Patents by Inventor Yasutaka Akashi

Yasutaka Akashi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20030123909
    Abstract: A developing assembly is disclosed having at least a developer container, a developer-carrying member and a developer layer thickness regulation member, wherein the developer is composed mainly of toner particles containing at least a binder resin and a colorant, and conductive fine particles, and the developer-carrying member has a substrate and a surface layer formed on the substrate of a non-magnetic metal, an alloy or a metallic compound. This developing assembly causes no sleeve ghost, enables electrostatic latent images to be faithfully developed, causes no fading phenomenon, and enables high-density images to be formed in every environment. Also disclosed are a process cartridge having the developing assembly and the latent-image-bearing member integrally set as one unit detachably mountable on the main body of an image-forming apparatus, and an image-forming method making use of the features of this developing assembly.
    Type: Application
    Filed: August 16, 2002
    Publication date: July 3, 2003
    Applicant: Canon Kabushiki Kaisha
    Inventors: Yasutaka Akashi, Yasuhide Goseki, Masayoshi Shimamura, Kenji Fujishima, Kazunori Saiki, Satoshi Otake, Naoki Okamoto
  • Publication number: 20020176931
    Abstract: A used developer-carrying member having a resin coating layer on a substrate is regenerated through a step of scraping the resin coating layer of the used developer-carrying member to form a developer-carrying member surface having unevenness showing a central line-average roughness Ra of at most 0.8 &mgr;m, and a step of coating the developer-carrying member surface having the unevenness with a coating layer of a resinous composition comprising at least a binder resin and electroconductive fine powder. The regenerated developer-carrying member can be reinstalled in a developing apparatus and subjected to repetitive electrophotographic image forming cycles.
    Type: Application
    Filed: January 14, 2002
    Publication date: November 28, 2002
    Applicant: Canon Kabushiki Kaisha
    Inventors: Yasuhide Goseki, Masayoshi Shimamura, Yasutaka Akashi, Kenji Fujishima, Kazunori Saiki, Satoshi Otake, Naoki Okamoto
  • Publication number: 20020106575
    Abstract: An image forming method has the steps of
    Type: Application
    Filed: August 30, 1995
    Publication date: August 8, 2002
    Inventors: YASUTAKA AKASHI, YUSHI MIKURIYA
  • Patent number: 5849453
    Abstract: An image forming method has the steps of forming a toner image by developing through a developing means a latent image formed on a latent image bearing member; transferring the toner image formed, from the latent image bearing member to a transfer medium through a transfer means to which a bias is applied; cleaning the latent image bearing member from which the toner image has been transferred to the transfer medium, to recover and collect the toner remaining on the latent image bearing member; and feeding the toner recovered and collected, to the developing means for reuse in the developing step. The toner has a binder resin and at least one of a magnetic powder and a colorant. The toner has a weight average particle diameter (D.sub.4) of from 4 .mu.m to 11 .mu.m; a coefficient A of variation of number-base distribution, of not more than 40, which is a coefficient represented by the formula:A=S.sub.n /D.sub.1 .times.100wherein S.sub.n represents a standard deviation of number-base distribution, and D.sub.
    Type: Grant
    Filed: June 8, 1993
    Date of Patent: December 15, 1998
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yushi Mikuriya, Masaki Uchiyama, Yasutaka Akashi
  • Patent number: 5641600
    Abstract: A magnetic toner composed of a binder resin and magnetic fine particles, wherein the magnetic fine particles are coated with an iron-zinc oxide on their surfaces and the magnetic fine particles have a saturation magnetization (.sigma.s) of 50 Am.sup.2 /kg or above under a magnetic field of 79.58 kA/m (1K oersted) where the product of residual magnetization (.sigma.r, Am.sup.2 /kg) and coercive force (Hc, kA/m), .sigma.r.times.Hc, is in the range between 60 and 250 (kA.sup.2 m/kg).
    Type: Grant
    Filed: July 31, 1995
    Date of Patent: June 24, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takaaki Kotaki, Masaki Uchiyama, Yasutaka Akashi, Makoto Unno, Yushi Mikuriya, Tadashi Dojyo
  • Patent number: 5504272
    Abstract: An image forming method in which a toner-carrying member for carrying a specific magnetic toner is placed adjacent a latent image-bearing member for carrying an electrostatic latent image so as to form a developing region of a predetermined gap size. The magnetic toner on the toner-carrying member forms a toner layer of a regulated thickness smaller than the above-mentioned gap. An asymmetric bias is applied to the magnetic toner so as to cause the magnetic toner from the toner-carrying member to be conveyed to the latent image-bearing member thereby to develop the electrostatic latent image.
