Patents by Inventor Takafumi Iwamoto

Takafumi Iwamoto 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).

  • Patent number: 8148038
    Abstract: An image bearing member including an electroconductive substrate, a charge generating layer located overlying the electroconductive substrate, a charge transport layer located overlying the charge generating layer, the charge transport layer comprising a charge transport material and a protective layer having a thickness of from 3 to 15 ?m located overlying the charge transport layer, wherein the density of the charge transport material in the protective layer at depth of 2 ?m from the surface of the charge transport layer satisfies the following relationship: 10(%)?(Charge transport material)/{(Radical polymerizable monomer having a charge transport structure)+(Radical polymerizable monomer having no charge transport structure)+(Charge transport material)}×100?30(%).
    Type: Grant
    Filed: July 2, 2008
    Date of Patent: April 3, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Yukio Fujiwara, Tetsuro Suzuki, Hiroshi Tamura, Hiroshi Ikuno, Hidetoshi Kami, Takafumi Iwamoto
  • Patent number: 8119317
    Abstract: An electrophotographic photoreceptor, including an electroconductive substrate; a photosensitive layer, located overlying the electroconductive substrate; and a crosslinked resin surface layer, located overlying the photo sensitive layer, wherein the crosslinked resin surface layer includes a crosslinked body of trimethylolpropanetriacrylate, isocyanate including a radical polymerizable functional group and a heat or a light-curable charge transport material.
    Type: Grant
    Filed: June 4, 2008
    Date of Patent: February 21, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Hidetoshi Kami, Tetsuro Suzuki, Hiroshi Tamura, Hiroshi Ikuno, Yukio Fujiwara, Takafumi Iwamoto
  • Publication number: 20120008978
    Abstract: An electrophotographic photoreceptor including a conductive substrate, a photosensitive layer located overlying the conductive substrate, and a hardened protective layer located overlying the photosensitive layer. The hardened protective layer comprises a hardened material of a hardenable composition comprising a radical-polymerizable compound (A) having a charge transport structure and a radical-polymerizable compound (B) having an adamantane skeleton.
    Type: Application
    Filed: June 6, 2011
    Publication date: January 12, 2012
    Inventors: Takafumi IWAMOTO, Naohiro Toda
  • Publication number: 20120009513
    Abstract: To provide an electrophotographic photoconductor, containing: a conductive support; a photosensitive layer provided above the conductive support; and a hardened protective layer provided above the photosensitive layer, wherein the hardened protective layer contains a hardened product of a radical polymerizable compound containing an adamantane skeleton.
    Type: Application
    Filed: June 29, 2011
    Publication date: January 12, 2012
    Inventors: Takafumi IWAMOTO, Naohiro Toda, Yoshitaka Uenoyama, Hidetoshi Ono
  • Patent number: 8084170
    Abstract: An object of the present invention is to provide an electrophotographic photoconductor having an extremely low increase in friction coefficient and wear, while also having superior cleanability even after long-term or large-volume printing, and to provide an electrophotographic apparatus for forming an image using a polymerization toner without providing a unit for externally supplying a lubricant to a photoconductor. Namely, the present invention provides an electrophotographic photoconductor having a photosensitive layer and a crosslinked resin surface layer over a conductive substrate, wherein the crosslinked resin surface layer at least contains trimethylolpropane triacrylate, a dimethylpolysiloxane having a radically polymerizable functional group, and lubricating fine particles.
    Type: Grant
    Filed: March 12, 2008
    Date of Patent: December 27, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Hidetoshi Kami, Tetsuro Suzuki, Hiroshi Tamura, Hiroshi Ikuno, Yukio Fujiwara, Takafumi Iwamoto
  • Publication number: 20110159419
    Abstract: An image bearing member including an electroconductive substrate, a charge generation layer, a charge transport layer and, a cross-linked type charge transport layer, the cross-linked type charge transport layer having a structure unit deriving from a first component, a second component, and a third component, the first component containing a copolymer having a cyclic structure and/or a structure represented by a Chemical structure 1 as a repeating unit, where Ra represents a hydrogen atom or methyl group and Rb represents a straight-chained saturated aliphatic hydrocarbon group having 8 to 34 carbon atoms, the second component containing at least one of a radical polymerizable monomer and a radical polymerizable oligomer without a charge transport structure, and the third component containing one or more kinds of radical polymerizable compounds having a charge transport structure.
