Patents by Inventor Narihito Kojima

Narihito Kojima 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: 20020197549
    Abstract: An electrophotographic photoreceptor including at least an electroconductive substrate; and a photosensitive layer overlying the electroconductive substrate and including at least a charge generation layer; a charge transport layer; and a protective layer including a filler, wherein the filler is dispersed in the protective layer so as to occupy an area of from 3 to 5% of a cross section of the protective layer; the filler has particle diameter distribution having a peak at a diameter of from 0.2 to 0.3 &mgr;m; and the particles of the filler having a particle diameter of not less than 0.3 &mgr;m occupies an area of from 10 to 30% of the area of all the filler in the cross section of the protective layer.
    Type: Application
    Filed: November 2, 2001
    Publication date: December 26, 2002
    Inventors: Yohta Sakon, Akio Kosuge, Tatsuya Niimi, Narihito Kojima
  • Publication number: 20020115005
    Abstract: An electrophotographic photoreceptor including an electroconductive substrate; a photosensitive layer located overlying the electroconductive substrate and including a resin; and a surface layer including a filler and a binder resin, wherein the surface layer and the photosensitive layer have a continuous structure, and wherein the surface layer satisfies the following relationship: &sgr;≦D/5, wherein D represents an average of maximum thicknesses of the surface layer in units of micrometers in 20 segments of 5 &mgr;m wide when a portion of a cross section of the photoreceptor of 100 &mgr;m wide is divided into the 20 segments, and &sgr; represents a standard deviation of the 20 maximum thicknesses.
    Type: Application
    Filed: November 2, 2001
    Publication date: August 22, 2002
    Inventors: Hiroshi Ikuno, Hidetoshi Kami, Ryohichi Kitajima, Narihito Kojima, Akihiko Matsuyama, Hiroshi Nagame, Katsuichi Ohta, Tetsuro Suzuki, Nozomu Tamoto, Hiroshi Tamura, Yohta Sakon, Eiji Kurimoto, Tatsuya Niimi, Yuka Miyamoto
  • Patent number: 6432596
    Abstract: An electrophotographic photoreceptor including an electroconductive substrate; a charge generation layer overlying the substrate; a charge transport layer formed overlying the substrate and including a charge transport material, a polycarbonate resin, an antioxidant having the following formula (1): and a sulfur-containing compound having an alkyl group having from 6 to 30 carbon atoms; and a protective layer comprising a binder resin and a filler dispersed in the binder resin and formed as a top layer.
    Type: Grant
    Filed: April 4, 2001
    Date of Patent: August 13, 2002
    Assignee: Ricoh Company Limited
    Inventors: Hiroshi Ikuno, Narihito Kojima, Eiji Kurimoto
  • Patent number: 6363237
    Abstract: A lubricity-imparting unit for imparting lubricity to a surface of an electrophotographic photoconductor, which is in contact with the surface of the photoconductor, wherein at least a surface of the lubricity-imparting unit which comes into contact with the surface of the photoconductor includes a flexible lubricating material, and has a length at least capable of covering an image formation region of the electrophotographic photoconductor lengthwise. An image formation apparatus and an image formation method using this lubricity-imparting unit are described.
    Type: Grant
    Filed: November 11, 1999
    Date of Patent: March 26, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Nagame, Narihito Kojima, Yohta Sakon, Ryuta Takeichi, Akiyo Nakajima
  • Publication number: 20010051307
    Abstract: An electrophotographic photoreceptor including an electroconductive substrate; a charge generation layer overlying the substrate; a charge transport layer formed overlying the substrate and including a charge transport material, a polycarbonate resin, an antioxidant having the following formula (1): 1
    Type: Application
    Filed: April 4, 2001
    Publication date: December 13, 2001
    Applicant: Ricoh Company Limited
    Inventors: Hiroshi Ikuno, Narihito Kojima, Eiji Kurimoto
  • Patent number: 6326112
    Abstract: An electrophotographic photoreceptor which includes an electroconductive substrate, and a photosensitive layer which is formed overlying the substrate, wherein the photosensitive layer includes a charge generation material, a charge transport polymer material including triarylamine structure and a soft segment in a main chain thereof, and a filler.
