Patents by Inventor Masataka Kawahara

Masataka Kawahara 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: 7749667
    Abstract: An image forming method is disclosed having a charging step, an exposure step, a developing step and a transfer step. This method uses a toner which includes toner particles containing a binder resin and a colorant, and inorganic fine powder, and uses a photosensitive member which has on its surface depressed portions which are independent of one another. The depressed portions have openings having an average minor-axis diameter Lpc satisfying the relationship of Dg<Lpc<Dt (Dt represents the weight-average particle diameter of the toner, and Dg represents the maximum number-average particle diameter among number-average particle diameter(s) of one or two or more types of inorganic fine powder constituting the inorganic fine powder, and the toner has an average circularity of from 0.925 to 0.995.
    Type: Grant
    Filed: June 28, 2007
    Date of Patent: July 6, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masataka Kawahara, Hiroki Uematsu, Akio Maruyama, Harunobu Ogaki, Atsushi Ochi, Akira Shimada, Kyoichi Teramoto, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Patent number: 7718331
    Abstract: An electrophotographic photosensitive member is disclosed which is excellent in cleaning performance, has improved durability, and suppresses image defects in various environments. The electrophotographic photosensitive member has a support and a photosensitive layer provided on the support. Depressed portions independent of one another are formed on the surface of the electrophotographic photosensitive member so that the number of the depressed portions per 100 ?m square is 76 or more and 1,000 or less. The openings of the depressed portions have an average major axis diameter of more than 3.0 ?m and 14.0 ?m or less.
    Type: Grant
    Filed: June 28, 2007
    Date of Patent: May 18, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hiroki Uematsu, Harunobu Ogaki, Masataka Kawahara, Atsushi Ochi, Akira Shimada, Akio Maruyama, Kyoichi Teramoto, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Patent number: 7629102
    Abstract: A method for preparing in high productivity and stably an electrophotographic photosensitive member having depressed portions on its surface, is provided. The method is characterized in that a coating liquid for a surface layer which includes a solvent including a hydrophilic solvent and a hydrophobic solvent and a polymer compound soluble in the hydrophobic solvent is used; the hydrophilic solvent has a boiling point equal to or higher than that of the hydrophobic solvent; the hydrophilic solvent has a dipole moment of 0 or more and less than 2.8, obtained by a structure optimized calculation using a semiempirical molecular orbital calculation; the total mass of the hydrophobic solvent is 50 mass % or more and less than 100 mass % of the total mass of the solvent included in the coating liquid for a surface layer; and after the coating liquid for a surface layer is applied, the depressed portions are formed by condensation on the surface on which the coating liquid for a surface layer is applied.
    Type: Grant
    Filed: February 4, 2008
    Date of Patent: December 8, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Atsushi Ochi, Harunobu Ogaki, Kazunori Noguchi, Hiroki Uematsu, Masataka Kawahara
  • Patent number: 7622238
    Abstract: A process for producing an electrophotographic photosensitive member, which has the step of bringing i) the surface of an electrophotographic photosensitive member having at least a charge transport layer on a cylindrical support and ii) a mold having a fine unevenness surface profile into pressure contact with each other to transfer the fine unevenness surface profile to the surface of the electrophotographic photosensitive member. The mold and the support are so temperature-controlled as to be T3<T1<T2 where the glass transition temperature of the charge transport layer is represented by T1 (°C.), the temperature of the mold by T2 (°C.), and the temperature of the support by T3 (°C.).
    Type: Grant
    Filed: June 28, 2007
    Date of Patent: November 24, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hiroki Uematsu, Akira Shimada, Masataka Kawahara, Harunobu Ogaki, Atsushi Ochi, Akio Maruyama, Kyoichi Teramoto, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Patent number: 7556901
    Abstract: An electrophotographic photosensitive member has a surface having a plurality of depressed portions, having a major-axis diameter Rpc of 0.1 to 10 ?m, a minor-axis diameter Lpc of 0.1 to 10 ?m and a deepest-part to opening distance Rdv of 0.1 to 10 ?m. Where the surface is equally divided into 4 regions in the rotational direction, which are then equally divided into 25 regions in the direction falling at right angles with the rotational direction, to obtain 100-spot regions A in total, and, in each thereof, square regions B of 50 ?m each per side one side of which is parallel to the rotational direction are provided and the regions B are each equally divided into 500 zones by straight lines parallel to the rotational direction, 400 to 499 lines among the straight lines pass through the depressed portions in each of the regions B.
