Patents by Inventor Naohiro Kumagai

Naohiro Kumagai 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: 20060177239
    Abstract: An imaging apparatus that is capable of realizing good cleaning characteristics and transfer characteristics, and obtaining a high quality image using toner having a high average roundness is provided. The imaging apparatus includes an image carrier, a charge unit, a developing unit, a transfer unit, and a cleaning unit. The transfer unit may directly transfer a toner image onto a recording medium that is carried by a transfer belt, or transfer the toner image onto the transfer belt first to then transfer the toner image onto the recording medium from the transfer belt. The cleaning unit includes a cleaning blade and a brush roller. The toner used in the imaging apparatus has an average roundness ? within a range of 0.93˜0.99, and a friction coefficient ?s of the image carrier satisfies a condition, friction coefficient ?s?3.6?3.3×average roundness ?.
    Type: Application
    Filed: March 17, 2006
    Publication date: August 10, 2006
    Inventors: Toshio Koike, Eisaku Murakami, Masato Yanagida, Takeshi Shintani, Naohiro Kumagai, Atsushi Sampe, Masami Tomita, Hiroyuki Nagashima, Masanori Kawasumi, Takeshi Uchitani
  • Patent number: 7085528
    Abstract: A cleaning unit cleans residual toner on the surface of a rotatable image carrier. The cleaning unit includes a cleaning blade that is in contact with the image carrier in such a manner that amplitude of a waveform at an edge of the cleaning blade is not greater than 40 ?m with respect to a downstream side of a direction of movement of the image carrier.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: August 1, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Takeshi Shintani, Naohiro Kumagai, Masato Yanagida, Toshio Koike, Eisaku Murakami, Masanori Kawasumi, Atsushi Sampe, Masami Tomita
  • Publication number: 20060165431
    Abstract: A charging device including a charging roller having a metal cylinder and an elastic layer located thereon, and a cleaner for cleaning the surface of the charging roller. The cleaner includes a driving shaft and a cleaning roller which is rotatably mounted on the driving shaft. The cleaning roller is made of a non-cellular foam resin having a density of from 5 to 15 kg/m3 and a tensile strength of from 1.2 to 2.2 kg/cm2.
    Type: Application
    Filed: March 30, 2006
    Publication date: July 27, 2006
    Inventors: Masato Yanagida, Hiroyuki Nagashima, Naohiro Kumagai, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Eisaku Murakami, Takeshi Uchitani, Masami Tomita, Takeshi Shintani, Tsutomu Yamakami
  • Patent number: 7065316
    Abstract: A cleaning unit is equipped with a cleaning blade that is in contact with a surface of a photosensitive drum and cleans the surface. A peak temperature of a loss tangent (tan ?) is in a range of 2° C. to ?30° C. when a sine-wave vibration of 10 Hz is applied to the cleaning blade. Moreover, the cleaning unit lowers a coefficient of static friction of the surface of the photosensitive drum that is to be cleaned.
    Type: Grant
    Filed: September 24, 2003
    Date of Patent: June 20, 2006
    Assignee: Ricoh Company, Limited
    Inventors: Masato Yanagida, Atsushi Sampe, Naohiro Kumagai, Toshio Koike, Takeshi Shintani, Masanori Kawasumi, Masami Tomita, Eisaku Murakami, Takeshi Uchitani
  • Patent number: 7062194
    Abstract: A charging device including a charging roller having a metallic cylinder with an elastic layer disposed thereon, and a cleaner for cleaning the surface of the charging roller. The cleaner includes a driving shaft and a cleaning roller rotatably mounted on the driving shaft. The cleaning roller is made of a non-cellular foam resin having a density of from 5 to 15 kg/m3 and a tensile strength of from 1.2 to 2.2 kg/cm2.
