Patents by Inventor Koutarou Yoshihara

Koutarou Yoshihara 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: 20030190546
    Abstract: An image forming method, a process cartridge, and an image forming apparatus are provided, with which an electrophotographic image that has superior image quality, superior fixing ability and remains good even in a hot and humid environment is obtainable. The image forming method includes: 0developing, with a developing agent, an electrostatic latent image formed on a surface of a photoreceptor to form a toner, image; transferring the toner image onto an image receiving member to form a transfer image; and fixing the transferred image onto the image receiving member to form an image, wherein the photoreceptor includes a layer that contains a siloxane compound having charge-transferability and a crosslinking structure, with a compound having acid-adsorbing ability being supplied to the surface of the photoreceptor. The process cartridge and the image forming apparatus are used in the image forming method.
    Type: Application
    Filed: August 26, 2002
    Publication date: October 9, 2003
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Susumu Yoshino, Koutarou Yoshihara, Masahiko Hodumi
  • Patent number: 6617088
    Abstract: A developer for a trickle developing method is used in formation of a full color image and is made of a mixture of a toner and a carrier. The toner contains inorganic fine particles as an internal additive and an external additive, a volume average particle diameter D50v of the toner is between 5.0 and 9.0 &mgr;m, a true specific gravity of the carrier is between 3.00 and 4.60, a volume average particle diameter of the carrier is between 15 and 60 &mgr;m, and the ratio of the volume average particle diameter of the carrier to the volume average particle diameter of the toner is between 3.00 and 7.00, and an image forming method using the developer.
    Type: Grant
    Filed: May 18, 2001
    Date of Patent: September 9, 2003
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Akihiro Iizuka, Susumu Yoshino, Koutarou Yoshihara, Tetsuya Taguchi
  • Publication number: 20020076635
    Abstract: An electrophotographic black toner comprising a colorant and a binder resin, wherein the toner has a metal oxide as the colorant of 20% by weight or less, said metal oxide having magnetization of 40 emu/g or smaller, and said toner has color coordinates such that L* has a value of 10 to 25, a* has a value of −3.0 to 3.0, and b* has a value of −3.0 to 3.0 as determined by a fixed image formed with the toner, as well as an electrophotographic developer and an image forming method using said electrophotographic black toner are provided. According to the present invention, the electrophotographic black toner having a high volume-specific resistance value, achieving a sufficient degree of blackness, less likely to cause high background and providing a high quality image can be obtained.
    Type: Application
    Filed: August 30, 2001
    Publication date: June 20, 2002
    Applicant: FUJI XEROX CO., LTD
    Inventors: Susumu Yoshino, Tetsuya Taguchi, Koutarou Yoshihara
  • Patent number: 6383704
    Abstract: A full color electrophotographic toner including toner particles containing at least a binder resin, a colorant and a wax, and external additives, at least one of the external additives being rutile titanium oxide having a volume resistivity of 1×1014 to 1×1018 &OHgr;cm, and a dispersion absolute deviation a of rutile titanium oxide being 0.17 or less, and a full color electrophotographic developer and an image forming method using the same are provided. In the full color electrophotographic toner, the full color electrophotographic developer and the image forming method of the invention, a retransfer phenomenon of the transferred toner can be prevented, a chargeability and a transferability are not problematic at all, a charging amount of the toner in long-term use can be rendered appropriate and stable, and a fluidity is also excellent.
    Type: Grant
    Filed: November 28, 2000
    Date of Patent: May 7, 2002
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Rieko Kataoka, Susumu Yoshino, Akihiro Iizuka, Koutarou Yoshihara, Haruhide Ishida, Tetsuya Taguchi, Fumiaki Mera, Hiroshi Takano, Yasuhiro Oya, Michio Take
  • Patent number: 6379857
    Abstract: Provided is a method for image formation capable of stably outputting high-quality images with no image density unevenness for a long period of time, in which the images formed are free from image defects of edge deletions and other deletions therein and which ensures good and uniform developability everywhere in the latent image region to be developed with preventing the latent image support used from being degraded.
