Patents by Inventor Nozomu Tamoto

Nozomu Tamoto 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: 20100150606
    Abstract: A method of manufacturing an image bearing member including forming a charge generation layer overlying an electroconductive substrate, forming a charge transport layer overlying the charge generation layer, the charge transport layer including a charge transport material having a molecular weight of from 600 to 900 and a binder resin, and forming a protection layer overlying the charge transport layer by applying a liquid application containing a polymerizable compound having a charge transport structure, a polymerizable compound having no charge transport structure, a filler, a polycarboxylic acid compound, and cyclopentanone and curing the polymerizable compound having a charge transport structure, and the polymerizable compound having no charge transport structure.
    Type: Application
    Filed: December 11, 2009
    Publication date: June 17, 2010
    Applicant: RICOH COMPANY, LTD.
    Inventors: Nozomu TAMOTO, Hideo Nakamori, Mitsuaki Hirose
  • Patent number: 7670743
    Abstract: An image is formed by projecting an image by way of an image irradiating device onto an image bearing member configured to operate at a linear velocity of at least 300 mm/sec, and which is constructed of(i) an electroconductive substrate having an image bearing surface that has an established surface charge having an electric field intensity of at least 32.
    Type: Grant
    Filed: January 14, 2008
    Date of Patent: March 2, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Katsuichi Ohta, Tatsuya Niimi, Nozomu Tamoto
  • 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: 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
  • Patent number: 7560203
    Abstract: An electrophotographic photoconductor that is excellent in the stability of image quality and can realize high durability is provided. In an electrophotographic photoconductor in which an underlying layer, a photoconductive layer, and a crosslinked-type charge transportation layer are stacked on an electrically conductive support in order, the underlying layer is composed of at least two layers being a layer containing an inorganic pigment and a layer including no inorganic pigment, and the crosslinked-type charge transportation layer is formed by curing, at least, a three-or-more-functional radical-polymerizable monomer having no charge transporting structure and a radical-polymerizable compound having one-functional charge transporting structure.
    Type: Grant
    Filed: December 1, 2004
    Date of Patent: July 14, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Nozomu Tamoto, Tatsuya Niimi, Tetsuro Suzuki, Katsuichi Ohta
  • Patent number: 7534538
    Abstract: A coating liquid for an intermediate layer of an electrophotographic photoconductor comprises at least one of alcohol solvents; and N-methoxymethylated nylon, in which the N-methoxymethylated nylon has solution viscosity within a range from 43 mPa·s to 50 mPa·s when dissolving into methanol at 30° C. in a concentration of 20% by mass.
    Type: Grant
    Filed: September 7, 2005
    Date of Patent: May 19, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Tatsuya Niimi, Maiko Kondo, Nozomu Tamoto, Katsuichi Ohta
  • Patent number: 7507511
    Abstract: An electrophotographic photoreceptor, including: an electroconductive substrate; a first undercoat layer including no metal oxide, located overlying the electroconductive substrate; a second undercoat layer including a metal oxide and a binder resin, located overlying the first undercoat layer; and a photosensitive layer located overlying the second undercoat layer, wherein the metal oxide included in the second undercoat layer has a specific resistivity not less than 107 ?·cm and a block isocyanate compound.
    Type: Grant
    Filed: January 17, 2006
    Date of Patent: March 24, 2009
    Assignee: Ricoh Company Ltd.
    Inventors: Nozomu Tamoto, Tatsuya Niimi, Maiko Koeda, Tetsuro Suzuki, Takehiko Kinoshita, Suzuka Nozoe, Katsuichi Ohta
  • Publication number: 20090035017
    Abstract: There is provided an electrophotographic photoconductor containing a conductive substrate, and a photosensitive layer, disposed thereon, containing a charge transporting material having a triarylamine structure represented by General Formula 1, and wherein the photosensitive layer satisfies Mathematical Formula 1 when peak heights in raman scattering spectra of the triarylamine structure are measured at a wavenumber of 1,324±2 cm?1 by a confocal raman spectroscopy using z-polarized light: where Ar1, Ar2, and Ar3 are substituted or unsubstituted aromatic hydrocarbon groups, and Ar1 and Ar2, Ar2 and Ar3, and Ar3 and Ar1 are optionally combined to form heterocyclic rings, respectively, ?=I(inside)/I(surface)?1.
    Type: Application
    Filed: September 10, 2007
    Publication date: February 5, 2009
    Inventors: Hiromi TADA, Nozomu TAMOTO, Katsuichi OHTA
  • Publication number: 20080227007
    Abstract: An image forming apparatus including an image bearing member, a charger, an irradiator, and a developing device, wherein the relationships T1?T2 and T2=W/V are satisfied, wherein T1 (msec) represents a real transit time, defined as a value on X-axis of a first flection point, at which a surface potential (Y) of the image bearing member firstly rises up when a time (X) between irradiating the image bearing member and measuring the surface potential of the irradiated portion thereof is shortened, in a graph showing a relationship between X and Y; T2 (msec) represents a charging time; W (mm) represents a charging width of the charger; and V (mm/msec) represents a linear velocity of the image bearing member.