    Type: Grant
    Filed: May 20, 1994
    Date of Patent: April 2, 1996
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaki Uchiyama, Hirohide Tanikawa, Yasutaka Akashi, Masaaki Taya, Makoto Unno
  • Patent number: 5500318
    Abstract: A toner for developing an electrostatic image is constituted by a binder resin and a colorant The binder resin is characterized by containing at least 20 wt. % of an extraction residue after 6 hours of extraction and below 20 wt. % of an extraction residue after 72 hours of extraction respectively by Soxhlet extraction with tetrahydrofuran. The toner shows a dynamic modulus and a loss modulus, respectively at 200.degree. C. and 0.1 Hz, which are substantially unchanging with time. The properties provide the toner with a harmonization of anti-offset characteristic and fixability as well as stable viscoelasticity under heating.
    Type: Grant
    Filed: June 27, 1994
    Date of Patent: March 19, 1996
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Masaki Uchiyama, Yoshinobu Joh, Yasutaka Akashi, Masaaki Taya, Makoto Unno
  • Patent number: 5480755
    Abstract: A magnetic toner has magnetic resin particles containing at least a binder resin, a charge control agent and a magnetic powder. The surface-modified fine silica powder being a fine silica powder has been treated with a hydrophobicizing agent. The fine silica powder has a specific surface area of not less than 180 m.sup.2 /g, a hydrophobicity of from 60% to 95% and a bulk density of from 35 g/lit. to 49 g/lit.
    Type: Grant
    Filed: August 19, 1994
    Date of Patent: January 2, 1996
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaki Uchiyama, Yoshinobu Jo, Yasutaka Akashi, Masaaki Taya, Makoto Unno
  • Patent number: 5348829
    Abstract: A monocomponent-type developer for developing electrostatic images, includes a magnetic toner containing at least a binder resin and magnetic powder, and 0.5-10 wt. % (based on the magnetic toner) of inorganic fine powder having a length-average particle size of 0.1-5 .mu.m. The developer has a number-basis particle size distribution such that particles of 4 .mu.m or smaller are contained at 5-18% by number and particles of 4-10 .mu.m are contained at at least 60% by number. The developer has a volume basis particle size distribution such that particles of 12.7 .mu.m or larger are contained at at most 10% by volume. The developer has a weight-average particle size of 7-11 .mu.m. The developer is particularly useful for development under application of a DC-superposed asymmetric AC bias electric field including a development-side voltage component with a larger magnitude and a shorter duration than a reverse development-side voltage component.
    Type: Grant
    Filed: November 6, 1992
    Date of Patent: September 20, 1994
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaki Uchiyama, Yasutaka Akashi, Masaaki Taya, Makoto Unno
  • Patent number: 5338894
    Abstract: An image forming method in which a toner-carrying member for carrying a specific magnetic toner is placed adjacent a latent image-bearing member for carrying an electrostatic latent image so as to form a developing region of a predetermined gap size. The magnetic toner on the toner-carrying member forms a toner layer of a regulated thickness smaller than the above-mentioned gap. An asymmetric bias is applied to the magnetic toner so as to cause the magnetic toner from the toner-carrying member to be conveyed to the latent image-bearing member thereby to develop the electrostatic latent image.
    Type: Grant
    Filed: September 20, 1991
    Date of Patent: August 16, 1994
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaki Uchiyama, Hirohide Tanikawa, Yasutaka Akashi, Masaaki Taya, Makoto Unno
  • Patent number: 5330871
    Abstract: A toner for developing an electrostatic image is constituted by a binder resin and a colorant. The binder resin is characterized by containing at least 20 wt. % of an extraction residue after 6 hours of extraction and below 20 wt. % of an extraction residue after 72 hours of extraction respectively by Soxhlet extraction with tetrahydrofuran. The toner shows a dynamic modulus and a loss modulus, respectively at 200.degree. C. and 0.1 Hz, which are substantially unchanging with time. The properties provide the toner with a harmonization of anti-offset characteristic and fixability as well as stable viscoelasticity under heating.
