Patents by Inventor Hiroyuki Ohkaji

Hiroyuki Ohkaji 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: 6898383
    Abstract: A control system for an image forming device includes a sensor mounted on an optical path unobstructed by elements that are subject to wear for detecting a time varying signal representing reflected light from both a photoconductive element and a transfer sheet internal to the image forming device, a memory storing reference values, and a controller to control an image forming operation based on the reference values stored in the memory and the time-varying signal received from the sensor. The controller reads the time-varying signal from the sensor and compares the time-varying signal read to the reference values to determine a condition of the image forming device.
    Type: Grant
    Filed: July 2, 2003
    Date of Patent: May 24, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Mayumi Ohori, Masaru Tanaka, Haruji Mizuishi, Hiroyuki Ohkaji, Kenzo Tatsumi, Hiroshi Mizusawa, Ken Amemiya, Hideki Zenba, Fumio Kishi
  • Publication number: 20040071475
    Abstract: A control system for an image forming device includes a sensor mounted on an optical path unobstructed by elements that are subject to wear for detecting a time varying signal representing reflected light from both a photoconductive element and a transfer sheet internal to the image forming device, a memory storing reference values, and a controller to control an image forming operation based on the reference values stored in the memory and the time-varying signal received from the sensor. The controller reads the time-varying signal from the sensor and compares the time-varying signal read to the reference values to determine a condition of the image forming device.
    Type: Application
    Filed: July 2, 2003
    Publication date: April 15, 2004
    Inventors: Mayumi Ohori, Masaru Tanaka, Haruji Mizuishi, Hiroyuki Ohkaji, Kenzo Tatsumi, Hiroshi Mizusawa, Ken Amemiya, Hideki Zenba, Fumio Kishi
  • Patent number: 6628903
    Abstract: An image forming apparatus with a sensing control system having an optical sensor and a control device. A detected object is recognized by using the difference of an output characteristics correspond to a quantity of reflected light. Thus, one or more detected objects may be precisely detected by the one optical sensor.
    Type: Grant
    Filed: July 27, 2000
    Date of Patent: September 30, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Mayumi Ohori, Masaru Tanaka, Haruji Mizuishi, Hiroyuki Ohkaji, Kenzo Tatsumi, Hiroshi Mizusawa, Ken Amemiya, Hideki Zenba, Fumio Kishi
  • Patent number: 6160969
    Abstract: An image forming apparatus transfers a toner image from a photoconductive image carrier to a recording medium with a transfer roller and senses the density of a particular toner pattern formed on the image carrier with an optical sensor. A voltage of a first polarity opposite the polarity of the toner is applied to the transfer roller when the toner image is to be transferred to the recording medium. A voltage of a second polarity identical to the polarity of the toner is applied to the transfer roller when the toner pattern is to be moved between the image carrier and the transfer roller. Thus, even when a toner pattern is brought to the transfer roller, the transfer roller is not released from the photoconductive element.
    Type: Grant
    Filed: August 17, 1998
    Date of Patent: December 12, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Kouji Ishigaki, Haruji Mizuishi, Masaru Tanaka, Hiroyuki Ohkaji, Kenzou Tatsumi, Hiroshi Mizusawa, Ken Amemiya, Hideki Zenba, Mayumi Ohori
  • Patent number: 6144811
    Abstract: A image forming apparatus with a sensing control system having an optical sensor and a control device. An detected object is recognized by using the difference of an output characteristics correspond to a quantity of reflected light. Thus, one or more detected objects may be precisely detected by the one optical sensor.
    Type: Grant
    Filed: February 2, 1999
    Date of Patent: November 7, 2000
    Assignee: Ricoh Company
    Inventors: Mayumi Ohori, Masaru Tanaka, Haruji Mizuishi, Hiroyuki Ohkaji, Kenzo Tatsumi, Hiroshi Mizusawa, Ken Amemiya, Hideki Zenba, Fumio Kishi
  • Patent number: 6085062
    Abstract: An electrophotographic image forming apparatus is disclosed which is provided within a cleaning device with a rotative conveying member for conveying a residual toner after removal thereof from a photoreceptor up to an inlet of a toner dropping path while rotating. Within the toner dropping path is disposed a toner bridge preventing member for preventing the formation of a toner bridge in the same path. The toner bridge preventing member is driven by the rotative conveying member so as to reciprocate substantially in parallel with the toner dropping direction.
    Type: Grant
    Filed: April 12, 1999
    Date of Patent: July 4, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Haruji Mizuishi, Ken Amemiya, Hiroshi Mizusawa, Hiroyuki Ohkaji, Mayumi Ohori, Masaru Tanaka, Hideki Zenba, Kenzou Tatsumi
  • Patent number: 5719684
    Abstract: In an image forming apparatus having an endless transferring and conveying device for conveying a recording medium and electrostatically transferring a toner image from an image carrier to the medium, the mechanical operation of an image forming section is interrupted throughout the duration of preselected image processing executed by image processing means. As a result, the amount of toner to reach a cleaning section assigned to the endless transferring and conveying means is reduced. This frees the recording medium from contamination ascribable to defective cleaning and thereby insures attractive images.
    Type: Grant
    Filed: May 22, 1996
    Date of Patent: February 17, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroyuki Ohkaji, Masato Yokoyama, Masumi Sato
  • Patent number: 5189479
    Abstract: An image transferring device incorporated in a color image recorder has a belt made of a dielectric material and movable while sequentially contacting a plurality of photoconductive elements at successive image transfer positions. Toner images formed on the photoconductive elements are sequentially transferred to the belt or a recording medium one above another by transfer chargers. Conductive members are located to face opposite surfaces of the belt and fully spaced apart from the latter by a predetermined distance, and each has an insulating member on the surface thereof that faces the belt. The conductive members are located between a position immediately succeeding the image transfer position on the most upstreamside and the position where the recording medium leaves the belt. A belt pressing member and a transfer charge limiting member are disposed in a position immediately preceding any one of the image transfer positions with respect to an intended direction of movement of the belt.
    Type: Grant
    Filed: June 28, 1991
    Date of Patent: February 23, 1993
    Assignee: Ricoh Company, Ltd.
    Inventors: Itaru Matsuda, Hiroyuki Ohkaji
  • Patent number: 4984024
    Abstract: An image transfer unit for an image recording apparatus which comprises a plurality of photoconductor units on which a toner image is formed, a dielectric transfer belt which circulates along and in contact with the plurality of photoconductor units, a record paper conveyed by the transfer belt, at least one transfer charger for transferring the toner image from each of the photoconductor units to the record paper in such a way that a plurality of toner images are superposed on each other one by one. The electric conductive member is disposed behind and in the vicinity of the transfer belt.
    Type: Grant
    Filed: May 9, 1989
    Date of Patent: January 8, 1991
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroyuki Ohkaji, Itaru Matsuda, Masato Yanagida