi, Kiyokazu Suzuki
  • Patent number: 6969574
    Abstract: A toner for developing an electrostatic latent image, including toner particles each containing a black colorant and a binder resin, wherein the black colorant comprises a metal oxide having a number average particle diameter in the range of 20 to 100 nm in an amount of 10 to 40% by weight based on a total weight of the toner particles.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: November 29, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Hachiro Tosaka, Tomiaki Ito, Yuji Natori
  • Patent number: 6964835
    Abstract: A toner including a at least a binder resin; a colorant; and a zirconium compound including zirconium and at least one of an aromatic oxycarboxylic acid and a salt thereof, wherein the zirconium compound having a main diffraction peak (A) at a Bragg (2?) angle of 5.5±0.3° and a diffraction intensity of from 2,000 to 15,000 cps when irradiated with a specific X-ray of CuK?.
    Type: Grant
    Filed: July 21, 2003
    Date of Patent: November 15, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Kumi Hasegawa, Mitsuo Aoki
  • Patent number: 6946230
    Abstract: Compositions and methods for electrographic image development, wherein the image development process employs a two-component developer that includes toner particles having a radius RT and magnetic carrier particles having a radius RC, wherein RC is preferably less than about 5RT and is more preferably less than or equal to about 3RT.
    Type: Grant
    Filed: November 13, 2001
    Date of Patent: September 20, 2005
    Assignee: Heidelberger Druckmaschinen AG
    Inventors: Eric C. Stelter, Joseph E. Guth, Ulrich Mutze
  • Patent number: 6846601
    Abstract: In a negatively chargeable toner having i) negatively chargeable toner particles containing at least a binder resin, a colorant and a vinyl copolymer and ii) an inorganic fine powder, the negatively chargeable toner has a weight-average particle diameter of from 4 ?m to 12 ?m and contains, in particle size distribution of the toner, less than 50% by volume of particles of 10.1 ?m or more in particle diameter, and the vinyl copolymer is a vinyl copolymer obtained by copolymerizing a monomer composition which contains at least i) a vinyl monomer such as an N-substituted acryl- or methacrylamide or a ring-structure acryl- or methacrylamide and ii) a vinyl monomer having as a functional group a carboxyl group or a carboxyl group made into salt structure. An image-forming method and a process cartridge make use of such a negatively chargeable toner.
    Type: Grant
    Filed: March 10, 2003
    Date of Patent: January 25, 2005
    Assignee: Canon Kabushiki Kaisha
    Inventors: Minoru Shimojo, Satoshi Matsunaga
  • Publication number: 20040253528
    Abstract: A carrier including a magnetic core material and a layer located on a surface of the magnetic core material, wherein the carrier satisfies the following relationships (1) to (3): 0.90≦(&sgr;a/&sgr;b)<1.00 (1); 200≦(&sgr;b·&rgr;c)≦400 (2); 10≦(&sgr;b/&rgr;c)≦20 (3), wherein &sgr;b represents a magnetization of the carrier at 1,000 Oe, &sgr;a represents a magnetization of the carrier after frictionized with a cylindrical sleeve under a specific condition and &rgr;c represents a true specific gravity of the carrier, wherein the carrier has a weight-average particle diameter of about 25 to about 65 &mgr;m and includes carrier particles having a weight-average particle diameter not greater than about 12 &mgr;m in an amount of not greater than about 0.3% by weight, wherein a ratio between the weight-average particle diameter and a number-average particle diameter of the carrier is about 1 to about 1.3, and wherein an electric resistance is from about 1.0×109 to about 1.
    Type: Application
    Filed: January 30, 2004
    Publication date: December 16, 2004
    Inventors: Masahide Yamashita, Satoshi Mochizuki, Tomio Kondou, Kohsuke Suzuki
  • Publication number: 20040253529
    Abstract: A magnetic carrier includes a magnetic material-dispersed resin core containing at least a magnetic material and a binder resin. The surface of the magnetic material-dispersed resin core is coated with a coating material containing at least a fluorine resin and 1 to 40 parts by weight of fine particles based on 100 parts by weight of the fluorine resin. The coating material is in an amount of 0.3 to 4.0 parts by weight based on 100 parts by weight of the magnetic material-dispersed resin core. The magnetic carrier has a contact angle of 95 to 125°. A two-component developer is also provided which makes use of the magnetic carrier.