    Type: Grant
    Filed: June 28, 2007
    Date of Patent: July 7, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takashi Anezaki, Harunobu Ogaki, Hiroki Uematsu, Masataka Kawahara, Atsushi Ochi, Kyoichi Teramoto, Akira Shimada, Akio Maruyama, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida, Hirotoshi Uesugi
  • Publication number: 20090170023
    Abstract: A process for producing an electrophotographic photosensitive member. The electrophotographic photosensitive member includes a conductive support and a surface layer provided thereon containing at least a resin. The process has the step of forming a plurality of depressed portions on the surface layer by irradiation with laser light having a wavelength of 400 nm or less and having an output characteristic of a pulse width of 100 ns or less.
    Type: Application
    Filed: February 19, 2009
    Publication date: July 2, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Akira Shimada, Hiroki Uematsu, Masataka Kawahara, Kyoichi Teramoto, Akio Maruyama, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Patent number: 7551878
    Abstract: An electrophotographic photosensitive member has, on the surface of its photosensitive layer, has a plurality of depressed portions which are independent from one another, and, where the major-axis diameter of each depressed portion is represented by Rpc and the depth that shows the distance between the deepest part of each depressed portion and the opening thereof is represented by Rdv, the depressed portions each have a ratio of depth to major-axis diameter, Rdv/Rpc, of from more than 1.0 to 7.0 or less.
    Type: Grant
    Filed: June 28, 2007
    Date of Patent: June 23, 2009
    Assignee: Canon Kabushiki Kaisha
    Inventors: Harunobu Ogaki, Hiroki Uematsu, Masataka Kawahara, Atsushi Ochi, Kyoichi Teramoto, Akira Shimada, Akio Maruyama, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Publication number: 20090123176
    Abstract: The present invention relates to a polyvinyl acetal resin having a specific repeating structural unit, an electrophotographic photosensitive member using the polyvinyl acetal resin, and a process cartridge and an electrophotographic apparatus each having the electrophotographic photosensitive member.
    Type: Application
    Filed: December 5, 2006
    Publication date: May 14, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Masato Tanaka, Atsushi Fujii, Yuka Ishiduka, Masataka Kawahara, Masaki Nonaka
  • Publication number: 20090023091
    Abstract: A method for preparing in high productivity and stably an electrophotographic photosensitive member having depressed portions on its surface, is provided. The method is characterized in that a coating liquid for a surface layer which includes a solvent including a hydrophilic solvent and a hydrophobic solvent and a polymer compound soluble in the hydrophobic solvent is used; the hydrophilic solvent has a boiling point equal to or higher than that of the hydrophobic solvent; the hydrophilic solvent has a dipole moment of 0 or more and less than 2.8, obtained by a structure optimized calculation using a semiempirical molecular orbital calculation; the total mass of the hydrophobic solvent is 50 mass % or more and less than 100 mass % of the total mass of the solvent included in the coating liquid for a surface layer; and after the coating liquid for a surface layer is applied, the depressed portions are formed by condensation on the surface on which the coating liquid for a surface layer is applied.
    Type: Application
    Filed: February 4, 2008
    Publication date: January 22, 2009
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Atsushi Ochi, Harunobu Ogaki, Kazunori Noguchi, Hiroki Uematsu, Masataka Kawahara
  • Patent number: 7452644
    Abstract: An electrophotographic photosensitive member capable of outputting an image in which a defect such as a ghost is suppressed even in a high-temperature-and-high-humidity environment, and in which a defect such as a change in density due to an abrupt change in light-area potential at an initial stage or a ghost due to long-term durable use is suppressed even in a low-humidity environment; and a process cartridge and an electrophotographic apparatus each having the electrophotographic photosensitive member; are provided. The electrophotographic photosensitive member has a layer which comprises a compound having a specific structure between a support and a charge-generating layer.