    Type: Application
    Filed: December 28, 2010
    Publication date: June 30, 2011
    Inventors: Takafumi Iwamoto, Naohiro Toda
  • Publication number: 20100129112
    Abstract: An electrophotographic photoreceptor, including a charge generation layer and a charge transport layer on an electroconductive substrate, wherein the charge generation layer includes titanylphthalocyanine and a binder resin which is a crosslinked material of a resin comprising a polyvinylbutyral site having the following formula (1) and an isocyanate compound having the following formula (2): wherein R1 and R2 independently represent an alkyl group having 1 to 3 carbon atoms; k, l, m and n represent composition ratios and k+l is from 0.60 to 0.80, wherein k or l may be 0, m is from 0.02 to 0.03, and n is from 0.20 to 0.40; wherein A represents a substituted or unsubstituted organic group having 2 to 4 valences; and O represents an integer of from 2 to 4.
    Type: Application
    Filed: November 25, 2009
    Publication date: May 27, 2010
    Applicant: RICOH COMPANY, LTD.
    Inventors: Hiromi TADA, Naohiro TODA, Yuuji TANAKA, Norio NAGAYAMA, Yoshinori INABA, Takafumi IWAMOTO
  • Publication number: 20090324281
    Abstract: An electrophotographic photoreceptor is provided that contains a conductive substrate, an undercoat layer, a charge generation layer, and a charge transport layer, wherein the under coat layer contains a binder resin and multiple inorganic pigments each having different average primary particle diameters in a total amount of from 75 to 86% by weight, the charge generation layer contains a binder resin and a titanyl phthalocyanine pigment having a specific X-ray diffraction spectrum in an amount of from 70 to 85% by weight, the charge transport layer comprises a specific distyryl compound, and the following formulae (2-1) to (2-3) are satisfied: 0.2?(D(F2)/D(G))?0.5??(2-1) 0.2?D(F1)??(2-2) D(F2)?D(F1)??(2-3) wherein D(F1) (?m) and D(F2) (?m) represent average primary particle diameters of the largest and smallest inorganic pigments, respectively, and D(G) (?m) represents an average primary particle diameter of the titanyl phthalocyanine pigment.
    Type: Application
    Filed: June 23, 2009
    Publication date: December 31, 2009
    Applicant: RICOH COMPANY, LTD.
    Inventors: Hiromi Tada, Nozomu Tamoto, Tomoyuki Shimada, Takafumi Iwamoto
  • Publication number: 20090291302
    Abstract: The present invention provides a nanowire production method that is simpler than conventional nanowire production methods, and that makes it easier to control the size and shape of the nanowires by using a technique completely different from the conventional ones. A powder particle containing a metal element is divided into nanometer-size wires containing the metal element by irradiating a suspension of the powder particles with a femtosecond laser. The present invention also makes it possible to divide the nanometer-size wires thus formed into nanometer-size particles containing the metal element by irradiating further the nanometer-size wires with the femtosecond laser.
    Type: Application
    Filed: June 27, 2006
    Publication date: November 26, 2009
    Applicant: KYOTO UNIVERSITY
    Inventors: Yasuhiko Shimotsuma, Kiyotaka Miura, Kazuyuki Hirao, Mitsuo Kawasaki, Osamu Kajita, Takafumi Iwamoto, Eitaro Yasuda, Shigeyuki Kimura
  • Publication number: 20090185821
    Abstract: An electrophotographic photoreceptor including a conductive substrate; a charge generation layer comprising a metal phthalocyanine pigment as a charge generation material, located overlying the conductive substrate; a charge transport layer comprising a charge transport material having a triarylamine structure, located overlying the charge generation layer; and a cross-linked charge transport layer formed by hardening a radical-polymerizable monomer having no charge transport structure and a radical-polymerizable compound having a charge transport structure, located overlying the charge transport layer. The electrophotographic photoreceptor satisfies the following equations (1) and (2): ?0.16?Ip(T)?Ip(G)?0.07 ??(1) 0.07<Ip(O)?Ip(G)?0.33 ??(2) wherein Ip(G), Ip(T), and Ip(O) represent ionization potentials of the charge generation layer, the charge transport layer, and the cross-linked charge transport layer, respectively.
    Type: Application
    Filed: January 12, 2009
    Publication date: July 23, 2009
    Applicant: RICOH COMPANY, LTD
    Inventors: Takafumi Iwamoto, Nozomu Tamoto, Hiromi Tada
  • Publication number: 20090180788
    Abstract: An image forming apparatus including an image bearing member bearing an electrostatic latent image thereon, a charging device charging the image bearing member, a light irradiating device irradiating the charged image bearing member with light to form the electrostatic latent image, and a developing device developing the electrostatic latent image to form a toner image, wherein the charging time determined by dividing the width of a charging area charged by the charging device in units of mm by the linear velocity of the image bearing member in units of mm/msec is not shorter than the transit time of the image bearing member. The transit time is defined as the time at which an inflection point is firstly observed in a curve showing relationship of the interval between light irradiation and measurement of potential of an irradiated portion with the potential of the irradiated portion, when the interval is shortened.