    Type: Application
    Filed: April 29, 2004
    Publication date: December 16, 2004
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Yoshinobu Baba, Ryoichi Fujita, Takaaki Kaya, Kazuo Terauchi
  • Publication number: 20040248025
    Abstract: The present invention provides toners of different colors in which coloring agents of at least four unicolors are internally added to, respectively, and hydrophobic silica particles and metallic soap particles are externally added to toner mother particles, wherein color superposition of the toners is conducted during development of latent images on a latent image carrier or during transfer to a recording medium after the development, being characterized in that the difference (absolute value) between the work functions of two of said toners is 0.02 eV or more, the color superposition is conducted with the toners sequentially from the toner having the largest work function in descending order of work function of the toners, and the difference (absolute value) between the work function of the toner mother particles and the work function of the metallic soap particles is 0.
    Type: Application
    Filed: February 5, 2004
    Publication date: December 9, 2004
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Nobuhiro Miyakawa
  • Patent number: 6824942
    Abstract: A toner comprised of resin, colorant and calcium stearate.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: November 30, 2004
    Assignee: Xerox Corporation
    Inventors: Scott M. Silence, William H. Hollenbaugh, Jr., Thomas R. Pickering, Amy L. Stamp, Roger N. Ciccarelli, Denise R. Bayley, Samuel Kaplan, Alexander N. Klymachyov, John S. Walters, Padam K. Angra
  • Publication number: 20040234877
    Abstract: The present invention relates to an image forming method including: a charging step; an electrostatic latent image forming step; a developing step; a transfer step; a fixing step; and a cleaning step, wherein an electrostatic latent image developing agent comprises a toner and a carrier, wherein particles which have a volume resistivity of at least 1×1014 &OHgr;cm and an average primary particle diameter of 50 nm or less has a higher covering ratio than other particles on the toner particle surfaces, a shape factor SF1 of the toner is in the range of from 100 to 140, the carrier is a resin coated carrier, and at least a coating resin layer comprises a positively charging resin and a quaternary ammonium salt compound.
    Type: Application
    Filed: December 11, 2003
    Publication date: November 25, 2004
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Susumu Yoshino, Yoshifumi Iida, Seki Yamaguchi, Motoko Sakai, Sueko Sakai
  • Patent number: 6818371
    Abstract: An electrophotographic developer comprising at least one element selected from the group consisting of boron and phosphorus in a content of 0.1 to 100 ppm, which the developer is excellent in flowability and shelf stability, does not give image defects such as occurrence of white stripes and attains almost constant image quality even when the ambient conditions including temperature and humidity fluctuate. A production process of a polymerized toner used in the developer, a production process of the developer, and an image forming process.
    Type: Grant
    Filed: August 1, 2002
    Date of Patent: November 16, 2004
    Assignee: Zeon Corporation
    Inventors: Takashi Iga, Kojiro Masuo, Kazuhiro Sato
  • Publication number: 20040191665
    Abstract: To provide an method for forming an image capable of effectively suppressing a toner from deteriorating and also capable of keeping the quality of an image for a long period of time, even when the method is applied to an apparatus with as high process speed.
    Type: Application
    Filed: January 7, 2004
    Publication date: September 30, 2004
    Inventors: Shuntaro Watanabe, Yushi Mikuriya, Takeshi Yamamoto, Shinya Yachi, Katsuyuki Nonaka
  • Publication number: 20040185366
    Abstract: Disclosed is a carrier core material for an electrophotographic developing agent, which comprises 100 parts by weight of a ferrite component represented by a formula (A) and 0.1 to 5.0 parts by weight of ZrO2 that is present in the ferrite component without forming a solid solution, and which has a magnetization, at 1000(103/4&pgr;·A/m), of 65 to 85 Am2/kg and an electrical resistance, at an applied voltage of 1000 V, of 105 to 109 &OHgr;.
    Type: Application
    Filed: February 6, 2004
    Publication date: September 23, 2004
    Inventors: Issei Shinmura, Hiromichi Kobayashi, Tsuyoshi Itagoshi, Yuji Sato
  • Patent number: 6790575
    Abstract: A two component developer comprising a magnetic toner containing a binder resin and a magnetic particle, and a magnetic carrier containing a magnetic particle, wherein the magnetic toner has an average particle diameter of 4.0 to 10.0 &mgr;m, and contains 5 to 80 No. % of toner particles having particle diameter of 5 &mgr;m or less, and exhibits magnetization of 10 to 25 emu/g under magnetic field of 5 kiloersteds.