    Type: Grant
    Filed: August 21, 2000
    Date of Patent: December 4, 2001
    Assignee: Ricoh Company Limited
    Inventors: Hiroshi Tamura, Hidetoshi Kami, Katsuichi Ohta, Tetsuro Suzuki, Tatsuya Niimi, Narihito Kojima
  • Publication number: 20010031411
    Abstract: An electrophotographic photoreceptor including a photosensitive layer on an electroconductive substrate, wherein nitrate ion is present on the surface of the photosensitive layer in an amount of from 50 to 300 &mgr;g per 1 m2 of the surface of the photosensitive layer when the nitrate ion is determined by an ion chromatographic method. Preferably a material having a fluorine atom and a carbon atom or a fatty acid metal salt such as zinc stearate is further present on the surface of the photosensitive layer such that the F/C ratio is from 0.05 to 0.5 or the Zn/C ratio is from 0.001 to 0.1. An image forming apparatus using the photoreceptor is also provided.
    Type: Application
    Filed: March 2, 2001
    Publication date: October 18, 2001
    Applicant: Ricoh Company Limited
    Inventors: Narihito Kojima, Ryuta Takeichi, Akiyo Namiki, Hiroshi Nagame, Yohta Sakon
  • Patent number: 6160977
    Abstract: In an image forming apparatus of the type sequentially executing charging, exposure, development and image transfer, a device for applying a lubricant to the surface of an image carrier includes a lubricant applying member rotatable in contact with the image carrier for applying, at a position where the lubricant applying member contacts the image carrier, the lubricant to the surface of the image carrier while deforming its contour in accordance with a bite of the surface of the image carrier. A lubricant feeding unit feeds the lubricant to the lubricant applying member and includes a lubricant providing unit having a preselected thickness t. The surface of the image carrier bites into the lubricant applying member by an amount T while the lubricant providing unit bites into the lubricant applying member by an amount t' smaller than the amount T, but substantially equal to or slightly greater than the thickness t.
    Type: Grant
    Filed: November 29, 1999
    Date of Patent: December 12, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryuta Takeichi, Akiyo Nakajima, Narihito Kojima, Hiroshi Nagame, Yohta Sakon
  • Patent number: 6151468
    Abstract: An electrophotographic photoconductor including a photoconductive layer which is formed overlying an electroconductive substrate and which includes at least a charge transporting polymer material, wherein the photoconductive layer has a water vapor permeability not greater than about 200 g.multidot.m.sup.-2 .multidot.24 h.sup.-1. The photoconductive layer may be a functionally separated photoconductive layer including a charge generating layer and a charge transporting layer which is formed overlying the charge generating layer and which includes the charge transporting polymer material, wherein the charge transporting layer has a water vapor permeability not greater than about 200 g.multidot.m.sup.-2 .multidot.24 h.sup.-1.
    Type: Grant
    Filed: November 29, 1999
    Date of Patent: November 21, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Hidetoshi Kami, Tetsuro Suzuki, Narihito Kojima, Hiroshi Nagame, Hiroshi Tamura, Yohta Sakon, Hiroshi Ikuno
  • Patent number: 6118964
    Abstract: A charging or image transfer unit for use in an image formation process including the steps of charging, image formation exposure, image development, image transfer, image fixing and cleaning, for applying an electric field to the surface of an electrophotographic photoconductor by coming into contact therewith, and also for controlling surface properties of the electrophotographic photo-conductor. The unit includes an electric field application member applying the electric field to the surface of the electrophotographic photoconductor and a lubricity-imparting member for controlling a friction coefficient of the surface of the electrophotographic photoconductor wherein the electric field application member includes an electrophotoconductive material and a lubricity-imparting member includes a fluoroplastic material.