    Type: Grant
    Filed: November 26, 1991
    Date of Patent: July 19, 1994
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Masaki Uchiyama, Yoshinobu Joh, Yasutaka Akashi, Masaaki Taya, Makoto Unno
  • Patent number: 5296326
    Abstract: A magnetic toner for electrophotography having stable triboelectric chargeability under various environmental conditions may be provided by using magnetic iron oxide particles having a moderately high surface Feo content, specified by the following conditions: (a) a dissolved Fe (II) content in dissolved total iron of 14-33.3 wt. % at a dissolved total iron percentage of 5.+-.1 wt. %, (b) a dissolved Fe (II) content in dissolved total iron of 17-33.3 wt. % at a dissolved total iron percentage of 10.+-.1 wt. %, and (c) a dissolved Fe (II) content in dissolved total iron of 18-33.3 wt. % at a dissolved total iron percentage of 15.+-.1 wt.
    Type: Grant
    Filed: December 21, 1992
    Date of Patent: March 22, 1994
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masaaki Taya, Hirohide Tanikawa, Yasutaka Akashi, Makoto Unno, Masaki Uchiyama, Kiichiro Sakashita
  • Patent number: 5268248
    Abstract: A toner for developing an electrostatic image is provided as a pulverized mixture including a binder resin and a colorant. The binder resin is characterized by a molecular weight distribution on a GPC chromatogram of its tetrahydrofuran (THF)-soluble resin content including below 15% of a resin component in a molecular weight region of at most 5000 and at least 5 wt. % of a resin component in a molecular weight region of at least 5.times.10.sup.6 and showing a main peak in a molecular weight region of 5000 to 5.times.10.sup.6. The THF-soluble resin component in the molecular weight region of at least 5.times.10.sup.6 is extremely enriched during a melt-kneading step during the toner production, so as to effectively prevent toner flowout from a member for cleaning a fixing roller.
    Type: Grant
    Filed: November 26, 1991
    Date of Patent: December 7, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Masaki Uchiyama, Yoshinobu Joh, Yasutaka Akashi, Masaaki Taya, Makoto Unno, Kazuyoshi Hagiwara
  • Patent number: 5219946
    Abstract: A binder resin comprises a vinyl copolymer, a mixture of vinyl copolymers, or a mixture of a vinyl copolymer and a vinyl polymer. A resin component with a molecular weight of not more than 10,000 is contained in an amount of from 5 to 50% by weight based on the whole resin. The vinyl copolymer or the mixture of vinyl copolymers has an acid anhydride group and a carboxyl group.
    Type: Grant
    Filed: November 8, 1990
    Date of Patent: June 15, 1993
    Inventors: Hirohide Tanikawa, Masaki Uchiyama, Tsutomu Kukimoto, Yasutaka Akashi, Masaaki Taya, Makoto Unno, Seiichi Takagi
  • Patent number: 5215854
    Abstract: A microcapsule toner is produced through the steps of: passing resinous base particles (A1) comprising at least a binder resin and modifier particles (B) having a particle size ratio of 0.2 or less with respect to the base particles (A1) through an impact zone having a minimum clearance of 0.5-5 mm between a rotating member and a fixed member or between at least two rotating members at an ambient temperature of 10.degree.-90.degree. C. thereby to fix the modifier particles (B) onto the surfaces of the base particles (A1) under the action of a mechanical impact force to form particles (A2), the modifier particles (B) being particles selected from the group consisting of charge-controlling particles releasing particles, colored particles, charge-suppressing particles and abrasive particles; and passing the particles (A2) and shell-forming resin particles (C) having a particle size ratio of 0.2 or less with respect to the particles (A2) through an impact zone having a minimum clearance of 0.
    Type: Grant
    Filed: October 4, 1989
    Date of Patent: June 1, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masuo Yamazaki, Atsuko Kobayashi, Hitoshi Kanda, Yusuke Karami, Yasuhide Goseki, Yasutaka Akashi
  • Patent number: 5212524
    Abstract: A toner for developing electrostatic images, comprises a binder resin and a colorant, wherein the binder resin comprises a vinyl copolymer having an acid anhydride group, and the binder resin has a total acid value (A) of 2-100 mgKOH/g and a total acid value (B) attributable to acid anhydride group of below 6 mgKOH/g so that [(B)/(A)].times.100 is 60% or less. Because the binder resin has a specified acid value partly attributable to acid anhydride group, the toner is provided with an adequate balance between chargeability and dischargeability, so that the toner shows a stable performance under various environmental conditions. The toner is particularly advantageously constituted as a magnetic toner of fine particle sizes suitably used under application of unsymmetrical alternating bias electric field.