    Type: Grant
    Filed: February 22, 2006
    Date of Patent: November 18, 2008
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masato Tanaka, Masataka Kawahara, Atsushi Fujii, Yuka Ishizuka
  • Publication number: 20080124637
    Abstract: An electrophotographic photosensitive member is disclosed which is excellent in cleaning performance, has improved durability, and suppresses image defects in various environments. The electrophotographic photosensitive member has a support and a photosensitive layer provided on the support. Depressed portions independent of one another are formed on the surface of the electrophotographic photosensitive member so that the number of the depressed portions per 100 ?m square is 76 or more and 1,000 or less. The openings of the depressed portions have an average major axis diameter of more than 3.0 ?m and 14.0 ?m or less.
    Type: Application
    Filed: June 28, 2007
    Publication date: May 29, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Hiroki Uematsu, Harunobu Ogaki, Masataka Kawahara, Atsushi Ochi, Akira Shimada, Akio Maruyama, Kyoichi Teramoto, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Publication number: 20080124126
    Abstract: An electrophotographic photosensitive member has a surface having a plurality of depressed portions, having a major-axis diameter Rpc of 0.1 to 10 ?m, a minor-axis diameter Lpc of 0.1 to 10 ?m and a deepest-part to opening distance Rdv of 0.1 to 10 ?m. Where the surface is equally divided into 4 regions in the rotational direction, which are then equally divided into 25 regions in the direction falling at right angles with the rotational direction, to obtain 100-spot regions A in total, and, in each thereof, square regions B of 50 ?m each per side one side of which is parallel to the rotational direction are provided and the regions B are each equally divided into 500 zones by straight lines parallel to the rotational direction, 400 to 499 lines among the straight lines pass through the depressed portions in each of the regions B.
    Type: Application
    Filed: June 28, 2007
    Publication date: May 29, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Takashi Anezaki, Harunobu Ogaki, Hiroki Uematsu, Masataka Kawahara, Atsushi Ochi, Kyoichi Teramoto, Akira Shimada, Akio Maruyama, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida, Hirotoshi Uesugi
  • Publication number: 20080096123
    Abstract: A process for producing an electrophotographic photosensitive member is disclosed. The electrophotographic photosensitive member includes a conductive support and a surface layer provided thereon containing at least a resin. The process has the step of forming a plurality of depressed portions on the surface layer by irradiation with laser light having a wavelength of 400 nm or less and having an output characteristic of a pulse width of 100 ns or less.
    Type: Application
    Filed: June 28, 2007
    Publication date: April 24, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Akira Shimada, Hiroki Uematsu, Masataka Kawahara, Kyoichi Teramoto, Akio Maruyama, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Patent number: 7333752
    Abstract: An electrophotographic apparatus is disclosed using an electrophotographic photosensitive member which employs light with a short wavelength (380 nm to 500 nm) as image exposure light and is good in photoelectric conversion efficiency on the whole at that wavelength. The electrophotographic photosensitive member is composed of a reflecting layer, a charge generation layer and a charge transport layer formed on a support. The total reflectance and specular reflectance of the reflecting layer are 30% or more (with respect to a standard white board) and less than 15%, respectively, at that short-wavelength light. The absorbance of the charge generation layer is 1.0 or less at that short-wavelength light.
    Type: Grant
    Filed: July 7, 2006
    Date of Patent: February 19, 2008
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masataka Kawahara, Masato Tanaka, Atsushi Fujii, Yuka Ishizuka, Masaki Nonaka
  • Publication number: 20080019735
    Abstract: An electrophotographic photosensitive member has, on the surface of its photosensitive layer, has a plurality of depressed portions which are independent from one another, and, where the major-axis diameter of each depressed portion is represented by Rpc and the depth that shows the distance between the deepest part of each depressed portion and the opening thereof is represented by Rdv, the depressed portions each have a ratio of depth to major-axis diameter, Rdv/Rpc, of from more than 1.0 to 7.0 or less.