    Type: Grant
    Filed: May 12, 2004
    Date of Patent: June 13, 2006
    Assignee: Ricoh Company Limited
    Inventors: Masato Yanagida, Hiroyuki Nagashima, Naohiro Kumagai, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Eisaku Murakami, Takeshi Uchitani, Masami Tomita, Takeshi Shintani, Tsutomu Yamakami
  • Patent number: 7050741
    Abstract: An imaging apparatus that is capable of realizing good cleaning characteristics and transfer characteristics, and obtaining a high quality image using toner having a high average roundness is provided. The imaging apparatus includes an image carrier, a charge unit, a developing unit, a transfer unit, and a cleaning unit. The transfer unit may directly transfer a toner image onto a recording medium that is carried by a transfer belt, or transfer the toner image onto the transfer belt first to then transfer the toner image onto the recording medium from the transfer belt. The cleaning unit includes a cleaning blade and a brush roller. The toner used in the imaging apparatus has an average roundness ? within a range of 0.93˜0.99, and a friction coefficient ?s of the image carrier satisfies a condition, friction coefficient ?s?3.6?3.3×average roundness ?.
    Type: Grant
    Filed: April 9, 2004
    Date of Patent: May 23, 2006
    Assignee: Ricoh Company, Ltd.
    Inventors: Toshio Koike, Eisaku Murakami, Masato Yanagida, Takeshi Shintani, Naohiro Kumagai, Atsushi Sampe, Masami Tomita, Hiroyuki Nagashima, Masanori Kawasumi, Takeshi Uchitani
  • Publication number: 20050164108
    Abstract: An lubricant for electrophotography is applied to a latent image carrier that is supplied with toner having a sphericity of 0.94 or more. The lubricant for electrophotography is added with an inorganic additive having the following relationship: 2Y/1000?X?Y/10 where Y is a toner particle size (micrometer), and X is an inorganic additive particle size (micrometer).
    Type: Application
    Filed: December 10, 2004
    Publication date: July 28, 2005
    Inventors: Eisaku Murakami, Masami Tomita, Ken Amemiya, Masato Yanagida, Naohiro Kumagai, Takeshi Shintani, Takaaki Tawada, Yuji Arai, Toshio Koike, Takeshi Tabuchi, Yutaka Takahashi, Takeshi Uchitani, Masanori Kawasumi
  • Publication number: 20050084271
    Abstract: An image forming apparatus includes an image carrier, a charging unit that charges the image carrier, a latent image forming unit that forms a latent image on the image carrier, a developing unit that develops the latent image to form a toner image, a transferring unit that transfers the toner image to a recording medium, a cleaning unit that cleans toner remaining on the image carrier, a lubricant applying unit that applies a solid lubricant to a surface of the image carrier, and a detecting unit that detects whether the image carrier is brand new. The toner has an average roundness of 0.94 or more. The lubricant applying unit is operated when the detecting unit detects that the image carrier is brand new.
    Type: Application
    Filed: August 20, 2004
    Publication date: April 21, 2005
    Inventors: Toshio Koike, Ken Amemiya, Naohiro Kumagai, Masato Yanagida, Masanori Kawasumi, Takeshi Uchitani, Yutaka Takahashi, Yuji Arai, Takaaki Tawada, Masami Tomita, Takeshi Tabuchi, Eisaku Murakami, Takeshi Shintani, Takuji Yoneda
  • Publication number: 20050074264
    Abstract: A cleaning unit includes a cleaning blade that cleans toner on an image carrier and a brush-shaped roller that applies a lubricant of a molded lubricant on the image carrier. The brush-shaped roller is insulative, and delivers the toner cleaned by the cleaning blade to inside of the cleaning unit.
    Type: Application
    Filed: August 20, 2004
    Publication date: April 7, 2005
    Inventors: Ken Amemiya, Masato Yanagida, Naohiro Kumagai, Takeshi Shintani, Takaaki Tawada, Yuji Arai, Toshio Koike, Takuji Yoneda, Takeshi Tabuchi, Yutaka Takahashi, Eisaku Murakami, Takeshi Uchitani, Masami Tomita, Masanori Kawasumi
  • Publication number: 20050036805
    Abstract: An image forming apparatus includes an image bearing member configured to form an electrostatic latent image on a surface thereof, and a separating mechanism configured to separate an irregular charge toner from a residual toner remaining on the surface of the image bearing member after a completion of an image forming process, to provide an extra travel passage to give a time delay to the irregular charge toner, and to return the irregular charge toner with the time delay to the surface of the image bearing member.