    Type: Application
    Filed: January 9, 2009
    Publication date: July 16, 2009
    Applicant: RICOH COMPANY, LTD.
    Inventors: Nozomu Tamoto, Hiromi Tada, Takafumi Iwamoto, Yoshinori Inaba
  • Publication number: 20090148180
    Abstract: An image bearing member including an electroconductive substrate, a charge generating layer located overlying the electroconductive substrate, a charge transport layer located overlying the charge generating layer, the charge transport layer comprising a charge transport material and a protective layer having a thickness of from 3 to 15 ?m located overlying the charge transport layer, wherein the density of the charge transport material in the protective layer at depth of 2 ?m from the surface of the charge transport layer satisfies the following relationship: 10(%)?(Charge transport material)/{(Radical polymerizable monomer having a charge transport structure)+(Radical polymerizable monomer having no charge transport structure)+(Charge transport material)}×100?30(%).
    Type: Application
    Filed: July 2, 2008
    Publication date: June 11, 2009
    Inventors: Yukio Fujiwara, Tetsuro Suzuki, Hiroshi Tamura, Hiroshi Ikuno, Hidetoshi Kami, Takafumi Iwamoto
  • Publication number: 20090053523
    Abstract: There is provided a method for efficiently manufacturing metal nano particles without condensing laser beams by using a lens etc. In this method, first, metallic foil pieces, which are a starting material, are dispersed in a dispersion liquid. Next, laser beams are irradiated directly to the metallic foil pieces without providing a condensing means, by which many metal fine particles are yielded. The particle diameters of the metal fine particles obtained can be controlled to sizes from nano particles to submicron particles by utilizing the relationship between the shape (especially thickness) of the metallic foil piece which is a starting material and the absorbed energy of the laser beam.
    Type: Application
    Filed: August 22, 2005
    Publication date: February 26, 2009
    Inventors: Mitsuo Kawasaki, Osamu Kajita, Ayu Onishi, Sachiko Masuoka, Takafumi Iwamoto, Eitaro Yasuda
  • Publication number: 20080311499
    Abstract: An electrophotographic photoreceptor, including an electroconductive substrate; a photosensitive layer, located overlying the electroconductive substrate; and a crosslinked resin surface layer, located overlying the photo sensitive layer, wherein the crosslinked resin surface layer includes a crosslinked body of trimethylolpropanetriacrylate, isocyanate including a radical polymerizable functional group and a heat or a light-curable charge transport material.
    Type: Application
    Filed: June 4, 2008
    Publication date: December 18, 2008
    Applicant: RICOH COMPANY, LTD.
    Inventors: Hidetoshi KAMI, Tetsuro Suzuki, Hiroshi Tamura, Hiroshi Ikuno, Yukio Fujiwara, Takafumi Iwamoto
  • Publication number: 20080227008
    Abstract: An object of the present invention is to provide an electrophotographic photoconductor having an extremely low increase in friction coefficient and wear, while also having superior cleanability even after long-term or large-volume printing, and to provide an electrophotographic apparatus for forming an image using a polymerization toner without providing a unit for externally supplying a lubricant to a photoconductor. Namely, the present invention provides an electrophotographic photoconductor having a photosensitive layer and a crosslinked resin surface layer over a conductive substrate, wherein the crosslinked resin surface layer at least contains trimethylolpropane triacrylate, a dimethylpolysiloxane having a radically polymerizable functional group, and lubricating fine particles.
    Type: Application
    Filed: March 12, 2008
    Publication date: September 18, 2008
    Inventors: Hidetoshi Kami, Tetsuro Suzuki, Hiroshi Tamura, Hiroshi Ikuno, Yukio Fujiwara, Takafumi Iwamoto
  • Publication number: 20080199217
    Abstract: An object is to provide an electrophotographic photoconductor which prevents an increase in the friction coefficient of the photoconductor surface caused when printing takes place for a long period of time or in large amounts, which has sustainability of the low photoconductor surface friction coefficient, low wear properties and high durability, and which is particularly superior in polymerized toner (or spherical toner) cleaning capability; a process cartridge incorporating the electrophotographic photoconductor; and an image forming apparatus incorporating the electrophotographic photoconductor.
    Type: Application
    Filed: February 21, 2008
    Publication date: August 21, 2008
    Inventors: Takafumi IWAMOTO, Tetsuro Suzuki, Hiroshi Tamura, Hiroshi Ikuno, Hidetoshi Kami, Yukio Fujiwara