    Type: Application
    Filed: June 28, 2007
    Publication date: January 24, 2008
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Harunobu Ogaki, Hiroki Uematsu, Masataka Kawahara, Atsushi Ochi, Kyoichi Teramoto, Akira Shimada, Akio Maruyama, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Publication number: 20070281239
    Abstract: A process for producing an electrophotographic photosensitive member, which has the step of bringing i) the surface of an electrophotographic photosensitive member having at least a charge transport layer on a cylindrical support and ii) a mold having a fine unevenness surface profile into pressure contact with each other to transfer the fine unevenness surface profile to the surface of the electrophotographic photosensitive member. The mold and the support are so temperature-controlled as to be T3<T1<T2 where the glass transition temperature of the charge transport layer is represented by T1 (° C.), the temperature of the mold by T2 (° C.), and the temperature of the support by T3 (° C.).
    Type: Application
    Filed: June 28, 2007
    Publication date: December 6, 2007
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Hiroki Uematsu, Akira Shimada, Masataka Kawahara, Harunobu Ogaki, Atsushi Ochi, Akio Maruyama, Kyoichi Teramoto, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Publication number: 20070254232
    Abstract: An image forming method is disclosed having a charging step, an exposure step, a developing step and a transfer step. This method uses a toner which includes toner particles containing a binder resin and a colorant, and inorganic fine powder, and uses a photosensitive member which has on its surface depressed portions which are independent of one another. The depressed portions have openings having an average minor-axis diameter Lpc satisfying the relationship of Dg<Lpc<Dt (Dt represents the weight-average particle diameter of the toner, and Dg represents the maximum number-average particle diameter among number-average particle diameter(s) of one or two or more types of inorganic fine powder constituting the inorganic fine powder, and the toner has an average circularity of from 0.925 to 0.995.
    Type: Application
    Filed: June 28, 2007
    Publication date: November 1, 2007
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Masataka Kawahara, Hiroki Uematsu, Akio Maruyama, Harunobu Ogaki, Atsushi Ochi, Akira Shimada, Kyoichi Teramoto, Toshihiro Kikuchi, Akio Koganei, Takayuki Sumida
  • Patent number: 7160659
    Abstract: An electrophotographic apparatus adopts a contact development system as a development system, which hardly causes toner fusion, and which hardly causes fogging in an output image; and a process cartridge is detachably attached to a main body of the electrophotographic apparatus. Specifically, provided are: an electrophotographic apparatus equipped with an electrophotographic photoreceptor having a surface layer containing a diorganopolysiloxane having a specific repeating structural unit; and a process cartridge that is detachably attached to a main body of the electrophotographic apparatus.
    Type: Grant
    Filed: April 20, 2005
    Date of Patent: January 9, 2007
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hirotoshi Uesugi, Akira Yoshida, Kazushige Nakamura, Masataka Kawahara
  • Publication number: 20070003851
    Abstract: An electrophotographic apparatus is disclosed using an electrophotographic photosensitive member which employs light with a short wavelength (380 nm to 500 nm) as image exposure light and is good in photoelectric conversion efficiency on the whole at that wavelength. The electrophotographic photosensitive member is composed of a reflecting layer, a charge generation layer and a charge transport layer formed on a support. The total reflectance and specular reflectance of the reflecting layer are 30% or more (with respect to a standard white board) and less than 15%, respectively, at that short-wavelength light. The absorbance of the charge generation layer is 1.0 or less at that short-wavelength light.
    Type: Application
    Filed: July 7, 2006
    Publication date: January 4, 2007
    Applicant: CANON KABUSHIKI KAISHA
    Inventors: Masataka Kawahara, Masato Tanaka, Atsushi Fujii, Yuka Ishizuka, Masaki Nonaka
  • Patent number: 7097950
    Abstract: An electrophotographic photosensitive member capable of outputting an image in which a defect such as a ghost is suppressed even in a high-temperature-and-high-humidity environment, and in which a defect such as a change in density due to an abrupt change in light-area potential at an initial stage or a ghost due to long-term durable use is suppressed even in a low-humidity environment; and a process cartridge and an electrophotographic apparatus each having the electrophotographic photosensitive member; are provided. The electrophotographic photosensitive member has a layer which comprises a compound having a specific structure between a support and a charge-generating layer.
    Type: Grant
    Filed: June 14, 2005
    Date of Patent: August 29, 2006
    Assignee: Canon Kabushiki Kaisha
    Inventors: Masato Tanaka, Masataka Kawahara, Atsushi Fujii, Yuka Ishizuka