    Type: Grant
    Filed: December 10, 1998
    Date of Patent: September 12, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Narihito Kojima, Hiroshi Nagame, Ryuta Takeichi, Yukiko Iwasaki, Akiyo Nakajima, Hiroyuki Fushimi
  • Patent number: 6060205
    Abstract: An image forming apparatus comprising a lubricant supplying device which supplies a lubricant to a rotating image carrier, wherein the lubricant comprises at least one of low molecular weight polytetrafluoroethylene, a fluorine-containing resin including a filler, polytetrafluoroethylene which has been subjected to heat or radiation decomposition treatment, a fluorine-containing resin which has been prepared by a compression molding method, and a porous fluorine-containing resin. The lubricant preferably has a concave portion on the surface thereof contacting the image carrier. The lubricant is preferably disposed so that an acute angle formed by a line parallel to a compression direction of the lubricant, during the compression molding of the lubricant, and a line parallel to a moving direction of the image carrier, is from about 45 to about 90.degree..
    Type: Grant
    Filed: April 19, 1999
    Date of Patent: May 9, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryuta Takeichi, Narihito Kojima, Hiroshi Nagame, Yohta Sakon, Akiyo Nakajima
  • Patent number: 6030733
    Abstract: An electrophotographic photoconductor including a photoconductive layer which is formed overlying an electroconductive substrate and which includes at least a charge transporting polymer material, wherein the photoconductive layer has a water vapor permeability not greater than about 200 g.multidot.m.sup.-2 .multidot.24 h.sup.-1. The photoconductive layer may be a functionally separated photoconductive layer including a charge generating layer and a charge transporting layer which is formed overlying the charge generating layer and which includes the charge transporting polymer material, wherein the charge transporting layer has a water vapor permeability not greater than about 200 g.multidot.m.sup.2 .multidot.24 h.sup.-1.
    Type: Grant
    Filed: February 3, 1999
    Date of Patent: February 29, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Hidetoshi Kami, Tetsuro Suzuki, Narihito Kojima, Hiroshi Nagame, Hiroshi Tamura, Yohta Sakon, Hiroshi Ikuno
  • Patent number: 6014532
    Abstract: An image forming apparatus capable of adequately adjusting the amount of a low friction agent to be applied to the surface of a photoconductive element in accordance with image quality is disclosed. After preselected initialization, an electrophotographic image forming section records a usual image or a particular image for evaluation on a paper. A toner image formed on the photoconductive element and a toner image transferred from the element to a paper are read. Image data representative of such toner images and the initial image data are compared to see if the read images are defective or not. The low friction agent is applied to the photoconductive element in an amount controlled on the basis of the result of the decision.
    Type: Grant
    Filed: November 3, 1998
    Date of Patent: January 11, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryuta Takeichi, Yukiko Iwasaki, Akiyo Nakajima, Hiroshi Nagame, Narihito Kojima, Hiroyuki Fushimi
  • Patent number: 5871876
    Abstract: An electrophotographic photoconductor has an electroconductive support and a photoconductive layer formed thereon, which contains a charge transport material with a polycarbonate structure having a triarylamino group at least on the main chain or side chain thereof, and a charge generation material with a phthalocyanine skeleton.
    Type: Grant
    Filed: May 23, 1997
    Date of Patent: February 16, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Ikuno, Hiroshi Nagame, Tetsuro Suzuki, Hidetoshi Kami, Jun Aoto, Hiroshi Tamura, Narihito Kojima, Tatsuya Niimi
  • Patent number: 5870657
    Abstract: A charging apparatus for a photoconductor composed of an electroconductive charging member and mechanism for feeding a voltage to the charging member. This charging apparatus is composed of a material capable of adsorbing ozone. The charging apparatus may be in the form of a roller type, a blade type or the like. Carbon fibers having micro pores can be used as the charging member.
    Type: Grant
    Filed: May 5, 1997
    Date of Patent: February 9, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Nagame, Narihito Kojima, Hiroshi Ikuno
  • Patent number: 5840455
    Abstract: An electrophotographic photoconductor, having a conductive supporting substrate, a photoconductive layer disposed thereon, and a surface protective layer formed on the photoconductive layer, with the surface protective layer being made of hydrogenated diamond-like carbon or hydrogenated amorphous carbon and containing at least one additional element selected from the group consisting of nitrogen, fluorine, boron, phosphorus, chlorine, bromine and iodine, with the atomic ratio of total additional elements to carbon in the surface protective layer being smaller in close proximity to the photoconductive layer than in the remainder of the surface protective layer, and having a Knoop hardness of more than or equal to 1000 kg/mm.sup.2 in the outermost portion of the surface protective layer is provided which has improved resistance against peeling and scratch, and is thus capable of forming electrophotographic images of high quality for repeated use over an extended period of time.