    Type: Application
    Filed: March 7, 2008
    Publication date: September 18, 2008
    Inventors: Nozomu Tamoto, Hiromi Tada, Yoshinori Inaba, Katsuichi Ohta
  • Publication number: 20080145778
    Abstract: An image forming apparatus including an image bearing member to operate at a linear velocity of at least 300 mm/sec, which includes an electroconductive substrate, a charge blocking layer located overlying the electroconductive substrate, a moiré prevention layer located overlying the charge blocking layer, and a photosensitive layer located overlying the moiré prevention layer. The photosensitive layer contains titanyl phthalocyanine having a primary particle diameter of not greater than 0.25 ?m and having a crystal form having a CuK? X ray diffraction spectrum having a wavelength of 1.542 ? such that the maximum diffraction peak is observed at a Bragg (2?) angle of 27.2±0.2°, main peaks are observed at a Bragg (2?) angle of 9.4±0.2°, 9.6±0.2°, and 24.0±0.2°, and a peak is observed at a Bragg (2?) angle of 7.3±0.2° as the lowest angle diffraction peak, while there is no peak between 9.4±0.2° and 7.3±0.2° and there is no peak at 26.3±0.2°).
    Type: Application
    Filed: January 14, 2008
    Publication date: June 19, 2008
    Inventors: Katsuichi Ohta, Tatsuya Niimi, Nozomu Tamoto
  • Patent number: 7381511
    Abstract: A photoreceptor including an electroconductive substrate; a photosensitive layer; and optionally a protective layer, wherein an outermost layer thereof includes a filler, an organic compound having an acid value of from 10 to 700 mg KOH/g and at least one compound selected from the group consisting of compounds having the following formulae (1) and (2): wherein R1 (R3) and R2 (R4) independently represent a substituted or an unsubstituted aromatic hydrocarbon group, or a substituted or an unsubstituted alkyl group, and optionally share bond connectivity to form a heterocyclic group including a nitrogen atom; Ar1 (Ar3) and Ar2 (Ar4) independently represent a substituted or a unsubstituted aromatic ring group; k (K) and m (M) independently represent 0 or an integer of from 1 to 3, wherein k (K) and m (M) are not 0 at the same time; and n (n?) represents an integer of from 1 to 3.
    Type: Grant
    Filed: June 1, 2004
    Date of Patent: June 3, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Takaaki Ikegami, Tomoyuki Shimada, Yasuo Suzuki, Nozomu Tamoto, Hidetoshi Kami, Yuuji Takana
  • Patent number: 7383013
    Abstract: An image forming apparatus of the present invention includes a movable body to be charged and a charger including a charging member that contacts or adjoins the body to be charged and applies a voltage, including an AC component, to the charging member for thereby charging the body. A protection substance for protecting the surface of the body from deterioration ascribable to charging is caused to exist on the body. The number of particular elements, contained in the protection substance and detected by an X-ray photon spectral analyzer (XPS) in a zone where the charging member charges the body, is held in a particular ratio to the total number of all elements constituting the outermost surface of the body and also detected by the XPS.
    Type: Grant
    Filed: June 19, 2007
    Date of Patent: June 3, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiko Watanabe, Kenji Sugiura, Yasushi Nakazato, Kazuhito Watanabe, Masahiko Shakuto, Daichi Yamaguchi, Yasuo Suzuki, Nozomu Tamoto, Hiroshi Nakai, Takahiko Tokumasu, Kohichi Ohshima, Nekka Matsuura
  • Patent number: 7371491
    Abstract: A photoreceptor including an electroconductive substrate; and a charge blocking layer; a moiré preventing layer; and a photosensitive layer, which are overlaid overlying the substrate in this order, wherein the photosensitive layer includes a titanyl phthalocyanine crystal which has an average primary particle diameter not greater than 0.25 ?m, and has an X-ray diffraction spectrum such that a maximum peak is observed at a Bragg (2?) angle of 27.2°±0.2°; a peak is observed at Bragg (2?) angle of 9.4°±0.2°, 9.6±0.2° and 24.0±0.2°; a lowest angle peak is observed at an angle of 7.3°±0.2°; no peak is observed between the lowest angle peak and the 9.4° peak; and no peak is observed at a Bragg (2?) angle of 26.3°±0.2°, when a Cu—K? X-ray having a wavelength of 0.1542 nm (1.542 ?) is used.