    Type: Grant
    Filed: August 31, 1992
    Date of Patent: May 18, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Yasutaka Akashi, Masaki Uchiyama, Makoto Unno, Masaaki Taya
  • Patent number: 5202731
    Abstract: An image forming apparatus is formed by providing a latent image-bearing member for holding an electrostatic image thereon and a toner-carrying member for carrying a prescribed magnetic toner comprising a binder resin and magnetic powder and having a particle size distribution including 12% by number or more of magnetic toner particles of 5 microns or smaller, 33% by number or less of magnetic toner particles of 8-12.7 microns and 2% by volume or less of magnetic toner particles of 16 microns or larger so as to provide a volume-average particle size of 4-10 microns. At the developing station, an alternating bias voltage comprising a DC voltage and an unsymmetrical AC voltage in superposition is applied between the toner-carrying member and the latent image-bearing member to provide an alternating bias electric field comprising a development-side voltage component and a reverse-development side voltage component.
    Type: Grant
    Filed: August 26, 1992
    Date of Patent: April 13, 1993
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Yasutaka Akashi, Masaaki Taya, Kuniko Kobayashi, Masaki Uchiyama
  • Patent number: 5175070
    Abstract: An image forming apparatus is formed by providing a latent image-bearing member for holding an electrostatic image thereon and a toner-carrying member for carrying a prescribed magnetic toner comprising a binder resin and magnetic powder and having a particle size distribution including 12% by number or more of magnetic toner particles of 5 microns or smaller, 33% by number or less of magnetic toner particles of 8-12.7 microns and 2% by volume or less of magnetic toner parcitles of 16 microns or larger so as to provide a volume-average particle size of 4-10 microns. At the developing station, an alternating bias voltage comprising a DC voltage and an unsymmetrical AC voltage in superposition is applied between the toner-carrying member and the latent image-bearing member to provide an alternating bias electric field comprising a development-side voltage component and a reverse-development side voltage component.
    Type: Grant
    Filed: September 26, 1990
    Date of Patent: December 29, 1992
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Yasutaka Akashi, Masaaki Taya, Kuniko Kobayashi, Masaki Uchiyama
  • Patent number: 5169738
    Abstract: A toner for developing electrostatic images, comprises a binder resin and a colorant, wherein the binder resin comprises a vinyl copolymer having an acid anhydride group, and the binder resin has a total acid value (A) of 2-100 mgKOH/g and a total acid value (B) attributable to acid anhydride group of below 6 mgKOH/g so that [(B)/(A)].times.100 is 60% or less. Because the binder resin has a specified acid value partly attributable to acid anhydride group, the toner is provided with an adequate balance between chargeability and dischargeability, so that the toner shows a stable performance under various environmental conditions. The toner is particularly advantageously constituted as a magnetic toner of fine particle sizes suitably used under application of unsymmetrical alternating bias electric field.
    Type: Grant
    Filed: October 29, 1990
    Date of Patent: December 8, 1992
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirohide Tanikawa, Yasutaka Akashi, Masaki Uchiyama, Makoto Unno, Masaaki Taya
  • Patent number: 4904562
    Abstract: An encapsulated toner for electrophotography is produced through a process, comprising: preparing a solution of a shell material resin set to an acidic (or basic) pH region; dispersing solid core particles in the solution to form a dispersion; changing the pH of the dispersion to a pH region, which is preferably a basic (or acidic) pH region, where the shell material resin is precipitated from the dispersion; and coating the solid core particles with the precipitated shell material resin. The shell material is preferably a proton-attracting basic (or dissociative acidic) vinyl-type copolymer and is dissolved in a pH-adjusted aqueous medium comprising water and a polar solvent, such as a lower alcohol. Thus, an encapsulated toner with excellent triboelectric chargeability and environmental characteristic is prepared without coalescence of capsules or formation of free shells.
    Type: Grant
    Filed: September 23, 1987
    Date of Patent: February 27, 1990
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hiroshi Yusa, Takaaki Kohtaki, Masuo Yamazaki, Yasutaka Akashi