Patents by Inventor Kohichi Ohshima

Kohichi Ohshima 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: 8543037
    Abstract: The image forming apparatus includes a photoreceptor bearing an electrostatic image; a developing device developing the electrostatic image with a developer including a toner to form a toner image on the photoreceptor; a transferring device transferring the toner image onto a receiving material; and a cleaning device having a cleaning blade cleaning the surface of the photoreceptor. The photoreceptor includes an electroconductive substrate, a photosensitive layer and an outermost layer having projected portions thereon. The outermost layer and projected portions include the same crosslinked charge transport material. The outermost layer has a surface roughness property such that the number of projected portions having height greater than Rz/2 is from 40 to 90 in a length of 12 mm, wherein Rz represents ten-point mean roughness of the outermost layer. The tip of the cleaning blade is contacted with the photoreceptor at a linear pressure of from 80 g/cm to 150 g/cm.
    Type: Grant
    Filed: November 2, 2009
    Date of Patent: September 24, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiro Egawa, Yukio Fujiwara, Hidetoshi Kami, Kohichi Ohshima
  • Patent number: 8420284
    Abstract: An electrophotographic photoreceptor, including an electroconductive substrate; a photosensitive layer, located overlying the electroconductive substrate; and an outermost layer comprising a convexity, wherein each of the outermost layer and the convexity includes a crosslinked body including a structural unit having a same charge transportable structure, and wherein the number of convexity having a height not less than ½×RzJIS is from 30 to 300 in a measurement length of 12 mm, wherein RzJIS is an average of ten-point mean roughness specified in JIS B0601 of 2001 and measured at least 4 random positions in an area the outermost layer is formed on, and wherein the height of the convexity is a distance from the deepest valley to a top of the convexity in the measurement length of 12 mm.
    Type: Grant
    Filed: December 18, 2009
    Date of Patent: April 16, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohichi Ohshima, Hidetoshi Kami, Yukio Fujiwara, Kazuhiro Egawa
  • Patent number: 7862969
    Abstract: The present invention provides an image bearing member that includes: a photoconductor; and a heating unit which heats the photoconductor, wherein the photoconductor includes: a support; a charge generating layer on the support, a charge transport layer, and a crosslinked charge transport layer in this order, wherein the crosslinked charge transport layer includes a reaction product of a radically polymerizable compound with three or more functional groups which does not have a charge transporting structure, and a radically polymerizable compound with one functional group, which compound has a charge transporting structure.
    Type: Grant
    Filed: January 10, 2007
    Date of Patent: January 4, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasuo Suzuki, Kohichi Ohshima, Tetsuro Suzuki, Michitaka Sasaki
  • Publication number: 20100172670
    Abstract: An electrophotographic photoreceptor, including an electroconductive substrate; a photosensitive layer, located overlying the electroconductive substrate; and an outermost layer comprising a convexity, wherein each of the outermost layer and the convexity includes a crosslinked body including a structural unit having a same charge transportable structure, and wherein the number of convexity having a height not less than ½×RzJIS is from 30 to 300 in a measurement length of 12 mm, wherein RzJIS is an average of ten-point mean roughness specified in JIS B0601 of 2001 and measured at least 4 random positions in an area the outermost layer is formed on, and wherein the height of the convexity is a distance from the deepest valley to a top of the convexity in the measurement length of 12 mm.
    Type: Application
    Filed: December 18, 2009
    Publication date: July 8, 2010
    Applicant: RICOH COMPANY, LTD.
    Inventors: Kohichi OHSHIMA, Hidetoshi Kami, Yukio Fujiwara, Kazuhiro Egawa
  • Publication number: 20100124712
    Abstract: The image forming apparatus includes a photoreceptor bearing an electrostatic image; a developing device developing the electrostatic image with a developer including a toner to form a toner image on the photoreceptor; a transferring device transferring the toner image onto a receiving material; and a cleaning device having a cleaning blade cleaning the surface of the photoreceptor. The photoreceptor includes an electroconductive substrate, a photosensitive layer and an outermost layer having projected portions thereon. The outermost layer and projected portions include the same crosslinked charge transport material. The outermost layer has a surface roughness property such that the number of projected portions having height greater than Rz/2 is from 40 to 90 in a length of 12 mm, wherein Rz represents ten-point mean roughness of the outermost layer. The tip of the cleaning blade is contacted with the photoreceptor at a linear pressure of from 80 g/cm to 150 g/cm.
    Type: Application
    Filed: November 2, 2009
    Publication date: May 20, 2010
    Applicant: RICOH COMPANY, LTD.
