Patents by Inventor Takashi Mama

Takashi Mama 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: 5852499
    Abstract: In an image forming apparatus, a device for removing an image forming substance from a paper or similar image holding medium senses the orientation of fibers constituting the paper. While a light beam is emitted obliquely toward the paper, the diffused distribution distribution of the resulting reflection is measured in order to determine the orientation of the fibers. A preselected relation is set up between the fibers and the direction of paper transport on the basis of the determined orientation. Further, a condition for applying an unstabilizing liquid to the paper and a condition for drying the paper are varied on the basis of the determined orientation.
    Type: Grant
    Filed: September 18, 1997
    Date of Patent: December 22, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Kan Tomita, Nobuo Sakuma, Takashi Mama
  • Patent number: 5803622
    Abstract: Servicing of an image forming device, such as a digital photocopier, is made convenient by providing an access opening exposing each of a number of prescribed serviceable components enclosed in a sealed casing. These serviceable components may include a light source scanner, lens group and beam detector. The casing bears removable cover units on the access openings. The serviceable components are located under the access openings, fixed in place by the cover units or elements attached to the cover units. Electrical switches coupled to the cover units may deactivate the components when the cover units are removed.
    Type: Grant
    Filed: May 11, 1995
    Date of Patent: September 8, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Mama, Takeshi Yamakawa
  • Patent number: 5729349
    Abstract: In an image forming apparatus, a device for removing an image forming substance from a paper or similar image holding medium senses the orientation of fibers constituting the paper. While a light beam is emitted obliquely toward the paper, the diffused distribution distribution of the resulting reflection is measured in order to determine the orientation of the fibers. A preselected relation is set up between the fibers and the direction of paper transport on the basis of the determined orientation. Further, a condition for applying an unstabilizing liquid to the paper and a condition for drying the paper are varied on the basis of the determined orientation.
    Type: Grant
    Filed: February 9, 1996
    Date of Patent: March 17, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Kan Tomita, Nobuo Sakuma, Takashi Mama
  • Patent number: 5729353
    Abstract: In an image forming apparatus, a method of correcting a position for writing an image on a photoconductive element on the basis of a signal representative of a pattern formed on the element and detected, and a device therefor. A single photoconductive element is used to form a plurality of different colored images using a single rotating polygonal mirror and a plurality of light sources. The toner images can be sensed either while they are on the single photoconductive element or by sensing them through a transport belt.
    Type: Grant
    Filed: March 4, 1997
    Date of Patent: March 17, 1998
    Assignee: Ricoh Company, Ltd.
    Inventors: Noboru Sawayama, Takashi Mama
  • Patent number: 5627649
    Abstract: In an image forming apparatus, a method of correcting a position for writing an image on a photoconductive element on the basis of a signal representative of a pattern formed on the element and detected, and a device therefor. A single photoconductive element is used to form a plurality of different colored images using a single rotating polygonal mirror and a plurality of light sources. The toner images can be sensed either while they are on the single photoconductive element or by sensing them through a transport belt.
    Type: Grant
    Filed: June 17, 1993
    Date of Patent: May 6, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Noboru Sawayama, Takashi Mama
  • Patent number: 5610651
    Abstract: A scanning time after a detection signal from a first laser beam detection sensor is inputted until a detection sensor from a second laser beam detection sensor is inputted by a counter, flip-flops, a corrected write frequency f1 is computed by a control circuit from a value T1 corresponding to the measured scanning time and a function F (T1) for computing a correction factor using the basic write frequency f0 and the value T1 above and through the equation of "f1=f0.times.F (T1)", and the write clock frequency is corrected by a clock generation circuit, thus the write clock frequency being controlled according to a change in the scanning speed.
    Type: Grant
    Filed: May 13, 1994
    Date of Patent: March 11, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Takeshi Yamakawa, Takashi Mama, Kenichi Ono, Norio Michiie
  • Patent number: 5587813
    Abstract: A data transfer device for transferring data in a color digital copier, color printer or similar image forming apparatus of the type using a plurality of different kinds of data. A sending unit assigns other data to a predetermined number of bits of multilevel data to thereby send a plurality of kinds of data over common data lines. A receiving unit receives and separates the plurality of kinds of data. The device reduces the number of signal lines required for data transfer when a plurality of different kinds of data are not transferred at the same time.
    Type: Grant
    Filed: July 29, 1993
    Date of Patent: December 24, 1996
    Assignee: Ricoh Company, Ltd.