    Type: Grant
    Filed: March 21, 2002
    Date of Patent: September 14, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Fumihiro Sasaki, Hiroaki Matsuda, Bing Shu, Maiko Kondo, Hiroshi Nakai, Hiroto Higuchi, Yasuaki Iwamoto, Yoshihiro Suguro, Hiroyuki Yoshikawa, Masahide Yamashita, Kazuyuki Yazaki
  • Patent number: 6764798
    Abstract: A two-component developer comprising a toner onto which a hydrophobic silica having an average particle size of 25 nm or more is externally added, and a carrier having a saturation magnetization of from 50 to 95 Am2/kg, wherein the carrier has a ratio of surface resistivity to volume resistivity of from 1×102 to 1×104 m−1 at an electric field strength of 100 V/cm; and a method for development comprising applying the above two-component developer to an electrophotographic device comprising a photoconductor having a peripheral speed of 400 mm/sec or more, and developing a latent image. The two-component developer can be used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: July 20, 2004
    Assignee: Kao Corporation
    Inventors: Masahito Yamazaki, Koji Kameyama, Koji Akiyama
  • Publication number: 20040137358
    Abstract: An electrophotographic toner is formed as a blend of toner particles and external additives. The external additives include (1) first inorganic fine particles having an average primary particle size of 80-800 nm of oxide of a metal selected from the group consisting of titanium, aluminum, zinc and zirconium, (2) second inorganic fine particles other than silica having an average primary particle size of below 80 nm and (3) silica fine particles having an average primary particle size of below 30 nm. As a result, the toner can be made free from difficulties, such as melt-sticking onto an image-bearing member in a low humidity environment, roughening of halftone images in a low humidity environment, toner blot-down after storage at high temperatures or in continuous image formation on a large number of sheets, fog in continuous formations of images of low color area percentage in a low humidity environment, and re-transfer in multi-color image formation.
    Type: Application
    Filed: December 23, 2003
    Publication date: July 15, 2004
    Inventors: Keita Nozawa, Atsushi Kubo, Masanori Ito, Tomoaki Igarashi, Kiyokazu Suzuki
  • Publication number: 20040137349
    Abstract: Electrophotographic color toner prepared as a mixture of white toner and chromatic color toner in an electrophotographic toner composition at least containing a colorant, a binder resin and an additive, wherein a colorant of the white toner is one member selected from the group consisting of silver white pigment, titanium white pigment, zinc white pigment, and titanium strontium white pigment.
    Type: Application
    Filed: October 8, 2003
    Publication date: July 15, 2004
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Yuzo Horikoshi, Katsuji Ebisu, Takahiro Kashikawa
  • Patent number: 6760561
    Abstract: A developing device of the present invention includes a developing roller provided with a plurality of magnetic poles. The magnetic poles include a main pole and two auxiliary poles positioned at both sides of the main pole for helping the main pole form a magnetic force. The auxiliary poles reduce the half width of the main pole. An AC-biased DC bias for development is applied to the developing roller and disturbs carrier grains close to the developing roller. Images free from various defects including granularity and local omission are achievable with the developing device.
    Type: Grant
    Filed: September 9, 2002
    Date of Patent: July 6, 2004
    Assignee: Ricoh Company, Ltd.
    Inventor: Hisao Kurosu
  • Patent number: 6753122
    Abstract: A toner for forming a color image comprises chromatic toners and a black toner is disclosed. Each of the toners is produced by polymerization of a polymerizable monomer in an aqueous medium, the difference of re-dispersion electro-conductivity of each of the toners is within the range of from 0.8 to 12 &mgr;s/cm, the number of free colorant particles on the black toner surface is less than 9 per 500 toner particles, and a light absorbance at 500 nm of a black toner dispersion is nor more than 0.08.
    Type: Grant
    Filed: December 11, 2001
    Date of Patent: June 22, 2004
    Assignee: Konica Corporation
    Inventors: Ken Ohmura, Ryuji Kitani, Yasuko Yamauchi, Kaori Soeda
  • Publication number: 20040106057
    Abstract: A toner including toner particles including a binder resin and a colorant, wherein particles of the toner have such a rolling property as to relatively easily roll in one direction compared to other directions. It is preferable that the toner particles preferably have a spindle form and satisfies the following relationships: 0.5≦(r2/r1)≦0.8, 0.7≦(r3/r2)≦1.0, and r3≦r2≦r1, wherein r1, r2 and r3 represent an average major axis particle diameter, an average minor axis particle diameter and an average thickness of the toner particles. An image forming apparatus including at least an image bearing member; a developing device configured to develop an electrostatic latent image with a developer including the above-mentioned toner; a transferring device configured to transfer a toner image onto a receiving material; and a cleaning device configured to clean a surface of the image bearing member.
    Type: Application
    Filed: November 14, 2003
    Publication date: June 3, 2004
    Inventors: Masami Tomita, Hiroaki Matsuda