    Type: Grant
    Filed: November 8, 2000
    Date of Patent: April 30, 2002
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Tetsuya Taguchi, Akihiro Iizuka, Koutarou Yoshihara, Susumu Yoshino, Haruhide Ishida, Rieko Kataoka
  • Publication number: 20020022190
    Abstract: A developer for a trickle developing method is used in formation of a full color image and is made of a mixture of a toner and a carrier. The toner contains inorganic fine particles as an internal additive and an external additive, a volume average particle diameter D50v of the toner is between 5.0 and 9.0 &mgr;m, a true specific gravity of the carrier is between 3.00 and 4.60, a volume average particle diameter of the carrier is between 15 and 60 &mgr;m, and the ratio of the volume average particle diameter of the carrier to the volume average particle diameter of the toner is between 3.00 and 7.00, and an image forming method using the developer.
    Type: Application
    Filed: May 18, 2001
    Publication date: February 21, 2002
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Akihiro Iizuka, Susumu Yoshino, Koutarou Yoshihara, Tetsuya Taguchi
  • Patent number: 6203958
    Abstract: Provided is a toner having good offset resistance and capable of giving non-glaring, high-quality images with high OHP transparency, and a method of image formation with it. The toner includes at least a binder resin, a colorant and a wax. The THF soluble component of the toner, as analyzed through gel permeation chromatography, has a number-average molecular weight falling between 2500 and 5500, a weight-average molecular weight falling between 13000 and 25000, and a peak molecular weight falling between 5000 and 15000, and contains a fraction having a molecular weight of at least 105 in a ratio of at most 10% by weight of the component and a fraction having a molecular weight of at least 104 in a ratio of from 30 to 70% by weight of the component, and the wax in the toner has a DSC endothermic peak falling between 50 and 120° C.
    Type: Grant
    Filed: March 6, 2000
    Date of Patent: March 20, 2001
    Assignee: Fuji Xerox Co., LTD
    Inventors: Yasuhiro Oya, Susumu Yoshino, Masanobu Ninomiya, Hirokazu Hamano, Kaori Oishi, Tetsuya Taguchi, Koutarou Yoshihara
  • Patent number: 6187489
    Abstract: A full-color latent image developing toner composed of toner particles containing a binder resin, a coloring agent, and a surface lubricant, and at least one kind of an external additive, wherein the toner contains at least about 3% the surface lubricant, the toner includes irregular-shaped particles of ML2/A≧125, and when the emission voltage caused by the carbon originated in the binder resin of the toner particles is X and the emission voltage caused by the element originated in the external additive is Y, and when the relationship between X(⅔) and Y are primary-regressed to the straight line passing through origin of a coordinate, the correlation factor of the element originated in at least one external additive is not less than 0.4. As the external additive, a titanium compound obtained by reacting TiO(OH)2 prepared by a wet method and a silane compound is preferably used.
    Type: Grant
    Filed: February 29, 2000
    Date of Patent: February 13, 2001
    Assignee: Fuji Xerox Co., LTD
    Inventors: Kaori Oishi, Susumu Yoshino, Yasuhiro Oya, Hirokazu Hamano, Masanobu Ninomiya, Tetsuya Taguchi, Koutarou Yoshihara
  • Patent number: 6132915
    Abstract: Provided is an image-forming process including a step of forming an electrostatic latent image on a latent image-carrier and a step of developing the latent image by a developer on a developer-carrier disposed facing the electrostatic latent image-carrier, a developer contains a color toner containing a wax which amount is from 1 to 10% by weight of the toner is used, and the developer-carrier wherein a ten-point average roughness (Rz) of the surface thereof of and the average spacing (Sm) of roughness peaks meet the following formula is used; 5.ltoreq.Rz.times.20.ltoreq.Sm. By the process, the conveying property of the developer is good, staining of the surface of the developer-carrier can be prevented, and images having a high quality and excellent in the fixing property over a long period time is obtained even in the case of using oil-less color toners containing a wax.