    Inventors: Kazuhiro EGAWA, Yukio Fujiwara, Hidetoshi Kami, Kohichi Ohshima
  • Patent number: 7662533
    Abstract: An image forming method including: forming an electrostatic latent image on an image bearing member; developing the latent image with a toner; transferring the toner image onto a receiving material; and fixing the toner image. The image bearing member includes a substrate, and a charge generation layer, a charge transport layer and a crosslinked charge transport layer, wherein the crosslinked charge transport layer includes a compound obtained from radical polymerizable monomers including a monomer having three or more functional groups and no charge transport structure and a monomer having one functional group and a charge transport structure. The toner includes a binder resin, a colorant, and a release agent, wherein tetrahydrofuran-soluble components of the binder resin have a molecular weight distribution such that at least one peak is observed in a range of from 1,000 to 10,000 and the half-width of the molecular weight distribution curve is not greater than 15,000.
    Type: Grant
    Filed: June 24, 2005
    Date of Patent: February 16, 2010
    Assignee: Ricoh Company Limited
    Inventors: Kohichi Ohshima, Yasuo Suzuki, Tetsuro Suzuki, Michitaka Sasaki
  • Patent number: 7550238
    Abstract: An image forming process using an electrostatic latent image carrier containing a support and a photoconductive layer including: a charge generating layer, a charge transportable layer, and a cross-linked charge transportable layer which are disposed on the support in this order and the cross-linked charge transportable layer comprises a compound produced by the reaction between a trifunctional or more functional radical-polymerizable compound having no charge transportable structure, and a monofunctional radical-polymerizable compound having a charge transportable structure, and a toner produced in the form of particles by producing an adhesive base material through reacting a compound having an active hydrogen group with a polymer which can be reacted with the above-noted compound having an active hydrogen group in an aqueous medium.
    Type: Grant
    Filed: April 21, 2005
    Date of Patent: June 23, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Kohichi Ohshima, Yasuo Suzuki, Tetsuro Suzuki, Michitaka Sasaki
  • Patent number: 7517625
    Abstract: An image forming apparatus including: an electrophotographic photoreceptor; a non-contact charger located close to the electrophotographic photoreceptor, charging the electrophotographic photoreceptor; an irradiator irradiating the electrophotographic photoreceptor to form an electrostatic latent image thereon; an image developer developing the electrostatic latent image with a toner to form a toner image on the electrophotographic photoreceptor; and a transferer transferring the toner image onto a transfer material, wherein the electrophotographic photoreceptor comprises: an electroconductive substrate; a charge generation layer located overlying the electroconductive substrate; a charge transport layer located overlying the charge generation layer; and a crosslinked charge transport layer, located overlying the charge transport layer, wherein the crosslinked charge transport layer is formed by hardening a radical polymeric monomer having three or more functional groups without a charge transport structu
    Type: Grant
    Filed: September 6, 2005
    Date of Patent: April 14, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasuo Suzuki, Michitaka Sasaki, Tetsuro Suzuki, Kohichi Ohshima
  • 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: 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
  • Publication number: 20070212625
    Abstract: The present invention provides an image bearing member that includes: a photoconductor; and a heating unit which heats the photoconductor, wherein the photoconductor includes: a support; a charge generating layer on the support, a charge transport layer, and a crosslinked charge transport layer in this order, wherein the crosslinked charge transport layer includes a reaction product of a radically polymerizable compound with three or more functional groups which does not have a charge transporting structure, and a radically polymerizable compound with one functional group, which compound has a charge transporting structure.
    Type: Application
    Filed: January 10, 2007
    Publication date: September 13, 2007
    Inventors: Yasuo Suzuki, Kohichi Ohshima, Tetsuro Suzuki, Michitaka Sasaki
  • Patent number: 7251437
    Abstract: An image formation apparatus including at least a moving body to be charged, a charging device for charging the body to be charged using discharge caused by applying a voltage to a charging member provided in contact with or proximity to the body to be charged, a latent image formation device for forming a latent image on a surface of the body to be charged which is charged by the charging device, and a development device for depositing toner on an image portion of the latent image formed by the latent image formation device, wherein an elastic displacement ratio ?e for the surface of the body to be charged is equal to or greater than 40% which is defined by the following formula, elastic displacement ratio ?e (%)=[(maximum displacement)-(plastic displacement)]/(maximum displacement)×100, and the image formation apparatus further includes a protective material feeding device for depositing a protective material on at least a discharge area of the surface of the body to be charged.