    Inventors: Shuichi Yamazaki, Takashi Mama, Nobuyuki Sato, Takeshi Yamakawa, Shinji Kobayashi, Yoshio Kaneko, Koji Oshikiri
  • Patent number: 5376994
    Abstract: An image forming apparatus having deflection scanning type and line type exposing devices and first and second developing devices arranged around a photoconductive element, so that parts around the photoconductive element are arranged with ease to promote the miniaturization of the apparatus. The exposing devices are selected based on the principle that the image quality is enhanced for an image of particular color and is lowered for an image of another color expected to be printed less frequently. Specifically, the deflection scanning type exposing device forms the image of the particular color, and the line type exposing device which has an inherently long optical path and simple structure forms the image of another color. Fans are provided to produce cooling air flow to the line type exposing device and to draw out toner dirt and ozone produced by the charger associated therewith.
    Type: Grant
    Filed: February 16, 1993
    Date of Patent: December 27, 1994
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Mama, Yuji Yasuda, Kan Tomita, Fumihiro Miyagawa, Shinji Kobayashi, Takanobu Fujioka, Hidetoshi Kanai, Yoshiki Yoshida
  • Patent number: 5309182
    Abstract: A bicolor image forming apparatus having first and second exposing means and first and second developing means arranged around a photoconductive element. The first and second developing means are implemented as a deflection scanning type and a line type, respectively. Parts around a photoconductive element are arranged with ease to promote the miniaturization of the apparatus. This stems from the principle that the image quality may be enhanced for an image of particular color and lowered for an image of another color expected to be printed less frequently. Specifically, the apparatus has deflection scanning type exposing means for forming the image of particular color, and line type exposing means which has an inherently long optical path and simple structure for forming the image of another color.
    Type: Grant
    Filed: October 30, 1992
    Date of Patent: May 3, 1994
    Assignee: Ricoh Co., Ltd.
    Inventors: Takashi Mama, Yuji Yasuda, Kan Tomita, Fumihiro Miyagawa, Shinji Kobayashi, Takanobu Fujioka, Hidetoshi Kanai, Yoshiki Yoshida
  • Patent number: 5084715
    Abstract: A light beam scanning apparatus includes a laser light source emitting a laser beam, an optical system focusing the laser beam emitted from the laser light source onto a rotating photosensitive drum, a beam scan mechanism moving the point of focus of laser beam on the photosensitive drum, in a direction perpendicular to the direction of main scan, a scan line correction mechanism correcting a scan line to a straight line when the scan line is curved.
    Type: Grant
    Filed: January 30, 1990
    Date of Patent: January 28, 1992
    Assignee: Ricoh Company, Ltd.
    Inventor: Takashi Mama
  • Patent number: 4933549
    Abstract: A multi-beam detecting apparatus adapted to an optical system in which a recording medium is scanned by a plurality of light beams emitted from respective light sources, includes a photodetector, a light interrupting member, and a control circuit. The photodetector produces detection signals when the corresponding light beams come to a predetermined position. The light interrupting member is interposed between the light sources and the light detecting member, and has transparent portions related to the respective light beams. A controlling circuit controls ON/OFF states of the light source in accordance with the respective detection signals related to the corresponding light beams passing through the respective transparent portions in the light interrupting member.
    Type: Grant
    Filed: December 8, 1988
    Date of Patent: June 12, 1990
    Assignee: Ricoh Company, Ltd.
    Inventors: Takanobu Fujioka, Takashi Mama, Yoshio Kaneko, Kenichirou Asada
  • Patent number: 4914459
    Abstract: An electrophotographic copier, facsimile machine, laser printer or similar image forming apparatus for reproducing an image on a paper sheet by transforming an image signal representative of the image into an image forming signal by pulse width modulation, causing a spot beam in the form of a laser beam which is modulated by the image forming signal to scan a photoconductive element to form an electrostatic latent image thereon, developing the latent image to render it visible, and transferring the visible image to a paper sheet. The laser beam output, the set pulse widths of the image forming signal (beam turn-on times) and the bias voltage for development are changed in association with the deterioration of the laser beam power and the sensitivity of the photoconductive element.
    Type: Grant
    Filed: April 14, 1989
    Date of Patent: April 3, 1990
    Assignee: Ricoh Company, Ltd.
    Inventors: Takashi Mama, Kenichirou Asada, Takanobu Fujioka, Yoshio Kaneko, Masaaki Kogure
  • Patent number: 4796265
    Abstract: An imaging system includes a plurality of semiconductor lasers for emitting a plurality of laser beams for use in forming an image on a photosensitive member. A laser driver circuit is provided for each of the plurality of lasers, and a plurality of photodectors are also provided, each detecting the light intensity of the corresponding one of the laser beams emitted from the lasers. A light intensity stabilizing control circuit is provided to stabilize the light intensity of each of the plurality of laser beams using one of the detected light intensities as a reference and adjusting the light intensity of each of the other beams such that a difference between the reference and the light intensity of each of the other beams is within a predetermined range.
    Type: Grant
    Filed: April 6, 1987
    Date of Patent: January 3, 1989
    Assignee: Ricoh Company, Limited
    Inventors: Kenichiro Asada, Takashi Mama, Takanobu Fujioka