    Type: Grant
    Filed: May 24, 1996
    Date of Patent: November 24, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Ikuno, Narihito Kojima, Hiroshi Nagame
  • Patent number: 5656406
    Abstract: An electrophotographic photoconductor includes an electroconductive support; a photoconductive layer formed on the electroconductive support; and a surface protective layer formed on the photoconductive layer, the surface protective layer having a hydrogen-containing diamond-like carbon structure or amorphous carbon structure, which contains at least one additive element selected from the group consisting of nitrogen, fluorine, boron, phosphorus, chlorine, bromine and iodine, with the atomic ratio of the additive element to the carbon in the carbon structure having such a distribution in the direction of the thickness of the surface protective layer that the atomic ratio is smaller in the vicinity of the top surface of the surface protective layer and in the vicinity of the photoconductive layer adjacent to the surface protective layer than in the other portion of the surface protective layer.
    Type: Grant
    Filed: January 11, 1995
    Date of Patent: August 12, 1997
    Assignees: Ricoh Company, Ltd., Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hiroshi Ikuno, Narihito Kojima, Hiroshi Nagame, Shunpei Yamazaki, Shigenori Hayashi
  • Patent number: 5540815
    Abstract: A method of recycling a copy sheet carrying a hydrophobic image thereon by impregnating the sheet with a water-containing separating liquid, causing the to image contact an image separating member, and heating the sheet for thereby transferring the image to the image separating member. The image separating member has a critical surface tension of 25 mN/m or above.
    Type: Grant
    Filed: December 9, 1994
    Date of Patent: July 30, 1996
    Assignee: Ricoh Company, Ltd.
    Inventors: Masato Igarashi, Toshiyuki Kawanishi, Eiichi Kawamura, Narihito Kojima
  • Patent number: 5525447
    Abstract: An electrophotographic photoconductor includes an electroconductive support; a photoconductive layer formed on the electroconductive support; and a surface protective layer formed on the photoconductive layer, the surface protective layer having a hydrogen-containing diamond-like carbon structure or amorphous carbon structure, containing therein an additive element selected from the group consisting of nitrogen, fluorine, boron, phosphorous, chlorine, bromine and iodine, with the atomic ratio of the additive element to the carbon contained in the surface protective layer being larger in the vicinity of the top surface of the surface protective layer than in the vicinity of the photoconductive layer adjacent to the surface protective layer.
    Type: Grant
    Filed: October 7, 1994
    Date of Patent: June 11, 1996
    Assignees: Ricoh Company, Ltd., Semiconductor Energy Laboratory Co., Ltd.
    Inventors: Hiroshi Ikuno, Narihito Kojima, Hiroshi Nagame, Shunpei Yamazaki, Shigenori Hayashi
  • Patent number: 5452061
    Abstract: An electrophotographic image formation apparatus using a photoconductor which is composed of a substrate, a photoconductive layer provided on the substrate, and a protective layer formed directly or via an intermediate layer on the photoconductive layer and capable of performing an electrophotographic process including the steps of conducting a first charging for uniformly charging the surface of the photoconductor, exposing the charged surface of the photoconductor to light images to form latent electrostatic images corresponding to the light images, developing the latent electrostatic images to toner images, transferring the toner images to a transfer sheet, cleaning the surface of the photoconductor to remove residual toners therefrom, and fixing the toner images to the transfer sheet, includes a charger for charging the photoconductor with a polarity opposite to that of the charge applied in the step of the first charging prior to the step of the first charging.
    Type: Grant
    Filed: December 2, 1993
    Date of Patent: September 19, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Narihito Kojima, Hiroshi Nagame, Hiroshi Ikuno