    Type: Grant
    Filed: March 1, 2005
    Date of Patent: July 31, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Nozomu Tamoto, Tetsuro Suzuki, Yasuo Suzuki, Takahiko Tokumasu, Kazuhiko Watanabe, Hiroshi Nakai, Kohichi Ohshima, Noboru Tsukude, Nekka Matsuura
  • Patent number: 7251438
    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: May 11, 2006
    Date of Patent: July 31, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiko Watanabe, Kazuhito Watanabe, Yasuo Suzuki, Nozomu Tamoto, Hiroshi Nakai, Takahiko Tokumasu, Kohichi Ohshima
  • Publication number: 20060204259
    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: May 11, 2006
    Publication date: September 14, 2006
    Inventors: Kazuhiko Watanabe, Kazuhito Watanabe, Yasuo Suzuki, Nozomu Tamoto, Hiroshi Nakai, Takahiko Tokumasu, Kohichi Ohshima
  • Patent number: 7103301
    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: February 3, 2004
    Date of Patent: September 5, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Kazuhiko Watanabe, Kazuhito Watanabe, Yasuo Suzuki, Nozomu Tamoto, Hiroshi Nakai, Takahiko Tokumasu, Kohichi Ohshima, Nekka Matsuura
  • Publication number: 20060093955
    Abstract: An image forming method including forming a toner image on an image bearing member; transferring the toner image onto a receiving material; and then cleaning the surface of the image bearing member with a cleaning member while applying a voltage to the cleaning member such that the cleaning member electrostatically attracts toner particles remaining on the image bearing member, wherein the image bearing member has, as an outermost layer, a crosslinked charge transport layer comprising a crosslinked resin including at least one unit obtained from at least one radical polymerizable polyfunctional monomer having three or more radical polymerizable functional groups and no charge transport structure, and a unit obtained from a radical polymerizable functional monomer having one or more radical polymerizable functional groups and a charge transport structure. An image forming apparatus and a process cartridge using the image forming method are also provided.
    Type: Application
    Filed: October 31, 2005
    Publication date: May 4, 2006
    Inventors: Kohichi Ohshima, Yasuo Suzuki, Tetsuro Suzuki, Michitaka Sasaki
  • Publication number: 20060068308
    Abstract: An image forming process is provided, which is consisting of forming step for forming a latent electrostatic image on a photoconductor, developing step, transferring step, and fixing step, wherein the photoconductor contains the crosslinked charge transporting layer containing a cured product formed from at least a radical polymerizable compound having three or more functionalities and no charge transport structure, and a radical polymerizable compound having one functionality and a charge transport structure, wherein the developer includes a toner and a carrier, the carrier has core particles and a coating layer for coating the core particles, the content of the core particles having a particle diameter of smaller than 44 ?m in the carrier is 70% by mass or more, and the content of the core particles having a particle diameter of smaller than 22 ?m in the carrier is 7% by mass or less, a mass average particle diameter of the carrier (Dw) is 25 ?m to 45 ?m, and a ratio (Dw/Dp) of Dw to a number average partic
    Type: Application
    Filed: September 20, 2005
    Publication date: March 30, 2006
    Inventors: Kohichi Ohshima, Yasuo Suzuki, Tetsuro Suzuki, Michitaka Sasaki
  • Publication number: 20060051689
    Abstract: An image forming apparatus including: an electrophotographic photoreceptor; a non-contact charger located close to the electrophotographic photoreceptor, charging the electrophotographic photoreceptor; an irradiator irradiating the electrophotographic photoreceptor to form an electrostatic latent image thereon; an image developer developing the electrostatic latent image with a toner to form a toner image on the electrophotographic photoreceptor; and a transferer transferring the toner image onto a transfer material, wherein the electrophotographic photoreceptor comprises: an electroconductive substrate; a charge generation layer located overlying the electroconductive substrate; a charge transport layer located overlying the charge generation layer; and a crosslinked charge transport layer, located overlying the charge transport layer, wherein the crosslinked charge transport layer is formed by hardening a radical polymeric monomer having three or more functional groups without a charge transport structure a
    Type: Application
    Filed: September 6, 2005
    Publication date: March 9, 2006
    Inventors: Yasuo Suzuki, Michitaka Sasaki, Tetsuro Suzuki, Kohichi Ohshima
  • Publication number: 20060014096
    Abstract: An image forming method including: charging an electrophotographic photoreceptor including: an electroconductive substrate; and a photosensitive layer comprising a crosslinked surface layer on a surface thereof, which is located overlying the electroconductive substrate, irradiating the electrophotographic photoreceptor with imagewise light to form an electrostatic latent image thereon; developing the electrostatic latent image with a toner to form a toner image on the electrophotographic photoreceptor; transferring the toner image onto a transfer material; and fixing the toner image on the transfer material, wherein the photosensitive layer is sensitive to light having a wavelength of from 400 to 450 nm, and the crosslinked surface layer is formed by crosslinking and hardening a radical polymerizing monomer having three or more functional groups without a charge transport structure and a radical polymerizing compound having one functional group with charge transport structure.
    Type: Application
    Filed: June 27, 2005
    Publication date: January 19, 2006
    Inventors: Kohichi Ohshima, Yasuo Suzuki, Tetsuro Suzuki, Michitaka Sasaki