    Type: Grant
    Filed: November 30, 1999
    Date of Patent: October 17, 2000
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Susumu Yoshino, Yasuhiro Oya, Masanobu Ninomiya, Hirokazu Hamano, Koutarou Yoshihara, Kaori Oishi, Tetsuya Taguchi, Haruhide Ishida
  • Patent number: 5965312
    Abstract: A one-component developer comprising an external additive, and toner particles containing a binder resin and a colorant, wherein the external additive contains a titanium compound obtained by the reaction of TiO(OH).sub.2 and a silane compound, and an image forming method using the one-component developer are disclosed. The one-component developer and the image forming method provide excellent flow and a narrow charge distribution, can reduce fluctuation of the charge property due to the environmental change, and can thus form a high-quality image without fogging and the damage to a latent image retainer by filming can be prevented.
    Type: Grant
    Filed: May 15, 1997
    Date of Patent: October 12, 1999
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Hiroshi Nakazawa, Koutarou Yoshihara, Etsuo Tominaga, Hiroe Okuyama, Masahiro Uchida, Chiaki Suzuki, Yoshifumi Iida, Toyofumi Inoue, Hiroyoshi Okuno
  • Patent number: 5891600
    Abstract: The present invention provides a mono-component developer comprising toner particles containing a binding resin, a colorant and an additive and a method of forming images by use thereof. In the present invention said additive is preferably a titanium compound prepared by through the reaction between TiO(OH).sub.2 and a silane compound or through the reaction between TiO(OH).sub.2 and a silicone oil. The specific gravity of the said titanium compound is in the range of 2.8 to 3.6. The average particle diameter thereof is in the range of 10 to 70 nm. The said toner particle is preferably a non-magnetic particle. By making use of the mono-component developer and the method for forming an image using it, charging of the toner, and carriage of the toner can be stabilized over a long period of time, and stable image formation can be obtained.
    Type: Grant
    Filed: October 9, 1997
    Date of Patent: April 6, 1999
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Hiroyoshi Okuno, Etsuo Tominaga, Toyofumi Inoue, Tetsu Torigoe, Hiroe Okuyama, Takahisa Fujii, Koutarou Yoshihara, Masahiro Uchida, Hiroshi Nakazawa, Chiaki Suzuki, Yoshifumi Iida
  • Patent number: 5827631
    Abstract: A non-magnetic one-component developer comprising a binder resin, a colorant and a charge controlling agent, the binder resin being a polyester resin which has a number average molecular weight of from 2,500 to 3,500, a weight average molecular weight of from 8,000 to 15,000 and a softening point of from 110.degree. C. to 130.degree. C., and which is substantially free from an ingredient insoluble in tetrahydrofuran, and the charge controlling agent comprising a metal complex salt compound represented by the following formula (1): ##STR1## wherein M represents a metal element selected from the group consisting of zinc, iron, nickel and cobalt, and R.sup.1 and R.sup.2 each represents a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms.
    Type: Grant
    Filed: February 5, 1997
    Date of Patent: October 27, 1998
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Koutarou Yoshihara, Seiichi Takagi, Toyofumi Inoue, Hiroyoshi Okuno, Tetsu Torigoe, Hiroe Okuyama, Masahiro Uchida
  • Patent number: 5738966
    Abstract: A negatively electrifiable, non-magnetic and single component developer comprising a binder resin, a carbon black and a charge control agent, wherein the carbon black has an average primary particle diameter of 20 to 50 nm and a pH of 2 to 5, and the charge control agent comprises a compound represented by the following formula: ##STR1## wherein M represents a metal atom selected from the group consisting of zinc, iron, nickel and cobalt, and R.sub.1 and R.sub.2 each represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. An image forming process using the developer is also disclosed. This one-component developer, which is suitable for use as a black toner in color image formation, can be stably charged and transported over long to give images free from fogging and having evenness of density and hardly poses problems such as dirts and color mixing over long.
    Type: Grant
    Filed: December 3, 1996
    Date of Patent: April 14, 1998
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Hiroyoshi Okuno, Toyofumi Inoue, Tetsu Torigoe, Hiroe Okuyama, Koutarou Yoshihara, Masahiro Uchida