    Type: Grant
    Filed: September 20, 2004
    Date of Patent: May 13, 2008
    Assignee: Ricoh Company Limited
    Inventors: Tatsuya Niimi, Nozomu Tamoto, Katsuichi Ohta
  • Patent number: 7371490
    Abstract: The object of the present invention is to provide a photoconductor that is highly sensitive, stable in image quality under repeated usages, and affords prolonged life. In order attain the object, a photoconductor is provided that comprises a charge generating layer, a charge transporting layer, and a crosslinked charge transporting layer, on an substrate in order, the charge generating layer contains titanyl phthalocyanine crystal particles that exhibit a highest peak at 27.2°, main peaks at 9.4°, 9.6° and 24.0°, a peak at 7.3° as the lowest angle, and with no peaks in a range between 7.3° and 9.4°, and with no peak at 26.3° as Bragg 2?angles (±0.2°) in terms of CuK-? characteristic X-ray wavelength at 1.542 ?, and the averaged primary particle size of the titanyl phthalocyanine crystal particles is 0.
    Type: Grant
    Filed: October 28, 2004
    Date of Patent: May 13, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Nozomu Tamoto, Tatsuya Niimi, Tetsuro Suzuki, Katsuichi Ohta
  • Publication number: 20080102391
    Abstract: A method for preparing a photoreceptor including forming a photosensitive layer overlying an electroconductive substrate; coating a liquid including a radically polymerizable compound to form a protective layer; irradiating the protective layer with light to crosslink the protective layer; and then contacting the protective layer with a fluid, which is selected from the group consisting of supercritical fluids and subcritical fluids and which includes a charge transport material. A photoreceptor prepared by the method. An image forming method, an image forming apparatus and a process cartridge using the photoreceptor.
    Type: Application
    Filed: October 29, 2007
    Publication date: May 1, 2008
    Inventors: Yoshiki YANAGAWA, Michio Kimura, Nozomu Tamoto, Hiromi Tada, Tetsuya Toshine, Tomoyuki Shimada, Chiaki Tanaka
  • Publication number: 20080063962
    Abstract: The present invention provides an electrophotographic photoconductor capable of reducing latent electrostatic image stability defects caused by adhesion/adsorption of an electric discharge product formed by a charger in an image forming process, degradation of charge transportability and cleaning defects caused when removing a residual toner.
    Type: Application
    Filed: September 5, 2007
    Publication date: March 13, 2008
    Inventors: Tetsuya TOSHINE, Chiaki Tanaka, Michio Kimura, Tomoyuki Shimada, Nozomu Tamoto, Yoshiki Yanagawa, Hiromi Tada
  • 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
  • Publication number: 20070242992
    Abstract: An image forming apparatus of the present invention includes a movable body to be charged and a charger including a charging member that contacts or adjoins the body to be charged and applies a voltage, including an AC component, to the charging member for thereby charging the body. A protection substance for protecting the surface of the body from deterioration ascribable to charging is caused to exist on the body. The number of particular elements, contained in the protection substance and detected by an X-ray photon spectral analyzer (XPS) in a zone where the charging member charges the body, is held in a particular ratio to the total number of all elements constituting the outermost surface of the body and also detected by the XPS.
    Type: Application
    Filed: June 19, 2007
    Publication date: October 18, 2007
    Inventors: Kazuhiko Watanabe, Kenji Sugiura, Yasushi Nakazato, Kazuhito Watanabe, Masahiko Shakuto, Daichi Yamaguchi, Yasuo Suzuki, Nozomu Tamoto, Hiroshi Nakai, Takahiko Tokumasu, Kohichi Ohshima, Nekka Matsuura
  • Patent number: 7282529
    Abstract: An electrophotographic photoreceptor including an electroconductive substrate, a photosensitive layer located overlying the electroconductive substrate, and optionally a protective layer overlying the photosensitive layer, wherein an outermost layer of the photoreceptor includes a filler, a binder resin and an organic compound having an acid value of from 10 to 700 mgKOH/g. The photosensitive layer can be the outermost layer. A coating liquid for an outermost layer of a photoreceptor including a filler, a binder resin, an organic compound having an acid value of from 10 to 700 mgKOH/g and plural organic solvents. A method for preparing a photoreceptor including forming a photosensitive layer, and coating the coating liquid on the photosensitive layer. An image forming method and apparatus and a process cartridge using the photoreceptor are also provided.
    Type: Grant
    Filed: July 24, 2003
    Date of Patent: October 16, 2007
    Assignee: Ricoh Company Limited
    Inventors: Nozomu Tamoto, Tetsuro Suzuki, Hiroshi Tamura, Tatsuya Niimi, Akihiko Matsuyama, Eiji Kurimoto, Hidetoshi Kami