    Type: Application
    Filed: June 24, 2004
    Publication date: February 17, 2005
    Inventors: Eisaku Murakami, Toshio Koike, Masato Yanagida, Naohiro Kumagai, Takeshi Shintani, Masanori Kawasumi, Atsushi Sampe, Masami Tomita, Hiroyuki Nagashima, Takeshi Uchitani
  • Publication number: 20050025520
    Abstract: An image forming apparatus including a latent image bearing member, a charger, a latent image forming device, a developing device, a surface moving member, a transfer device, a cleaner having a cleaning blade and an irradiating device configured to discharge the latent image bearing member. This developing device is configured to develop images with a toner having a circularity not less than 0.94. The irradiating device is disposed on the upstream from the cleaner relative to the rotation direction of the latent image bearing member.
    Type: Application
    Filed: June 24, 2004
    Publication date: February 3, 2005
    Inventors: Eisaku Murakami, Hiroyuki Nagashima, Masato Yanagida, Naohiro Kumagai, Takeshi Shintani, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Masami Tomita, Takeshi Uchitani
  • Publication number: 20050002705
    Abstract: A cleaning device, a process cartridge, an image forming apparatus and toner are disclosed to maintain improved cleaning performance for a long time. The cleaning device includes a cleaning blade, an antifriction agent coating part and a toner removing part. The cleaning blade is disposed in contact with a surface of an image support body. The antifriction agent coating part coats a solid antifriction agent on the surface of the image support body, and is disposed in an upstream side from the cleaning blade with respect to a rotational direction of the image support body. The toner removing part removes toner particles, and is disposed in an upstream side from the antifriction agent coating part with respect to the rotational direction of the image support body.
    Type: Application
    Filed: May 3, 2004
    Publication date: January 6, 2005
    Inventors: Takeshi Shintani, Takuji Yoneda, Toshio Koike, Masato Yanagida, Naohiro Kumagai, Hiroyuki Nagashima, Atsushi Sampe, Eisaku Murakami, Masanori Kawasumi, Takeshi Uchitani, Masami Tomita
  • Publication number: 20040228648
    Abstract: A charging device including a charging roller having a metallic cylinder with an elastic layer disposed thereon, and a cleaner for cleaning the surface of the charging roller. The cleaner includes a driving shaft and a cleaning roller rotatably mounted on the driving shaft. The cleaning roller is made of a non-cellular foam resin having a density of from 5 to 15 kg/m3 and a tensile strength of from 1.2 to 2.2 kg/cm2.
    Type: Application
    Filed: May 12, 2004
    Publication date: November 18, 2004
    Inventors: Masato Yanagida, Hiroyuki Nagashima, Naohiro Kumagai, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Eisaku Murakami, Takeshi Uchitani, Masami Tomita, Takeshi Shintani, Tsutomu Yamakami
  • Publication number: 20040213597
    Abstract: A charging device including: a charging roller having a metal cylinder and an elastic layer located on the metal cylinder; a cleaner configured to clean the charging roller, which includes an electroconductive brush roller including a roller having a shaft; and hair located overlying the roller, wherein the hair includes a fiber which has a width of from 0.1 to 20 denier, and a length of from 0.3 to 2.5 mm and which is planted at a density of from 7,000 to 46,000 lines/cm2, and a member configured to impart substantially the same potential as that of the charging roller to the electroconductive brush roller when a bias voltage is applied to the charging roller. A process cartridge and an image forming apparatus including the charging device are also provided.
    Type: Application
    Filed: February 11, 2004
    Publication date: October 28, 2004
    Inventors: Masato Yanagida, Hiroyuki Nagashima, Naohiro Kumagai, Toshio Koike, Atsushi Sampe, Masanori Kawasumi, Eisaku Murakami, Takeshi Uchitani, Tokuya Ohjimi, Masami Tomita, Takeshi Shintani
  • Publication number: 20040202495
    Abstract: An imaging apparatus that is capable of realizing good cleaning characteristics and transfer characteristics, and obtaining a high quality image using toner having a high average roundness is provided. The imaging apparatus includes an image carrier, a charge unit, a developing unit, a transfer unit, and a cleaning unit. The transfer unit may directly transfer a toner image onto a recording medium that is carried by a transfer belt, or transfer the toner image onto the transfer belt first to then transfer the toner image onto the recording medium from the transfer belt. The cleaning unit includes a cleaning blade and a brush roller. The toner used in the imaging apparatus has an average roundness &PSgr; within a range of 0.93˜0.99, and a friction coefficient &mgr;s of the image carrier satisfies a condition, friction coefficient &mgr;s≦3.6−3.3×average roundness &PSgr;.
    Type: Application
    Filed: April 9, 2004
    Publication date: October 14, 2004
    Inventors: Toshio Koike, Eisaku Murakami, Masato Yanagida, Takeshi Shintani, Naohiro Kumagai, Atsushi Sampe, Masami Tomita, Hiroyuki Nagashima, Masanori Kawasumi, Takeshi Uchitani
  • Publication number: 20040170455
    Abstract: A cleaning unit cleans residual toner on the surface of a rotatable image carrier. The cleaning unit includes a cleaning blade that is in contact with the image carrier in such a manner that amplitude of a waveform at an edge of the cleaning blade is not greater than 40 &mgr;m with respect to a downstream side of a direction of movement of the image carrier.
    Type: Application
    Filed: December 3, 2003
    Publication date: September 2, 2004
    Inventors: Takeshi Shintani, Naohiro Kumagai, Masato Yanagida, Toshio Koike, Eisaku Murakami, Masanori Kawasumi, Atsushi Sampe, Masami Tomita
  • Publication number: 20040141779
    Abstract: A cleaning unit is equipped with a cleaning blade that is in contact with a surface of a photosensitive drum and cleans the surface. A peak temperature of a loss tangent (tan &dgr;) is in a range of 2° C. to −30° C. when a sine-wave vibration of 10 Hz is applied to the cleaning blade. Moreover, the cleaning unit lowers a coefficient of static friction of the surface of the photosensitive drum that is to be cleaned.
    Type: Application
    Filed: September 24, 2003
    Publication date: July 22, 2004
    Inventors: Masato Yanagida, Atsushi Sampe, Naohiro Kumagai, Toshio Koike, Takeshi Shintani, Masanori Kawasumi, Masami Tomita, Eisaku Murakami, Takeshi Uchitani
  • Publication number: 20040136763
    Abstract: A cleaning unit includes a first blade and a second blade. The first blade is in contact with an image carrier or a paper carrier and removes adhered substances remained on surface of these. The second blade has an abrasive layer that is formed by including abrasive particles in an elastic material and is disposed in the downstream side of the first blade. The second blade is allowed to be in contact with the image carrier 1 or the paper carrier. Volume occupancy of abrasive particles in an area of contact of the second blade with either the image carrier or the paper carrier is not less than 50 percent and not more than 90 percent.
    Type: Application
    Filed: September 24, 2003
    Publication date: July 15, 2004
    Inventors: Eisaku Murakami, Masami Tomita, Masanori Kawasumi, Toshio Koike, Naohiro Kumagai, Atsushi Sampe, Takeshi Shintani, Masato Yanagida, Yutaka Takahashi, Hiroya Hirose, Shin Hasegawa, Hiroyuki Nagashima, Takeshi Uchitani, Kazunori Karasawa, Kentaroh Matsumoto, Tokuya Ohjimi, Mugijiroh Uno